              OFFICE OF CHEMICAL SAFETY
AND POLLUTION PREVENTION
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
                                       
                                       
                                       
                                       
                                       
                               January 23, 2012

                                                                PC Code: 129131
MEMORANDUM	DP Barcode: 391431

SUBJECT:	Fenpyroximate: Drinking Water Exposure Assessment for Proposed New Uses on Snap Beans and Tropical Fruits including Avocado and a Proposed Outdoor Use on Cucumbers

FROM:	Greg Orrick, Environmental Scientist
	ERB2/EFED (7507P)

THROUGH:  James Lin, Environmental Engineer
	Kristina Garber, Senior Biologist
	Brian Anderson, Chief
	ERB2/EFED (7507P)

TO:	George Kramer, Ph.D., Senior Chemist
	Dana Vogel, Chief
	RAB1/HED (7509P)

	Sidney Jackson, Product Manager
	Barbara Madden, Team Leader, RM Team 5
	RIMUERB/RD (7505P)


1. EXECUTIVE SUMMARY

	This assessment provides estimated drinking water concentrations (EDWC) of fenpyroximate in surface water and in ground water in support of human health risk assessment.  Screening EDWCs (Table 1) of fenpyroximate were generated with FIRST and a Provisional Cranberry Model for surface water and with SCI-GROW for ground water.  Modeled use patterns are those of current and proposed end-use labels that result in the highest exposure.  Model input parameters were chosen according to current guidance (USEPA, 2009).  EDWCs reflect exposure in drinking water to the residues of concern of fenpyroximate, which include fenpyroximate parent, its cis isomer M-1, and its carboxylic acid M-3, all of which are assumed to have similar toxicity (USEPA, 2003).  Labeled application buffers to fish-bearing waters were not modeled.  The EDWCs listed in this assessment are the result of a coarse screen and do not necessarily reflect actual exposures that may occur or may have occurred.  If the screening EDWCs listed in this assessment result in dietary risk exceedances, contact Greg Orrick (703-305-6140) of Environmental Risk Branch II (7507P) to request a refined drinking water exposure assessment.

Table 1.1.  Maximum Screening Drinking Water Exposure Estimates for Current and Proposed Fenpyroximate Uses [A]
Source (Tier: Model)
Use (Maximum Annual Rate)
                             Peak Exposure (μg/L)
                         Annual Mean Exposure (μg/L)
Surface water (Tier I: FIRST)
Ornamentals (0.69 lbs a.i./A)
                                      29
                                      1.9
Surface water (Tier I: Cranberry model)
Cranberries (0.20 lbs a.i./A)
                                      43
                                      8.6
Ground water (Tier I: SCI-GROW)
Ornamentals (0.69 lbs a.i./A)
                                    <=0.27
[A] Maximum values in bold.

	A maximum screening exposure estimate in fish that may be consumed by humans was also calculated with the Provisional Cranberry Model and KABAM, at 30 mg/kg-bw (ww).

	Fenpyroximate is a pyrazole contact insecticide and miticide that inhibits mitochondrial complex I electron transport.  The compound is relatively nonvolatile, lipophilic, and may bioconcentrate in fish.  Fenpyroximate is slightly to hardly mobile in soil and may move to surface water through runoff of residues sorbed to suspended sediment.  Fenpyroximate degrades mainly via moderate biodegradation in soil and water bodies (half-lives of 23-41 days in aerobic and anaerobic systems).  The compound is also rapidly photoisomerized to reach equilibrium with its cis isomer M-1 and photolyzed in shallow, illuminated water (fenpyroximate half-life of 1.5 hours; M-1 half-life of 10.5 hours).  However, the importance of this degradation pathway is expected to be limited because fenpyroximate and its isomer are expected to partition to sediment in water bodies, where aqueous photolysis is limited.

	Fenpyroximate's cis isomer M-1, its carboxylic acid M-3, and cleavage products M-6, M-8, M-11, M-16, and carbon dioxide are its major transformation products that were isolated in submitted environmental fate studies.  M-1 and M-3 are included with the parent as residues of concern.  Due to lack of toxicity data, the residues of concern are assumed to have equivalent toxicity (USEPA, 2003).  Exposure estimates in this assessment reflect total residues of concern (TRC).

	EPA Reg. No. 71711-4 states "Do not apply more than 48 fl oz per crop cycle or per growing season, whichever is longer."  This was interpreted as an annual application rate limit.  However, the label language is vague and could be misinterpreted.  It is recommended to reword this limitation as an annual application rate limit in terms of mass of active ingredient per area.

2. PROBLEM FORMULATION

	This drinking water assessment uses environmental modeling to provide estimates of surface water and ground water concentrations in drinking water source water (pre-treatment) resulting from fenpyroximate use on vulnerable sites.  Estimates reflect drinking water exposure to fenpyroximate residues of concern in drinking water, which include the parent compound, its cis isomer M-1, and its carboxylic acid M-3 (chemical names and structures are in Table A.1, Appendix A), on a per molar basis (USEPA, 2003).  Primary routes of transport to source water include spray drift and runoff of dissolved residues (mainly M-3) and residues sorbed to suspended sediment (mainly fenpyroximate and M-1).  Exposure in surface water from proposed and current fenpyroximate uses due to runoff, erosion, and spray drift was assessed with the Tier I screening model, FIRST, and a Provisional Cranberry Model.  Exposure in ground water due to leaching was assessed with the Tier I screening ground water model SCI-GROW.  Exposure in fish consumed by humans was assessed with the Provisional Cranberry Model and KABAM.

   2.1.    Nature of the Chemical
      
      Fenpyroximate is a pyrazole contact insecticide and miticide that inhibits mitochondrial complex I electron transport.  The mode of action blocks cell respiration by blocking formation of adenosine triphosphate (ATP), causing the target pest to lose motor control and collapse.  Fenpyroximate specifically targets the proton-translocation in NADH:ubiquinone oxidoreductase enzyme blocking ubiquinone reduction.
      
      NADH:ubiquinone oxidoreductase, also known as respiratory complex I of mitochondria, transfers electrons from NADH to ubiquinone (coenzyme Q) and links this process with translocation of protons across the inner membrane to the cytoplasmic side creating a proton gradient which drives the synthesis of ATP.  NADH:ubiquinone oxidoreductase enzyme is comprised of a number of subunits.  The number of subunits and total mass of this enzyme and density within mitochondria depends on the organism.  It consists of at least 41 different subunits in mammals.  The highest number of subunits is 46 for bovine heart mitochondria, whereas bacteria have a minimum of 14 subunits.  The total mass of the enzymes ranges from approximately 500 to 1000 kiloDaltons (kDa), depending on the organism.  Sensitivity of an organism to fenpyroximate is expected to be affected by the specific organism NADH:ubiquinone oxidoreductase enzyme affinity with fenpyroximate, the density of the NADH:ubiquinone oxidoreductase enzyme within mitochondria, and the presence of alternative energy pathways.
         
      In addition to the acute respiratory activity, at sub lethal levels fenpyroximate causes inhibition of molting of all immature stages (as in insect growth regulators), inhibits oviposition, and decreases feeding action.

