
[Federal Register Volume 81, Number 247 (Friday, December 23, 2016)]
[Notices]
[Pages 94370-94371]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-31049]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OW-2016-0353; FRL 9957-26-OW]


Draft Field-Based Methods for Developing Aquatic Life Criteria 
for Specific Conductivity

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: The Environmental Protection Agency (EPA) is announcing the 
availability of Draft Field-Based Methods for Developing Aquatic Life 
Criteria for Specific Conductivity for public comment. Elevated ionic 
concentration measured as specific conductivity has been shown to 
negatively impact aquatic life in a range of freshwater resources. Once 
finalized, states and authorized tribes located in any region of the 
country may use the methods to develop field-based conductivity 
criteria for flowing waters. This document does not impose binding 
water quality criteria on any state, but instead provides methods to 
assist states and tribes that seek to develop such criteria for 
adoption into their water quality standards. The draft document 
provides a scientific assessment of ecological effects and is not a 
regulation. Following closure of this 60-day public comment period, EPA 
will consider the comments, revise the document, as appropriate, and 
then publish a final document that will provide methods for states and 
authorized tribes that they may use to develop water quality standards.

DATES: Comments must be received on or before February 21, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2016-0353, to the Federal eRulemaking Portal: http://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or withdrawn. EPA 
may publish any comment received to its public docket. Do not submit 
electronically any information you consider to be Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Multimedia submissions (audio, video, etc.) must be 
accompanied by a written comment. The written comment is considered the 
official comment and should include discussion of all points you wish 
to make. EPA will generally not consider comments or comment contents 
located outside of the primary submission (i.e., on the web, cloud, or 
other file sharing system). For additional submission methods, the full 
EPA public comment policy, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Colleen Flaherty, Health and 
Ecological Criteria Division (Mail Code 4304T), Environmental 
Protection Agency, 1200 Pennsylvania Avenue NW., Washington,

[[Page 94371]]

DC 20460; telephone: (202) 564-5939; or email: 
flaherty.colleen@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. How can I get copies of this document and other related information?

    1. Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Water Docket, EPA/DC, EPA 
West, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public 
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the Water 
Docket is (202) 566-2426. For additional information about EPA's public 
docket, visit EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.

II. Information on the Draft Field-Based Methods for Developing Aquatic 
Life Criteria for Specific Conductivity

    EPA has developed a set of draft methods that states and authorized 
tribes may use to derive field-based ecoregional ambient aquatic life 
criteria for ionic mixtures measured as specific conductivity, a 
measurement of ionic concentration, in flowing waters. Elevated ionic 
concentration measured as specific conductivity has been shown to 
impact aquatic life in a range of freshwater resources. Different 
mixtures of ions that increase specific conductivity are associated 
with natural and anthropogenic sources.
    EPA's draft methods provide flexible approaches for developing 
science-based conductivity criteria for flowing waters that reflect 
ecoregional- or state-specific factors. Once final, states and 
authorized tribes located in any region of the country may use the 
methods to develop field-based conductivity criteria for flowing 
waters. The document does not impose binding water quality criteria on 
any state, but instead provides methods to assist states and tribes 
that seek to develop such criteria for adoption into their water 
quality standards. The draft document provides a scientific assessment 
of ecological effects and is not a regulation.
    EPA's draft methods are based on effects observed in streams with 
different levels of specific conductivity and take into account natural 
variation in background specific conductivity and the aquatic species 
adapted to it. The draft document describes how to derive protective 
field-based aquatic life criteria for specific conductivity, including 
how to estimate a criterion continuous concentration for chronic 
exposures, how to estimate a maximum exposure concentration protective 
of acute toxicity, how to assess geographic applicability and potential 
confounding factors, and how to determine duration and frequency 
parameters.
    EPA is also providing four case studies to illustrate how states 
and tribes may use the draft field-based methods to develop criteria in 
ecoregions with different background ionic concentrations measured as 
specific conductivity and demonstrate how to assess the applicability 
of criteria developed for one ecoregion to a different ecoregion. The 
case studies use field data to demonstrate how to apply the methods to 
derive example criteria for specific conductivity for flowing waters 
dominated by sulfate and bicarbonate salts but not for flowing waters 
dominated by chloride salts.
    EPA typically relies on laboratory toxicity test data for surrogate 
species as defined in the Agency's Guidelines for Deriving Numerical 
National Water Quality Criteria for the Protection of Aquatic Organisms 
and Their Uses (1985) for aquatic life criteria development. The draft 
field-based methods for specific conductivity were adapted to be 
consistent with the Agency's traditional approach to derive aquatic 
life criteria. The draft field-based methods rely on geographically 
referenced, paired observations of specific conductivity and the 
presence and absence or abundance of freshwater benthic 
macroinvertebrate genera from wadeable perennial streams. An analysis 
of data for fish from a composite of case study ecoregions demonstrates 
that the example criteria based on macroinvertebrates are also 
protective of fish.
    This document underwent an internal EPA review and two independent 
contractor-led external peer reviews.

III. Solicitation of Scientific Views

    EPA is soliciting additional scientific views, data, and 
information regarding the science and technical approach used in the 
derivation of the draft field-based methods. EPA is also soliciting 
suggestions from the public for additional ecoregional case studies for 
future consideration.

    Dated: December 16, 2016.
Joel Beauvais,
Deputy Assistant Administrator, Office of Water.
[FR Doc. 2016-31049 Filed 12-22-16; 8:45 am]
 BILLING CODE 6560-50-P


