Economic Analysis for Water Quality Standards Applicable to the State of Washington
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                March 10, 2022
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                 Prepared for:
                 United States Environmental Protection Agency
                                Office of Water
                       Office of Science and Technology
                        1200 Pennsylvania Avenue, N.W.
                            Washington, D.C. 20460
                                       
                                       








































Contents
Exhibits	ii
Acronym List	iv
Executive Summary	vi
1.	Introduction	1
1.1	Background	1
1.2	Purpose and Scope of the Analysis	2
1.3	Organization of Report	2
2.	Baseline for the Analysis	4
2.1	Water Quality Criteria and Implementation Procedures	4
2.2	Sources of Toxic Pollutants to Surface Waters	8
2.3	Water Quality	11
3.	Revised Criteria	15
4.	Method for Estimating Potential Costs: Point Sources	19
4.1	Major Dischargers -- Process Wastewater	19
4.2	Minor Dischargers -- Process Wastewater	27
4.3	Urban Stormwater	27
5.	Methods for Identifying Potential Costs: Incremental Impairments	29
5.1	Identifying Exceedances	29
5.2	Identifying Nonpoint Source Compliance Actions and Costs	31
5.3	Estimating TMDL Administrative Costs	32
6.	Potential Compliance Costs	33
6.1	Point Sources	33
6.2	Nonpoint Sources	33
6.3	TMDL Administrative Costs	34
6.4	Total Costs	34
6.5	Uncertainties and Quality Assurance	34
7.	Discussion of Potential Benefits	36
8.	References	37
Appendix A  -  Facility Analyses	40

Exhibits
Exhibit ES-1. Summary of Cost Estimates for Revised Human Health Criteria	viii
Exhibit 2-1. Baseline Freshwater and Marine Water Quality Criteria for Pollutants with Human Health Criteria in Washington (ug/L) except as noted	5
Exhibit 2-2. Number of Dischargers in Washington by Category	8
Exhibit 2-3. Category 4 and 5 Listings for Pollutants Covered by Proposed Action (as of 2012)	12
Exhibit 2-4. Summary of TMDLs for Pollutants Covered by the Proposed Action	13
Exhibit 3-1. Summary of Key Assumptions for Calculating Human Health Criteria	15
Exhibit 3-2. Revised Human Health Criteria (ug/L)	16
Exhibit 4-1. Summary of Major Dischargers by Industrial Category	20
Exhibit 4-2. Summary of Major Discharger Sample	20
Exhibit 4-3. Summary of Sample Facilities with Reasonable Potential	22
Exhibit 4-4. Summary of Calculated Effluent Limitations for Facilities with Reasonable Potential -- Baseline Scenario	25
Exhibit 4-5. Summary of Calculated Effluent Limitations for Facilities with Reasonable Potential -- Policy Scenario	26
Exhibit 5-1. Potential Incremental Impairments	30
Exhibit 6-1. Summary of Cost Estimates for Revised Human Health Criteria	34
Exhibit 6-2. Uncertainties in Analysis of Costs	35
Exhibit A-1. Summary of Effluent Data (2018 to 2020): BP Cherry Point Refinery	40
Exhibit A-2. Ambient Receiving Water Concentrations: Strait of Georgia	41
Exhibit A-3. Summary of Effluent Data (2018 to 2020): Cosmo Specialty Fibers	43
Exhibit A-4. Human Health Reasonable Potential Analysis for Cosmo Specialty Fibers  -  Baseline Scenario (ug/L)	45
Exhibit A-5. Human Health Based Effluent Limitations for Cosmo Specialty Fibers  -  Baseline Scenario (ug/L)	46
Exhibit A-6. Human Health Reasonable Potential Analysis for Cosmo Specialty Fibers  -  Policy Scenario (ug/L)	47
Exhibit A-7. Human Health Based Effluent Limitations for Cosmo Specialty Fibers  -  Policy Scenario (ug/L)	47
Exhibit A-8. Summary of Effluent Data (2017 to 2020): Emerald Kalama Chemical	49
Exhibit A-9. Human Health Reasonable Potential Analysis for Emerald Kalama Chemical  -  Baseline Scenario (ug/L)	50
Exhibit A-10. Human Health Based Effluent Limitations for Emerald Kalama Chemical  -  Baseline Scenario (ug/L)	51
Exhibit A-11. Human Health Reasonable Potential Analysis for Emerald Kalama Chemical  -  Policy Scenario (ug/L)	51
Exhibit A-12. Human Health Based Effluent Limitations for Emerald Kalama Chemical  -  Policy Scenario (ug/L)	51
Exhibit A-13. Summary of Effluent Data (2018 to 2020): Intalco Aluminum	53
Exhibit A-14. Ambient Receiving Water Concentrations: Strait of Georgia (ug/L)	54
Exhibit A-15. Human Health Reasonable Potential Analysis for Intalco Aluminum  -  Baseline Scenario (ug/L)	54
Exhibit A-16. Human Health Based Effluent Limitations for Intalco Aluminum  -  Baseline Scenario (ug/L)	54
Exhibit A-17. Human Health Reasonable Potential Analysis for Intalco Aluminum  -  Policy Scenario (ug/L)	55
Exhibit A-18. Human Health Based Effluent Limitations for Intalco Aluminum  -  Policy Scenario (ug/L)	55
Exhibit A-19. Summary of Effluent Data (2009 to 2014): King County South	56
Exhibit A-20. Ambient Receiving Water Concentrations: Puget Sound	57
Exhibit A-21. Summary of Effluent Data (2009 to 2013): King County West Point	59
Exhibit A-22. Ambient Receiving Water Concentrations: Puget Sound	59
Exhibit A-23. Summary of Effluent Data (2018 to 2020): Pasco Wastewater Treatment Works	61
Exhibit A-24. Ambient Receiving Water Concentrations: Columbia River	61
Exhibit A-25. Summary of Effluent Data (2009 to 2019): Puget Sound Naval Shipyard	63
Exhibit A-26. Summary of Effluent Data (2012 to 2017): Quincy Industrial	64
Exhibit A-27. Summary of Effluent Data (2018 to 2020): Redondo WWTP	66
Exhibit A-28. Ambient Receiving Water Concentrations: Puget Sound	66
Exhibit A-29. Summary of Effluent Data (2018-2020): Salmon Creek WWTP	68
Exhibit A-30. Ambient Receiving Water Concentrations (2013-2017): Puget Sound	68
Exhibit A-31. Summary of Effluent Data: Sonoco Products	69
Exhibit A-32. Ambient Receiving Water Concentrations: White River	70
Exhibit A-33. Summary of Effluent Data (2018 to 2020): Steelscape Inc.	71
Exhibit A-34. Summary of Effluent Data (2018-2020): Transalta Centralia Generation	72
Exhibit A-35. Summary of Effluent Data: U.S. Oil and Refining (2016 - 2018)	75
Exhibit A-36. Ambient Receiving Water Concentrations: Blair Waterway	76
Exhibit A-37. Summary of Effluent Data (2018 to 2020): Weyerhaeuser Longview	77
Exhibit A-38. Ambient Receiving Water Concentrations: Columbia River (ug/L)	78
Exhibit A-39. Human Health Reasonable Potential Analysis for Weyerhaeuser Longview  -  Baseline Scenario (ug/L)	79
Exhibit A-40. Human Health Based Effluent Limitations for Weyerhaeuser Longview  -  Baseline Scenario (ug/L)	79
Exhibit A-41. Human Health Reasonable Potential Analysis for Weyerhaeuser Longview  -  Policy Scenario (ug/L)	80
Exhibit A-42. Human Health Based Effluent Limitations for Weyerhaeuser Longview  -  Policy Scenario (ug/L)	80

Acronym List
AML			Average monthly effluent limitation 
BMP			Best management practices
CSO			Combined sewer overflow
CWA		 	Clean Water Act
DL				Detection limit
DMR			Discharge monitoring report
DWEC			Drinking water exposure concentration
ECHO			Enforcement and Compliance History Online
Ecology		Washington Department of Ecology
EIM			Environmental Information Management
EPA			United States Environmental Protection Agency
FCR			Fish consumption rate
HHC			Human health criteria
MDL			Maximum daily effluent limit
MGD			Million gallons per day
MEC			Maximum effluent concentration
MEP			Maximum extent practicable
MS4			Municipal separate storm sewer systems
NHD			National Hydrography Dataset
NPDES			National Pollutant Discharge Elimination System
NTR			National Toxics Rule
PARIS			Permitting and Reporting Information System
POTW			Publicly owned treatment works
QL				Quantitation limit
RP				Reasonable potential
RPA			Reasonable potential analysis
SMS			Sediment management standards 
SWMP			Stormwater management plan
SWPPP			Stormwater pollution prevention plan
TEC			Tissue exposure concentration
TMDL			Total maximum daily load
WAC			Washington Administrative Code
WLA			Waste load allocation
WQBEL		Water quality based effluent limitation
WQS			Water quality standards
WWTF			Wastewater treatment facility 
WWTP			Wastewater treatment plant

Executive Summary
The United States Environmental Protection Agency (EPA) has determined that many of Washington's human health criteria (HHC) are not protective of Washington's designated uses and are not based on sound science and, accordingly, is proposing to restore protective HHC for Washington's waters. Specifically, EPA is proposing to reinstate the majority of the HHC that EPA promulgated for Washington waters in November 2016, after disapproving HHC submitted by Washington. This report provides estimates of the potential incremental compliance actions and costs that may be associated with the regulation. This report also qualitatively describes some of the potential benefits of the proposed rule.
Background and Proposed Criteria
In 2016, EPA promulgated federal HHC for Washington after disapproving HHC that Washington submitted to EPA for action under Clean Water Act (CWA) section 303(c). EPA withdrew the 2016 federally promulgated HHC in June 2020 after approving, in May 2019, the same Washington-submitted HHC that the Agency had previously disapproved in 2016. EPA is reaffirming the basis for its previous disapproval, namely that those HHC are not sufficiently protective of Washington's designated uses and are not based on sound science. Based on EPA's reconsideration of its 2019 approval of the previously disapproved state HHC and its 2020 withdrawal of the federal HHC, this action proposes reinstating the majority of the federal HHC that EPA promulgated in November 2016.
Although the rule does not establish any requirements directly applicable to entities regulated under the National Pollutant Discharge Elimination System (NPDES) program or to other sources of pollution, EPA implementation (NPDES permits for federal facilities) and state implementation (all other sources) may result in new or revised NPDES permit conditions for point source dischargers and additional controls on nonpoint sources of pollutant loadings. This analysis provides information on the potential for incremental costs to be associated with such incremental controls to assure attainment of state designated uses protected by the criteria in the rule. 
Point Source Compliance Costs
EPA identified 406 point source facilities that could ultimately be affected by the rule. Of these potentially affected facilities, 73 are classified as major dischargers, and 333 are minor dischargers. Minor facilities are less likely to incur costs as a result of implementation of the rule because of the typical characteristics of their effluent. To be categorized as minor, facilities typically discharge at a low effluent flow rate (e.g., less than one million gallons per day (MGD) for publicly owned treatment works or POTWs) and do not discharge toxic pollutants in toxic amounts. Although lower HHC could potentially change this general characterization (effluent monitoring could indicate concentrations at levels of concern), EPA did not have effluent data on toxic pollutants to systematically evaluate minor dischargers for this analysis. EPA also did not have data to evaluate general permits for which permit conditions typically focus on best management practices (e.g., general permits for stormwater discharges). Furthermore, EPA was not able to evaluate general permits that cover categories of point sources subject to numeric effluent limits for pollutants other than those for which EPA is proposing federal HHC.
Of the 73 major dischargers that are potentially affected by the revised criteria (including 29 industrial facilities and 44 POTWs), EPA evaluated a sample of 18 major facilities. EPA evaluated the 2 major POTWs with design flows greater than 100 MGD and the largest industrial facility in an attempt to capture potential for the largest costs. For the remaining major facilities, EPA evaluated a random sample of facilities to represent discharger type and category. For all sample facilities, EPA evaluated existing baseline permit conditions, reasonable potential to exceed the proposed HHC, and potential to exceed projected effluent limitations based on the last three years of effluent monitoring data (if available). 
Analysis of the available data for the sampled facilities indicates that there are likely to be exceedances of projected effluent limits for some facilities and parameters under the rule. However, existing effluent concentrations were already reported as being below accepted minimum quantitation limits. For this analysis, EPA assumed that the accepted quantitation limits meet the sufficiently sensitive method requirements of 40 Code of Federal Regulations 122.44(i)(1)(iv)(A)(2) and, based on EPA (EPA, 2005) and State of Washington Department of Ecology (Ecology, 2018), that they would represent the compliance assessment levels for the sampled facilities. As such, EPA did not identify any facilities that would need to achieve incremental pollutant loading reductions under the proposed rule relative to the baseline scenario. This does not mean that EPA anticipates there would be no costs to point sources over time to implement controls or modify processes to meet future permit limits, only that available data did not indicate the immediate need for the facilities evaluated. However, any attempt to estimate potential future costs on a premise of being able to measure pollutants that could be present at lower levels or changes to facility operations or practices would be highly speculative.
Incremental Impairments
States utilize applicable WQS to conduct water quality assessments and identify impaired waters that need total maximum daily loads (TMDLs) under section 303(d) of the CWA. TMDLs typically identify needed pollutant reductions from point sources and nonpoint sources. As such, revised HHC could also have implications for nonpoint sources. However, it is difficult to model and evaluate the potential cost impacts of this rule to those sources because they are intermittent, variable, and occur under hydrologic or climatic conditions associated with precipitation events. Also, data are not available on instream and discharged levels of the pollutants of concern after dischargers have implemented controls to meet current water quality standards, total maximum daily loads (TMDLs) for impaired waters, or other water quality improvement plans. Therefore, determining which sources would need an incremental level of control attributable to the revised HHC after complying with existing regulations and policies is not possible for this analysis.
EPA identified potential incremental exceedances of the revised HHC based on available data in the State of Washington Department of Ecology (Ecology) Environmental Information Management System (EIM). According to the state's water quality assessment methodology (Ecology, 2012a; Ecology, 2020), Ecology generally uses the last ten years of data to determine impairment status of surface waters. EPA used available surface water monitoring data on pollutants of concern from EIM for the years 2011 to 2020. For each monitoring station and parameter, EPA compared the pollutant concentration to both the existing baseline HHC and the proposed revised HHC. Station results that would indicate impairment under EPA's proposed HHC but not under the existing baseline HHC may represent potential incremental impairments.
Using the baseline criteria values, monitoring data indicate potential impairment on the basis of HHC exceedances in the water column at 36 stations. Using the revised criteria, there would be exceedances in the water column at 66 stations, for a total of 30 potential incremental exceedances.
If the net increase in potential impairments is any indication of the potential increase in the number of TMDL allocations that would need to be developed, then the total administrative costs for TMDL development could be in the range of $1.17 million to $1.26 million, based on national average single-cause single-waterbody TMDL development costs from U.S. EPA (2001). Actual costs may be reduced if Ecology develops multi-cause or multi-waterbody TMDLs.
Total Costs 
Exhibit ES-1 a summary of the estimated costs for the rule. It indicates the lack of estimated costs for point sources to comply with revised permit limits and the onetime administrative costs to develop TMDLs for impaired waters. It does not include costs to nonpoint sources that may be affected by TMDL-based load allocations. The total annual costs of the rule range from $98,000 to $179,000, at a 3 percent discount rate.
Exhibit ES-1. Summary of Cost Estimates for Revised Human Health Criteria
Item
Cost Range
Annual costs for point source controls[a]
                                                                             $0
Annual TMDL development costs[b][,c]
                                                          $98,000  -  $179,000 
Total annual cost
                                                           $98,000  -  $179,000
Notes:
[a] EPA did not identify any incremental control actions for sample facilities; see Section 4.
[b] One-time costs for TMDL development are annualized over 8 to 15 years, at a 3 percent discount rate. The range includes both a range of unit costs and a range of years. The lowest unit cost annualized over 15 years corresponds to the lower bound, and the upper bound is the highest unit cost annualized over 8 years.
[c] One-time costs for TMDL development at a 7 percent discount rate range from $128,000 to $211,000.

Introduction
The United States Environmental Protection Agency (EPA) has determined that many of Washington's human health criteria (HHC) are not protective of Washington's designated uses and are not based on sound science and, accordingly, is proposing to restore protective HHC for Washington's waters. Specifically, EPA is proposing to reinstate the majority of the HHC that EPA promulgated for Washington waters in November 2016, after disapproving HHC submitted by Washington. This report provides estimates of the potential incremental compliance actions and costs that may be associated with the regulation.
Background
The Clean Water Act (CWA) sets the basic structure for regulating pollutant discharges into the waters of the United States. In the CWA, Congress established the national objective to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters," and to achieve "wherever attainable, an interim goal of water quality which provides for the protection and propagation of fish, shellfish, and wildlife and for recreation in and on the water" (CWA sections 101(a) and 101(a)(2)).
The CWA establishes the basis for the current water quality standards (WQS) regulation and program. CWA section 303(c) addresses the development of state and authorized tribal WQS. WQS reflect the CWA national objectives for each water body. The core components of these standards are designated uses, water quality criteria, and antidegradation requirements. Designated uses establish the environmental objectives for a water body, while water quality criteria define the minimum conditions necessary to achieve those environmental objectives. The antidegradation program complements designated uses and criteria by providing a framework for maintaining and protecting water quality.
After states, authorized tribes, territories, and the District of Columbia (hereafter, states and authorized tribes) designate the uses of waters under their jurisdiction, they must establish water quality criteria that protect those designated uses. EPA's regulation at §131.11(a)(1) provides that that such criteria "must be based on sound scientific rationale and must contain sufficient parameters or constituents to protect the designated use." States and authorized tribes must also adopt antidegradation policies to protect and maintain high quality waters and existing uses of all waters and identify specific methods to implement those policies (§131.12).
The CWA also requires states and authorized tribes to hold public hearings once every three years for the purpose of reviewing applicable WQS and, as appropriate, modifying and adopting standards. The results of this triennial review must be submitted to EPA, and EPA must approve or disapprove any new or revised standards. CWA Section 303(c)(4)(B) authorizes the Administrator to determine, even in the absence of a state submission, that a new or revised standard is needed to meet CWA requirements.
In 2016, EPA promulgated federal HHC for Washington after disapproving HHC that Washington submitted to EPA for action under CWA section 303(c). EPA withdrew the 2016 federally promulgated HHC in June 2020 after approving, in May 2019, the same Washington-submitted HHC that the Agency had previously disapproved in 2016. EPA is reaffirming the basis for its previous disapproval, namely that those HHC are not sufficiently protective of Washington's designated uses and are not based on sound science. Based on EPA's reconsideration of its 2019 approval of the previously disapproved state HHC and its 2020 withdrawal of the federal HHC, this action proposes reinstating the majority of the federal HHC that EPA promulgated in November 2016.
Purpose and Scope of the Analysis
The primary purpose of this analysis is to identify, using available water quality and discharge data and information, the incremental compliance actions and costs that publicly owned treatment works (POTWs) and industrial point source dischargers may incur as a result of EPA's revised criteria. Although the rule does not establish any requirements directly applicable to entities regulated under the National Pollutant Discharge Elimination System (NPDES) program or to other sources of pollution, state implementation by Washington's Department of Ecology (hereafter Ecology) and EPA implementation (NPDES permits for federal facilities) may result in new or revised NPDES permit conditions for point source dischargers to incorporate revised water quality-based effluent limits (WQBELs). EPA examined a sample of major dischargers, with the aim to extrapolate estimates of statewide compliance costs.
The revised criteria may also result in incremental determinations that waters exceed WQS. As such, Ecology may need to develop additional total maximum daily loads (TMDLs) for impaired waters. There may also be incremental controls and costs associated with load allocations for nonpoint sources under such TMDLs to attain standards. However, the data and information available to evaluate potential nonpoint source control needs are more limited. EPA identified the potential for incremental impairment, and thus incremental controls and costs for nonpoint sources, but did not develop statewide cost estimates, except for the administrative costs for the state to develop TMDLs.
Organization of Report
The remainder of this report is organized as follows:
Section 2: Baseline for the Analysis  -  describes the current applicable HHC for toxic pollutants and Ecology procedures for implementing the criteria in NPDES permits, sources of toxic pollutants to surface waters, water quality impairments from toxic pollutants, and ongoing efforts to reduce and eliminate these impairments. 
Section 3: Revised Criteria  -  outlines the changes EPA is proposing to existing water quality standards.
Section 4: Method for Estimating Potential Costs: Point Sources  -  describes the method for estimating compliance costs associated with revised criteria for point sources in terms of revisions to NPDES permits.
Section 5: Method for Identifying Potential Costs: Incremental Impairments  -  describes the method for identifying waters that may be newly categorized as impaired based on assessment using the revised criteria, as well as administrative costs for TMDL development.
Section 6: Potential Compliance Costs  -  provides estimates of potential costs to comply with the revised criteria and discusses the uncertainties associated with the estimates.
Section 7: Discussion of Potential Benefits  -  provides a brief discussion of the types of benefits that could be associated with the proposed rule.
Section 8: References  -  provides the references used in the analysis. 
Appendix A  -  provides data and information on individual sample facilities and analyses of potential impacts under the rule.