3. ANALYSIS

   3.1.    Use Characterization

      Fenpyroximate is proposed for use on snap beans and tropical fruits including avocado.  Use on greenhouse-grown cucumbers is also proposed to be expanded to include cucumbers grown outdoors.  The proposed use of fenpyroximate on tropical fruits (including avocado) is by ground application at a maximum single application rate of 0.10 pounds of active ingredient per acre (lbs a.i./A).  A second application may be made at this rate a minimum of 14 days later, to meet a seasonal application rate limit of 0.20 lbs a.i./A per growing season.  Supplemental proposed labels propose the same application directions and limitations for snap beans and cucumbers (grown outdoors) as for tropical fruits.
      
      The fenpyroximate uses of maximum aquatic exposure are the current uses on ornamentals and cranberries.  The single and seasonal maximum application rates for ornamentals are 0.343 lbs a.i./A and 0.686 lbs a.i./A, respectively.  The seasonal application rate limit was inferred based on a label statement to "not apply more than 48 fl oz per crop cycle or per growing season, whichever is longer."  It was assumed that this label statement was intended to be in terms of fl oz per acre per crop cycle or growing season, which results in the seasonal rate limit of 0.686 lbs a.i./A.  A reapplication interval was not provided.  Aerial application was not disallowed.  Use directions for low-growing berries (including cranberries) are similar to those of the proposed uses.  Table 3.1 lists all of the currently labeled and proposed maximum use patterns for fenpyroximate.
      
      
Table 3.1.  Proposed and current uses of fenpyroximate
                                 EPA Reg. No.
                             Active Ingredient (%)
                                      Use
                             Max. Single App. Rate
                                 (lbs a.i./A)
                      Max. Annual App. Rate (lbs a.i./A)
                               App. Interval (d)
                               Application Type
                       Additional Application Directions
                                    71711-4
                              Fenpyroximate (5%)
        Ornamentals, Christmas trees, nonbearing fruit trees and vines
                                     0.343
                                    0.686 A
                                  Not stated
                               Aerial or ground
Do not use products with the same mode of action in consecutive applications.
                                       
                                       
                       Greenhouse cucumbers and tomotoes
                                     0.105
                                     0.42
                                      14
                                    Ground

                                   71711-19
                              Fenpyroximate (5%)
Avocado, black sapote, canistel, mamey sapote, mango, papaya, sapodilla, and star apple
                                     0.10
                                   0.20 [B]
                                      14
                               Aerial or ground
Do not apply within 75 feet of fish-bearing waters.  Do not use products with the same mode of action in consecutive applications.
                                       
                                       
                                  Snap beans
                                       
                                   0.20 [C]
                                       
                                       
                                       
                                       
                                       
                                   Cucumbers
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                           Melons (crop subgroup 9A)
                                     0.10
                                       
                                  Not stated
                                       
                                       
                                       
                                       
                  Low-growing berry (crop subgroup 13-07G) D
                                     0.10
                                   0.20 [C]
                                      14
                                    Ground
                                       
                                       
                                       
          Citrus fruits (crop group 10) east of the Mississippi River
                                     0.20
                                   0.20 [B]
                                       
                               Aerial or ground
Do not apply by air except in FL and TX.  Do not apply within 75 feet of fish-bearing waters.  For aerial use in FL, do not apply within 150 feet of all aquatic areas.  Do not use products with the same mode of action in consecutive applications.
                                       
                                       
          Citrus fruits (crop group 10) west of the Mississippi River
                                     0.20
                                   0.40 [B]
                                       
                                       
Do not apply by air except in TX.  Do not apply within 75 feet of fish-bearing waters.  Do not use products with the same mode of action in consecutive applications.  
                                       
                                       
                                    Cotton
                                     0.10
                                    0.10 B
                                       
                                       
Do not apply within 75 feet of fish-bearing waters.  Do not use products with the same mode of action in consecutive applications.
                                       
                                       
                      Fruiting vegetables (crop group 8)
                                     0.10
                                   0.20 [C]
                                  Not stated
                                       
                                       
                                       
                                       
                                    Grapes
                                     0.10
                                   0.10 [B]
                                       
                                    Ground
                                       
                                       
                                       
                                     Hops
                                     0.15
                                   0.15 [B]
                                       
                                       
                                       
                                       
                                       
                                     Mint
                                     0.10
                                   0.20 [B]
                                       7
                                       
                                       
                                       
                                       
                 Nonbearing fruit trees, nut trees, and vines
                                     0.10 
                                   0.10 [B]
                                  Not stated
                                       
                                       
                                       
                                       
                                  Ornamentals
                                     0.10
                                   0.10 [B]
                                       
                                       
                                       
                                       
                                       
                          Pome fruits (crop group 11)
                                     0.10
                                   0.10 [B]
                                Not applicable
                                       
                                       
                                       
                                       
             Almonds and pistachios west of the Mississippi River
                                     0.20
                                    0.40 B
                                      14
                                       
                                       
                                       
                                       
Tree nuts (crop group 14) excluding almonds and pistachios, west of the Mississippi River
                                     0.20
                                    0.20 B
                                       
                                       
                                       
                                       
                                       
            Tree nuts (crop group 14) east of the Mississippi River
                                     0.10
                                   0.10 [B]
                                Not applicable
                                       
                                       
A	The label vaguely provides a maximum product volume per crop cycle or growing season, whichever is longer.  This is interpreted as an annual rate limit.
B	The labeled application rate limit is given per growing season, which is interpreted as per year.
C	The labeled application rate limit is given per crop cycle.  These crops are not typically planted more than once per year in the same field (USEPA, 2007).  Therefore, the application rate limits per crop cycle were used as annual rate limits.
D	The low-growing berry crop subgroup (13-07G) includes cranberries.


   3.2.    Fate and Transport Characterization

      Fenpyroximate [tert-butyl (E)-α-(1,3-dimethyl-5-phenoxypyrazol-4-ylmethyleneaminooxy)-p-toluate; CAS# 134098-61-6] is a trans stereoisomer) and a tert-butyl ester (chemical structure is in Appendix A).  The compound is relatively nonvolatile, lipophilic, and slightly to hardly mobile in soil.  Fenpyroximate degrades mainly via moderate biodegradation in soil and water bodies (half-lives of 23-41 days in aerobic and anaerobic systems).  The compound is also rapidly photoisomerized to reach equilibrium with its cis isomer M-1 and photolyzed in shallow, illuminated water (fenpyroximate half-life of 1.5 hours; M-1 half-life of 10.5 hours).  However, the importance of this degradation pathway is expected to be limited because fenpyroximate and its isomer are expected to partition to sediment in water bodies, where aqueous photolysis is limited.  Fenpyroximate does not hydrolyze readily and may bioconcentrate in fish.  Fenpyroximate's cis isomer M-1, its carboxylic acid M-3, and cleavage products M-6, M-8, M-11, M-16, and carbon dioxide are its major transformation products (chemical names and structures are in Appendix A).

      Fenpyroximate is not expected to move to ground water but may move to surface water bodies via spray drift and runoff of residues sorbed to suspended sediment.  Table 3.2 summarizes the submitted chemical and environmental fate data for fenpyroximate.
 