Baseline for the Analysis
This section describes the applicable baseline for evaluating the incremental costs associated with the revised WQS, including current water quality criteria and associated implementation procedures, potential sources of the pollutants of concern, the current level of impairment, and listing procedures.
The baseline is a reference point that serves as a starting point for conducting an economic analysis. According to EPA's Guidelines for Preparing Economic Analyses (U.S. EPA 2014a), the baseline is defined as the world without the proposed regulation or policy action. As a general rule, EPA typically assumes full compliance with existing and newly promulgated rules (even if they are not yet fully implemented) as a basis for estimating the cost and benefits of proposed regulations. This baseline approach ensures that the cost and benefits of the existing rules are not double counted. Therefore, the baseline reflects EPA's expectations of how current regulations will be implemented by permitting authorities, and the costs associated with the revised water quality criteria represent incremental actions above those associated with the baseline.
Water Quality Criteria and Implementation Procedures
Exhibit 2-1 shows the applicable baseline criteria for toxic pollutants for which there are HHC, based on Ecology's PermitCalc spreadsheet tool. These represent the criteria currently in effect in Washington for the pollutants which are subject to the revised criteria in EPA's proposed rule. Ecology's Water Quality Program Permit Writer's Manual (Ecology, 2018) specifies the procedures for applying water quality criteria in NPDES permits.
Ecology designates all surface waters for the protection of both aquatic life and human health. EPA did not analyze further those pollutants for which the aquatic life criteria are more stringent than the revised human health criteria because the more stringent aquatic life criteria coupled with the implementing procedures (e.g., allowable dilution factors) would always result in more stringent effluent limitations. The rule would not lead to additional compliance costs for these pollutants.
Exhibit 2-1. Baseline Freshwater and Marine Water Quality Criteria for Pollutants with Human Health Criteria in Washington (ug/L)[a] except as noted
Parameter
Freshwater AL
Marine AL
HH

Acute
Chronic
Acute
Chronic
Water/Fish
Fish Only
Acenaphthene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        110.00 
                                                                        110.00 
Acrolein
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           1.0 
                                                                           1.1 
Acrylonitrile
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.019 
                                                                         0.028 
Aldrin
                                                                            2.5
                                                                         0.0019
                                                                           0.71
                                                                         0.0019
                                                                      0.0000057
                                                                      0.0000058
Anthracene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          3100 
                                                                          4600 
Antimony
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            12 
                                                                           180 
Arsenic
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.018 
                                                                          0.14 
Asbestos (fibers/L)
                                                                               
                                                                               
                                                                               
                                                                               
                                                                       7000000 
                                                                               
Benzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.44 
                                                                           1.6 
Benzidine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        0.00002
                                                                       0.000023
Benzo(a) Anthracene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.014
                                                                          0.021
Benzo(a) Pyrene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.0014
                                                                         0.0021
Benzo(b) Fluoranthene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.014
                                                                          0.021
Benzo(k) Fluoranthene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.014
                                                                           0.21
alpha-BHC
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.0005
                                                                        0.00056
beta-BHC
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        0.0018 
                                                                         0.002 
Hexachlorocyclohexane (gamma-BHC; Lindane)
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            15 
                                                                            17 
Bis(2 Chloro-1-Methylethyl) Ether
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           400 
                                                                           900 
Bis(2-Ethylhexyl) Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.23 
                                                                          0.25 
Bromoform
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           5.8 
                                                                            27 
Butylbenzyl Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.56 
                                                                          0.58 
Carbon Tetrachloride
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           0.2 
                                                                          0.35 
Chlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           380 
                                                                           890 
Chlordane
                                                                            2.4
                                                                         0.0043
                                                                           0.09
                                                                          0.004
                                                                       0.000093
                                                                       0.000093
Chlorodibromomethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.65 
                                                                             3 
2-Chloronaphthalene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           170 
                                                                           180 
Bis(2-Chloroethyl) Ether
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.02 
                                                                          0.06 
Chloroform
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           260 
                                                                           1200
2-Chlorophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            15 
                                                                            17 
Chrysene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           1.4 
                                                                           2.1 
Copper
                                                                               
                                                                               
                                                                            4.8
                                                                            3.1
                                                                          1300 
                                                                               
Cyanide
                                                                           22.0
                                                                            5.2
                                                                            1.0
                                                                            1.0
                                                                            19 
                                                                           270 
4,4'-DDT
                                                                            1.1
                                                                         0.0010
                                                                           0.13
                                                                         0.0010
                                                                       0.000025
                                                                       0.000025
4,4'-DDE
                                                                            1.1
                                                                         0.0010
                                                                           0.13
                                                                         0.0010
                                                                       0.000051
                                                                       0.000051
4,4'-DDD
                                                                            1.1
                                                                         0.0010
                                                                           0.13
                                                                         0.0010
                                                                       0.000036
                                                                       0.000036
Dibenzo(a,h) Anthracene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.0014
                                                                         0.0021
Di-n-Butylphthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           450 
                                                                           510 
1,2-Dichlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          2000 
                                                                          2500 
1,3-Dichlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            13 
                                                                            16 
1,4-Dichlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           460 
                                                                           580 
3,3'-Dichlorobenzidine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        0.0031 
                                                                        0.0033 
Dichlorobromomethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.77 
                                                                           3.6 
1,2-Dichloroethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           9.3 
                                                                            120
1,1-Dichloroethylene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          1200 
                                                                          4100 
2,4-Dichlorophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            25 
                                                                            34 
1,2-Dichloropropane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.71 
                                                                           3.1 
1,3-Dichloropropene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.24 
                                                                            2. 
Dieldrin
                                                                            2.5
                                                                         0.0019
                                                                           0.71
                                                                         0.0019
                                                                      0.0000061
                                                                      0.0000061
Diethyl Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          4200 
                                                                          5000 
2,4-Dimethylphenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            85 
                                                                            97 
Dimethyl Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         92000 
                                                                        130000 
Di-n-Butyl Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           450 
                                                                           510 
2-Methyl-4,6-Dinitrophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           7.1 
                                                                            25 
2,4-Dinitrophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            60 
                                                                           610 
2,4-Dinitrotoluene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.039 
                                                                          0.18 
2,3,7,8-TCDD (Dioxin)
                                                                               
                                                                               
                                                                               
                                                                               
                                                            0.0000000646.40E-08
                                                            0.0000000646.40E-08
1,2-Diphenylhydrazine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.015 
                                                                         0.023 
Bis(2-Ethylhexyl) Phthalate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.23 
                                                                          0.25 
alpha-Endosulfan
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           9.7 
                                                                            10 
beta-Endosulfan
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           9.7 
                                                                            10 
Endosulfan Sulfate
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           9.7 
                                                                            10 
Endrin
                                                                           0.18
                                                                         0.0023
                                                                          0.037
                                                                         0.0023
                                                                         0.034 
                                                                         0.035 
Endrin Aldehyde
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.034 
                                                                         0.035 
Ethylbenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            200
                                                                            270
Fluoranthene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            16 
                                                                            16 
Fluorene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           420 
                                                                           610 
Heptachlor
                                                                           0.52
                                                                         0.0038
                                                                         0.0530
                                                                         0.0036
                                                                      0.0000099
                                                                        0.00001
Heptachlor Epoxide
                                                                           0.52
                                                                         0.0038
                                                                         0.0530
                                                                         0.0036
                                                                      0.0000074
                                                                      0.0000074
Hexachlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                      0.000051 
                                                                      0.000052 
Hexachlorobutadiene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.69 
                                                                            4.1
alpha-BHC
                                                                               
                                                                               
                                                                               
                                                                               
                                                                       0.00050 
                                                                       0.00056 
beta-BHC
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        0.0018 
                                                                        0.0020 
Hexachlorocyclohexane (gamma-BHC; Lindane)
                                                                              2
                                                                           0.08
                                                                           0.16
                                                                               
                                                                            15 
                                                                            17 
Hexachlorocyclopentadiene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           150 
                                                                           630 
Hexachloroethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.11 
                                                                          0.13 
Indeno(1,2,3-cd) Pyrene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.014 
                                                                         0.021 
Isophorone
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            27 
                                                                            110
3-Methyl-4-Chlorophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            36 
                                                                            36 
Methyl Bromide
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           520 
                                                                          2400 
Methylene Chloride
                                                                               
                                                                               
                                                                               
                                                                               
                                                                            16 
                                                                           250 
Methylmercury
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.030 
Mercury
                                                                            2.1
                                                                          0.012
                                                                            1.8
                                                                          0.025
                                                                          0.14 
                                                                          0.15 
Nickel
                                                                               
                                                                               
                                                                           74.0
                                                                            8.2
                                                                            150
                                                                            190
Nitrobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                             55
                                                                            320
N-Nitrosodimethylamine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                       0.00065 
                                                                          0.34 
N-Nitrosodi-n-Propylamine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                        0.0044 
                                                                         0.058 
N-Nitrosodiphenylamine
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           0.62
                                                                           0.69
Pentachlorophenol (PCP)
                                                                          0.010
                                                                          0.010
                                                                             13
                                                                            7.9
                                                                         0.046 
                                                                           0.1 
Phenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         18000 
                                                                        200000 
Polychlorinated Biphenyls (PCBs)
                                                                            2.0
                                                                          0.014
                                                                             10
                                                                          0.030
                                                                       0.00017 
                                                                       0.00017 
Pyrene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           310 
                                                                           460 
Selenium
                                                                            20 
                                                                           5.0 
                                                                           290 
                                                                          71.0 
                                                                           120 
                                                                           480 
1,1,2,2-Tetrachloroethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.12 
                                                                          0.46 
Tetrachloroethylene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           4.9 
                                                                           7.1 
Thallium
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.24 
                                                                          0.27 
Toluene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           180 
                                                                           410 
Toxaphene
                                                                           0.73
                                                                        0.00020
                                                                           0.21
                                                                        0.00020
                                                                      0.000032 
                                                                      0.000032 
1,2-Trans-Dichloroethylene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                           600 
                                                                          5800 
1,2,4-Trichlorobenzene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.12 
                                                                          0.14 
1,1,1-Trichloroethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         47000 
                                                                        160000 
1,1,2-Trichloroethane
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.44 
                                                                           1.8 
Trichloroethylene
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.38 
                                                                          0.86 
2,4,6-Trichlorophenol
                                                                               
                                                                               
                                                                               
                                                                               
                                                                          0.25 
                                                                          0.28 
Vinyl Chloride
                                                                               
                                                                               
                                                                               
                                                                               
                                                                         0.020 
                                                                          0.26 
Zinc
                                                                              
                                                                              
                                                                             90
                                                                             81
                                                                          2300 
                                                                          2900 
Source: based on criteria enumerated in Washington's PermitCalc spreadsheet.
Notes: 
AL = aquatic life; HH = human health
[a] Metals criteria are in dissolved form; blanks indicate no baseline criteria.

Sources of Toxic Pollutants to Surface Waters
Toxic pollutants can be introduced to surface water through natural and human activities, including municipal and industrial effluents, stormwater discharges, agricultural runoff, forestry (chemical application), atmospheric deposition, and contaminated sediments. 
POTWs and Industrial Process Wastewater Dischargers
EPA's Enforcement and Compliance History Online (ECHO) database indicates that there are 406 major and minor individually permitted NPDES dischargers in Washington. Exhibit 2-2 shows the number of facilities by type (major/minor) and category (based on industry classification codes, including POTWs, provided in ECHO and facility-specific fact sheets).
Exhibit 2-2. Number of Dischargers in Washington by Category
Category
Minor
Major
All
Agricultural Production  -  Livestock and Animal Specialties
                                       0
                                       5
                                       5
Metal Mining
                                       0
                                       1
                                       1
Coal Mining
                                       1
                                       1
                                       2
Mining and Quarrying of Nonmetallic Minerals, Except Fuels
                                       0
                                       1
                                       1
Food and Kindred Products
                                       1
                                      25
                                      26
Lumber and Wood Products, Except Furniture
                                       0
                                      10
                                      10
Paper and Allied Products
                                      12
                                       2
                                      14
Printing, Publishing and Allied Industries
                                       0
                                       1
                                       1
Chemicals and Allied Products
                                       1
                                       5
                                       6
Petroleum Refining and Related Industries
                                       5
                                       2
                                       7
Stone, Clay, Glass, and Concrete Products
                                       0
                                       5
                                       5
Primary Metal Industries
                                       3
                                       4
                                       7
Fabricated Metal Products
                                       1
                                       1
                                       2
Electronic & Other Electrical Equipment & Components
                                       0
                                       1
                                       1
Transportation Equipment
                                       0
                                      14
                                      14
Motor Freight Transportation
                                       0
                                       2
                                       2
Water Transportation
                                       0
                                       3
                                       3
Transportation by Air
                                       0
                                       1
                                       1
Transportation Services
                                       0
                                       1
                                       1
Electric, Gas and Sanitary Services
                                       4
                                      30
                                      34
Wholesale Trade  -  Durable Goods
                                       0
                                       4
                                       4
Wholesale Trade  -  Nondurable Goods
                                       0
                                       8
                                       8
Automotive Dealers and Gasoline Service Stations
                                       0
                                       1
                                       1
Hotels, Rooming Houses, Camps, and Other Lodging Places
                                       0
                                       2
                                       2
Amusement and Recreation Services
                                       0
                                       1
                                       1
Health Services
                                       0
                                       2
                                       2
Engineering, Accounting, Research, and Management Services
                                       0
                                       2
                                       2
Executive, Legislative & General Government, Except Finance
                                       0
                                       4
                                       4
Justice, Public Order and Safety
                                       0
                                       4
                                       4
National Security and International Affairs
                                       1
                                       3
                                       4
Unclassified
                                       0
                                      18
                                      18
Publicly Owned Treatment Works
                                      44
                                      169
                                      213
Total
                                      73
                                      333
                                      406
Source: Based on data from EPA's Enforcement and Compliance History Online (ECHO) database and supplementary data from facility fact sheets. Categorizations based on 2-digit SIC codes.

In addition to individual permits, Ecology issues general NPDES permits for different discharger categories such as boatyards, concentrated animal feeding operations, sand and gravel operations, and wineries. 
Urban Stormwater
Stormwater discharges are generated by precipitation and runoff from land, pavement, building rooftops, and other surfaces. Stormwater from municipal and industrial areas and from construction projects may contribute pollutants (including toxic pollutants) to surface waters (for example, see Ecology, 2019a).
Ecology regulates stormwater discharges from municipal separate storm sewer systems (MS4s) through four general permits. The MS4 permits require the discharger to develop and implement a stormwater management program (SWMP), with the goal of controlling pollutant discharges to the maximum extent practicable (MEP). Elements of a SWMP include stormwater planning; public education, outreach, involvement, and participation; MS4 mapping and documentation; illicit discharge detection programs; control of runoff from new development, redevelopment, and construction sites; operations and maintenance programs; and source control program for existing development. Each of these elements has specific minimum requirements enumerated in the permits.
Ecology issued a Phase I MS4 permit (Ecology, 2019c), which covers large and medium MS4s, including the systems in Seattle and Tacoma and in Clark, King, Pierce, and Snohomish counties. Secondary permittees have separate SWMP requirements. Secondary permittees include University of Washington, Seattle; Seattle School District # 1; Metropolitan Park District of Tacoma; Tacoma Community College; Port of Seattle; Port of Tacoma; Washington State Military Department; and Washington State Department of Corrections. The Phase II general permits cover those systems serving municipalities with populations less than 100,000 located within Census Bureau-defined urbanized areas. There are two Phase II stormwater permits: one for Eastern Washington (Ecology, 2019d) and one for Western Washington (Ecology, 2019e). A fourth MS4 permit specifically covers the Washington State Department of Transportation and addresses stormwater discharges from state highways and transportation-related facilities, rest areas, park and ride lots, ferry terminals, and maintenance facilities within urban areas of Washington (Ecology, 2019b).
Industrial dischargers, including those engaged in manufacturing, transportation, mining, and steam electric power industries, scrap yards, landfills, certain sewage treatment plants, and hazardous waste management facilities may have stormwater requirements in their individual NPDES permits. Ecology also issued an Industrial Stormwater general permit (Ecology, 2019f), which requires industrial stormwater dischargers covered under the permit to develop a Stormwater Pollution Prevention Plan (SWPPP) that includes best management practices (BMPs) to prevent, control, and treat stormwater pollution; a monitoring plan; and discussion of the site controls that the discharger will implement to prevent stormwater pollution.
Ecology issued a Construction Stormwater general permit (Ecology, 2020b) to regulate stormwater discharges from construction activities that involve clearing, grading, or excavation resulting in the disturbance of one or more acres or that occur on a site that is smaller than one acre but is part of a larger common plan of development or sale that will ultimately disturb one acre or more. The permit requires operators of construction sites covered under the permit to develop a SWPPP and implement sediment, erosion, and pollution prevention control measures.
Agriculture and Forestry
Pesticides and herbicides applied to agricultural or forestry lands can reach surface waters through irrigation return flow, stormwater runoff, and erosion of soils. In addition, Ecology works with farmers in Washington to incentivize and implement BMPs on agricultural land to reduce runoff of pollutants from agricultural lands. Washington regulates forestry activities on State and private lands through the Washington Forest Practices Act (chapter 76.09 RCW), Stewardship of Non-industrial Forests and Woodlands (chapter 76.13 RCW), and the associated forest practices rules (Title 222 WAC). The Washington Forest Practices Board (the authority empowered to enforce forest practices rules) designed and adopted the forest practice rules, in part, to meet the requirements of the CWA and state water quality standards. The rules cover a variety of forestry activities, including timber harvesting, thinning, road construction, fertilization, and chemical application.
Atmospheric Deposition
Atmospheric deposition is a potential nonpoint source of pollutants to surface waters through either direct or indirect deposition. Direct deposition occurs when pollutants are deposited directly on surface waters from the atmosphere. Indirect deposition reflects the process by which metals and other pollutants such as pesticides deposited on the land surface are washed off during storm events and enter surface water through stormwater runoff.
Contaminated Sediments
When pollutants enter a waterbody through runoff, precipitation, or other means, they can accumulate in sediments and contribute to poor water quality for many years (U.S. EPA, 2012). Many waterbody sediments are contaminated by legacy pollutants including DDT, PCBs, and other pesticides. To address sediment contamination, Washington implemented the Washington State Sediment Management Standards (SMS) Chapter 173-204 WAC (Ecology, 2013) to reduce and ultimately eliminate sediment contamination in Washington waterbodies. The SMS set numeric and narrative criteria for sediments, apply the standards to reduce pollutant discharges, and provide a decision process for the cleanup of contaminated sites. 
Water Quality
Ecology classifies all surface waters into one of five categories, based on available monitoring data, as follows:
Category 1 waters are those for which sufficient monitoring data are available to determine that the water is below all applicable criteria (i.e., it is not impaired);
Category 2 waters are "waters of concern," but lack sufficient data for an impairment classification;
Category 3 waters for which there are insufficient data to determine whether it is impaired;
Category 4 waters are impaired, but Ecology is not pursuing TMDLs for them because a) there is an EPA-approved TMDL, b) there is a pollution control program in place, or c) it is impaired by a cause other than a pollutant; and
Category 5 waters are impaired and a TMDL or pollution control plan is required.
Ecology's most recent approved Water Quality Assessment and 303(d) List for Washington State was approved by EPA in July 2016. This assessment updated freshwater listings based on data collected as of the end of 2010. The integrated report identified impaired waters and reports on the status of water quality statewide. 
The approved assessment report/list was developed using Washington's Water Quality Assessment Policy that was effective at that time (Ecology, 2012a). Based on that assessment methodology, a water is classified as Category 5 (impaired and in need of a TMDL) when it has two or more exceedances of an applicable criteria within a 3-year period. Waters could also be placed into Category 5 on the basis of fish tissue concentrations if the mean of the three highest available resident fish tissue observations exceeds the fish tissue criteria, which are derived from surface water concentrations using bioconcentration factors.
Exhibit 2-3 summarizes the Category 4 and 5 listings (not including listings for sediment) for each of the pollutants covered by the proposed action. Exhibit 2-4 summarizes existing TMDLs targeting or including pollutants covered by the proposed action in waters in Washington. 
Exhibit 2-3. Category 4 and 5 Listings for Pollutants Covered by Proposed Action (as of 2012)
Parameter
Lake/Marine Assessment Units
River/Stream Assessment Units
Total Assessment Units
4,4'-DDD
                                                                              3
                                                                             28
                                                                             31
4,4'-DDE
                                                                             16
                                                                             74
                                                                             90
4,4'-DDT
                                                                              4
                                                                             18
                                                                             22
Aldrin
                                                                              2
                                                                              2
                                                                              4
Aldrin/Dieldrin
                                                                               
                                                                              1
                                                                              1
Alpha-BHC
                                                                              8
                                                                              2
                                                                             10
Benzo(a)anthracene
                                                                             25
                                                                               
                                                                             25
Benzo(a)pyrene
                                                                             23
                                                                               
                                                                             23
Benzo(b)fluoranthene
                                                                             28
                                                                               
                                                                             28
Benzo(k)fluoranthene
                                                                             23
                                                                               
                                                                             23
Beta-BHC
                                                                              3
                                                                               
                                                                              3
Bis(2-Ethylhexyl)phthalate
                                                                              3
                                                                               
                                                                              3
Chlordane
                                                                              6
                                                                              7
                                                                             13
Chrysene
                                                                             34
                                                                               
                                                                             34
DDT (and metabolites)
                                                                              1
                                                                             39
                                                                             40
Dibenzo(a,h)anthracene
                                                                             11
                                                                               
                                                                             11
Dieldrin
                                                                             23
                                                                             31
                                                                             54
Heptachlor Epoxide
                                                                               
                                                                              2
                                                                              2
Hexachlorobenzene
                                                                              6
                                                                              4
                                                                             10
Indeno(1,2,3-c,d)pyrene
                                                                             16
                                                                               
                                                                             16
Zinc
                                                                               
                                                                             12
                                                                             12
Source: Based on data from the Current Water Quality Assessment Database, as of June 2021 (available at: https://apps.ecology.wa.gov/ApprovedWQA/ApprovedPages/ApprovedSearch.aspx).

Exhibit 2-4. Summary of TMDLs for Pollutants Covered by the Proposed Action
Waterbody
Parameter(s)
Status and Notes
Source
Walla Walla River Watershed
Chlorinated pesticides, PCBs
Exceedances of human health criteria for chlorinated pesticides and PCBs attributed to historical application of chlorinated pesticides to soils and crops in agricultural areas of the watershed.
Ecology (2006a)
Palouse River
Chlorinated pesticides and PCBs
Exceedances of human health criteria attributed to WWTPs and nonpoint sources.
Ecology (2007a)
Yakima River Watershed
Toxics and Pesticides
Exceedances of human health and aquatic life criteria are attributed to historical applications.
Ecology (2012b; 2010)
Mission Creek/ Wenatchee River Area
DDT
Exceedances of human health criteria are attributed to historical applications to pear and apple orchards.
Ecology (2007b)
Lake Chelan
DDT and PCBs
Exceedances of human health criteria are attributed to historical applications.
Ecology (2006b)
Lower Okanogan River Basin
DDT and PCBs
Exceedances of human health and aquatic life criteria are attributed to historical applications.
Ecology (2005)
Spokane River
Dissolved metals
Exceedances of aquatic life criteria for dissolved metals attributed to point sources in Idaho (upstream) and Washington.
Ecology (1999)
Notes:
TMDL = total maximum daily load; WWTP = wastewater treatment plant

Subsequent to the publication and approval of the 2012 303(d) list, Ecology modified its assessment methodology for identifying exceedances pursuant to HHC, as described in Water Quality Program Policy 1-11 (Ecology 2020). In the 2020 policy, Ecology notes that HHC are designed to protect designated uses associated with human consumption of fish and domestic water supply, but that there are challenges with using HHC alone as the basis for determining impairment. Specifically, the policy states:
   One key challenge is that many of the HHC pollutants are not quantifiable at low enough levels because the HHC concentrations are below detection and quantification limits. Given the challenges with using numeric HHC alone to determine impairment, listing methodologies are also included that are based on a direct evaluation of impairment to the designated uses that the HHC were designed to protect.
The policy then describes three approaches for assessing toxics data for human health protection:
 Directly assessing HHC by conducting a statistically valid study to evaluate if HHC are being met. 
 Evaluating the support of fish and shellfish harvest uses, primarily based upon tissue exposure concentrations (TEC). 
 Evaluating the support of domestic water supply uses, primarily based on drinking water exposure concentrations (DWEC).
The exposure thresholds (TECs and DWECs) used in approaches 2 and 3 are based on assumptions related to reference doses, risk levels, body weights, drinking water rates, and/or cancer slope factors. Freshwater data are used to evaluate both the harvest and drinking water uses and marine water data are used to evaluate the harvest use only, with the primary lines of evidence being fish tissue data to determine that the harvest use is being met and water column data to determine that the HHC or domestic drinking water supply use is being met.
With regard to directly assessing HHC, the policy states: 
   The completion of a statistically rigorous study is the only pathway for Ecology to directly evaluate whether or not the human health criteria are being met in a waterbody AU. A direct evaluation of human health criteria attainment takes priority over the water supply use assessment methodology described in this policy. Attainment of the human health criteria in the water column may not result in a determination that the harvest use is supported unless the study includes adequate consideration of the harvest use being protected. Interested parties can work with Ecology to design and implement a study to directly evaluate the attainment of human health criteria for the harvest use, as it is not practical to describe the study requirements in this policy for each toxic substance.
To obtain a comparable set of differences in impaired waters under baseline conditions and policy conditions (i.e., using the revised criteria), it is necessary to use a consistent methodology. It was not possible to estimate baseline (or incremental) impairments of fish and shellfish harvest uses or domestic water supply uses for the updated HHC rule analysis using the approach as described in the 2020 assessment policy because:
 the TEC exposure thresholds are based on tissue concentration data and these data are not available for the analysis;
 the DWEC exposure thresholds are often higher than the baseline HHC, proposed HHC, detection limit (DL), and quantitation limit (QL), in some cases by several orders of magnitude; and
 Direct assessment of HHC would require custom statistical analyses to identify impairments of the harvest use in the absence of tissue data and to identify impairments of the domestic water supply use in cases where much higher DWEC thresholds are not exceeded.
Consequently, EPA's analysis of baseline and incremental impairments in this report was based on the former analytical approach of categorizing waters with two exceedances of criteria in a three-year period as impaired. EPA assumes that this approach yields a reasonable estimate of what baseline and incremental impairments would be pursuant to a statistically rigorous method linked to the applicable HHC. The impairments analysis uses monitoring data for the years 2011 to 2020.

Revised Criteria
EPA is proposing HHC based on the following equations (EPA, 2000):
AWQC = (RfD xRSC) x BWDI+(FIxBAF)
AWQC=10-6q1*xBWDI+(FIxBAF)
where,
AWQC		= 	ambient water quality criterion (mg/L)
BW	 		= 	human body weight (kg)
RfD 		= 	reference dose based on noncancer human health effects (mg/kg BW-day)
RSC 		= 	relative source contribution (%)
DI	 		= 	drinking water intake (L/day)
FI			= 	human fish consumption (kg fish/day)
BAF 		= 	bioaccumulation factor (L/kg fish)
q1*	 		= 	cancer potency factor in (kg BW-day/mg).

EPA used the following inputs to derive the proposed criteria. Note that RSC is a feature reserved for use in deriving criteria based on an RfD, and not a q1*, for pollutants addressed in this proposed rule.
Exhibit 3-1. Summary of Key Assumptions for Calculating Human Health Criteria
Variable
Value
Fish consumption rate (FCR; g/day)
                                      175
Body weight (BW; kg)
                                      80
Drinking water intake (DWI; L/day)
                                      2.4
Excess cancer risk level (RL)
                                    10[-6]
Relative source contribution (RSC)
                                  0.5 to 0.8
Toxicity factors (RfD, q1*) basis
See 80 Fed. Reg. 36986 and Human Health Ambient Water Quality Criteria: 2015 Update (EPA 2015) 

Exhibit 3-1 summarizes the HHC for the pollutants of concern derived using the assumptions in Exhibit 3-2. The exhibit also shows Ecology's detection limits (DLs) and quantitation limits (QLs) which represent the minimum levels to which dischargers need to measure each pollutant. Compared with the revised HHC, the state's freshwater aquatic life criteria are more stringent for cyanide, gamma-BHC, and selenium, while the marine aquatic life criteria are more stringent for cyanide, nickel, selenium, and zinc (see Exhibit 3-2). Because the aquatic life criteria are more stringent than the revised HHC, EPA did not analyze discharges of these pollutants in those waterbody types. 
Exhibit 3-2. Revised Human Health Criteria (ug/L)
Parameter[a]
Revised Human Health Criteria
DL
QL

Water/Fish
Fish Only


 1,1,1-Trichloroethane
                                                                          20000
                                                                          50000
                                                                              1
                                                                              2
 1,1,2,2-Tetrachloroethane
                                                                            0.1
                                                                            0.3
                                                                            1.9
                                                                              2
 1,1,2-Trichloroethane
                                                                           0.35
                                                                           0.90
                                                                              1
                                                                              2
 1,1-Dichloroethylene
                                                                            700
                                                                           4000
                                                                              1
                                                                              2
 1,2,4-Trichlorobenzene
                                                                          0.036
                                                                          0.037
                                                                            0.3
                                                                            0.6
 1,2-Dichlorobenzene
                                                                            700
                                                                            800
                                                                            1.9
                                                                            7.6
 1,2-Dichloroethane
                                                                            8.9
                                                                             73
                                                                              1
                                                                              2
 1,2-Diphenylhydrazine
                                                                           0.01
                                                                           0.02
                                                                              5
                                                                             20
 1,2-Trans-Dichloroethylene
                                                                            200
                                                                           1000
                                                                              1
                                                                              2
 1,3-Dichlorobenzene
                                                                              2
                                                                              2
                                                                            1.9
                                                                            7.6
 1,3-Dichloropropene
                                                                           0.22
                                                                            1.2
                                                                              1
                                                                              2
 1,4-Dichlorobenzene
                                                                            200
                                                                            200
                                                                            4.4
                                                                           17.6
 2,4-Dichlorophenol
                                                                             10
                                                                             10
                                                                            0.5
                                                                              1
 2,4-Dinitrophenol
                                                                             30
                                                                            100
                                                                              1
                                                                              2
 2-Chloronaphthalene
                                                                            100
                                                                            100
                                                                            0.3
                                                                            0.6
 2-Methyl-4,6-Dinitrophenol
                                                                              3
                                                                              7
                                                                              1
                                                                              2
 4,4′-DDD
                                                                      0.0000079
                                                                      0.0000079
                                                                          0.025
                                                                           0.05
 4,4′-DDE
                                                                     0.00000088
                                                                     0.00000088
                                                                          0.025
                                                                          0.051
 4,4′-DDT
                                                                      0.0000012
                                                                      0.0000012
                                                                          0.025
                                                                           0.05
 Acenaphthene
                                                                             30
                                                                             30
                                                                            0.2
                                                                            0.4
 Aldrin
                                                                    0.000000041
                                                                    0.000000041
                                                                          0.025
                                                                           0.05
 alpha-BHC
                                                                       0.000048
                                                                       0.000048
                                                                          0.025
                                                                           0.05
 alpha-Endosulfan
                                                                              6
                                                                              7
                                                                          0.025
                                                                           0.05
 Anthracene
                                                                            100
                                                                            100
                                                                            0.3
                                                                            0.6
 Antimony
                                                                              6
                                                                             90
                                                                            0.3
                                                                              1
 Benzo(a) Anthracene
                                                                        0.00016
                                                                        0.00016
                                                                            0.3
                                                                            0.6
 Benzo(a) Pyrene
                                                                       0.000016
                                                                       0.000016
                                                                            0.5
                                                                              1
 Benzo(b) Fluoranthene
                                                                        0.00016
                                                                        0.00016
                                                                            0.8
                                                                            1.6
 Benzo(k) Fluoranthene
                                                                         0.0016
                                                                         0.0016
                                                                            0.8
                                                                            1.6
 beta-BHC
                                                                         0.0013
                                                                         0.0014
                                                                          0.025
                                                                           0.05
 Bis(2-Ethylhexyl) Phthalate
                                                                          0.045
                                                                          0.046
                                                                            0.1
                                                                            0.5
 Bromoform
                                                                            4.6
                                                                             12
                                                                              1
                                                                              2
 Butylbenzyl Phthalate
                                                                          0.013
                                                                          0.013
                                                                            0.3
                                                                            0.6
 Chlordane
                                                                       0.000022
                                                                       0.000022
                                                                          0.025
                                                                           0.05
 Chlorobenzene
                                                                            100
                                                                            200
                                                                              1
                                                                              2
 Chlorodibromomethane
                                                                           0.60
                                                                            2.2
                                                                              1
                                                                              2
 Chloroform
                                                                            100
                                                                            600
                                                                              1
                                                                              2
 Chrysene
                                                                          0.016
                                                                          0.016
                                                                            0.3
                                                                            0.6
 Cyanide
                                                                              9
                                                                            100
                                                                              5
                                                                             10
 Dibenzo(a,h) Anthracene
                                                                       0.000016
                                                                       0.000016
                                                                            0.8
                                                                            1.6
 Dichlorobromomethane
                                                                           0.73
                                                                            2.8
                                                                              1
                                                                              2
 Dieldrin
                                                                    0.000000070
                                                                    0.000000070
                                                                          0.025
                                                                           0.05
 Diethyl Phthalate
                                                                            200
                                                                            200
                                                                            1.9
                                                                            7.6
 Dimethyl Phthalate
                                                                            600
                                                                            600
                                                                            1.6
                                                                            6.4
 Di-n-Butyl Phthalate
                                                                              8
                                                                              8
                                                                            0.5
                                                                              1
 Endosulfan Sulfate
                                                                              9
                                                                             NA
                                                                          0.025
                                                                           0.05
 Endrin
                                                                          0.002
                                                                          0.002
                                                                          0.025
                                                                           0.05
 Ethylbenzene
                                                                             29
                                                                             31
                                                                              1
                                                                              2
 Fluoranthene
                                                                              6
                                                                              6
                                                                            0.3
                                                                            0.6
 Fluorene
                                                                             10
                                                                             10
                                                                            0.3
                                                                            0.6
 Gamma-BHC; Lindane
                                                                           0.43
                                                                           0.43
                                                                          0.025
                                                                           0.05
 Heptachlor
                                                                     0.00000034
                                                                     0.00000034
                                                                          0.025
                                                                           0.05
 Heptachlor Epoxide
                                                                      0.0000024
                                                                      0.0000024
                                                                          0.025
                                                                           0.05
 Hexachlorobenzene
                                                                      0.0000050
                                                                      0.0000050
                                                                            0.3
                                                                            0.6
 Hexachlorobutadiene
                                                                           0.01
                                                                           0.01
                                                                            0.5
                                                                              1
 Hexachlorocyclopentadiene
                                                                              1
                                                                              1
                                                                            0.5
                                                                              1
 Hexachloroethane
                                                                           0.02
                                                                           0.02
                                                                            0.5
                                                                              1
 Indeno(1,2,3-cd) Pyrene
                                                                        0.00016
                                                                        0.00016
                                                                            0.5
                                                                              1
 Methyl Bromide
                                                                            300
                                                                             NA
                                                                              5
                                                                             10
 Methylene Chloride
                                                                             10
                                                                            100
                                                                              5
                                                                             10
 Nickel
                                                                             80
                                                                            100
                                                                            0.1
                                                                            0.5
 Nitrobenzene
                                                                             30
                                                                            100
                                                                            0.5
                                                                              1
 Pentachlorophenol (PCP)
                                                                          0.002
                                                                          0.002
                                                                            0.5
                                                                              1
 Phenol
                                                                           9000
                                                                          70000
                                                                              2
                                                                             50
 Polychlorinated Biphenyls (PCBs)
                                                                       0.000007
                                                                       0.000007
                                                                              0
                                                                            0.5
 Pyrene
                                                                              8
                                                                              8
                                                                            0.3
                                                                            0.6
 Selenium
                                                                             60
                                                                            200
                                                                              1
                                                                              1
 Tetrachloroethylene
                                                                            2.4
                                                                            2.9
                                                                              1
                                                                              2
 Toluene
                                                                             72
                                                                            130
                                                                              1
                                                                              2
 Trichloroethylene
                                                                            0.3
                                                                            0.7
                                                                              1
                                                                              2
 Vinyl Chloride
                                                                             NA
                                                                           0.18
                                                                              1
                                                                              2
 Zinc
                                                                           1000
                                                                           1000
                                                                            0.5
                                                                            2.5
Notes: 
NA = not applicable; NR = not reported
[a] The existing aquatic life criteria are more stringent than the revised freshwater criteria for cyanide, gamma-BHC, and selenium, and the revised marine criteria for cyanide, nickel, selenium, and zinc. As such, EPA did not analyze discharges of these pollutants in those waterbody types. 



Method for Estimating Potential Costs: Point Sources
This section describes the method for estimating the potential costs to point sources associated with compliance with the revised HHC relative to the baseline. Compliance costs for municipal and industrial point sources may result from changes to NPDES permit requirements and associated effluent limitations. See Section 6 for the results, and appendices for additional details and calculations.
Major Dischargers -- Process Wastewater
EPA estimates costs to major municipal and industrial dischargers based on implementing the revised criteria by estimating costs to a representative sample of facilities, then extrapolating the results to the rest of the facilities in the state (by category). This section describes EPA's methods for sample selection, the reasonable potential analysis, identification of limits under the revised criteria, comparison to existing discharges, and estimation of costs to meet revised criteria.
Methodology for Sampling
Factors that may affect the potential magnitude of compliance costs include flow and type of facility. Larger flows are typically associated with the largest treatment costs, although per-unit costs may decrease due to economies of scale. Industrial category may also be indicative of the potential to incur costs. Treatment requirements differ for POTWs and industrial discharges, and effluent quality may be similar across categories of facilities. As shown in Exhibit 4-1, there are 406 total individually permitted dischargers, including 73 major dischargers (44 POTWs and 29 industrial dischargers) and 333 minor dischargers (169 POTWs and 164 industrial dischargers). 
EPA selected a representative sample of 18 major dischargers to evaluate potential costs in detail and to allow extrapolation of costs with industry categories. This sample size represents 25 percent of the major dischargers (18 out of 73). First, EPA analyzed a certainty sample comprising the two largest municipal facilities and the largest industrial facility. This certainty sample is intended to ensure that the analysis captures facilities with the highest potential for cost. From the remaining major dischargers, EPA selected a stratified random sample. Stratification by industry category allows EPA to extrapolate sample results within each industry category. The sample includes the five facilities that were the only dischargers in their respective industry categories: Mining, Food and Kindred Products, Chemicals and Allied Products, Fabricated Metal Products, and National Security and International Affairs. The other sample dischargers were randomly selected from the industries with multiple dischargers. Thus, the sample representation proportions vary by industry. Exhibit 4-2 provides a summary of major discharger categories and the distribution of the sample across those categories. 
Exhibit 4-1. Summary of Major Dischargers by Industrial Category
Category
Universe
Sample

Facilities
Design Flow (MGD)
Facilities
Design Flow (MGD)
POTW
                                      44
                                    1,402.4
                                    6 (14%)
                                  447.7 (32%)
Coal Mining
                                       1
                                      0.0
                                   1 (100%)
                                   0.0 (N/A)
Food and Kindred Products
                                       1
                                      2.1
                                   1 (100%)
                                  2.1 (100%)
Paper and Allied Products
                                      12
                                     283.1
                                    3 (25%)
                                  89.7 (32%)
Chemicals and Allied Products
                                       1
                                     15.0
                                   1 (100%)
                                  15.0 (100%)
Petroleum Refining and Related Industries
                                       5
                                     31.5
                                    2 (40%)
                                  13.9 (44%)
Primary Metal Industries
                                       3
                                     34.6
                                    1 (33%)
                                   9.0 (26%)
Fabricated Metal Products
                                       1
                                      0.2
                                   1 (100%)
                                  0.2 (100%)
Electric, Gas and Sanitary Services
                                       4
                                     29.5
                                    1 (25%)
                                  12.1 (41%)
National Security and International Affairs
                                       1
                                      7.2
                                   1 (100%)
                                  7.2 (100%)
Total
                                      73
                                    1,805.6
                                   18 (25%)
                                  596.9 (33%)
Notes:
MGD = million gallons per day; POTW = publicly owned treatment works

Exhibit 4-2. Summary of Major Discharger Sample provides a summary of the sample for evaluation. Appendix A provides additional information on these facilities.
Exhibit 4-2. Summary of Major Discharger Sample
NPDES Number
Facility Name
Category
Design Flow (MGD)
Certainty Sample
WA0029581
King County South WWTP
POTW
                                     144.0
WA0029181
King County West Point WWTP
POTW
                                     215.0
WA0000124
Weyerhaeuser Co Longview
Paper and Allied Products
                                     65.1
Random Sample
WA0039624
Chambers Creek WWTP
POTW
                                     28.7
WA0044962
Pasco WWTP
POTW
                                     24.5
WA0023451
Redondo WWTP
POTW
                                     11.2
WA0022772
Salmon Creek WWTP
POTW
                                     24.3
WA0022900
BP Cherry Point Refinery
Petroleum Refining and Related Industries
                                     13.0
WA0000809
Cosmo Specialty Fibers Inc.
Paper and Allied Products
                                     24.0
WA0000281
Emerald Kalama Chemical LLC 
Chemicals and Allied Products
                                     15.0
WA0002950
Intalco Aluminum Corp Ferndale
Primary Metal Industries
                                      9.0
WA0002062
Puget Sound Naval Shipyard
National Security and International Affairs
                                      7.2
WA0021067
Quincy Industrial
Food and Kindred Products
                                      2.1
WA0000884
Sonoco Products
Paper and Allied Products
                                      0.6
WA0040851
Steelscape INC
Fabricated Metal Products
                                      0.2
WA0001546
TransAlta Centralia Generating Station
Electric, Gas and Sanitary Services
                                     12.1
WA0037338
TransAlta Centralia Mining
Coal Mining
                                      0.0
WA0001783
U.S. Oil and Refining Tacoma
Petroleum Refining and Related Industries
                                      0.9
Notes:
MGD = million gallons per day; POTW = publicly owned treatment works; WWTP = wastewater treatment plant; STP = sewage treatment plant

Reasonable Potential Analysis
For each facility in the sample, EPA conducted a reasonable potential analysis (RPA) to determine whether there is reasonable potential (RP) for the effluent to cause, have the reasonable potential to cause, or contribute to an excursion of water quality standards for any parameter that has revised criteria (as summarized in Section 3). For consistency with state implementation procedures (Ecology, 2018), EPA used Ecology's spreadsheet tool (PermitCalc) for permit writers to assess RP. 
For each facility and parameter, the RPA uses data on effluent concentrations, receiving water characteristics, ambient parameter concentrations, and dilution factors. EPA gathered these data from a variety of sources, including:
Facility-specific permit fact sheets, available from Ecology's Water Quality Permitting and Reporting Information System (PARIS);
Discharge Monitoring Report (DMR) data available from PARIS;
Ambient pollutant concentrations from permit fact sheets or the Environmental Information Management (EIM) database; and
Other facility documentation, such as inspection reports and permit applications, available from PARIS.
The RPA was limited by data availability to the facilities and parameters for which sufficient data were available. In particular, parameters for which there were no data or all results were below DLs could not be analyzed, and for these parameters EPA assumed that the facility would not have RP or any WQBELs under either the baseline or policy scenarios. 
In cases where an RPA calculation would use the 50th percentile of a large effluent concentration data set, data limitations typically required use of a mean in the analysis for this report. In cases where there were some detected concentrations and some non-detects, EPA calculated mean concentrations assuming half the DL for all non-detects (unless the DL exceeds the criteria in which case EPA assumed half the criteria for all non-detects to avoid the possibility of having a non-detect value exceed a criterion). Reported concentrations below the QL, but without a data qualifier, were used as reported. 
Appendix A provides facility-specific RPA results under both the baseline permit conditions and revised criteria and additional information on the specific data sources used for each facility. Exhibit 4-3 summarizes the results for facilities where EPA found RP pursuant to this analysis.
Exhibit 4-3. Summary of Sample Facilities with Reasonable Potential
Facility
Parameters with Reasonable Potential

Baseline Scenario
Policy Scenario
Cosmo Specialty Fibers (Outfall 001)
Aldrin
Aldrin
Cosmo Specialty Fibers (Outfall 002)
Dichlorobromomethane
PCBs
Dichlorobromomethane
PCBs
Bis (2-ethylhexyl) phthalate
Emerald Kalama Chemical
Hexachlorobenzene
Benzo(a) pyrene
Hexachlorobenzene
Intalco Aluminum
Benzo(a) pyrene
Benzo(a) pyrene
Benzo(a) anthracene
Benzo(b) fluoranthene
Weyerhaeuser Longview
Aldrin
Dieldrin
Aldrin
4,4'-DDE
Dieldrin
Pentachlorophenol (PCP)
Notes:
Calculated using Ecology's PermitCalc spreadsheet based on available effluent data, ambient data, and dilution factors from Ecology's PARIS and EIM databases and facility permit fact sheets. 
See Appendix A for details on each analysis.