Table 3.2.  Chemical Properties and Environmental Fate Parameters of Fenpyroximate
Parameter
Value
Source
                     Selected Physical/Chemical Parameters
Molecular mass (molecular formula)
421.50 g/mol (C24H27N3O4)
(Calculated)
Vapor pressure (25 °C)
5.6 x 10[-8] torr
MRID 44781003
Aqueous solubility (25C)
pH 5: 0.023 mg/L	pH 7: 0.026 mg/L
pH 9: 0.034 mg/L
MRID 44781003
Henry's Law Constant (25°C, pH 7)
1.2 x10[-][6] atm-m[3]/mol
(Calculated)
Log octanol-to-water partition coefficient
(log KOW)
5.01
MRID 44781003
Dissociation constant (pKb)
Not determined
MRID 44781003
                                  Persistence
Hydrolysis half-life (25C)
pH 5: 180 d	pH 7: 226 d
pH 9: 221 d
MRID 44847909
Aqueous photolysis half-life (25C)
1.8 hrs (0.15 solar days)
MRID 44781016
Soil photolysis half-life (25C)
24 d
MRID 45649705
Aerobic soil metabolism half-life (25°C)
28, 41 d
MRID 45187901/ 45649706

39 d
MRID 46158501
Anaerobic aquatic metabolism half-life (25C)
33 d
MRID 45649707
Aerobic aquatic metabolism half-life (20C)
23, 34 d
MRID 47521406
                                   Mobility
Freundlich soil-water partition coefficients (KF); Freundlich organic carbon-normalized coefficients (KFOC)
83, 93, 175, 290, 1,370 L/kg;
7,550, 18,600,  41,400, 44,000, 58,300 L/kgOC
MRID 45649709
                               Field Dissipation
Terrestrial field dissipation half-life
1 d (German sandy silt loam),
11 d (German sandy loam),
12 (German loamy sand),
24 d (German sandy loam)
MRID 45649710/ 45649711

3.6 d (Commerce silt loam, AR),
4.1 d (Cajon sandy loam, CA),
15 d (Norfolk sandy loam, NC)
MRID 45649712/ 45734203
                             Fish Bioconcentration
Fish bioconcentration factors (steady-state, total residues)
770-1100 (edible), 2800-4100 (inedible), 1800-2700 (whole fish)
MRID 48381102

      1..1.       Transport and Mobility

	Fenpyroximate will not significantly volatilize despite having a low solubility in water (0.023-0.034 mg/L at pH 5-9, 25°C; MRID 44781003) and moderate Henry's Law Constant (1.2 x 10[-6] atm-m[3]/mol) because of its low vapor pressure (5.6 x 10[-][8] torr at 25°C; MRID 44781003) and high KOW of 100,000 (log KOW of 5.01; MRID 44781003).  Minimal volatility was observed in the environmental fate studies because of high sorption to soil.

	Fenpyroximate is slightly to hardly mobile in soil, with KFOC values of 7,550-58,300 L/kgOC (MRID 45649709).  Sorption to soil correlates with the organic carbon fraction in soil (i.e., the coefficient of variation across five soils for KFOC (60%) is less than that for KF (136%)).  The compound is not expected to move to ground water via leaching but may be sorbed to suspended sediment in runoff feeding surface water bodies.

      2..2.       Degradation

	Fenpyroximate slowly hydrolyzes at environmental pH values, with half-lives of 180-226 days at pH 5-9 (MRID 44847909).  In contrast, fenpyroximate is rapidly photoisomerized to reach equilibrium with its cis isomer, M-1, and photolyzed in water, with a half-life of 1.8 hours (MRID 44781016).  The photolysis half-life of M-1 was 12 hours.  M-11 was the predominant photoproduct of fenpyroximate and M-1. The importance of phototransformation is expected to be limited, however, because fenpyroximate and its isomer are expected to partition to sediment in water bodies, where aqueous photolysis is limited.

	Fenpyroximate moderately degraded in aerobic soil with half-lives of 28, 39, and 41 days (MRID 45187901/45649706, 46158501).  M-3, M-8, and carbon dioxide were major degradates in soil.  In aerobic aquatic systems, the compound moderately degraded at similar rates, with half-lives of 23 and 34 days (MRID 47521406).  M-3, M-8, and M-11 were major degradates in these systems.  Under anaerobic aquatic conditions, fenpyroximate degraded at a similar rate, with a half-life of 33 days (MRID 45649707).  M-3, M-8, M-11, and M-16 were the major degradates in anaerobic conditions.

      3..3.       Field Studies

	Fenpyroximate dissipated under terrestrial field conditions with half-lives of 1-24 days (MRID 45649710/-11 and 45649712/45734203), based on the results of three bare ground field experiments conducted in the United States and four conducted in Germany.  These field dissipation half-lives range from being shorter than to similar to laboratory-derived degradation half-lives in soil (28-41 days).  At the U.S. sites, half-lives of fenpyroximate + M-1 + M-3 were 35 days in the silt loam soil in Arkansas, 15 days in the sandy loam soil in California, and 43 days in the sandy loam soil in North Carolina.  Fenpyroximate plus M-1 was not detected below the 15-cm soil depth, and was not detected at any site after 61 days posttreatment.  The soils were also analyzed for the transformation products M-3, M-8, and M-11.  M-8 and M-11 were not detected at any of the sites.  M-3 was detected in all three U.S. studies.  At the German sites, fenpyroximate + M-1 + M-3 dissipated with half-lives of 3 to 37 days.  Fenpyroximate was not detected below the 10-cm depth, except at one site at one sampling interval, and was not detected at any site after 56 days posttreatment.

      4..4.       Fish Bioconcentration

      Fenpyroximate may bioaccumulate in aquatic organisms, with fish bioconcentration factors of up to 1100, 4100, and 2700 for edible, inedible, and whole fish tissues, respectively (factors are uncertain due to high total organic carbon concentrations in the test systems; MRID 48381102).  Only one concentration of fenpyroximate was studied and degradation was not monitored in this study.  Depuration half-lives for the edible, inedible, and whole fish tissues were 5.2-5.3 days.  The respective depuration rate constant for whole fish (kT of 0.131 d[-1]) was well above the sum of elimination constants estimated by KABAM (k2+kE+kG of 0.035 d[-1]), which indicates that the compound was metabolized in fish (KABAM neglects metabolism by default).  The KABAM-estimated BCF for fenpyroximate was 4900, which is higher than the study-derived values of 1800-2700 for whole fish.  However, the KABAM-estimated BCF for fenpyroximate based on the contribution of fish concentrations due to respiration is reduced from 3900 to 1100 when a metabolism rate constant (kM) for small to large fish of 0.096 d[-1] is used.  This metabolism rate constant was calculated by subtracting the sum of elimination rate constants estimated by KABAM (k2 + kE +kG of 0.035 d[-1]) from the study-derived depuration rate constant (kT of 0.131 d[-1]).  The BCF estimate of 1100 is lower than the study-derived BCF values of 1800-2700, which indicates that the calculated metabolism rate constant may be overestimated.