Projecting Effluent Limitations
For dischargers and parameters with RP, EPA calculated average monthly effluent limitations (AMLs) and maximum daily effluent limitations (MDLs) based on procedures contained in the PermitCalc tool. These procedures specify that the permit writer first derive a waste load allocation (WLA) according to the following equation:
	WLA = D x WQC  -  Cb x (D  -  1)
   where,
      WLA		= waste load allocation (in units of concentration)
      D		= dilution factor
      WQC		= water quality criterion concentration (applicable human health criterion)
      Cb		= ambient background concentration (geometric mean).
In instances where the receiving water is impaired, (i.e., Cb > WQC), EPA set the WLA equal to the HHC to ensure that the discharge would not cause, have the reasonable potential to cause, or contribute to an instream excursion of the criteria. 
According to Chapter 7, Section 5.1 of the Washington Water Quality Program Permit Writer's Manual (Ecology, 2018), the projected AML to protect human health is computed by setting the AML equal to the applicable WLA:
	AML = WLA (in units of concentration)
Chapter 7, Section 5.1 of the Washington Water Quality Program Permit Writer's Manual (Ecology, 2018) further states that the MDL is calculated within PermitCalc based on factors from Table 5-3 of EPA's Technical Support Document for Water Quality-based Toxics Control (EPA, 1991).
To estimate compliance costs attributable to the rule, EPA compares the projected AML and MDL for each pollutant under the policy scenario to the existing NPDES permit limitations for that pollutant. If the projected AML and MDL are more stringent than existing NPDES permit limitations, EPA would estimate the costs for the control mechanisms required to ensure compliance with the projected AML and MDL.
In several instances EPA determined that a facility had reasonable potential for a parameter under the baseline scenario, but the existing permit for the facility does not include WQBELs for that parameter. Based on EPA's evaluation of the NPDES permit fact sheets for the sample facilities there may be a number of reasons for the absence of WQBELs in the sample facility NPDES permits, including the availability of additional effluent data since the time the permit was issued. Further, as described in Section 2.1, Washington's baseline HHC have been in flux with various conflicting EPA actions, most recently in May 2020. Because most of the sample facilities' existing permits pre-date the criteria revisions (prior to 2016), they were not developed using the baseline criteria, and current limits do not represent the outcome of an RPA under the baseline criteria. In other words, when the facilities' permits are renewed at the conclusion of their existing terms, they will be evaluated relative to revised criteria both under the baseline scenario and the policy scenario. Costs associated with meeting the current criteria are not considered costs of this rule.
Because of these factors, the lack of existing WQBELs based on HHC may not accurately characterize the baseline condition from which to measure the potential impacts attributable to the proposed HHC revisions. Therefore, EPA evaluated RP based on the existing HHC to confirm whether a WQBEL would be included under the baseline scenario during the next permit cycle using the existing criteria. This approach reflects compliance with 40 CFR 122.44(d)(1), which states that effluent limitations must be established when a pollutant is discharged "...at a level which will cause, have the reasonable potential to cause, or contribute to an excursion above any State water quality standard, including State narrative criteria for water quality." It is possible for EPA's RPA to indicate that there is RP under the baseline criteria and that a WQBEL is needed even when the existing permit does not include a WQBEL. 
In all cases, an AML would be more stringent than the corresponding MDL. In cases where a facility had RP under both the baseline and the policy scenario, EPA compared the baseline AML to the projected AML to determine whether the discharger would be in compliance with the new effluent limitation. In cases where there was RP under the policy scenario but not under the baseline scenario, EPA compared the maximum observed effluent concentration (MEC) to the projected AML to determine whether the discharger would be in compliance with the new effluent limitation. If the baseline AML or MEC exceeds the projected AML, compliance actions and associated costs would be likely. 
EPA estimated the pollutant loading reduction required to comply with WQBELs (in the baseline or policy scenario) based on the difference between the MEC and the AML, in most circumstances, according to the following equation:
   LR = 0.00834 x Q x (MEC  -  AML) x 365
   where, 
      LR	=	load reduction (lbs/year)
      0.00834	=	conversion factor [(lbs)(L)/(ug)(mg)]
      Q	=	effluent flow rate (mgd)
      MEC	=	maximum effluent concentration (ug/L)
      AML	=	average monthly effluent limitation (ug/L)
      365	=	days/year
EPA then calculated the incremental load reduction under the policy scenario by subtracting the load reduction required to comply with the baseline AML from the load reduction required to comply with the policy scenario AML (i.e., pursuant to the revised criteria). Where there was no AML under the baseline scenario, the required loading reduction would be zero under the baseline scenario.
   ILR = LRpolicy  -  LRbaseline 
   where,
      ILR 		= incremental load reduction (lbs/year)
      LRpolicy		= load reduction to meet the revised criteria (lbs/year)
      LRbaseline	= load reduction to meet the baseline permit conditions (lbs/year).
Chapter 6, Section 4.3 of Ecology's Permit Writer's Manual (Ecology, 2018) states that, in cases where a calculated effluent limit is below the QL (see Exhibit 4-4), the permit should include the limit as calculated together with a footnote indicating what will be used as the "compliance assessment level" for the parameter. For this analysis, in cases where the calculated AML was below the QL for a parameter, EPA assumed that facilities would need to reduce concentrations below the QL to ensure compliance. If a facility's MEC and AML are both below the QL, no further reductions would be needed. 
Exhibit 4-5 summarizes the calculated AMLs for facilities with RP, compared to the MEC and the QL and determines whether any reductions would be needed for permit compliance for the baseline scenario. Exhibit 4-5 summarizes calculated AMLs for facilities with RP under the policy scenario and compares the policy scenario AML to the MEC or baseline AML to determine whether any incremental reductions would be required for permit compliance beyond what would be needed under the baseline scenario.
Based on this analysis, one facility, Intalco Aluminum, would need to reduce benzo(a) pyrene concentrations under the baseline scenario. Pursuant to these reductions, the facility would achieve concentrations below the QL and, as such, would not need to achieve further reductions under the policy scenario. In all other cases, facilities with RP under the baseline and policy scenario or the policy scenario alone achieve effluent concentrations below the QL and would not need to achieve further reductions under either scenario. In addition to the calculated AMLs, EPA also reviewed the corresponding MDLs in comparison to the QL and confirmed that there were no dischargers for which the baseline scenario MDL was above the QL, but the policy scenario MDL was below the QL. In this situation, a facility might have needed to achieve incremental load reductions to reduce its daily discharge to below the QL to comply with the policy scenario MDL.
Exhibit 4-4. Summary of Calculated Effluent Limitations for Facilities with Reasonable Potential -- Baseline Scenario
Facility
Parameter
MEC (ug/L)
AML
(ug/L)
QL
(ug/L)
Reduction Needed?
Cosmo Specialty Fibers (Outfall 001)
Aldrin
                                                                          0.011
                                                                        0.00043
                                                                           0.05
                                                                             No
Cosmo Specialty Fibers (Outfall 002)
Bis(2-Ethylhexyl) Phthalate
                                                                           0.15
                                                                           0.23
                                                                            0.5
                                                                             No

Dichlorobromomethane
                                                                            1.2
                                                                           0.77
                                                                              2
                                                                             No

Polychlorinated Biphenyls (PCBs)
                                                                          0.093
                                                                        0.00017
                                                                            0.5
                                                                             No
Emerald Kalama Chemical
Hexachlorobenzene
                                                                           0.28
                                                                          0.047
                                                                            0.6
                                                                             No
Intalco Aluminum
Benzo(a) pyrene
                                                                              2
                                                                           0.16
                                                                              1
                                                                            Yes
Weyerhaeuser Longview
Aldrin
                                                                         0.0031
                                                                        0.00056
                                                                           0.05
                                                                             No

Dieldrin
                                                                         0.0058
                                                                        0.00060
                                                                           0.05
                                                                             No
Notes:
AML = average monthly effluent limit; MEC = maximum effluent concentration; QL = quantification limit
Exhibit 4-5. Summary of Calculated Effluent Limitations for Facilities with Reasonable Potential -- Policy Scenario
Facility
Parameter
MEC/
Baseline AML (ug/L)
AML
(ug/L)
QL
(ug/L)
Reduction Needed?
Cosmo Specialty Fibers (Outfall 001)
Aldrin
                                                                        0.00043
                                                                      0.0000030
                                                                           0.05
                                                                             No
Cosmo Specialty Fibers (Outfall 002)
Bis(2-Ethylhexyl) Phthalate
                                                                           0.23
                                                                          0.045
                                                                              2
                                                                             No

Dichlorobromomethane
                                                                           0.77
                                                                           0.73
                                                                              2
                                                                             No

Polychlorinated Biphenyls (PCBs)
                                                                        0.00017
                                                                      0.0000070
                                                                            0.5
                                                                             No

Benzo(a) pyrene
                                                                           0.38
                                                                          0.015
                                                                              1
                                                                             No

Hexachlorobenzene
                                                                          0.047
                                                                         0.0046
                                                                            0.6
                                                                             No
Emerald Kalama Chemical
Benzo(a) pyrene
                                                                           0.38
                                                                          0.015
                                                                              1
                                                                             No

Hexachlorobenzene
                                                                          0.047
                                                                         0.0046
                                                                            0.6
                                                                             No
Intalco Aluminum
Benzo(a) anthracene
                                                                           0.30
                                                                          0.012
                                                                            0.6
                                                                             No

Benzo(a) pyrene
                                                                           0.16
                                                                         0.0012
                                                                              1
                                                                             No

Benzo(b) fluoranthene
                                                                           0.29
                                                                          0.012
                                                                            1.6
                                                                             No
Weyerhaeuser Longview
Aldrin
                                                                        0.00056
                                                                      0.0000040
                                                                           0.05
                                                                             No

4,4'-DDE
                                                                         0.0034
                                                                       0.000086
                                                                          0.051
                                                                             No

Dieldrin
                                                                        0.00060
                                                                      0.0000068
                                                                           0.05
                                                                             No

Pentachlorophenol (PCP)
                                                                           0.77
                                                                           0.20
                                                                              1
                                                                             No
Notes:
AML = average monthly effluent limit; MEC = maximum effluent concentration; QL = quantification limit

Identifying Compliance Permit Conditions and Costs
As shown in Exhibit 4-5, EPA did not identify any facilities that would need to achieve incremental loading reductions under the revised criteria relative to the baseline scenario.
Minor Dischargers -- Process Wastewater
Minor dischargers often do not have monitoring requirements for toxic pollutants and may not contribute significantly to instream loads even if such pollutants were present in the effluent from these facilities. Thus, the potential for minor facilities to incur costs as a result of revised HHC is low.
EPA reviewed data and information contained in the NPDES permit fact sheets for two minor industrial dischargers to evaluate potential for impact under the rule [KB Alloys, LLC (WA0002976), and Sandvik Special Metals, LLC (WA0003701)] because they had some information about pollutant levels available. The permit data for most of the minor dischargers were not available to determine potential impacts of the revised criteria. The primary pollutants of concern for which data were available are metals (e.g., aluminum, chromium, cyanide, lead, nickel, and zinc). For metals, aquatic life protection criteria are more stringent than the revised HHC. For both facilities, due in part to the lack of background pollutant data (i.e., background was set equal to zero) and the dilution factors applied to each facility's discharge, there was no RP to exceed water quality criteria for the metals. The NPDES permits include technology-based effluent limitations for the metals of concern.
Effluent data were not available for other pollutants for which HHC are being revised. In the fact sheets for each facility, Ecology had determined that discharges from each facility are unlikely to contain chemicals regulated to protect human health. Additional data would be needed to confirm or dispute this finding under the rule.
Urban Stormwater
As discussed in Section 2.2.2, Ecology regulates most stormwater discharges through general permits. These general permits require dischargers covered under the permits to develop and implement programs and plans to reduce pollutant discharges. For the most part, the general permits do not include numeric WQBELs for toxic pollutants; however, the Industrial Stormwater general permit (Ecology, 2019f) includes benchmark values for some toxic pollutants (e.g., cyanide, zinc) that, if exceeded by a discharger required to monitor for those pollutants, trigger requirements to take corrective actions. EPA anticipates that the proposed HHC would not cause an incremental impact on discharges subject to these benchmarks because Ecology states in the fact sheet for the permit that:
   Because most human health-based criteria are based on lifetime exposures, direct comparisons of receiving water criteria with pollutant concentrations in intermittent stormwater discharges are not appropriate. This and the high variation in stormwater pollutant concentrations and discharge volumes, both between storms and during a single storm, make the application of human health criteria to stormwater particularly problematic.
   Based on the authority of 40 CFR §122.44(k)(3), Ecology is requiring the implementation of best management practices to control or abate pollutants because it is infeasible to derive appropriate numeric effluent limits for the human health criteria.
In addition to benchmarks, the Industrial Stormwater general permit includes sampling requirements and WQBELs for discharges of certain pollutants to a CWA section 303(d)-listed water body. These pollutants include pentachlorophenol (PCP) and zinc, for which revised HHC are proposed. For PCP and zinc, the permit notes that a site-specific effluent limitation will be established at the time of permit coverage.
As discussed in Section 5.1, EPA identified potential incremental impairments based on the proposed HHC. Some incremental impairments were for PCP and zinc. However, sufficient data are not available to match industrial stormwater discharges to water body segments with potential incremental impairments. Furthermore, even if stormwater discharges to waters with potential incremental impairments for PCP and zinc could be identified, Ecology states in the general permit that it would establish site-specific limits for these pollutants. EPA does not have the data needed to estimate such limits or determine whether Ecology would conclude that BMPs are sufficient for stormwater discharges to impaired waters. To the extent that additional WQBELs to protect human health are required, these effluent limits may result in increased or additional nonstructural BMPs (e.g., institutional, education, or pollution prevention practices designed to limit generation of runoff or reduce the pollutant load of runoff); and structural controls (e.g., engineered and constructed systems designed to provide water quantity or quality control).
Methods for Identifying Potential Costs: Incremental Impairments
Changes in water quality criteria could result in incremental impacts on nonpoint sources of pollution, such as agriculture, urban areas, and forestry, through TMDLs or other pollution cleanup plans. Section 2.2 discusses the nonpoint sources of pollution, and Section 2.3 summarizes the process by which Ecology categorizes waterbodies. Ambient water quality data can be used to determine the impact that a change in HHC may have on the attainment of the criteria and thus the potential for incremental control strategies and costs for nonpoint sources. If additional TMDLs are needed as a result of the revised criteria, there may be some additional administrative costs to regulatory entities to develop the TMDLs. There also may be additional costs of controls to meet TMDLs, although those costs are beyond the scope of this analysis. A credible analysis of those costs would require information about specific nonpoint source loadings and transport in specific watersheds which is not readily available and would be too speculative to make an informed estimate.
Identifying Exceedances
EPA identified potential incremental impairments based on available data in EIM following the methodology used for the most recent approved 303(d) list (see Section 2.1). According to the state's water quality assessment methodology (Ecology, 2012a; Ecology, 2020), Ecology generally uses the last ten years of data to determine impairment status of surface waters. EPA used available surface water monitoring data on pollutants of interest from EIM for the years 2011 to 2020. 
EPA first eliminated observations that were total recoverable metals concentrations (since the dissolved form is the appropriate metric for ambient concentration); observations that resulted from sampling at known contamination sites, cleanups, groundwater, and outfall monitoring stations; and observations with data qualifiers indicating unusable results. EPA then grouped monitoring data into assessment units (AUs) based on the National Hydrography Dataset (NHD) code linked to the monitoring station, where available. In cases where the NHD code was not available, EPA assumed that each monitoring location represented an AU. This approach may result in an overestimate of the number of AUs if some of these monitoring stations are located in the same waterbody segment.
For each AU and parameter, EPA compared the pollutant concentration to both the existing baseline HHC and the revised criteria. Station results that would represent impairment under the revised criteria but not under the existing baseline criteria may represent potential incremental impairments.
Exhibit 5-1 shows the results of this analysis. Using the baseline criteria values, monitoring data indicate potential impairment on the basis of HHC impairments in 36 AUs. Using the revised criteria there would be impairments in 66 AUs, for a total of 30 potential incremental impairments. 
Exhibit 5-1. Potential Incremental Impairments
Parameter
Number of Locations[a]
Potential Impairments


Baseline[b]
Revised[b]
Incremental[c]
alpha-Endosulfan
                                                                              4
                                                                              0
                                                                              0
                                                                              0
4,4'-DDD
                                                                              4
                                                                              3
                                                                              3
                                                                              0
4,4'-DDE
                                                                              6
                                                                              4
                                                                              4
                                                                              0
4,4'-DDT
                                                                              5
                                                                              3
                                                                              3
                                                                              0
Acenaphthene
                                                                             10
                                                                              0
                                                                              0
                                                                              0
Anthracene
                                                                              8
                                                                              0
                                                                              0
                                                                              0
Antimony
                                                                             20
                                                                              0
                                                                              0
                                                                              0
Benz[a]anthracene
                                                                              5
                                                                              0
                                                                              1
                                                                              1
Benzo(a)pyrene
                                                                              6
                                                                              1
                                                                              1
                                                                              0
Benzo(b)fluoranthene
                                                                              4
                                                                              0
                                                                              0
                                                                              0
Benzo(k)fluoranthene
                                                                              2
                                                                              0
                                                                              0
                                                                              0
beta-BHC
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Butyl benzyl phthalate
                                                                              2
                                                                              0
                                                                              0
                                                                              0
Chrysene
                                                                              7
                                                                              0
                                                                              1
                                                                              1
Di(2-ethylhexyl) phthalate
                                                                              7
                                                                              1
                                                                              1
                                                                              0
Dibenzo(a,h)anthracene
                                                                              3
                                                                              1
                                                                              1
                                                                              0
Dibutyl phthalate
                                                                             10
                                                                              0
                                                                              0
                                                                              0
Dieldrin
                                                                              2
                                                                              2
                                                                              2
                                                                              0
Diethyl phthalate
                                                                             11
                                                                              0
                                                                              0
                                                                              0
Dimethyl phthalate
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Endosulfan Sulfate
                                                                              2
                                                                              0
                                                                              0
                                                                              0
Ethylbenzene
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Fluoranthene
                                                                             18
                                                                              0
                                                                              0
                                                                              0
Fluorene
                                                                              9
                                                                              0
                                                                              0
                                                                              0
Heptachlor Epoxide
                                                                              2
                                                                              0
                                                                              0
                                                                              0
Hexachlorobutadiene
                                                                              3
                                                                              0
                                                                              0
                                                                              0
Indeno(1,2,3-cd)pyrene
                                                                              5
                                                                              0
                                                                              1
                                                                              1
Lindane
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Methylene Chloride
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Nickel[d]
                                                                             86
                                                                              0
                                                                              0
                                                                              0
PCB, Sum of Congeners[e]
                                                                             30
                                                                             16
                                                                             27
                                                                             11
Pentachlorophenol
                                                                             20
                                                                              4
                                                                             19
                                                                             15
Phenol
                                                                              2
                                                                              0
                                                                              0
                                                                              0
Pyrene
                                                                             12
                                                                              0
                                                                              0
                                                                              0
Toluene
                                                                              6
                                                                              0
                                                                              0
                                                                              0
Trans-1,2-Dichloroethene
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Trichloroethene
                                                                              2
                                                                              0
                                                                              0
                                                                              0
Vinyl Chloride
                                                                              1
                                                                              0
                                                                              0
                                                                              0
Zinc[d]
                                                                            155
                                                                              0
                                                                              1
                                                                              1
Total
                                                                               
                                                                             36
                                                                             66
                                                                             30
Source: Analysis based on 2011 to 2020 surface water monitoring data from Washington's Environmental Information Management System (EIM).
Notes:
[a] Monitoring data is grouped by National Hydrography Dataset (NHD) code where available (based on data from EIM) or sampling station ID code.
[b] Number of locations at which monitoring data indicate two or more exceedances of the human health criteria within 3 years.
[c] Represents difference in results between baseline and revised criteria.
[d] For zinc and nickel, includes only freshwaters since the aquatic life criteria are more stringent than revised human health criteria for marine waters.
[e] For PCBs, based on "sum of congeners" when reported, or calculated sum of congeners. Note that the analytical methods used for some of the water quality analyses have DLs that are lower than the regulatory limit in Section 2. Thus, it is possible to distinguish potential water quality impairment below the limit in Section 2.

--------------------------------------------------------------------------------
Identifying Nonpoint Source Compliance Actions and Costs
EPA does not have data on all parameters for all waterbodies, or data on the sources of loadings to potentially impaired waterbodies. Additionally, Ecology published its management plan for nonpoint source pollution in 2015 (see Ecology, 2015). Reductions in nonpoint source pollution loadings arising from this plan will occur in the absence of the rule and represent baseline requirements. 
If the revised criteria lead to additional waters being listed on the state's 303(d) list for exceedances of human health-based water quality criteria, the magnitude of cost impacts to nonpoint sources depends on the extent to which additional practices are needed for compliance with the potential revisions in comparison to compliance with existing baseline standards. For this analysis, EPA lacks the information necessary to provide a quantitative estimate of these costs. 
If nonpoint sources are the primary cause of some incremental impairment, then the revised criteria may result in some costs to nonpoint sources, including: 
Agricultural and forest lands  -  sediment and erosion controls beyond those specified under existing state and federal regulations and plans;
Mining  -  cleanup and remediation including excavation and onsite capping of contaminated soils, capping of onsite solid waste mining debris, regrading of tailings to mitigate mass wasting and off-site migration, and abatement and mitigation of physical hazards; and
Control of nonpoint sources of the pollutants of concern could also alter costs to point sources. 
Estimating TMDL Administrative Costs 
If an additional number of TMDLs are needed under the revised criteria, there may be an increase in government regulatory costs. U.S. EPA (2001) estimates that TMDL development costs per water body typically range from under $26,000 to over $500,000 depending on the number of TMDLs, the level of complexity, and the extent to which impaired waters are clustered together for TMDL development. 
For a TMDL that addresses a single cause of impairment, U.S. EPA (2001) estimates that a typical range of costs is between $6,000 and $154,000 with a national average cost of $27,000 to $29,000. Updated to 2020 dollars using the Implicit Price Deflator, average single-cause TMDL development costs are in the range of $39,000 to $42,000. 
To estimate the potential magnitude of government administration costs associated with the development of new TMDLs pursuant to the revised criteria, EPA multiplied this per-TMDL cost by the number of potential incremental impairments identified in Section 5.1. This approach is based on the conservative assumption that each combination of AU (as defined by NHD codes or monitoring station ID codes) and pollutant represents a water body with a single impairment. It is possible that a potentially impaired water body encompasses several such AUs. However, EPA deemed it beyond the scope of this analysis to investigate the degree to which the number of incremental impairments is overestimated. Therefore, the approach results in an upper bound estimate of incremental TMDLs. See Section 6.3 for the results of this calculation.