      5..5.       Environmental Degradates

      Major identified environmental transformation products of fenpyroximate are its cis isomer M-1, its carboxylic acid M-3, and cleavage products M-6, M-8, M-11, M-16, and carbon dioxide (chemical names and structures are in Appendix A).  Figure A.1 of Appendix A illustrates the transformation pathway of fenpyroximate in the environment.
      
      Major organic degradates of fenpyroximate (and M-1) tend to have higher mobility in soil than the parent compound (and its isomer).  Mean KFOC values for M-3, M-8, and M-11 are 660, 90, and 611 L/kgOC (n=4; MRID 45649708 and 47521401).  As expected for a carboxylic acid, M-3 is orders of magnitude more soluble in water (solubility of >=25 mg/L at 25°C; MRID 45649708) than fenpyroximate.

      6..6.       Residues of Concern

	The Metabolism Assessment Review Committee (MARC) of the Health Effects Division included as residues of concern in drinking water, fenpyroximate parent, its cis isomer M-1, and its carboxylic acid M-3 (USEPA, 2003).  Due to the structural similarity of the compounds and the lack of toxicity data, they are assumed to have equivalent toxicity.

	Drinking water exposure to the residues of concern is estimated using available chemical properties and environmental fate data.  A total residues of concern (TRC) approach was used because the residues are assumed to have equivalent toxicity and degradation studies were not performed on M-3.  Table 3.3 lists the environmental fate parameters for the fenpyroximate TRC that are relevant for exposure modeling.  Degradation half-lives reflect regression of the total residues at each study interval.  Batch equilibrium data were available for M-3 (MRID 45649708).  Chemical properties of the parent compound were used to represent those of the residues of concern due to the lack of data on M-3.

Table 3.3.  Environmental fate parameters of the total residues of concern
Parameter
Value
Source
                                  Persistence
Hydrolysis half-life (25C)
Stable (pH 5, 7, 9)
MRID 44847909
Aqueous photolysis half-life (25C)
12 hrs (0.98 solar days)
MRID 44781016
Aerobic soil metabolism half-life (25C)
31, 47 d
MRID 45187901/ 45649706

53 d
MRID 46158501
Aerobic aquatic metabolism half-life (20C)
37, 44 d
MRID 47521406
Anaerobic aquatic metabolism half-life (25C)
149 d
MRID 45649707
                                   Mobility
Range of Freundlich organic carbon normalized partition coefficients (KFOC)
Parent: 7,550-58,300 L/kgOC (n=5)
MRID 45649709

M-3: 124-1,310 L/kgOC (n=4)
MRID 45649708

   .1.    Drinking Water Exposure Modeling

      .1.1.       Models
      
         .1.1.1.   FIRST

      The FQPA Index Reservoir Screening Tool (FIRST v1.1.1, Mar. 25, 2008; USEPA, 2008) is a Tier I screening model that simulates the upper-end exposure of the standard water body, the Index Reservoir, to pesticide residues in runoff and spray drift from an application within the standard watershed.  Peak and annual mean EDWCs are generated to estimate acute and chronic exposure.  The Index Reservoir covers 5.2 hectares (ha) with an average depth of 2.74 meters (m) in a standard watershed of 172.8 ha.  A more detailed description of the index reservoir watershed can be found in Jones et al., 2010.  The FIRST model and user's manual are available from the EPA Water Models web-page (USEPA, 2012).
      
         .1.1.2.   Provisional Cranberry Model
      
      The Provisional Cranberry Model is a provisional refinement to the Tier I Rice Model (v1.0, May 8, 2007).  Refinements include the addition of simple degradation processes in dry and flooded conditions and a water depth of twelve inches, rather than the water depth of four inches used in the rice model.  These modifications allow estimation of screening-level peak and annual mean EDWCs of fenpyroximate residues of concern that may occur in untreated surface water used as drinking water following use on cranberries.

      The Tier I Rice Model relies on an equilibrium partitioning concept to provide conservative estimates of EDWCs resulting from application of pesticides to rice paddies.  When a pesticide is applied to a rice paddy, the model assumes that it will instantaneously partition between a water phase and a sediment phase.  The model does not account for pesticide degradation, mass transfer between the aqueous phase and the sediment, volatilization, dilution, or other dissipation processes.  The Tier I Rice Model was calibrated to generate estimates that are consistent with or conservative for dissolved concentrations measured within rice paddies and in discharged paddy water.  The model was not evaluated or calibrated for concentrations measured in sediment and does not account for residues bound to suspended sediment.  Guidance for using the Tier I Rice Model may be found on the U.S. Environmental Protection Agency (EPA) Water Models web-page (USEPA, 2012).  
      
      The Provisional Cranberry Model is based on the same assumptions as the Tier I Rice Model, with the addition of degradation processes in dry and flood conditions and a water depth of twelve inches in the flooded cranberry bog.  Degradation of fenpyroximate residues of concern is assumed to occur predominantly via aerobic microbial metabolism, whether on dry cranberry bog soil or in bog flood water.
      
      The cranberry bog water depth of twelve inches is a maximum depth recommended by the Cape Cod Cranberry Growers Association (2001).  Previous assessments of mesotrione uses that employed the Provisional Cranberry Model assumed a water depth of eighteen inches (DP barcode 339984, USEPA, 2004; DP barcode 325840, USEPA, 2006a), which is within the range of water depths traditionally used.  However, modern water conservation pressures are causing cranberry growers to reduce the flood depth to fewer inches above the vertical cranberry branches, which grow up to eight inches high (Cape Cod Cranberry Growers Association, 2001; The Cranberry Institute, 2008).  Therefore, a twelve-inch deep flood is a reasonable refinement to model assumptions.  The equations used in the Provisional Cranberry Model are briefly described in Appendix C.

	EDWCs generated with the Provisional Cranberry Model have not been evaluated.  However, the Tier I Rice Model is expected to generate conservative EDWCs that exceed peak measured concentrations of pesticides in water bodies well downstream of rice paddies by less than one order of magnitude to multiple orders of magnitude.
      
         .1.1.3.   SCI-GROW
      
      Screening Concentration in Ground Water (SCI-GROW v2.3, Jul. 29, 2003; USEPA, 2002) is a regression model used as a screening tool to estimate pesticide concentrations found in ground water used as drinking water.  SCI-GROW was developed by fitting a linear model to ground water concentrations with the Relative Index of Leaching Potential (RILP) as the independent variable.  Ground water concentrations were taken from 90-day average high concentrations from Prospective Ground Water studies.  The RILP is a function of aerobic soil metabolism and the soil-water partition coefficient.  The output of SCI-GROW represents the concentrations of pesticide residue that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination and likely to serve as a drinking water source.  The SCI-GROW model and user's manual is also available from the EPA Water Models web-page (USEPA, 2012).  FIRST, the Provisional Cranberry Model, and SCI-GROW were used to estimate screening-level exposure of drinking water sources to total residues of concern of fenpyroximate.

      .1.2.       Input Parameters
      
         .1.2.1.   FIRST

	Input parameters for FIRST follow in Table 3.4.  The modeled use pattern represents the current or proposed use pattern of highest estimated exposure, which is the current use on ornamentals (two aerial applications per year at 0.343 lbs a.i./acre).  A reapplication interval for use on ornamentals is not stated on the label; however, the label prohibits consecutive applications of products with the same mode of action.  Therefore, a reapplication interval of 6 days was modeled, assuming that treatments may be necessary every 3 days, with an alternative chemistry applied between applications of fenpyroximate.

Table 3.4.  FIRST input parameters for total residues of fenpyroximate [A]
Input Parameter
Value
Comments
Source
Application rate (lbs a.i./A)
0.343
Maximum proposed single application rate
EPA Reg. No. 71711-4
Number of applications per year
2
Number of applications at the maximum application rate that achieves the maximum rate per growing season.
EPA Reg. No. 71711-4
Application interval (d)
6
Assumed in the absence of label directions (see text for discussion).
EPA Reg. No. 71711-4
Percent cropped area
87%
Default agricultural PCA
Jones et al., 2010a
Organic carbon partition coefficient (KOC) (L/kgOC)
Parent: 34,000
M-3: 649
Represents the mean KFOC values for parent (n=5) and M-3 (n=5).
MRID 45649708, 45649709
Aerobic soil metabolism half-life (days)
56
Represents the upper 90% confidence bound on the mean of three half-lives for the residues of concern.
MRID 45187901/ 45649706, 46158501
Wetted in?
No
Not required.
EPA Reg. No. 71711-4
Method of application
Aerial
Application method assumed in the absence of label directions for ornamentals.
EPA Reg. No. 71711-4
Solubility in water (ppm)
Parent: 0.026
M-3: 25
Upper limit for parent and lower limit for M-3in pH 7 water.
MRID 44781003, 45649708
Aerobic aquatic metabolism
half-life (days)
51
Represents the upper 90% confidence bound on the mean of two half-lives for the residues of concern.
MRID 47521406
Aqueous photolysis half-life (days)
0.975
Represents the maximum half-life for the residues of concern.
MRID 44781016
 [A]  Source data are in Tables 3.1-3.3.
 
	Chemical property input values were chosen in accordance with current input parameter guidance (USEPA, 2009).  Based on analysis of total residues of concern, the 90% confidence bound on the mean half-life for aerobic soil metabolism (56 d) and for aerobic aquatic metabolism (51 d) were selected.  Water solubility limits and KOC inputs representing the mean values for the parent compound (n=5) and for M-3 (n=5) were modeled separately to bracket the potential exposure to residues of concern, representing cases of 1) no M-3 formation and 2) complete conversion of residues to M-3, which is more soluble in water and more mobile in soil than fenpyroximate and M-1.

	Standard percent cropped areas (PCA) are used as conservative default estimates of the extent of watershed on which agricultural crops of unknown specific PCA are grown (Jones et al., 2010a).  For this screening assessment, the default national PCA value of 87% was used to adjust exposure estimates because fenpyroximate is labeled for use on a variety of agricultural crops as well as ornamentals, many of which are agricultural, such as nonbearing fruit trees and vines.
      
         2.1.2.1.   Provisional Cranberry Model

      The current use of fenpyroximate on cranberries at the maximum proposed application rate (0.10 lbs a.i./acre) may occur no more than two times per year, resulting in an annual application rate limit of 0.20 lbs a.i./acre (EPA Reg. No. 71711-19).  The minimum reapplication interval of 14 days stated on the proposed label was modeled; however, this limitation is not on the current label.  If this reapplication interval is not implemented, then exposure should be reanalyzed assuming a shorter reapplication interval.
      
      Cranberry bogs are often flooded on the night before harvesting.  EPA Reg. No. 71711-19 states not to apply fenpyroximate to cranberries within 1 day of harvest.  Therefore, the single application rate (0.10 lbs a.i./acre) was aged on dry soil with the Provisional Cranberry Model for two durations that are 14 days apart: 16 and 2 days.  The resulting residues (in lbs a.i./acre) were summed together for each residue and input into the flooded component of the model to estimate exposure in bog tailwater following harvest.  Peak and annual mean EDWCs were calculated beginning three days after flooding to account for transport time to a down-gradient drinking water intake following release of bog tailwater not long after flooding.  Chemical property input values were calculated for modeling as was done for FIRST.  Model input parameters are listed in Table 3.5.  As stated above, the default national PCA value of 87% was used to adjust exposure estimates in this assessment.
      
Table 3.5.  Provisional Cranberry Model input parameters for total residues of fenpyroximate A
Input Parameter
Value
Comments
Source
Application rate
(lbs a.i./A)
0.10
Maximum proposed single application rate
EPA Reg. No. 71711-19
Applications per year
2
Maximum number of applications per year at the maximum single application rate
EPA Reg. No. 71711-19
Application-to-harvest intervals (d)
2, 16
Intervals between applications and harvest are discussed in the text above.
EPA Reg. No. 71711-19
Organic carbon partition coefficient (KOC) (L/kgOC)
Parent: 34,000
M-3: 649
Represents the mean KFOC values for parent (n=5) and M-3 (n=5).
MRID 45649708, 45649709
Aerobic soil metabolism half-life (days)
56
Represents the upper 90% confidence bound on the mean of three half-lives for the residues of concern.
MRID 45187901/ 45649706, 46158501
Aerobic aquatic metabolism
half-life (days)
51
Represents the upper 90% confidence bound on the mean of two half-lives for the residues of concern.
MRID 47521406
 [A]  Source data are in Tables 3.1-3.3.
      
         3.1.3.1.   SCI-GROW
 
	Input parameters for the SCI-GROW model appear in Table 3.6.  The lowest Freundlich organic carbon partition coefficients for fenpyroximate (KFOC = 7550 L/kgOC) and M-3 (KFOC = 124 L/kgOC) were selected to bracket exposure between residues of undegraded fenpyroximate and its isomer and residues of the carboxylic acid M-3 (as was explained for modeling with FIRST).  The mean total residue half-life (44 d) from three aerobic soils was selected to approximate the biodegradation kinetics of the residues of concern in aerobic soil environments.
 
Table 3.6.  SCI-GROW input parameters for total residues of fenpyroximate. A
Input Parameter
Value
Comments
Source
Application rate (lbs a.i./A)
0.343
Maximum proposed single application rate
EPA Reg. No. 71711-4
Number of applications per year
2
Number of applications at the maximum application rate that achieves the maximum rate per growing season.
EPA Reg. No. 71711-4
Organic carbon partition coefficient (KOC) (L/kgOC)
Parent: 7,550
M-3: 124
Represent the lowest KFOC values, due to greater than 3-fold variation.
MRID 45649708, 45649709
Aerobic soil metabolism half-life (days)
44
Represents the mean of three half-lives for the residues of concern.
MRID 45187901/ 45649706, 46158501
 [A]  Source data are in Tables 3.1-3.3.

      1.5.1.       Modeling Results

	Screening estimates generated for drinking water exposure assessment are listed in Table 3.7.  The current use on ornamentals was the use resulting in maximum surface water and ground water exposure using the FIRST and SCI-GROW models, as described above.  The current use on low growing berries was the use of maximum surface water exposure using the Provisional Cranberry Model.  Modeled estimates are peak and annual mean values for total residues, using a KOC input for either fenpyroximate parent or M-3, assuming complete conversion.  Model input/output data and filenames for these estimates are attached in Appendix B.