Potential Compliance Costs
This section summarizes the potential costs to point sources and nonpoint sources and administrative costs and discusses the limitations and uncertainties associated with the analyses. 
Point Sources
Incremental costs associated with the potential revised criteria represent the costs of any additional actions or controls needed for compliance with revised WQBELs under the rule. As discussed in Section 4.1.4, EPA did not identify any incremental costs to any major point source discharges of process wastewater from POTWs or industrial facilities attributable to the proposed criteria revisions. As discussed in Sections 4.2 and 4.3, EPA did not estimate incremental costs to minor process wastewater discharges from POTWs and industrial facilities or to stormwater discharges covered by general permits.
The lack of estimated costs in this analysis does not mean that EPA anticipates there would be no costs to point sources over time to implement controls or modify processes to meet future permit limits, only that available data did not indicate the immediate need for the facilities evaluated. However, any attempt to estimate potential future costs on a premise of being able to measure pollutants that could be present at lower levels or changes to facility operations or practices would be highly speculative.
One important contributing factor to examining point source costs is the limitations of required analytical methods to measure chemical concentrations in effluents. Nearly half of pollutant parameters addressed in this proposed rule have analytical quantitation limits that are above both the criteria currently in place and the proposed criteria. PCBs are a good example. The current criterion in place is 170 picograms per liter (pg/L) and the proposed criterion is 7 pg/L. However, the State identifies the analytical quantitation limit for effluent measurement as 500,000 pg/L. EPA has completed a multi-laboratory validation of a new analytical method for PCBs (method 1628) that has an average analytical quantitation limit for each PCB congener of approximately 2,000 pg/L, which is a substantial improvement over the current regulatory method, but still well above either the criterion currently in place or the proposed criterion. As a general matter, analytical methods and quantitation limits are subject to change over time. As such, it is important that WQS reflect the necessary level of protection regardless of contemporary limitations of analytical methods. 
Nonpoint Sources
Costs for compliance with baseline criteria include costs to nonpoint sources (e.g., agricultural and forest operations; contamination from historic mining sites) associated with implementation of existing programs and TMDLs. Incremental costs associated with compliance with the potential revised criteria represent the costs of any actions or controls above and beyond those needed to meet baseline requirements. EPA did not attempt to estimate incremental costs for nonpoint sources for this analysis. For situations in which controls beyond those required under the baseline are necessary, controls could include the development and implementation of TMDLs.
TMDL Administrative Costs 
If the revised criteria result in the need for additional TMDLs, Ecology may incur costs associated with the development and implementation of the TMDLs. Based on available ambient monitoring data, EPA identified 30 potential incremental impairments (see Section 5.1). If each incremental impairment results in a single-cause TMDL at an average cost of $39,000 to $42,000 (based on U.S. EPA (2001) and updated to 2020 dollars using the gross domestic product implicit price deflator; see Section 5.3), total administrative costs may be in the range of $1.17 million to $1.26 million. 
Actual costs associated with TMDL development may differ from these estimates, which are based on the estimate of 30 incremental impairments and standalone TMDLs. Costs can likely be reduced if Ecology instead develops TMDLs for waterbody with several causes of impairment, watershed-level TMDLs, or multiple-waterbody TMDLs for a single cause of impairment (e.g., a statewide or watershed-level approach to addressing PCP impairments, which account for half of the identified incremental impairments in Section 5.1).
Total Costs
Exhibit 6-1 provides a summary of the estimated costs for the rule. It indicates the lack of estimated costs for point sources to comply with revised permit limits and the one-time administrative costs to develop TMDLs for impaired waters. It does not include costs to nonpoint sources that may be affected by TMDL-based load allocations. The total annual costs of the rule range from $98,000 to $179,000, at a 3 percent discount rate.
Exhibit 6-1. Summary of Cost Estimates for Revised Human Health Criteria
Item
Cost Range
Annual costs for point source controls[a]
                                                                             $0
Annual TMDL development costs[b][,c]
                                                          $98,000  -  $179,000 
Total Annual Cost
                                                           $98,000  -  $179,000
Notes:
[a] EPA did not identify any incremental control actions for sample facilities; see Section 4.
[b] One-time costs for TMDL development are annualized over 8 to 15 years, at a 3 percent discount rate. The range includes both a range of unit costs and a range of years. The lowest unit cost annualized over 15 years corresponds to the lower bound, and the upper bound is the highest unit cost annualized over 8 years.
[c] One-time costs for TMDL development at a 7 percent discount rate range from $128,000 to $211,000.


Uncertainties and Quality Assurance
As noted previously, the rule does not establish any requirements directly applicable to regulated entities or other sources of pollution. State implementation of the rule may result in new or revised NPDES permit conditions for point source dischargers, and incremental control requirements for nonpoint sources. For point sources, EPA has estimated these impacts as the difference between compliance with the existing HHC and compliance with the revised HHC. However, there is substantial uncertainty associated with actual state implementation of the rule. 
The rule establishes HHC applicable to the waters in the state and as such there could be a need for additional controls on nonpoint sources of pollutant loadings to attain WQS. EPA estimated potential incremental impairments using readily available ambient water quality data. However, data are limited to identify specific incremental control actions and costs that may be required of nonpoint sources.
Exhibit 6-2 summarizes additional uncertainties and limitations in the analysis.
Exhibit 6-2. Uncertainties in Analysis of Costs
Uncertainty/Assumption
Effect on Cost Estimate
Notes
Sample facility costs are representative of all facilities in state (by category)
                                   Uncertain
Could result in an overestimate or underestimate of statewide costs if sample facilities are higher or lower than average costs.
Baseline controls
                                   Uncertain
EPA did not conduct extensive site-specific review of facility plans and information for addressing baseline water quality issues; thus, facility analyses could under- or overstate baseline and incremental actions and costs.
Incremental impairment estimate
                                   Uncertain
The estimate is based on existing water quality data and current permit conditions. The actual number of incremental impairments could be higher or lower depending on data availability and the effect of baseline TMDLs on water quality or discharge controls. Matching monitoring data to waterbodies could also result in a different estimate of incremental impairments. It is possible that the same water body has several monitoring stations which could reflect that the water body is impaired for a single pollutant. This could overestimate the impairments depending on the status of the water body in the baseline.
Incremental cost estimation method
                                   Uncertain
Under a TMDL, load and wasteload allocations may result in different requirements for point sources if nonpoint sources are the cause of impairments. In addition, the average unit cost per TMDL is based on standalone TMDL development. Costs for watershed or statewide TMDLs could be lower.
Zero compliance costs for sample facilities for which effluent data are not available
                                 Underestimate
If these facilities do need to take actions to comply with the revised requirements, the total cost of compliance would be greater than that estimated here.
 
EPA conducted quality assurance checks on the data, analyses, and results, consistent with the programmatic and project-specific quality assurance plans. In addition, EPA used Ecology's permit-writing tool, ensuring consistency with state permitting approaches and calculations. EPA also used Washington-specific data sources as available, and for all data entry, EPA confirmed the accuracy of data sources and documentation following procedures described in the quality assurance plans. These procedures include checks on all inputs and calculations and using multiple approaches to confirm results.
Discussion of Potential Benefits
Regardless of the degree to which the proposed revised criteria result in implementing additional pollutant control strategies that reduce human health risks, there is value in having fully protective criteria in place based on sound scientific rationale to ensure that assessments, discharge permits, and plans and other controls are based on the best possible information. To the extent that the proposed criteria ultimately result in pollutant reductions and cleaner water, the potential benefits include market benefits and nonmarket benefits.
Market benefits of improved water quality include its potential value to commercial fishing and water supply and use. Improvement in commercial seafood quality can enhance the value of products brought to market and increase the demand. Reducing contaminants in potable water supplies can lower the cost of treatment, and potentially avoids the need to develop alternative raw water sources. Additionally, protection of drinking water supplies may limit averting behavior from customers (e.g., purchasing of bottled water or in-home point of use water treatment systems).
Nonmarket benefits reflect the value of improved environmental goods and services used and valued by people, even if these goods and services are not traded in markets. Cleaner water may lead to a reduction in illness either through reduced consumption of contaminants in seafood or through reduced exposure to toxic chemicals in drinking water. Cleaner fish and shellfish can enhance the value of recreational experiences such as fishing by increasing the confidence that fish caught may be safely consumed. Improved water quality may translate into two components of recreational benefits: (1) an increase in the value of a recreational trip resulting from a more enjoyable experience, and (2) an increase in recreational participation.
Use benefits are values individuals hold for an environmental improvement that can be inferred through a change in demand for one or more market goods (i.e., purchases of complementary goods such as equipment and travel). In contract, nonuse benefits are values individuals hold for an environmental improvement that are independent of purchases of market goods and services or participation in recreational activities. Many people value water quality for its own sake or for the sake of others who more directly benefit. Small per capita nonuse values, such as option and existence values, held by a substantial fraction of the population can be very large in the aggregate.
For this analysis, EPA did not attempt to quantify the value of any of these potential benefits, but that does not mean they do not exist.

References
Department of Ecology, State of Washington (Ecology). 2020a. Water Quality Program Policy 1-11, Chapter 1: Washington's Water Quality Assessment Listing Methodology to Meet Clean Water Act Requirements. Publication Number 18-10-035.
Department of Ecology, State of Washington (Ecology). 2020b. Construction Stormwater General Permit. National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit for Stormwater Discharges Associated with Construction Activity. Issuance Date: November 18, 2020.
Department of Ecology, State of Washington (Ecology). 2019a. Stormwater Management Action Planning Guidance: Phase I and Western Washington Phase II Municipal Stormwater Permits. Publication 19-10-010.
Department of Ecology, State of Washington (Ecology). 2019b. Washington State Department of Transportation National Pollutant Discharge Elimination System and State Waste Discharge Municipal Stormwater General Permit. Issuance Date: March 6, 2019.
Department of Ecology, State of Washington (Ecology). 2019c. Phase I Municipal Stormwater Permit. National Pollutant Discharge Elimination System and State Waste Discharge General Permit for Discharges from Large and Medium Municipal Separate Storm Sewer Systems. Issuance Date: July 1, 2019.
Department of Ecology, State of Washington (Ecology). 2019d. Eastern Washington Phase II Municipal Stormwater Permit. National Pollutant Discharge Elimination System and State Waste Discharge General Permit for Discharges from Small Municipal Separate Storm Sewers in Eastern Washington. Issuance Date: July 1, 2019.
Department of Ecology, State of Washington (Ecology). 2019e. Western Washington Phase II Municipal Stormwater Permit. National Pollutant Discharge Elimination System and State Waste Discharge General Permit for Discharges from Small Municipal Separate Storm Sewers in Western Washington. Issuance Date: July 1, 2019.
Department of Ecology, State of Washington (Ecology). 2019f. Industrial Stormwater General Permit. A National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit for Stormwater Discharges Associated with Industrial Activities. Issuance Date: November 20, 2019.
Department of Ecology, State of Washington (Ecology). 2018. Water Quality Program Permit Writer's Manual. Publication Number 92-109.
Department of Ecology, State of Washington (Ecology). 2015. Washington's Water Quality Management Plan to Control Nonpoint Sources of Pollution. Publication No. 15-10-015.
Department of Ecology, State of Washington (Ecology). 2013. Sediment Management Standards: Chapter 173-204 WAC. Revised February 2013, Effective September 2013. Publication No. 13-09-055. 
Department of Ecology, State of Washington (Ecology). 2012a. Water Quality Program Policy: Assessment of Water Quality for the Clean Water Act Section 303(d) and 305(b) Integrated Report. Chapter 1: WQP Policy 1-11.
Department of Ecology, State of Washington (Ecology). 2012b. Water Quality Improvement Project, Yakima Watershed Area: Toxics. 
Department of Ecology, State of Washington (Ecology). 2010. Yakima River Pesticides and PCBs Total Maximum Daily Load. Volume 1: Water Quality Study Findings. Publication No. 10-03-018. 
Department of Ecology, State of Washington (Ecology). 2007a. Palouse River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Water Quality Improvement Report and Implementation Plan. Publication No. 07-03-018.
Department of Ecology, State of Washington (Ecology). 2007b. Mission Creek Watershed DDT Total Maximum Daily Load: Water Quality Improvement Report. Publication No. 07-10-046.
Department of Ecology, State of Washington (Ecology). 2006a. Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load (Water Cleanup Plan): Submittal Report. Publication No. 05-10-079.
Department of Ecology, State of Washington (Ecology). 2006b. Lake Chelan Watershed DDT and PCB Total Maximum Daily Load: Water Quality Improvement Report. Publication No. 06-10-022.
Department of Ecology, State of Washington (Ecology). 2005. Lower Okanogan River Basin DDT and PCBs Total Maximum Daily Load: Submittal Report. Publication No. 04-10-043.
Department of Ecology, State of Washington (Ecology). 2001. Inner Bellingham Bay Contaminated Sediments Total Maximum Daily Load: Submittal Report. Publication Number 99-58-WQ.
Department of Ecology, State of Washington (Ecology). 1999. Spokane River Dissolved Metals Total Maximum Daily Load: Submittal Report. Publication Number 99-49-WQ.
Department of Ecology, State of Washington (Ecology). 1991. Total Maximum Daily Loading (TMDL) to Limit Discharges of 2,3,7,8-TCDD (Dioxin) to the Columbia River Basin.
Final Updated Ambient Water Quality Criteria for the Protection of Human Health, 80 Federal Register 36986 (June 29, 2015).
United States Environmental Protection Agency (EPA). 2016. EPA Review of Washington 2012 303(d) Integrated Report.
United States Environmental Protection Agency (U.S. EPA). 2015. Human Health Ambient Water Quality Criteria: 2015 Update. EPA 820-F-15-001. June 2015. (available from: https://www.epa.gov/sites/default/files/2015-10/documents/human-health-2015-update-factsheet.pdf)
United States Environmental Protection Agency (EPA). 2014. Guidelines for Preparing Economic Analyses. December 17, 2010, updated May 2014. 
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United States Environmental Protection Agency (EPA). Guidance on Water Quality Based Effluent Limits Set Below Analytical Detection/Quantitation Limits. Memorandum from Cindy Godsey, NPDES Permits Unit; Michael Lidgard, Manager, NPDES Permits Unit; and Kim Ogle, Manager, NPDES Compliance Unit to NPDES Permits Unit Consistency Book. U.S. Environmental Protection Agency, Region 10, Seattle, Washington. April 25, 2005.
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 -  Facility Analyses
This appendix provides detailed analyses for the sample facilities in alphabetical order.
.	BP Cherry Point Refinery
The BP Cherry Point Refinery (NPDES permit number WA0022900) encompasses 740 acres in a rural area of Whatcom County. The facility's wastewater treatment plant treats process water, ballast water from tankers, tank water draws, and stormwater that falls in process areas of the site. The applicable 2012 permit also authorizes treatment of wastewater from the Praxair, Inc., Ferndale facility and a proposed cogeneration facility. The facility discharges treated effluent into the Strait of Georgia. The facility's average flow is 3.87 million gallons per day (MGD).
Treatment Processes
The 2012 NPDES permit for the facility lists treatment processes as four parallel oil/water separators, two induced gas floatation units, an equalization tank, a complete mix activated sludge unit, a secondary clarifier, and two clarification ponds. Process wastewater is discharged into the receiving water via Outfall 001. Outfalls 002 through 007 discharge stormwater.
Effluent Data 
Exhibit A-1 summarizes the last three years of effluent data for the treated wastewater for the pollutants of concern for which data are available. 
Exhibit A-1. Summary of Effluent Data (2018 to 2020): BP Cherry Point Refinery
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Max

Antimony
                                                                              3
                                                                              0
                                                                           0.94
                                                                            1.1
                                                                            0.3
Cyanide
                                                                              3
                                                                              1
                                                                             12
                                                                             20
                                                                              5
Nickel
                                                                              3
                                                                              0
                                                                           68.4
                                                                            105
                                                                            0.1
Phenol
                                                                              6
                                                                              4
                                                                           35.5
                                                                            180
                                                                              2
Selenium
                                                                              3
                                                                              0
                                                                            100
                                                                            103
                                                                              1
Thallium
                                                                              3
                                                                              0
                                                                           0.70
                                                                            1.1
                                                                           0.09
Zinc
                                                                              3
                                                                              0
                                                                             48
                                                                             81
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The Strait of Georgia has been categorized by Ecology as an "Extraordinary" marine receiving water for aquatic life uses and is designated for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. The Strait is also part of the Cherry Point Aquatic Reserve. The BP Cherry Point facility's NPDES permit contains requirements pursuant to the Cherry Point Reserve Plan. Further, the Strait of Georgia is on the 303(d) list as Category 5 (impaired) for benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, and chrysene concentrations in fish tissue. 
Exhibit A-2 summarizes the available ambient receiving water concentrations based on data from 1999 and 2005.
Exhibit A-2. Ambient Receiving Water Concentrations: Strait of Georgia 
Parameter
Geometric Mean Concentration (Dissolved; ug/L)
Zinc
                                                                          3.900
Source: Reported in 2012 permit fact sheet for BP Cherry Point NPDES permit (Appendix I) from Ecology's reasonable potential analysis. No monitoring data for relevant parameters were available in Ecology's Environmental Information Management database for 2018 - 2020.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. In this case, EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on effluent concentrations and available ambient data summarized above and dilution factors from the 2012 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the revised HHC. Based on effluent concentrations and available ambient data summarized above and dilution factors from the 2012 permit fact sheet, there is no reasonable potential to exceed revised HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario for this facility. 
.	Chambers Creek Regional Wastewater Treatment Facility
The Chambers Creek Regional Wastewater Treatment Facility (WWTF; NPDES permit WA0039624) is operating under a permit that was issued in 2009. The associated permit fact sheet indicates that the facility provides wastewater treatment to 65,000 households and 2,000 businesses in DuPont, Lakewood, Tacoma, University Place, Steilacoom, and other unincorporated areas. The facility also treats wastewater from five industrial users, including the Boeing Corporation Skin and Spar fabrication facility, the Land Recovery Incorporated Hidden Valley Landfill, James Hardie Building Products, and Fredrickson Power. According to the permit fact sheet, the facility discharges 14 to 20 MGD (dry weather flow and maximum monthly flow, respectively) to Puget Sound Gordon Point Area. 
More recently available information indicates that the facility underwent an expansion around 2016 to increase the total capacity from 28.7 MGD to 43 MGD, improve its treatment processes, and better meet its energy needs. At that time, the facility reported serving a population of approximately 250,000 people generating an average of 19 MGD.
Treatment Processes
The 2008 permit fact sheet indicates that the current treatment consists of screening equipment and primary sedimentation; secondary treatment includes bioselectors, secondary clarifiers and ultraviolet disinfection. All effluent passes through the discharge Outfall 001.
Effluent Data 
No recent effluent monitoring data for the WWTF were available for any of the pollutants for which HHC are being proposed. 
Receiving Water
The facility discharges to Puget Sound Gordon Point Area, which is designated for aquatic life uses as "Extraordinary" (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. 
Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. The addendum to the fact sheet for the facility's permit indicates that there were detectable levels of dieldrin and heptachlor in the effluent but that Ecology found no reasonable potential to exceed criteria for these parameters. The necessary data to confirm the reasonable potential analysis under the baseline scenario were not available. 
Policy Scenario
EPA did not have the necessary data to perform the reasonable potential analysis under the policy scenario. Thus, it could not determine reasonable potential or calculate permit limits and costs for this facility.
.	Cosmo Specialty Fibers
Cosmo Specialty Fibers (NPDES permit WA0000809) operates a paper mill that produces dissolving pulp of the acetate, viscose, and ether grades with a permitted capacity of 550 tons per day. The facility's current permit was issued in 2015. Average flow is approximately 16.91 MGD for Outfall 001 and 6.9 MGD for Outfall 002, with the facility discharging to Grays Harbor and the Chehalis River, respectively.
Treatment Processes
Primary treatment consists of an ash clarifier, a disco strainer, and a Brinkley screen. Secondary treatment consists of four aeration lagoons, two clarifiers, and disinfection. Wastewater is routed to a system of storage ponds and then discharged through Outfall 001 to Grays Harbor. Stormwater, truck wash overflow, and filter plant backwash are routed to a "sweet sewer" settling basin and discharged through Outfall 002 to the Chehalis River. 
Effluent Data 
Exhibit A-3 summarizes 2018 to 2020 effluent monitoring data for the facility discharge monitoring reports for Outfall 001 and for Outfall 002. 
Exhibit A-3. Summary of Effluent Data (2018 to 2020): Cosmo Specialty Fibers
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Maximum

                                  Outfall 001
Acenaphthene
                                                                              1
                                                                              0
                                                                           0.19
                                                                           0.19
                                                                            0.2
Aldrin
                                                                              1
                                                                              0
                                                                          0.011
                                                                          0.011
                                                                          0.025
Antimony
                                                                              1
                                                                              0
                                                                          0.716
                                                                          0.716
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                              1
                                                                              0
                                                                           0.45
                                                                           0.45
                                                                            0.1
Chloroform
                                                                             29
                                                                              0
                                                                           20.0
                                                                            110
                                                                              1
Cyanide
                                                                              1
                                                                              0
                                                                         0.0030
                                                                         0.0030
                                                                              5
Dichlorobromomethane
                                                                              1
                                                                              0
                                                                            1.9
                                                                            1.9
                                                                              1
2,4-Dichlorophenol
                                                                              1
                                                                              0
                                                                           0.16
                                                                           0.16
                                                                            0.5
2,3,7,8-TCDD (Dioxin)[d]
                                                                             14
                                                                             13
                                                                     0.00000053
                                                                      0.0000074
                                                                      0.0000013
Bis(2-Ethylhexyl) Phthalate
                                                                              1
                                                                              0
                                                                           0.45
                                                                           0.45
                                                                            0.1
Fluoranthene
                                                                              1
                                                                              0
                                                                           0.12
                                                                           0.12
                                                                            0.3
Fluorene
                                                                              1
                                                                              0
                                                                           0.26
                                                                           0.26
                                                                            0.3
Methylene Chloride
                                                                              1
                                                                              0
                                                                           0.14
                                                                           0.14
                                                                              5
Nickel
                                                                              1
                                                                              0
                                                                           3.31
                                                                           3.31
                                                                            0.1
Pentachlorophenol (PCP)
                                                                             29
                                                                             28
                                                                          0.024
                                                                           0.67
                                                                            0.4
Phenol
                                                                              2
                                                                              0
                                                                           0.67
                                                                            1.3
                                                                              2
Selenium
                                                                              1
                                                                              0
                                                                            0.2
                                                                            0.2
                                                                              1
Thallium
                                                                              1
                                                                              0
                                                                           0.05
                                                                           0.05
                                                                           0.09
Toluene
                                                                              1
                                                                              0
                                                                           0.08
                                                                           0.08
                                                                              1
Zinc
                                                                              1
                                                                              0
                                                                            423
                                                                            423
                                                                            0.5
                                  Outfall 002
Antimony
                                                                              1
                                                                              0
                                                                          0.048
                                                                          0.048
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                              1
                                                                              0
                                                                           0.15
                                                                           0.15
                                                                            0.1
Chloroform
                                                                              1
                                                                              0
                                                                            5.4
                                                                            5.4
                                                                              1
Cyanide
                                                                              1
                                                                              0
                                                                         0.0010
                                                                         0.0010
                                                                              5
Dichlorobromomethane
                                                                              1
                                                                              0
                                                                            1.2
                                                                            1.2
                                                                              1
Diethyl Phthalate
                                                                              1
                                                                              0
                                                                          0.024
                                                                          0.024
                                                                            1.9
Bis(2-Ethylhexyl) Phthalate
                                                                              1
                                                                              0
                                                                           0.15
                                                                           0.15
                                                                            0.1
Nickel
                                                                              1
                                                                              0
                                                                           0.87
                                                                           0.87
                                                                            0.1
Polychlorinated Biphenyls (PCBs)
                                                                              7
                                                                              6
                                                                          0.013
                                                                          0.093
                                                                           0.25
Thallium
                                                                              1
                                                                              0
                                                                          0.017
                                                                          0.017
                                                                           0.09
Toluene
                                                                              1
                                                                              0
                                                                          0.070
                                                                          0.070
                                                                              1
Zinc
                                                                              1
                                                                              0
                                                                            5.9
                                                                            5.9
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects (or the applicable criterion if it is below the DL). 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
[d] Includes samples taken from bleach plant effluent. All samples from Outfall 001 were reported as non-quantifiable or below the 
DL.
	