Table 3.7.  Maximum Drinking Water Exposure Estimates for the Current and Proposed Uses of Fenpyroximate. [A]
Source (Tier: Model)
                              KOC input (L/kgOC)
                            Peak Exposure (μg/L) B
                        Annual Mean Exposure (μg/L) B
Surface water (Tier I: FIRST)
                                Parent: 34,000
                                      11
                                     0.38

                                   M-3: 649
                                      29
                                      1.9
Surface water (Tier I: Cranberry model)
                                Parent: 34,000
                                      3.6
                                     0.72

                                   M-3: 649
                                      43
                                      8.6
Ground water (Tier I: SCI-GROW)
                                 Parent: 7,550
                                   <=0.005

                                   M-3: 124
                                    <=0.27
[A]  Maximum values per model are in bold.
[B]  Surface water concentrations calculated by FIRST are 1-in-10-year values.  Ground water concentrations calculated by SCI-GROW are the highest 90-day running average.

      Exposure estimates for M-3 were substantially higher than those for the parent compound.  In surface water, the maximum exposure estimates for M-3 following use on cranberries were a peak of 43 ug/L and an annual average of 8.6 ug/L.  Maximum exposure estimates for M-3 following use on ornamentals were lower, with a 1-in-10-year peak of 29 ug/L and a 1-in-10-year annual average of 1.9 ug/L.  The Tier I screening EDWC for M-3 in ground water was 0.27 ug/L.

      2.5.2.       Drinking Water Treatment

	The Office of Pesticide Programs (OPP) does not have direct data on the effects of drinking water treatment on fenpyroximate.  Flocculation and sedimentation removal may be effective at reducing fenpyroximate concentrations.  Carbon filtering is also likely to reduce fenpyroximate concentrations due to the compound's affinity to organic carbon.  
Carbon filtering may be less effective at reducing M-3 concentrations, however.  Because of the absence of data on fenpyroximate and M-3, the effects of drinking water treatment were not considered in this assessment.

   5.1.     Fish Exposure

      A screening estimate of fenpyroximate residues of concern in potentially human-consumed fish was generated using the KOW (based) Aquatic BioAccumulation Model (KABAM v.1.0) and the Provisional Cranberry Model.  
      
      Provisional Cranberry Model inputs are as listed in Table 3.5 for drinking water exposure modeling, with the KOC input of 34,000 L/kgOC for the parent compound (and M-1).  M-3 was included as a residue of concern in fish because its log KOW value (4.25) estimated by EpiSUITE (v4.1) is greater than three.  Whether it is included as a residue of concern does not substantially change fish concentrations.  The cranberry model output was 3.4 ug/L, which is the 30-day mean water concentration beginning 3 days after bog flooding.  A 30-day mean concentration was used because the 30 days is the time to steady-state estimated by KABAM.  A 3-day period between flooding and release of bog water was assumed to occur to allow for harvesting.
      
      KABAM was used to estimate screening concentrations of fenpyroximate residues of concern in large fish. The bioaccumulation portion of KABAM is based on an aquatic food web bioaccumulation model published by Arnot and Gobas (2004) that relies on a pesticide's octanol-water partition coefficient (KOW) to estimate uptake and elimination constants through respiration and diet of aquatic organisms in different trophic levels.  Pesticide tissue concentrations in aquatic organisms are calculated for different trophic levels of a food web through diet and respiration.  The KABAM model and user's manual are available from the EPA Water Models web-page (USEPA, 2012).
      
      KABAM was run in default mode (see user's guide for full description), with a log KOW of 5.01, a KOC of 34,000 L/kgOC, a metabolism rate constant (kM) for small to large fish of 0.096 d[-1], a study-derived water temperature of 22°C, and the single surface water and pore water 30-day mean concentration of 3.4 μg/L, which was generated with the Provisional Cranberry Model.  The metabolism rate constant was calculated by subtracting the sum of elimination rate constants estimated by KABAM (k2 + kE +kG of 0.035 d[-1]) from the study-derived depuration rate constant (kT of 0.131 d[-1]).  This was done because KABAM does not account for metabolism by default.  The resulting fenpyroximate residues concentration in large fish was 7.1 mg/kg-bw (ww).
      
      If fenpyroximate residues were to completely convert to M-3 in the environment, the residue concentration in large fish would be estimated at 30 mg/kg-bw (ww).  This is the result of entering the KOC input of 649 L/kgOC for M-3 into the Provisional Cranberry Model and KABAM and entering the resulting 7-day mean concentration in cranberry bog water (47 ug/L) and the EpiSUITE-estimated log KOW value of 4.25 into KABAM, leaving all other input values for the modeling of fenpyroximate unchanged.  However, complete conversion to M-3 is unlikely in the environment because M-3 only formed up to 15% and 25% of the applied in the submitted soil biodegradation (MRIDs 45649706 and 46158501) and aquatic biodegradation (MRID 47521406) studies, respectively.
      
      These screening estimates represent high-end concentrations in fish that may occur following release of cranberry bog water into a stagnant fish-bearing water body.  Dissipation processes such as dilution, flow downstream, and partitioning to water body sediment were neglected.  If these screening concentrations in fish result in risk concerns, then exposure assessment refinements are needed (the concentrations do not necessarily reflect actual exposure that may occur or may have occurred).

1. CONCLUSIONS

	Screening drinking water exposure estimates for proposed fenpyroximate uses on snap beans and tropical fruits including avocado and an outdoor use on cucumbers are represented by the maximum use patterns on cranberries and ornamentals (Tables 1.1 and 3.7).  The total residues of concern of fenpyroximate include fenpyroximate parent, its cis isomer M-1, and its carboxylic acid M-3, all of which are assumed to have similar toxicity.  Maximum screening Tier I exposure estimates in ground water (0.27 ug/L) are two orders of magnitude less than those in surface water (29-43 ug/L).  The maximum screening exposure estimate in fish that may be consumed by humans is 30 mg/kg-bw (ww).

2. LITERATURE CITATIONS

Arnot, J.A. and F.A.P.C. Gobas. 2004. A food web bioaccumulation model for organic chemicals in aquatic ecosystems. Environmental Toxicology and Chemistry, 23 (10): 2343-2355

Cape Cod Cranberry Growers Association.  2001.  Cranberry Water Use: An Information Fact Sheet.  June, 2001.  Online at: http://www.cranberries.org/pdf/wateruse.pdf.  Accessed Jan. 10, 2012.

Jones, R. D., K. Costello, J. Hetrick, J. Lin, R. Parker, N. Thurman, C. Peck.  2010.  Development and Use of the Index Reservoir in Drinking Water Exposure Assessments.  U.S. Environmental Protection Agency, Office of Pesticide Programs.  April 15, 2010.  Online at: http://www.epa.gov/oppefed1/models/water/index_reservoir_dwa.html

Jones, R. D., K. Costello, J. Hetrick, J. Lin, R. Parker, N. Thurman, C. Peck, G. Orrick.  2010a.  Development and Use of Percent Cropped Area Adjustment Factors in Drinking Water Exposure Assessments.  U.S. Environmental Protection Agency, Office of Pesticide Programs.  September 9, 2010.  Online at: http://www.epa.gov/oppefed1/models/water/pca_adjustment_dwa.html

 The Cranberry Institute.  2010.  About Cranberries.  2003-2010.  Online at: http://www.cranberryinstitute.org/about_cranberry.htm.  Accessed Jan. 10, 2012.

United States Environmental Protection Agency (USEPA).  2002.  SCI-GROW User's Manual.  U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division.  Nov. 1, 2001; revised Aug. 23, 2002.

USEPA.  2003.  Stokes, J.  Fenpyroximate: Conclusion and Briefing Memorandum for 07/09/03 Meeting of the Health Effects Division (HED) Metabolism Assessment Review Committee (MARC).  DP barcode 292639.  U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances, Health Effects Division.  Internal memorandum.  Aug. 12, 2003.

USEPA.  2008.  FIRST User's Manual.  Version 1.1.1.  U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division.  Mar. 26, 2008.

USEPA.  2009.  Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides.  Version 2.1.  U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division, Oct. 22, 2009.  Online at: http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

USEPA.  2012.  Water Models.  U.S. Environmental Protection Agency, Pesticides: Science and Policy, Models and Databases.  Last updated Jan. 10, 2012.  Online at: http://www.epa.gov/oppefed1/models/water/

   6.1.    Submitted Environmental Fate Studies

MRID
Citation Reference
44781003
Todhunter, J.; Hill, J. (1999) Fenpyroximate--Technical Active Ingredient (TGAI) and Fenpyroximate 5% SC (End Use Product): Product Chemistry, Series 63: Lab Project Number: NNI-FENPY-99-003. Unpublished study prepared by SRS International Corporation. 19 p. 
44781016
Swanson, M. (1993) Direct Photolysis of Pyrazole-(carbon-14)-Fenpyroximate in a Buffered Aqueous Solution Under Artificial Sunlight: Final Report: Lab Project Number: SC910077: SC910089: E-4015. Unpublished study prepared by Battelle Memorial Institute. 126 p. 
44847909
Saxena, A.; McCann, D. (1992) Hydrolysis of Pyrazole- (carbon-14)-Fenpyroximate in Buffered Aqueous Solutions: Final Report: Lab Project Number: SC900192. Unpublished study prepared by Battelle Memorial Institute. 97 p. 
44847910
Rombke, J.; Brodesser, J. (1992) Determination of the Degradation in Soil of Fenpyroximate: Final Report: Lab Project Number: E-4020: BE-ME-107-90-01SAB1. Unpublished study prepared by Battelle Europe. 46 p. 
44847911
McCann, D. (1992) Sorption/Desorption of Pyrazole- (carbon-14)-Fenpyroximate on Soils by the Batch Equilibrium Method: Final Report: Lab Project Number: SC9101024. Unpublished study prepared by Battelle Memorial Institute. 124 p. 
45187901
Funayama, S.; Atsuko, H.; Izawa, Y. (1990) Degradation of (Pyrazole-14C) and (Benzyl-14C) Fenpyroximate in Soils Under Laboratory Conditions: Lab Project Number: E-4005. Unpublished study prepared by Nihon Nohyaku Co., Ltd. 52 p. 
45649705
Concha, M. (2001) Photodegradation of (Carbon-14) Fenpyroximate in/on Soil by Artificial Light: Lab Project Number: E-4030: 870W-1: 870W. Unpublished study prepared by PTRL West, Inc. 188 p. 
45649706
Maks, M. (2002) Degradation of Pyrazole-(Carbon-14) and Benzyl-(Carbon-14) Fenpyroximate in Soils Under Laboratory Conditions: Lab Project Number: E-4005. Unpublished study prepared by Nichino America, Inc. 8 p. 
45649707
McKemie, T.; Shepler, K. (2001) Anaerobic Aquatic Metabolism of (Carbon 14) Fenpyroximate: Lab Project Number: 889W-1: 889W: E-4031. Unpublished study prepared by PTRL West, Inc. 232 p. 
45649708
Concha, M. (2002) Soil Adsorption/Desorption of (Carbon 14) M-3 by the Batch Equilibrium Method: Lab Project Number: 1045W. Unpublished study prepared by PTRL West, Inc. 132 p. 
45649709
Concha, M. (2002) Soil Adsorption/Desorption of (Carbon 14) Fenpyroximate by the Batch Equilibrium Method: Lab Project Number: 987W: E-4033. Unpublished study prepared by PTRL West, Inc. 151 p. 
45649710
Burstell, H.; Sochor, H. (1994) Fenpyroximate Water Miscible Suspension 50g/l: Investigation of the Degradation Behaviour in Soil Under Field Conditions: Lab Project Number: E-4028: ER91DEU824: A53773. Unpublished study prepared by Hoechst Schering AgrEvo GmbH. 55 p. 
45649711
Specht, W. (1993) Determination of the Residues of Fenpyroximate (HOE 094552), M-1 (HOE 112573) and M-3 (HOE 112721) in Soil: Lab Project Number: HOE-9107: 93615/91: A53773. Unpublished study prepared by Chemische Laboratorien GMBH. 146 p. 
45649712
Baker, F.; Mickelson, K.; Hiler, R. (2001) Field Soil Dissipation of Fenpyroximate in Bare Ground in North Carolina, Arkansas, and California: Lab Project Number: 803W-1: 803W: E-4032. Unpublished study prepared by Research for Hire. 253 p. 
45734203
Hiler, R. (2002) Quantification of Metabolites M-3, M-8, and M-11 in Soil from Field Soil Dissipation of Fenpyroximate in Bare Ground in North Carolina, Arkansas and California: Lab Project Number: E-4038: 1026W: 1026W-1. Unpublished study prepared by Research for Hire. 855 p. 
46158501
Shepler, K. (2003) Aerobic Soil Metabolism of (Carbon 14) Fenpyroximate. Project Number: 1038W. Unpublished study prepared by PTRL West, Inc. 160 p.
47521401
Hiler, T. (2008) Soil Adsorption/Desorption of M-8 and M-11 by the Batch Equilibrium Method. Project Number: 1705W, 1705W/1. Unpublished study prepared by PTRL West, Inc. 269 p.
47521406
Volkl, D. (2001) (Carbon-14) Fenpyroximate (NNI-850) [Pyrazole-labelled] Degradation and Metabolism in Aquatic Systems. Project Number: E/4027/SUPP/1, 7L365. Unpublished study prepared by RCC Ltd. 134 p.
48381102
Thomas, S.; Kendall, T.; Krueger, H. (2010) Fenpyroximate: A Bioconcentration Test with the Bluegill (Lepomis macrochirus): Final Report. Project Number: 397A/140. Unpublished study prepared by Wildlife International, Ltd. 93 p.