Receiving Water
Outfall 001 discharges to Grays Harbor, which is designated as "Good" for aquatic life uses; for primary contact recreation and is designated for harvest uses (excluding shellfish); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Outfall 002 discharges to the Chehalis River, which is designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values). Ambient data for these waters are not available.
Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. In this case, EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). 
Exhibit A-4 summarizes the RPA under the baseline scenario. Based on effluent concentrations summarized above, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed the HHC for several parameters under the baseline.
Exhibit A-4. Human Health Reasonable Potential Analysis for Cosmo Specialty Fibers  -  Baseline Scenario (ug/L)[a]
Parameter
Effluent Conc. 
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Outfall 001
Aldrin
                                                         0.011 x 2.490 = 0.0274
                                                                             NR
                                                                        0.00037
                                                                      0.0000058
Outfall 002
Bis(2-Ethylhexyl) Phthalate
                                                         0.15 x 2.490 = 0.3735 
                                                                             NR
                                                                           0.37
                                                                           0.23
Dichlorobromomethane
                                                           1.2 x 2.490 = 2.988 
                                                                               
                                                                            3.0
                                                                           0.77
Polychlorinated Biphenyls (PCBs)
                                                       0.093 x 0.8050 = 0.7487 
                                                                             NR
                                                                          0.075
                                                                        0.00017
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 74 for Outfall 001 and 1 (no dilution) for Outfall 002.

In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. Exhibit A-5 summarizes the calculated permit limits under the baseline scenario.
Exhibit A-5. Human Health Based Effluent Limitations for Cosmo Specialty Fibers  -  Baseline Scenario (ug/L) 
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc
Quantification Limit
Outfall 001
Aldrin
                                                                        0.00043
                                                                        0.00086
                                                                          0.011
                                                                           0.05
Outfall 002
Bis(2-Ethylhexyl) Phthalate
                                                                           0.23
                                                                           0.46
                                                                           0.15
                                                                            0.5
Dichlorobromomethane
                                                                           0.77
                                                                            1.5
                                                                            1.2
                                                                              2
Polychlorinated Biphenyls (PCBs)
                                                                        0.00017
                                                                        0.00034
                                                                          0.093
                                                                            0.5
Notes:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Aldrin (Outfall 001)
Under the baseline scenario, the discharger would have to meet an AML of 0.00043 ug/L and an MDL of 0.00086 ug/L. The maximum effluent concentration is 0.011 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of aldrin (Outfall 001) in its effluent to ensure that permit limits are consistently met. 
Bis(2-ethylhexyl) Phthalate (Outfall 002)
Under the baseline scenario, the discharger would have to meet an AML of 0.23 ug/L and an MDL of 0.46 ug/L. However, the maximum effluent concentration is 0.15 ug/L. As such, this facility would not need to reduce the concentration of bis(2-ethylhexyl) phthalate (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
Dichlorobromomethane (Outfall 002)
Under the baseline scenario, the discharger would have to meet an AML of 0.77 ug/L and an MDL of 1.5 ug/L. The maximum effluent concentration is 1.2 ug/L. However, the QL for this parameter is 2 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance this facility would not need to reduce the concentration of dichlorobromomethane (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
Polychlorinated Biphenyls (PCBs) (Outfall 002)
Under the baseline scenario, the discharger would have to meet an AML of 0.00017 ug/L and an MDL of 0.00034 ug/L. The maximum effluent concentration is 0.093 ug/L. However, the QL for this parameter is 0.5 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of PCBs (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
Policy Scenario
Exhibit A-6 summarizes the RPA under the policy scenario. Based on effluent concentrations and available ambient data summarized above, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed HHC for several parameters. 
Exhibit A-6. Human Health Reasonable Potential Analysis for Cosmo Specialty Fibers  -  Policy Scenario (ug/L)[a]
Parameter
Effluent Conc. 
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Revised Human Health Criterion
                                  Outfall 001
Aldrin
                                                                          0.011
                                                                             NR
                                                                        0.00037
                                                                    0.000000041
                                  Outfall 002
Bis(2-Ethylhexyl) Phthalate
                                                                           0.15
                                                                             NR
                                                                           0.37
                                                                          0.045
Dichlorobromomethane
                                                                            1.2
                                                                             NR
                                                                            3.0
                                                                           0.73
Polychlorinated Biphenyls (PCBs)
                                                                          0.093
                                                                             NR
                                                                          0.075
                                                                      0.0000070
Notes: NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or 95[th] percentile concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 74 for Outfall 001 and 1 (no dilution) for Outfall 002.

Exhibit A-7 summarizes the calculated permit limits under the policy scenario. 
Exhibit A-7. Human Health Based Effluent Limitations for Cosmo Specialty Fibers  -  Policy Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc./ Baseline AML
Quantification Limit
Outfall 001
Aldrin
                                                                      0.0000030
                                                                      0.0000057
                                                                        0.00043
                                                                           0.05
Outfall 002
Bis(2-Ethylhexyl) Phthalate
                                                                          0.045
                                                                          0.085
                                                                           0.23
                                                                            0.5
Dichlorobromomethane
                                                                           0.73
                                                                            1.4
                                                                           0.77
                                                                              2
Polychlorinated Biphenyls (PCBs)
                                                                      0.0000070
                                                                       0.000013
                                                                        0.00017
                                                                            0.5
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Aldrin (Outfall 001)
Under the policy scenario, the discharger would have to meet an AML of 0.0000030 ug/L and an MDL of 0.0000057 ug/L. The baseline AML is 0.0000043 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of aldrin (Outfall 001) in its effluent to ensure that permit limits are consistently met.
Bis(2-Ethylhexyl) Phthalate (Outfall 002)
Under the policy scenario, the discharger would have to meet an AML of 0.045 ug/L and an MDL of 0.085 ug/L. The maximum effluent concentration is 0.15 ug/L and the baseline AML is 0.23 ug/L. However, the QL for this parameter is 0.5 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of bis(2-ethylhexyl) phthalate (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
Dichlorobromomethane (Outfall 002)
Under the policy scenario, the discharger would have to meet an AML of 0.73 ug/L and an MDL of 1.4 ug/L. The maximum effluent concentration is 1.2 ug/L and the baseline AML is 0.77 ug/L. However, the QL for this parameter is 2 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of dichlorobromomethane (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
Polychlorinated Biphenyls (PCBs) (Outfall 002)
Under the policy scenario, the discharger would have to meet an AML of 0.0000070 ug/L and an MDL of 0.000013 ug/L. The maximum effluent concentration is 0.093 ug/L and the baseline AML is 0.00017 ug/L. However, the QL for this parameter is 0.5 ug/L, which is higher than the policy scenario AML and the baseline AML. As such, because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce its concentration of PCBs (Outfall 002) in its effluent to ensure that permit limits are consistently met. 
.	Emerald Kalama Chemical LLC
Emerald Kalama Chemical, LLC (NPDES permit number WA0000281), located in Kalama, Washington, is an organic chemical manufacturer whose varied products find use in in food preservatives, fragrances, perfumes, adhesives, resins, coatings, dyes, detergents, sunscreens, and solvents. The average process wastewater flow for this facility is 0.334 MGD while the maximum is 0.503 MGD.
Treatment Processes
The fact sheet for the 2021 NPDES permit for the facility lists primary and secondary treatment processes consisting of primary settling, anaerobic digestion, sequencing batch reactors, disinfection, summer season cooling, and re-aeration. 
Effluent Data 
Exhibit A-8 summarizes 2017 to 2020 effluent monitoring data for the facility based on data provided in the 2021 permit fact sheet. 
Exhibit A-8. Summary of Effluent Data (2017 to 2020): Emerald Kalama Chemical
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[b]


Mean
Maximum

Antimony
                                                                              4
                                                                            1.0
                                                                            3.6
                                                                            0.3
Benzo(a) Anthracene
                                                                             12
                                                                           0.15
                                                                           0.26
                                                                            0.3
Benzo(a) Pyrene
                                                                             12
                                                                           0.13
                                                                           0.38
                                                                            0.5
Benzo(k) Fluoranthene
                                                                             12
                                                                           0.14
                                                                           0.33
                                                                            0.8
Chlorobenzene
                                                                             12
                                                                           0.53
                                                                            1.0
                                                                              1
Chloroform
                                                                             12
                                                                           0.53
                                                                            1.0
                                                                              1
Chrysene
                                                                             12
                                                                           0.19
                                                                           0.41
                                                                            0.3
1,2-Dichlorobenzene
                                                                             12
                                                                           0.23
                                                                            1.0
                                                                            1.9
1,2-Dichloroethane
                                                                             12
                                                                           0.54
                                                                            1.0
                                                                              1
2,4-Dichlorophenol
                                                                             12
                                                                           0.54
                                                                           0.80
                                                                            0.5
Diethyl Phthalate
                                                                             12
                                                                           0.17
                                                                           0.34
                                                                            1.9
Dimethyl Phthalate
                                                                             12
                                                                           0.23
                                                                           0.73
                                                                            1.6
Di-n-Butyl Phthalate
                                                                             12
                                                                          0.530
                                                                           1.34
                                                                            0.5
2,4-Dinitrophenol
                                                                             12
                                                                           0.64
                                                                            1.1
                                                                              1
Ethylbenzene
                                                                             19
                                                                           0.44
                                                                            1.0
                                                                              1
Fluoranthene
                                                                             12
                                                                           0.19
                                                                           0.46
                                                                            0.3
Fluorene
                                                                             19
                                                                           0.13
                                                                           0.26
                                                                            0.3
Hexachlorobenzene
                                                                             12
                                                                           0.15
                                                                           0.28
                                                                            0.3
Hexachlorobutadiene
                                                                             12
                                                                           0.31
                                                                            1.0
                                                                            0.5
Hexachloroethane
                                                                             12
                                                                           0.29
                                                                            1.0
                                                                            0.5
Methylene Chloride
                                                                             12
                                                                           1.05
                                                                           1.63
                                                                              5
Chlorobenzene
                                                                             12
                                                                           0.53
                                                                            1.0
                                                                              1
Nickel
                                                                             43
                                                                           16.4
                                                                           27.8
                                                                            0.1
Nitrobenzene
                                                                             12
                                                                           0.14
                                                                           0.37
                                                                            0.5
Phenol
                                                                             19
                                                                           0.33
                                                                           0.84
                                                                              2
Pyrene
                                                                             12
                                                                           0.18
                                                                           0.48
                                                                            0.3
Tetrachloroethylene
                                                                             12
                                                                           0.58
                                                                            1.0
                                                                              1
Toluene
                                                                             19
                                                                           0.50
                                                                            1.0
                                                                              1
1,2,4-Trichlorobenzene
                                                                             12
                                                                           0.59
                                                                            1.0
                                                                            0.3
1,1,1-Trichloroethane
                                                                             12
                                                                           0.52
                                                                            1.0
                                                                              1
1,1,2-Trichloroethane
                                                                             12
                                                                           0.58
                                                                            1.0
                                                                              1
Trichloroethylene
                                                                             12
                                                                           0.54
                                                                            1.0
                                                                              1
Vinyl Chloride
                                                                             12
                                                                           0.56
                                                                            1.0
                                                                              1
Zinc
                                                                             43
                                                                             14
                                                                             68
                                                                            0.5
Source: Based on effluent data as summarized in 2021 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
Emerald Kalama discharges treated process wastewater to the Columbia River at River Mile 74, which is designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values).
Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. In this case, EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario).
Exhibit A-9 summarizes the RPA under the baseline scenario. Based on available effluent concentrations, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed the HHC for one parameter.
Exhibit A-9. Human Health Reasonable Potential Analysis for Emerald Kalama Chemical  -  Baseline Scenario (ug/L)[a] 
Parameter
Effluent Conc. 
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Hexachlorobenzene
                                                                           0.15
                                                                             NR
                                                                        0.00020
                                                                       0.000051
Notes: 
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 913.

In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. Exhibit A-10 summarizes the calculated permit limits under the baseline scenario.
Exhibit A-10. Human Health Based Effluent Limitations for Emerald Kalama Chemical  -  Baseline Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc.
Quantification Limit
Hexachlorobenzene
                                                                          0.047
                                                                          0.093
                                                                           0.28
                                                                            0.6
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Hexachlorobenzene (Outfall 001)
Under the baseline scenario, the discharger would have to meet an AML of 0.047 ug/L and an MDL of 0.093 ug/L. The maximum effluent concentration is 0.28 ug/L. However, the QL for this parameter is 0.6 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of hexachlorobenzene in its effluent to ensure that permit limits are consistently met.
Policy Scenario
Exhibit A-11 summarizes the RPA under the policy scenario. Based on available effluent concentrations and ambient data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors for the facility from the 2021 permit fact sheet, there is reasonable potential to exceed HHC for three parameters.
Exhibit A-11. Human Health Reasonable Potential Analysis for Emerald Kalama Chemical  -  Policy Scenario (ug/L)[a] 
Parameter
Effluent Conc. 
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Revised Human Health Criterion
Benzo(a) Pyrene
                                                                           0.13
                                                                             NR
                                                                        0.00014
                                                                       0.000016
Hexachlorobenzene
                                                                           0.15
                                                                             NR
                                                                        0.00016
                                                                       0.000005
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 913.

Exhibit A-12 summarizes the calculated permit limits under the policy scenario. 
Exhibit A-12. Human Health Based Effluent Limitations for Emerald Kalama Chemical  -  Policy Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc./ Baseline AML
Quantification Limit
Benzo(a) Pyrene
                                                                          0.015
                                                                          0.027
                                                                           0.38
                                                                              1
Hexachlorobenzene
                                                                         0.0046
                                                                         0.0086
                                                                          0.047
                                                                            0.6
Notes:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Benzo(a) Pyrene (Outfall 001)
Under the policy scenario, the discharger would have to meet an AML of 0.015 ug/L and an MDL of 0.027 ug/L. The maximum effluent concentration is 0.38 ug/L. However, the QL for this parameter is 1 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of benzo(a) pyrene (Outfall 001) in its effluent to ensure that permit limits are consistently met. 
Hexachlorobenzene (Outfall 001)
Under the policy scenario, the discharger would have to meet an AML of 0.0046 ug/L and an MDL of 0.0086 ug/L. The baseline AML is 0.047 ug/L. However, the QL for this parameter is 0.6 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of hexachlorobenzene (Outfall 001) in its effluent to ensure that permit limits are consistently met. 
.	Intalco Aluminum Corporation
Intalco Aluminum Corporation (NPDES permit WA0002950) operates multiple wastewater treatment plants that combine and discharge to the Strait of Georgia. Intalco Corp. is classified as a major facility and is currently operating at approximately two-thirds capacity. The facility operates 24 hours a day, seven days per week. The facility produces primary aluminum metal from alumina ore using the Hall-Heroult reduction process. Wastewater associated with the industrial process includes contact and non-contact cooling water for metal casting and anode production, and wastewater generated from wet air pollution control systems. Additionally, the facility generates domestic wastewater, wastewater from steam cleaning operating systems, and some stormwater. Annual average flow from Outfall 001 is 1.61 MGD.
Treatment Processes
The 2014 permit fact sheet for the facility states that the facility treats wastewater from the casting process and from the wet scrubbers using primary treatment consisting of an 800-gallon receiving tank, a polymer addition system, two clarifiers, two filter feed pumps, a mud recycle tank, a vacuum pump, a vacuum filter drum, a recycle tank, a caustic addition system, and three recycle pumps. Secondary treatment includes a one-million-gallon equalization tank and two treatment trains running in parallel consisting of reaction tanks and flocculation tanks that feed into a clarifier. Anode cooling water, which is contaminated with coke and pitch containing benzo(a)pyrene, is treated using a baffled settling chamber. Domestic sanitary wastewater treatment consists of inlet vault, lagoon system, outlet weir box, and ultraviolet disinfection. 
After processing, wastewater passes through Outfall 001 into the receiving water.
Effluent Data 
Exhibit A-13 summarizes 2018 to 2020 effluent monitoring data for the facility from the discharge monitoring reports.
Exhibit A-13. Summary of Effluent Data (2018 to 2020): Intalco Aluminum 
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Maximum

Antimony
                                                                             15
                                                                              8
                                                                            1.0
                                                                            4.2
                                                                            0.3
Benzo(a) Anthracene
                                                                              3
                                                                              2
                                                                           0.12
                                                                           0.30
                                                                            0.3
Benzo(a) Pyrene
                                                                             21
                                                                              9
                                                                           0.35
                                                                            2.0
                                                                            0.5
Benzo(b) Fluoranthene
                                                                              3
                                                                              2
                                                                           0.12
                                                                           0.29
                                                                            0.8
Bis(2-Ethylhexyl) Phthalate
                                                                              3
                                                                              2
                                                                           0.13
                                                                           0.30
                                                                            0.1
Chrysene
                                                                              3
                                                                              2
                                                                           0.11
                                                                           0.27
                                                                            0.3
Cyanide
                                                                            482
                                                                            228
                                                                            5.4
                                                                             27
                                                                              5
Fluoranthene
                                                                              3
                                                                              2
                                                                           0.11
                                                                           0.28
                                                                            0.3
Nickel
                                                                             15
                                                                              0
                                                                           25.7
                                                                            109
                                                                            0.1
Phenol
                                                                              6
                                                                              5
                                                                           22.0
                                                                            130
                                                                              2
Selenium
                                                                              3
                                                                              1
                                                                            8.1
                                                                             19
                                                                              1
Zinc
                                                                              3
                                                                              0
                                                                             11
                                                                             20
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington as reported in Form 2A.
	
Receiving Water
The Strait of Georgia has been categorized by Ecology as an "Extraordinary" marine receiving water for aquatic life uses (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat.
Exhibit A-14 summarizes the available ambient receiving water concentrations based on data from 2018 to 2020. 
Exhibit A-14. Ambient Receiving Water Concentrations: Strait of Georgia (ug/L)
Parameter
Geometric Mean 
90[th] Percentile or Max
Chrysene
                                                                             NR
                                                                           0.47
Indeno(1,2,3-cd) Pyrene
                                                                             NR
                                                                          0.012
Selenium
                                                                             NR
                                                                           0.57
Zinc (dissolved)
                                                                           0.57
                                                                             NR
Source: 2014 permit fact sheet; 90[th] percentile values are from Appendix E (reasonable potential analysis); average values based on Table 2 (from 10 samples collected upstream from Intalco discharges in July and September 1999).
Note:
NR = not reported

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario).
Exhibit A-15 summarizes the RPA under the baseline scenario. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed the baseline benzo(a) pyrene HHC.
Exhibit A-15. Human Health Reasonable Potential Analysis for Intalco Aluminum  -  Baseline Scenario (ug/L)[a]
Parameter
Effluent Conc. 
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Benzo(a) Pyrene
                                                                           0.35
                                                                             NR
                                                                         0.0046
                                                                         0.0021
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 77 from the permit fact sheet.

In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. Exhibit A-16 summarizes the calculated permit limits under the baseline scenario.
Exhibit A-16. Human Health Based Effluent Limitations for Intalco Aluminum  -  Baseline Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc.
Quantification Limit 
Benzo(a) Pyrene
                                                                           0.16
                                                                           0.22
                                                                              2
                                                                              1
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Benzo(a) Pyrene
Under the baseline scenario, the discharger would have to meet an AML of 0.16 ug/L and an MDL of 0.22 ug/L. The maximum effluent concentration is 2 ug/L. As such, this facility may need to reduce its concentration of benzo(a) pyrene in its effluent to ensure that permit limits are consistently met under the baseline based on the most recent data available.
Policy Scenario
Exhibit A-17 summarizes the RP analysis under the policy scenario. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed HHC for several parameters. 
Exhibit A-17. Human Health Reasonable Potential Analysis for Intalco Aluminum  -  Policy Scenario (ug/L)[a]
Parameter
Effluent Conc.
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Benzo(a) Anthracene
                                                          0.30 x 1.205 = 0.3615
                                                                             NR
                                                                         0.0047
                                                                        0.00016
Benzo(a) Pyrene
                                                                         0.3527
                                                                             NR
                                                                         0.0046
                                                                       0.000016
Benzo(b) Fluoranthene
                                                         0.29 x 1.205 = 0.3494 
                                                                             NR
                                                                         0.0045
                                                                        0.00016
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using dilution factors of 105 (non-carcinogens) or 77 (carcinogens).

Exhibit A-18 summarizes the calculated permit limits under the policy scenario.
Exhibit A-18. Human Health Based Effluent Limitations for Intalco Aluminum  -  Policy Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc./ Baseline AML
Quantification Limit
Benzo(a) Anthracene
                                                                          0.012
                                                                          0.023
                                                                           0.30
                                                                            0.6
Benzo(a) Pyrene
                                                                         0.0012
                                                                         0.0017
                                                                           0.16
                                                                              1
Benzo(b) Fluoranthene
                                                                          0.012
                                                                          0.023
                                                                           0.29
                                                                            1.6
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Benzo(a) Anthracene
Under the policy scenario, the discharger would have to meet an AML of 0.012 ug/L and an MDL of 0.023 ug/L. The maximum effluent concentration is 0.3 ug/L. However, the QL for this parameter is 0.6 ug/L, which is higher than the AML and the highest detected effluent value. As such, this facility would not need to reduce the concentration of benzo(a) anthracene in its effluent to ensure that permit limits are consistently met. 
Benzo(a) Pyrene
Under the policy scenario, the discharger would have to meet an AML of 0.0012 ug/L and an MDL of 0.0017 ug/L. The maximum effluent concentration is 2 ug/L. However, the baseline AML is 0.16 and the QL for this parameter is 1 ug/L, which is higher than the policy scenario AML and the baseline AML. As such, this facility would not need to further reduce the concentration of Benzo(a) Pyrene (i.e., beyond baseline reductions) to ensure that permit limits are consistently met. 
Benzo(b) Fluoranthene 
Under the policy scenario, the discharger would have to meet an AML of 0.012 ug/L and an MDL of 0.023 ug/L. The maximum effluent concentration is 0.29 ug/L. However, the QL for this parameter is 1.6 ug/L, which is higher than the AML and the highest detected effluent value. As such, this facility would not need to reduce the concentration of benzo(b) fluoranthene in its effluent to ensure that permit limits are consistently met.
.	King County South WWTP and CSO System
The King County Department of Natural Resources and Parks (Wastewater Treatment Division) operates the King County South Wastewater Treatment Plant (WWTP; NPDES permit WA0029581), which serves 25 jurisdictions and utility districts, including Seattle, across 152 square miles. Most of the flow to the treatment facility is from separated sanitary systems, with approximately 4% coming from a combined system in Seattle. Average WWTP flow is 106 MGD.
Treatment Processes
The 2015 permit fact sheet reports that primary treatment consists of screening and settling followed by primary clarification. Secondary treatment is an activated sludge process and includes aeration and secondary clarification. After disinfection (using sodium hypochlorite), effluent is discharged to Puget Sound.
Effluent Data 
Available discharge monitoring reports for this facility for the period 2018 to 2020 do not include data for parameters of interest. Exhibit A-19 summarizes available effluent data provided in the fact sheet for the 2015 permit.
Exhibit A-19. Summary of Effluent Data (2009 to 2014): King County South
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[b]


Mean
Maximum

Antimony
                                                                             29
                                                                           0.42
                                                                           0.63
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                             22
                                                                           1.37
                                                                           3.23
                                                                            0.1
Chloroform
                                                                             23
                                                                          0.500
                                                                           1.39
                                                                              1
Cyanide
                                                                             28
                                                                           2.50
                                                                           12.1
                                                                              5
1,4-Dichlorobenzene
                                                                             23
                                                                          0.500
                                                                           4.26
                                                                            4.4
2,4-Dichlorophenol
                                                                             22
                                                                          0.280
                                                                           1.66
                                                                            0.5
Diethyl Phthalate
                                                                             22
                                                                           0.24
                                                                           0.50
                                                                            1.9
Nickel
                                                                             29
                                                                           2.32
                                                                           3.15
                                                                            0.1
Tetrachloroethylene
                                                                             23
                                                                          0.500
                                                                           1.22
                                                                              1
Zinc
                                                                             29
                                                                          31.20
                                                                          43.72
                                                                            0.5
Source: Based on wastewater effluent data provided in Table 6 of the 2015 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
 
Receiving Water
The King County South facility discharges from Outfall 001 to Puget Sound, which is designated for aquatic life uses as "Extraordinary" (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Outfall 002 discharges for maintenance very infrequently to the Green River, which is designated for salmonid spawning, rearing, and migration; primary contact recreation; all water supply uses; and miscellaneous uses, including wildlife habitat, harvesting, commerce and navigation, boating, and aesthetics. Exhibit A-20 summarizes the available ambient receiving water concentrations based on data from King County Receiving Water Characterization Study  -  Final Report, June 2013, as summarized in the 2015 permit fact sheet. 
Exhibit A-20. Ambient Receiving Water Concentrations: Puget Sound
Parameter
Water Column Concentration (90[th] Percentile; ug/L)
Antimony
                                     0.172
Nickel
                                     0.428
Zinc
                                     0.605
Source: Based on data provided in Table 4 the 2015 permit fact sheet.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario).
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2015 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2015 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
.	King County West Point WWTP and CSO System
King County provides wholesale wastewater treatment services to 17 cities, 16 local sewer utilities, and one Indian tribe. The King County West Point WWTP and Combined Sewer Overflow (CSO) System (NPDES permit WA0029181) provides coverage for King County's West Point WWTP, four CSO treatment facilities (Alki, Carkeek, Elliott West, and Henderson/MLK), and 38 CSO outfalls. The WWTP discharges to Puget Sound, and the CSO treatment plants discharge to the Puget Sound, Elliot Bay, and Duwamish Waterway. Average annual WWTP flow is 95 MGD.
Treatment Processes
The 2014 permit fact sheet for the facility indicates that the West Point WWTP treats industrial, commercial, and domestic wastewater and CSO stormwater from the greater Seattle area using a high rate oxygenated activated sludge biological treatment process with chlorine disinfection before discharging the treated effluent to Central Puget Sound. The Alki, Carkeek, Denny/Elliott West, and Henderson/MLK CSO treatment plants have primary treatment with disinfection. The West Point WWTP permit includes effluent limits for CBOD, TSS, fecal coliform, pH, and total residual chlorine.
Effluent Data 
Available discharge monitoring reports for this facility for the period 2018 to 2020 do not include data for parameters of interest. Exhibit A-21 summarizes available effluent data provided in the fact sheet for the 2014 permit.
Exhibit A-21. Summary of Effluent Data (2009 to 2013): King County West Point
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[b]


Mean
Maximum

Antimony
                                                                             15
                                                                          0.440
                                                                          0.465
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                              9
                                                                              
                                                                          7.332
                                                                            0.1
Chloroform
                                                                              9
                                                                              
                                                                           5.68
                                                                              1
Cyanide
                                                                             15
                                                                              
                                                                           0.57
                                                                              5
1,2-Dichlorobenzene
                                                                              9
                                                                              
                                                                           10.2
                                                                            1.9
2,4-Dichlorophenol
                                                                              9
                                                                              
                                                                           0.96
                                                                            0.5
Diethyl Phthalate
                                                                              9
                                                                              
                                                                           0.85
                                                                            1.9
Methylene Chloride
                                                                              9
                                                                              
                                                                          5.300
                                                                              5
Nickel
                                                                             23
                                                                          2.810
                                                                          5.999
                                                                            0.1
Phenol
                                                                              9
                                                                              
                                                                         0.9500
                                                                              2
Pyrene
                                                                              9
                                                                              
                                                                           0.29
                                                                            0.3
Selenium
                                                                             15
                                                                           0.50
                                                                           0.74
                                                                              1
Thallium
                                                                             15
                                                                           0.40
                                                                           0.13
                                                                              0
Toluene
                                                                              9
                                                                              
                                                                            1.1
                                                                              1
Zinc
                                                                             23
                                                                              
                                                                          50.78
                                                                            0.5
Source: Based on data provided in Appendix F (Technical Calculations) of the 2014 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The West Point WWTP discharge is to Central Puget Sound which is designated for aquatic life uses as "Extraordinary" (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Exhibit A-22 summarizes the available ambient receiving water concentrations based on data from 1999 and 2005.
Exhibit A-22. Ambient Receiving Water Concentrations: Puget Sound 
Parameter
Geometric Mean Concentration (Dissolved; ug/L)
Maximum Concentration 
(Dissolved; ug/L)
Nickel
                                                                          0.408
                                                                          0.437
Zinc 
                                                                          0.438
                                                                          0.685
Source: Based on data reported in 2014 permit fact sheet. 

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2014 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2014 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
.	Pasco Wastewater Treatment Works
The Pasco Wastewater Treatment Works (NPDES permit WA0044962) provides wastewater treatment to 72,900 people in the City of Pasco and two permitted industrial users (Easterday Farms Produce Company and A1 Quality Services, a truck washing facility). The Wastewater Treatment Works discharges an annual average flow of 4.49 MGD to the Lake Wallula reach of the Columbia River.
Treatment Processes
The 2014 permit limits evaluation indicates that treatment processes include headworks with traveling screens, grit removal, primary clarifiers, a trickling filter, an intermediate clarifier, aeration basins, secondary clarifiers, ultraviolet disinfection, anaerobic digesters, sludge digestion, a drum thickener, and a sludge drying bed. 
Effluent Data 
Exhibit A-23 summarizes 2018 to 2020 effluent monitoring data for the facility from the discharge monitoring reports.
Exhibit A-23. Summary of Effluent Data (2018 to 2020): Pasco Wastewater Treatment Works
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Maximum

Cyanide
                                                                             24
                                                                             10
                                                                            7.5
                                                                             10
                                                                              5
Phenol
                                                                             24
                                                                              5
                                                                           88.5
                                                                            320
                                                                              2
Zinc
                                                                              3
                                                                              0
                                                                           69.3
                                                                           71.9
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.

Receiving Water
The facility discharges to the Lake Wallula reach of the Columbia River which is designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values). According to the 2010 permit, monitoring station 36A070 -- located on the Columbia River near Vernitaؙ -- is the nearest monitoring station with available water column data. Exhibit A-24 summarizes the available ambient receiving water concentrations for the station based on data from Ecology's Environmental Information Management System between 2004 and 2014.
Exhibit A-24. Ambient Receiving Water Concentrations: Columbia River 
Pollutant
Water Column Concentration (ug/L)

Maximum
Average
Nickel
                                     0.71
                                     0.62
Zinc
                                      6.2
                                      5.0
Source: Washington State Department of Ecology Environmental Information Management System, 2004 - 2014 data for station 36A070.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2010 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the revised HHC. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2010 permit fact sheet, there is no reasonable potential to exceed revised HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario for this facility. 
.	Puget Sound Naval Shipyard
The Puget Sound Naval Shipyard and Intermediate Maintenance Facility is a tenant command located on the Naval Base Kitsap Bremerton property, which encompasses 354 acres on the north side of Sinclair Inlet in Puget Sound. The shipyard is composed of six dry docks, eight piers, four moorings, and various industrial yards and buildings. The facility has been owned and operated by the Navy since 1891 and is currently operating under a NPDES permit (WA002062) that was issued by EPA in 1994 and has been administratively continued since 1999. EPA is currently developing a new permit for the facility.
Treatment Processes
Wastewater from dry dock operations consists of floor process water, hydrostatic relief water, noncontact cooling water from vessels, building foundation draining, and cooling water. This wastewater is treated with sediment traps and is routed to sanitary sewers, the Bremerton POTWs, or to discharge outfalls depending on the turbidity, and all treated and untreated dry dock wastewater is discharged through outfalls 018A, 018B, 019, 096, PW3, and PW3A.
The NPDES permit also covers wastewater discharges from an on-site steam generation plant. In cases where the pH of reverse osmosis reject water is within a certain range, this reject water is discharged directly via outfall 021; otherwise, it is routed to a WWTP for pH adjustment before being discharged via outfall 021. 
Effluent Data
Available discharge monitoring reports for the facility for the period 2018 to 2020 do not include data for parameters of interest. Exhibit A-25 summarizes available effluent data for the dry dock wastewater discharges provided in the preliminary draft 2021 permit fact sheet.
Exhibit A-25. Summary of Effluent Data (2009 to 2019): Puget Sound Naval Shipyard
Parameter[a]
Number of Observations
Maximum Concentration (ug/L)[b]
DL (ug/L)[c]




Outfall 018
Bromoform
                                                                              2
                                                                            0.4
                                                                              1
Chloroform
                                                                              2
                                                                            2.4
                                                                              1
Dichlorobromomethane
                                                                              2
                                                                            0.2
                                                                              1
Trichloroethylene
                                                                              2
                                                                            0.9
                                                                              1
Outfalls 096/PW3
Trichloroethylene
                                                                              1
                                                                            1.9
                                                                              1
Source: Based on wastewater effluent data provided in the 2021 preliminary draft permit fact sheet (Appendix D). 
Notes:
DL = Detection limit
[a] Additional monitoring data for nickel and zinc were excluded since the facility discharges to a marine water where the aquatic life criteria are more stringent for these parameters.
[b] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
 
Receiving Water
The facility discharges to Sinclair Inlet in Puget Sound, which is designated as impaired for PCBs. This area of Puget Sound is designated as "Excellent" quality for aquatic life uses and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Ambient data for the parameters with effluent data are not available.
Baseline Scenario
EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on effluent concentrations summarized above and dilution factors from the 2021 preliminary draft permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the revised HHC. Based on effluent concentrations summarized above and dilution factors from the 2021 preliminary draft permit fact sheet, there is no reasonable potential to exceed revised HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario for this facility. 
Quincy Industrial Wastewater Treatment Facility
The City of Quincy, Washington, owns an industrial wastewater treatment facility (NPDES permit number WA0021067) that treats process wastewater from a potato and vegetable processor (ConAgra Foods and Quincy Foods, respectively). The facility discharges to a U.S. Bureau of Reclamation wasteway. Ecology has developed a proposed NPDES permit which contains requirements to develop a special study and reapplication to direct the discharge to a new location. The average flow is 1.71 MGD.
Treatment Processes
The fact sheet for the 2019 NPDES permit for the facility lists primary and secondary treatment processes consisting of primary settling, anaerobic digestion, sequencing batch reactors, disinfection, summer season cooling, and re-aeration. 
Effluent Data 
Available discharge monitoring reports for this facility for the period 2018 to 2020 do not include data for parameters of interest. Exhibit A-26 summarizes available effluent data provided in the fact sheet for the 2019 permit.
Exhibit A-26. Summary of Effluent Data (2012 to 2017): Quincy Industrial
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[b]


Mean
Maximum

Nickel
                                                                              4
                                                                            5.2
                                                                            5.6
                                                                            0.1
Zinc
                                                                              4
                                                                             14
                                                                             23
                                                                            0.5
Source: Based on data provided in Table 3 of the 2019 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
Quincy Industrial discharges treated process wastewater to the U.S. Bureau of Reclamation wasteway DW237. The wasteway joins with other wasteways and eventually discharges to Potholes Reservoir. The receiving water is designated for core summer salmonid habitat; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values).
Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the revised HHC. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed revised HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario for this facility. 
Redondo WWTP
The Lakehaven Utility District owns and operates the Redondo WWTP (NPDES permit WA0023451) which serves 37,700 residential and commercial customers. The WWTP discharges an annual average flow of 5.6 MGD to Puget Sound  -  Poverty Bay.
Treatment Processes
The 2018 fact sheet for the permit indicates that the facility employs primary and secondary treatment consisting of screening, grit removal and comminution, primary clarification, biological treatment using plastic media trickling filters, secondary clarification, and chlorine disinfection. In 2015, the ultraviolet disinfection suffered irreparable damage due to flooding in 2015, but design is underway for a new system. Wastewater discharges through Outfall 001.
Effluent Data 
Exhibit A-27 summarizes available effluent monitoring data for the WWTP from 2018 through 2020. 
Exhibit A-27. Summary of Effluent Data (2018 to 2020): Redondo WWTP
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Max

Antimony
                                                                              2
                                                                               
                                                                              
                                                                           0.33
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                             10
                                                                              3
                                                                           2.48
                                                                           9.88
                                                                            0.1
Chloroform
                                                                              2
                                                                               
                                                                              
                                                                            2.9
                                                                              1
Cyanide
                                                                              3
                                                                               
                                                                              
                                                                             10
                                                                              5
Diethyl Phthalate
                                                                              1
                                                                               
                                                                              
                                                                           0.29
                                                                            1.9
Phenol
                                                                              1
                                                                               
                                                                              
                                                                           0.59
                                                                              2
Selenium
                                                                              2
                                                                               
                                                                              
                                                                           0.90
                                                                              1
Toluene
                                                                              3
                                                                               
                                                                              
                                                                            2.1
                                                                              1
Zinc
                                                                              5
                                                                               
                                                                              
                                                                             55
                                                                            0.5
Source: 2018 - 2020 DMR Data (for bis (2-ethylhexyl phthalate) and 2018 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The Redondo WWTP discharges to Poverty Bay in mid-Puget Sound, which is designated for aquatic life uses as "Extraordinary" (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Exhibit A-28 summarizes the available ambient receiving water concentrations based on data from the 2018 permit fact sheet.
Exhibit A-28. Ambient Receiving Water Concentrations: Puget Sound 
Parameter
Geometric Mean Concentration (ug/L)
Antimony
                                     0.18
Nickel
                                     0.51
Zinc
                                     0.71
Source: Reported in 2018 permit fact sheet.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2018 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2018 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
Salmon Creek Wastewater Treatment Plant
The Salmon Creek WWTP (NPDES permit WA0022772), operated by the Southwest Suburban Sewer District (District), serves approximately 30,000 households and some commercial customers in King County. The facility does not serve any industrial customers. It has an average wet weather flow of 2.5 MGD and discharges to Puget Sound.
Treatment Processes
According to the 2018, treatment at the facility includes screening, grit removal, primary clarification, biological treatment, secondary clarification, and chlorine disinfection.
Effluent Data 
Exhibit A-29 summarizes the effluent data for the pollutants of concern for which data are available.
Exhibit A-29. Summary of Effluent Data (2018-2020): Salmon Creek WWTP
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Maximum

Antimony
                                                                              2
                                                                              0
                                                                           0.36
                                                                           0.41
                                                                            0.3
Bis(2-Ethylhexyl) Phthalate
                                                                              2
                                                                              1
                                                                            1.2
                                                                            2.3
                                                                            0.1
Nickel
                                                                              2
                                                                              0
                                                                           1.72
                                                                           1.73
                                                                            0.1
Phenol
                                                                              4
                                                                              2
                                                                           0.15
                                                                          0.088
                                                                            0.5
Selenium
                                                                              2
                                                                              0
                                                                           0.58
                                                                           0.62
                                                                              1
Zinc
                                                                              2
                                                                              0
                                                                           36.8
                                                                           51.4
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The facility discharges to Puget Sound, which is designated for aquatic life uses as "Extraordinary" (see footnote 18) and is designated for primary contact recreation; for all harvest uses (salmonid and other fish harvesting and crustacean and other shellfish harvesting); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. Exhibit A-30 summarizes the available ambient receiving water concentrations in Puget Sound based data provided in the 2018 permit fact sheet. 
Exhibit A-30. Ambient Receiving Water Concentrations (2013-2017): Puget Sound
Parameter
Maximum Water Column Concentration (ug/L)[a]
Nickel
                                     0.43
Zinc
                                     0.71
Source: 2018 final permit fact sheet.
Note:
[a] Metal concentrations are dissolved form.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2018 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2018 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
Sonoco Products
Sonoco Products (NPDES permit WA0000884) is a recycled paperboard manufacturing facility in Sumner, Washington, producing an average of 138 tons of paperboard per day from recycled materials (based on data between 2007 and 2012). The facility discharges to the White River via Outfall 001 with average wastewater discharge flow of 0.30 MGD.
Treatment Processes
The 2019 permit fact sheet indicates that the current treatment consists of primary clarification, activated sludge aeration, and secondary clarification. 
Effluent Data 
Exhibit A-31 summarizes available effluent data provided in the fact sheet for the 2019 permit.
Exhibit A-31. Summary of Effluent Data: Sonoco Products
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[b]


Mean
Maximum

Antimony
                                                                              4
                                                                              
                                                                           1.36
                                                                            0.3
Cyanide
                                                                              4
                                                                              
                                                                           12.1
                                                                              5
Nickel
                                                                              4
                                                                              
                                                                           2.53
                                                                            0.1
Zinc
                                                                              4
                                                                               
                                                                           14.7
                                                                            0.5
Source: Based on data for 2013 - 2017 provided in 2019 permit fact sheet.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.