Appendix A.  Chemical Names and Structures of Fenpyroximate and Its Transformation Products

 Table A.1.  Fenpyroximate and Its Environmental Transformation Products
Code Name/ Synonym
Chemical Name
                              Chemical Structure
                                    PARENT
Fenpyroximate (E-isomer)
IUPAC: tert-butyl (E)-α-(1,3-dimethyl-5-phenoxypyrazol-4-ylmethyleneaminooxy)-p-toluate

CAS: 1,1-dimethylethyl 4-[[[(E)-[(1,3-dimethyl-5-phenoxy-1H-pyrazol-4-yl)methylene]amino]oxy]methyl]benzoate

CAS No.: 134098-61-6

Formula: C24H27N3O4
MW: 421.50 g/mol
\s
                         MAJOR TRANSFORMATION PRODUCTS
M-1
(Z-isomer)

tert-butyl (Z)-4-[(1,3-dimethyl-5-phenoxypyrazol-4-yl)methylene-aminooxymethyl]-benzoate

Formula: C24H27N3O4
MW: 421.50 g/mol
                                      \s
M-3
(E)-4-[(1,3-dimethyl-5-phenoxypyrazol-4-yl)methylene-aminooxy-methyl]-benzoic acid
                                      \s
M-6
1,3-dimethyl-5-phenoxypyrazole-4-carbaldehyde
                                      \s
M-8
1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid
                                      \s
M-11
1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile
                                      \s
M-16
4-hydroxymethylbenzoic acid
                                      \s
Carbon dioxide
Carbon dioxide

Formula: CO2
MW: 44.1 g/mol
                                       

 
                                        
Figure A.1.  Environmental Transformation Route of Fenpyroximate (MRID 45187901, p 52).
                                        
Appendix B.  Model Input/Output Files



Input/Output Data for Individual Simulations

 FIRST Input/Output File
 
   RUN No.   1 FOR Fenpyroximate    ON   Ornamental    * INPUT VALUES * 
   --------------------------------------------------------------------
    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP
     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)
   --------------------------------------------------------------------
  0.343(  0.661)   2   6     649.0   25.0   AERIAL(16.0)  87.0   0.0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 
   --------------------------------------------------------------------
   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED
    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 
   --------------------------------------------------------------------
     56.00        2           0.00    0.98-  120.90   51.00      35.87

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1  MAR 26, 2008
   --------------------------------------------------------------------
        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      
          CONCENTRATION             CONCENTRATION            
   --------------------------------------------------------------------
             29.355                      1.909


   RUN No.   2 FOR Fenpyroximate    ON   Ornamental    * INPUT VALUES * 
   --------------------------------------------------------------------
    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP
     ONE(MULT)    INTERVAL    Koc   (PPB )   (%DRIFT)     AREA    (IN)
   --------------------------------------------------------------------
  0.343(  0.661)   2   6   34000.0   26.0   AERIAL(16.0)  87.0   0.0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 
   --------------------------------------------------------------------
   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED
    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 
   --------------------------------------------------------------------
     56.00        2          N/A      0.98-  120.90    51.00     35.87

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1  MAR 26, 2008
   --------------------------------------------------------------------
        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      
          CONCENTRATION             CONCENTRATION            
   --------------------------------------------------------------------
             10.756                      0.375

SCI-GROW Input/Output File

  SciGrow version 2.3
  chemical:Fenpyroximate
  time is  1/11/2012  10:27:46
  ------------------------------------------------------------------------
   Application      Number of       Total Use    Koc      Soil Aerobic
   rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
  ------------------------------------------------------------------------
       0.343           2.0           0.686      7.55E+03       44.0
  ------------------------------------------------------------------------
  groundwater screening cond (ppb) =   5.17E-03 
  ************************************************************************
  
  SciGrow version 2.3
  chemical:Fenpyroximate
  time is  1/11/2012  10:28:35
  ------------------------------------------------------------------------
   Application      Number of       Total Use    Koc      Soil Aerobic
   rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
  ------------------------------------------------------------------------
       0.343           2.0           0.686      1.24E+02       44.0
  ------------------------------------------------------------------------
  groundwater screening cond (ppb) =   2.69E-01 
  ************************************************************************
 
Appendix C.  Provisional Cranberry Model Equations

      The Provisional Cranberry Model is a refinement of the Tier I Rice Model v1.0 (Equations 1 and 2), which is a simple equilibrium partitioning equation that calculates a single, screening-level concentration in rice paddy water and released tailwater based on a compound's application rate and soil mobility.


 Equations 1-2:  Tier I Rice Model v1.0 (USEPA, 2007b).
 
		(1)
                                       
      and, if appropriate:
      
		(2)

      where,
      	Cw0 = initial water concentration [ug/L]
      mai' = mass applied per unit area [kg/ha]
      Kd = water-sediment partitioning coefficient [L/kg]
      KOC = organic carbon partitioning coefficient [L/kg]
      dw = water column depth = 0.10 m
      dsed = sediment depth = 0.01 m
      θsed = porosity of sediment = 0.509
      ρb = bulk density of sediment = 1300 kg/m[3]
 
 	First, the Tier I Rice Model was provisionally modified (Equation 3) to include as inputs degradation rate constants in order to estimate single, screening-level concentrations in paddy water or tailwater at a given time after application.
 
 
 Equation 3:  Provisional Modified Rice Model (Jones, 2006).
 
		(3)
    
    where,
    	Cw = water concentration [ug/L]
      t = interval since last application [d]
      k = upper 90[th] percentile degradation rate constant [1/d]

	Then, the Provisional Modified Rice Model water column depth was lengthened to a depth that is used to flood cranberry bogs (i.e., 12 inches; Cape Cod Cranberry Growers Association, 2001).


      i.e.,
      dw = water column depth = 0.305 m


	In order to model degradation prior to the flood at harvest, the application rates for n number of pre-harvest applications were independently degraded over the interim until flooding and then summed (Equation 4).


 Equation 4:  Degradation in a Dry Bog.
 
		(4)
    
    where,
      mai' = mass per unit area at flood [kg/ha]
      mai'n = mass applied per unit area on the n[th] application [kg/ha]
             k2 = upper 90[th] percentile degradation rate constant on dry bog [1/d]
      tn = interval from the n[th] application to harvest [d]
             n = number of pre-harvest applications


	These four equations and parameter sets constitute the Provisional Cranberry Model (reorganized below as Equations 4, 5, and 2 plus parameters).


 
 Equations 2, 4, and 5:  Provisional Cranberry Model.
 
		(4)
 
      where,
      mai' = mass per unit area at flood [kg/ha]
      mai'n = mass applied per unit area on the n[th] application [kg/ha]
             k2 = upper 90[th] percentile degradation rate constant on dry bog [1/d]
      tn = interval from the n[th] application to harvest [d]
             n = number of pre-harvest applications
 
      followed by:

		(5)

      and, if appropriate:

		(2)
      
      where,
      	Cw = water concentration [ug/L]
      t = interval since flood [d]
      k = upper 90[th] percentile degradation rate constant [1/d]
      Kd = water-sediment partitioning coefficient [L/kg]
      KOC = organic carbon partitioning coefficient [L/kg]
      dw = water column depth = 0.305 m
      dsed = sediment depth = 0.01 m
      θsed = porosity of sediment = 0.509
      ρb = bulk density of sediment = 1300 kg/m[3]
 