Receiving Water
The facility discharges to the White River, which is designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values). Exhibit A-32 summarizes the available ambient receiving water concentrations based on data reported in the 2013 permit fact sheet.
Exhibit A-32. Ambient Receiving Water Concentrations: White River
Pollutant
Average Water Column Concentration 
(Total Recoverable; ug/L)
Zinc
                                     1.91
Source: 2019 fact sheet for the permit (Table 2); average of 8 samples.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
Steelscape Inc.
Steelscape, Inc., located in Kalama, Washington, is an industrial facility (NPDES permit WA0040851) for the cold rolling and coating of steel sheet, strip, and bars. Production occurs round the clock, seven days a week. The facility is composed of four primary production lines, all of which generate wastewater: Pickle Line, Cold Rolling Mill, Metallic (zinc) Coating Line, and Coil Paint Line. 
Treatment Processes
The facility has two distinct wastewater treatment systems: one for treating "oily waste" from all process waters that are potentially contaminated with oil or grease, and the other for treating "metal waste." Domestic waste is treated by the Port of Kalama Municipal Wastewater Treatment System.
The oil waste system treats wastewater from the Cold Roll Mill, Metallic Coating, and Coil Paint lines using collection and blending, oil water separation, holding systems, and feeding systems for hydrochloric acid, de-emulsifier, coagulant, and polymer.
The metal waste system treats waste streams from the Pickle Line, Metallic Coating Line, Coil Paint Line, and other auxiliary wastewater from the facility (e.g., demineralizer regenerant waste, cooling tower blowdowns, and clear effluent from the oily waste system). The metal wastewater is chemically reduced, neutralized, oxidized, coagulated, precipitated, clarified, filtered, and dewatered (2010 fact sheet for the permit, p. 7 - 8).
Effluent Data 
Exhibit A-33 summarizes available effluent monitoring data for the facility for 2018 through 2020. Concentration-based effluent monitoring data were not available for the reasonable potential analysis.
Exhibit A-33. Summary of Effluent Data (2018 to 2020): Steelscape Inc.
Pollutant
Number of Observations
Quantified Values


Maximum
Average
Units
Cyanide
                                      53
                                    0.0052
                                    0.0020
                                    kg/day
Nickel (total)
                                      172
                                    0.0080
                                    0.0015
                                    kg/day
Tetrachloroethylene (total)
                                       9
                                    0.0012
                                    0.00030
                                    kg/day
Zinc (total)
                                      27
                                    0.0057
                                    0.0023
                                    kg/day
Source: Based on discharge monitoring reports submitted to Ecology.

Receiving Water
The facility discharges to the Columbia River through a submerged outfall that is shared with the Port of Kalama Municipal Wastewater Treatment Plant. The Columbia River at this location is designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values).
Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. Concentration-based data to confirm the reasonable potential analysis under the baseline scenario were not available.
Policy Scenario
EPA did not have concentration-based data to perform the reasonable potential analysis under the policy scenario and as such could not determine reasonable potential or calculate permit limits and costs.
TransAlta Centralia Generating Station
The TransAlta Centralia Generating Station (NPDES permit WA0001546) is a coal-fired power plant with two 702.5 Megawatt turbine units as well as a 250 Megawatt natural gas power plant on the same site. The facility generates process wastewater, stormwater runoff, and sanitary effluent, as well as sanitary effluent from the adjacent TransAlta Centralia Mining facility. Average flow for the facility is 0.82 MGD.
Treatment Processes
The fact sheet for the facility's 2017 NPDES permit lists current treatment processes as settling/sedimentation ponds, flocculation, and neutralization and the facility has effluent limits for selenium.
Effluent Data 
Exhibit A-34 summarizes the last three years of effluent data for the treated wastewater for the pollutants of concern for which data are available.
Exhibit A-34. Summary of Effluent Data (2018-2020): Transalta Centralia Generation 
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[a]
Max

Selenium
                                                                             21
                                                                              2
                                                                            2.5
                                                                            7.4
                                                                              1
Zinc
                                                                             19
                                                                              0
                                                                            3.7
                                                                            6.0
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The facility discharges to Packwood, Hanaford, and Mitchell Creeks which are designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values). Ambient water quality data are not available for this receiving water.
Baseline Scenario
The NPDES permit for facility does not have WQBELs based on HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). 
For the baseline scenario, EPA found no reasonable potential analysis for any of the pollutants of concern.
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
TransAlta Centralia Mining
TransAlta Centralia Mining (NPDES permit number WA0037338) mines and processes approximately 6 million tons of coal annually for use at the adjacent TransAlta Centralia Generating Station. The mine discharges stormwater overflow to Big Hanaford Creek and its tributaries. Average monthly flow is approximately 8 cubic feet per second (or 5 MGD).
Treatment Processes
The 2017 NPDES permit fact sheet for the facility lists current treatment processes as sedimentation ponds, which are built as excavation progresses and abandoned as reclamation progresses, in addition to flocculation and neutralization. Discharges from the facility consist of stormwater overflows. Sanitary effluent from the facility is treated by the TransAlta Centralia Generating Station.
Effluent Data 
No recent effluent monitoring data for the facility were available for any of the pollutants for which HHC are being proposed. 
Receiving Water
The facility discharges to Big Hanaford Creek and several tributaries, which are designated for salmonid spawning, rearing, and migration; primary contact recreation; and all water supply and miscellaneous uses (wildlife habitat, fish harvesting, commerce and navigation, boating, and aesthetic values).
Baseline Scenario
The NPDES permit for the facility does not have WQBELs based on HHC for the pollutants of concern. Due to the lack of available monitoring data, EPA could not evaluate reasonable potential and compliance costs for the facility under the baseline scenario.
Policy Scenario
EPA did not have the necessary data to perform the reasonable potential analysis under the policy scenario and as such could not determine reasonable potential or calculate any potential permit limits and costs under the policy scenario.
U.S. Oil & Refining Corporation
U.S. Oil and Refining Corporation (NPDES permit WA0001783) in Tacoma consists of an oil refinery, tank farm, and marine terminal. The facility encompasses 124 acres and has a daily throughput of 42,000 barrels per day. The refinery houses the process units and has approximately 1.4 million barrels tank capacity for crude oil and 1.3 million barrels tank capacity for refined products. The refinery separates crude oil into component parts and blends them into petroleum products including gasoline, jet fuel, diesel fuel, marine fuel, gas oils, and asphalts. The annual average flow into the Blair Waterway is 0.455 MGD. 
Treatment Processes
The 2019 permit fact sheet for the facility indicates that the facility employs primary and secondary treatment for process wastewater and contaminated stormwater before discharging to a City of Tacoma stormwater line and then into the Blair Waterway. Primary and secondary treatment units are operated 24 hours day, seven days a week. Primary treatment includes an API oil/water separator, an induced air flotation unit, and secondary treatment entailing an activated sludge biological unit and a clarifier. Sanitary waste from the facility is collected separately and treated by the City of Tacoma's municipal wastewater treatment plant. Treated process water is emitted from Outfall 001A, where it undergoes sampling.
Effluent Data 
Exhibit A-35 summarizes effluent monitoring data for the facility. According to the 2019 NPDES permit fact sheet, monitoring data for organic toxics are not reported because all samples were below detection limits.
Exhibit A-35. Summary of Effluent Data: U.S. Oil and Refining (2016 - 2018)
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Max

Antimony
                                                                              1
                                                                              0
                                                                          0.194
                                                                          0.194
                                                                            0.3
Chloroform
                                                                              3
                                                                              1
                                                                               
                                                                           0.30
                                                                              1
Diethyl Phthalate
                                                                              1
                                                                              0
                                                                           0.50
                                                                           0.50
                                                                            1.9
Methylene Chloride
                                                                              2
                                                                              1
                                                                           0.17
                                                                           0.49
                                                                              5
Nickel
                                                                              1
                                                                              0
                                                                          0.874
                                                                          0.874
                                                                            0.1
Phenol
                                                                              8
                                                                              6
                                                                            3.2
                                                                             10
                                                                              2
Selenium
                                                                              1
                                                                              0
                                                                           5.08
                                                                           5.08
                                                                              1
Thallium
                                                                              1
                                                                              0
                                                                          0.052
                                                                          0.052
                                                                           0.09
Toluene
                                                                              3
                                                                              1
                                                                               
                                                                           3.68
                                                                              1
Zinc
                                                                              6
                                                                              0
                                                                           6.45
                                                                           9.66
                                                                            0.5
Source: Based on data for 2016 - 2018 provided in 2020 permit fact sheet for chloroform and toluene; data for 2018 - 2020 discharge monitoring reports submitted to Washington Department of Ecology for other parameters.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
U.S. Oil and Refining discharges to the Lincoln Avenue Ditch, where it flows to the Blair Waterway which is a tidal inlet to Commencement Bay. The Blair Waterway is designated as "Good" for aquatic life uses (see footnote 22) and is designated for primary contact recreation; for harvest uses (excluding shellfish); and for the miscellaneous uses of aesthetics, boating, commerce/navigation, and wildlife habitat. 
Exhibit A-36 summarizes the available ambient receiving water concentrations from the 2019 permit fact sheet. 
Exhibit A-36. Ambient Receiving Water Concentrations: Blair Waterway
Parameter
Geometric Mean Concentration (Dissolved; ug/L)
90[th] Percentile Concentration (Dissolved; ug/L)
Antimony
                                                                          0.897
                                                                          0.156
Nickel
                                                                          0.353
                                                                          0.614
Selenium
                                                                          0.030
                                                                          0.052
Thallium
                                                                       0.000823
                                                                         0.0143
Zinc 
                                                                           3.08
                                                                           5.36
Source: Reported in 2019 permit fact sheet.

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the baseline scenario. 
Policy Scenario
EPA performed a reasonable potential analysis for each pollutant based on the proposed HHC. In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the 2019 permit fact sheet, there is no reasonable potential to exceed HHC for pollutants for which effluent data are available. Thus, there are no permit limits or costs associated with the policy scenario. 
Weyerhaeuser Co. Longview
The Weyerhaeuser facility (NPDES permit WA0000124) in Longview, Washington, encompasses approximately 700 acres along the shores of the Columbia River. The facility treats industrial wastewater from its onsite processes including kraft pulp mill, liquid packaging paper machine, extruder, sawmill, planer mill, lumber drying kiln, log yard and export, solid waste material recovery and transfer, and log truck shop. It also accepts additional wastewater for treatment from other facilities in the area including energy, chemicals, transportation, and other industries. Based on the fact sheet for the facility's permit, it has a design flow of 65.1 MGD and an average flow of 53.2 MGD.
Treatment Processes
The 2014 NPDES permit fact sheet lists treatment processes as a primary clarifier, three deep aeration tanks, four secondary clarifiers, and an auxiliary retention pond. The treated industrial and sanitary wastewater is discharged to the Columbia River through Outfalls 001 and 002, while other outfalls discharge stormwater or provide internal monitoring points.
Effluent Data 
Exhibit A-37 summarizes the last three years of effluent data for the treated wastewater for the pollutants of concern for which data are available. 
Exhibit A-37. Summary of Effluent Data (2018 to 2020): Weyerhaeuser Longview
Parameter
Number of Observations
Concentration (ug/L)[a]
DL (ug/L)[c]

Total
Non-detects
Mean[b]
Maximum

Aldrin
                                                                              6
                                                                              5
                                                                        0.00050
                                                                         0.0031
                                                                         0.0018
Antimony
                                                                              6
                                                                              0
                                                                          0.333
                                                                          0.444
                                                                            0.3
alpha-BHC
                                                                              6
                                                                              4
                                                                         0.0014
                                                                         0.0043
                                                                        0.00065
Bis(2-Ethylhexyl) Phthalate
                                                                              6
                                                                              2
                                                                           0.21
                                                                           0.36
                                                                            0.1
Bromoform
                                                                              6
                                                                              0
                                                                           0.98
                                                                            1.4
                                                                              1
Chloroform
                                                                              6
                                                                              0
                                                                             14
                                                                             18
                                                                              1
Cyanide
                                                                              6
                                                                              2
                                                                            2.5
                                                                            4.0
                                                                            0.9
4,4'-DDE
                                                                              6
                                                                              5
                                                                        0.00060
                                                                         0.0034
                                                                         0.0012
Dichlorobromomethane
                                                                              6
                                                                              0
                                                                          3.492
                                                                          4.675
                                                                              1
Dieldrin
                                                                              6
                                                                              4
                                                                         0.0017
                                                                         0.0058
                                                                        0.00086
Diethyl Phthalate
                                                                              6
                                                                              0
                                                                           0.14
                                                                         0.2100
                                                                            1.9
Fluorene
                                                                              6
                                                                              5
                                                                          0.017
                                                                          0.032
                                                                          0.029
Methylene Chloride
                                                                              6
                                                                              0
                                                                           0.33
                                                                           0.46
                                                                              5
Nickel
                                                                              6
                                                                              0
                                                                           2.03
                                                                           2.24
                                                                            0.1
Pentachlorophenol (PCP)
                                                                              7
                                                                              3
                                                                           0.41
                                                                           0.77
                                                                            0.5
Phenol
                                                                             12
                                                                             10
                                                                            1.8
                                                                            7.0
                                                                              2
Selenium
                                                                              6
                                                                              5
                                                                           0.15
                                                                           0.40
                                                                            0.2
Thallium
                                                                              6
                                                                              0
                                                                          0.027
                                                                          0.041
                                                                           0.09
Toluene
                                                                              6
                                                                              4
                                                                          0.188
                                                                          0.548
                                                                          0.032
Zinc
                                                                             13
                                                                              7
                                                                           24.5
                                                                            102
                                                                            0.5
Source: Based on discharge monitoring reports submitted to Washington Department of Ecology, 2018 - 2020. Includes all parameters for which there was at least one detected value.
Notes:
DL = Detection limit
[a] For parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] For parameters that have some detected values and some non-detects, mean values are calculated assuming half the DL for all non-detects. 
[c] DL is based on the standard values for Washington or the limit reported in the discharge monitoring reports, whichever is lower.
	
Receiving Water
The facility discharges to the Columbia River at mile 63.5, which is designated for salmonid spawning, rearing and harvesting; primary contact recreation; water supply (domestic, industrial, agricultural); stock water; wildlife habitat; commerce and navigation; and boating and aesthetic enjoyment.
Exhibit A-38 summarizes the available ambient receiving water concentrations based on data from 1999 and 2005 reported in the permit fact sheet. 
Exhibit A-38. Ambient Receiving Water Concentrations: Columbia River (ug/L)
Parameter
Geometric Mean 
90[th] Percentile or Max
Antimony
                                                                           0.09
                                                                              
Nickel
                                                                           0.39
                                                                           0.64
Selenium
                                                                              
                                                                           0.16
Zinc
                                                                              
                                                                           4.36
Source: Reported in 2014 permit fact sheet. 

Baseline Scenario
The permit does not include any WQBELs based on the existing HHC for the pollutants of concern. EPA performed a reasonable potential analysis for each pollutant to determine whether a WQBEL may be included in the next permit for the facility pursuant to existing applicable criteria (i.e., under the baseline scenario). 
Exhibit A-39 summarizes the RPA under the baseline scenario. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed the baseline dieldrin HHC. 
Exhibit A-39. Human Health Reasonable Potential Analysis for Weyerhaeuser Longview  -  Baseline Scenario (ug/L)[a]
Parameter
Effluent Conc.
Ambient Conc.
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Aldrin
                                                       0.0031 x 0.860 = 0.0267 
                                                                             NR
                                                                       0.000027
                                                                      0.0000057
Dieldrin
                                                      0.0058 x 0.860 = 0.00499 
                                                                             NR
                                                                       0.000051
                                                                      0.0000061
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used. 
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 97.5.

In cases of reasonable potential, EPA calculated a WQBEL using the existing HHC and evaluated compliance with this baseline WQBEL. 
Exhibit A-40 summarizes the calculated permit limits under the baseline scenario. 
Exhibit A-40. Human Health Based Effluent Limitations for Weyerhaeuser Longview  -  Baseline Scenario (ug/L)
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc.
Quantification Limit
Aldrin
                                                                        0.00056
                                                                         0.0011
                                                                         0.0031
                                                                           0.05
Dieldrin
                                                                        0.00060
                                                                         0.0012
                                                                         0.0058
                                                                           0.05
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Aldrin
Under the baseline scenario, the discharger would have to meet an AML of 0.00056 ug/L and an MDL of 0.0011 ug/L. The maximum effluent concentration is 0.0031 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of dieldrin in its effluent to ensure that permit limits are consistently met.
Dieldrin
Under the baseline scenario, the discharger would have to meet an AML of 0.00060 ug/L and an MDL of 0.0012 ug/L. The maximum effluent concentration is 0.0058 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of dieldrin in its effluent to ensure that permit limits are consistently met.
Policy Scenario
Exhibit A-41 summarizes the reasonable potential analysis under the policy scenario. Based on available effluent and ambient concentration data, reasonable potential multipliers from Ecology spreadsheets (where appropriate), and dilution factors from the permit fact sheet, there is reasonable potential to exceed HHC for several parameters.
Exhibit A-41. Human Health Reasonable Potential Analysis for Weyerhaeuser Longview  -  Policy Scenario (ug/L)[a]
Parameter
Conc. 
Ambient Conc. 
Conc. at Edge of Mixing Zone[b]
Human Health Criterion
Aldrin
                                                       0.0031 x 0.860 = 0.0267 
                                                                             NR
                                                                       0.000027
                                                                    0.000000041
4,4'-DDE
                                                       0.0034 x 0.860 = 0.00294
                                                                             NR
                                                                       0.000030
                                                                     0.00000088
Dieldrin
                                                      0.0058 x 0.860 = 0.00499 
                                                                             NR
                                                                       0.000051
                                                                    0.000000070
Pentachlorophenol (PCP)
                                                           0.77 x 0.805 = 0.620
                                                                             NR
                                                                         0.0064
                                                                         0.0020
Notes:
NR = not reported
[a] See effluent concentrations above; for parameters with fewer than 10 observations, the maximum or projected maximum effluent concentration is used in the reasonable potential analysis; for parameters with 10 or more observations, the mean is used.
[b] Based on Washington Department of Ecology's permit writer spreadsheet tool using a dilution factor of 97.5.

Exhibit A-42 summarizes the calculated permit limits under the policy scenario.
Exhibit A-42. Human Health Based Effluent Limitations for Weyerhaeuser Longview  -  Policy Scenario (ug/L) 
Parameter
Average Monthly Effluent Limit[a]
Maximum Daily Effluent Limit[a]
Maximum Effluent Conc./ Baseline AML
Quantification Limit
Aldrin
                                                                      0.0000040
                                                                      0.0000075
                                                                        0.00056
                                                                           0.05
4,4'-DDE
                                                                       0.000086
                                                                        0.00016
                                                                         0.0034
                                                                          0.051
Dieldrin
                                                                      0.0000068
                                                                       0.000013
                                                                        0.00060
                                                                           0.05
Pentachlorophenol (PCP)
                                                                           0.20
                                                                           0.37
                                                                           0.77
                                                                              1
Note:
[a] Based on Washington Department of Ecology's permit writer spreadsheet tool.

Aldrin
Under the policy scenario, the discharger would have to meet an AML of 0.0000040 ug/L and an MDL of 0.0000075 ug/L. The baseline AML is 0.00056 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of aldrin in its effluent to ensure that permit limits are consistently met. 
4,4' DDE
Under the policy scenario, the discharger would have to meet an AML of 0.000086 ug/L and an MDL of 0.00016 ug/L. The maximum effluent concentration is 0.0034 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of 4,4' DDE in its effluent to ensure that permit limits are consistently met. 
Dieldrin
Under the policy scenario, the discharger would have to meet an AML of 0.0000068 ug/L and an MDL of 0.000013 ug/L. The baseline AML is 0.00060 ug/L. However, the QL for this parameter is 0.05 ug/L, which is higher than the policy scenario AML and the baseline AML. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of dieldrin in its effluent to ensure that permit limits are consistently met.
Pentachlorophenol (PCP)
Under the policy scenario, the discharger would have to meet an AML of 0.20 ug/L and an MDL of 0.37 ug/L. The maximum effluent concentration is 0.77 ug/L. However, the QL for this parameter is 1 ug/L, which is higher than the AML and the highest detected effluent value. Because the QL would be used as the assessment level for permit compliance, this facility would not need to reduce the concentration of PCP in its effluent to ensure that permit limits are consistently met.
References and Sources
King County Department of Natural Resources and Parks. 2012. King County Long-term Combined Sewer Overflow Control Plan Amendment.
King County Department of Natural Resources. 2013. Receiving Water Characterization Study: King County NPDES Monitoring Program. Final Report prepared for the King County Department of Natural Resources and Parks and the Washington State Department of Ecology.
U.S. Environmental Protection Agency (EPA). 2004. Technical Support Document for the 2004 Effluent Guidelines Program Plan for the Petroleum Refining Category. EPA-821-R-04-014.
U.S. Environmental Protection Agency (EPA). 2021. Fact Sheet for Preliminary Draft NPDES Permit WA002062: Puget Sound Naval Shipyard and Intermediate Maintenance Facility.
Washington Department of Ecology. 2003. Fact Sheet for NPDES Permit WA0022772: Southwest Suburban Sewer District -- Salmon Creek Wastewater Treatment Plant.
Washington Department of Ecology. 2008. Fact Sheet for NPDES Permit WA0039624: Pierce County Chambers Creek Wastewater Facility.
Washington Department of Ecology. 2009. Fact Sheet for NPDES Permit WA0029581: King County South Wastewater Treatment Plant (WWTP).
Washington Department of Ecology. 2010. Fact Sheet for National Pollutant Discharge Elimination System (NPDES) Permit No. WA0001546: Transalta Centralia Generation LLC.
Washington Department of Ecology. 2010. Fact Sheet for National Pollutant Discharge Elimination System (NPDES) Permit No. WA0040851: Steelscape Washington LLC.
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Washington Department of Ecology. 2014. NPDES Form 2A Application Overview for NPDES Permit WA0044692: City of Pasco Wastewater Treatment Plant. 
Washington Department of Ecology. 2014. Fact Sheet for NPDES Permit WA0000124: Weyerhaeuser Longview. 
Washington Department of Ecology. 2015. Fact Sheet for NPDES Permit WA0000809: Cosmo Specialty Fibers Inc.
Washington Department of Ecology. 2017. Fact Sheet for National Pollutant Discharge Elimination System (NPDES) Permit No. WA0037338: Transalta Centralia Mining LLC.
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Washington Department of Ecology. 2018. Fact Sheet for National Pollutant Discharge Elimination System (NPDES) Permit No. WA0021067: City of Quincy Industrial Wastewater Treatment Facility.
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Washington Department of Ecology. 2019. Fact Sheet for NPDES Permit WA0001783: U.S. Oil and Refining Co. 
Washington Department of Ecology. 2020. Water Quality Program Policy 1-11, Chapter 1. Washington's Water Quality Assessment Listing Methodology to Meet Clean Water Act Requirements. Publication No. 18-10-035. July 2020 (revised from July 2018).
Washington Department of Ecology. 2021. Fact Sheet for National Pollutant Discharge Elimination System (NPDES) Permit No. WA0000281: Emerald Kalama Chemical LLC.
