### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

### WASHINGTON D.C. , 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### PC Code: 036501 

### DP Barcode : 409560 Date: August 20, 2013 

### MEMORANDUM SUBJECT: 

### TO:



### FROM: Revised Drinking Water Assessment for the Registration Review of Coumaphos Wilhelmena Livingston, Chemical Review Manager, Risk Management and Implementation Branch IV Pesticide Re-evaluation Division (7508P) Sheila Piper , Chemist Registration Action Branch 6 

### Health Effects Division (7509P) . ., 

# c**~** 

# g/'¥'/! 3 Faruque Khan , Ph.D. , Semor

# Sc1ent1**~** · Environmental Risk Branch I Environmental Fate and Effects Division 

### APPROVED 

# l ..

# ~A**~** BY: Sujatha Sankula, Ph.D., Branch Chief 

## l"lC0. --;;;;= Environmental Risk Branch I (7507P) Environmental Fate and Effects Division This memorandum p rovides revised estimated drinking water concentrations (EDWC) of coumaphos and its oxygen analog coumaphoxon in surface water and groundwater in support of human health risk assessment. Coumaphos (0-[3-chloro-4-methyl-2-oxo-2H-1-benzopyran
-7-yl] 0,0-diethyl phosphorothioate) is an organophosphate insecticide/acaricide . Coumaphos can be applied by dip vats, aerosol can, dustbags, hand-held dus ters , hand-held sprayers, backrubber oiler, mechanical dusters, shaker can, and squeeze applicator. Based on the above understanding ofthe uses and methods of application on animals, there is a potential for indirect exposure of coumaphos in the environment via dislodging of applied chemical from animal hides. Coumaphos is also registered for the control of insects, mites, · and ticks on livestock and swine bedding, and to control varroa mites and small hive beetles in 

### bee hives. However, the indoor use ofcoumaphos (e.g., 

### to treat swine bedding) and the placement of coumaphos
-treated strips in bee hives would not be considered in the drinking water assessment because they do not provide complete routes of exposure to surface waters or groundwater.

### In the previous assessments, the Environmental Fate and Effects Division (EFED) assumed that the disposal of bioremidiated coumaphos dip vat solution on non-agricultural land would be a major exposure route to drinking water sources for human consumptions. Since dried sludge generated in evaporation ponds containing bioremediated dip vat solution is discarded in a landfill by USDA APHIS (US EPA, 2008), EFED concludes that exposure via application of bioremediated spent dip vat solutions to land is not an exposure pathway for drinking water sources. Therefore, the application ofbioremediated spent dip vat solutions to land is not included in estimating EDWCs in surface water and groundwater. However, during a rain event, coumaphos wash
- off from treated cattle can be potentially adsorbed into manure as well as transported as effluent from concentrated animal feeding operations (CAFOs) and pasture/rangeland. The EDWCs from runoff and wash
- off were calculated using the maximum annual application rate 

### (i.e., spray: 3 applications@ 0.021lb a.i./animal = 

### 0.063 lb a . i./animal/yr)for cattle as well as data from acceptable registrantsubmitted studies (MRID 425 1 2601) quantifying the fraction of coumaphos that becomes available for exposure after soaking a cow hide in water 

### (i.e . , wash-off fraction). 

### Table 1 provides application rates of coumaphos for selected scenarios. Since estimated application rate from rangeland runofi is approximately 38 times lower than the application rate coumaphos containing manure, the EDWCs are based on a single application of the highest coumaphos containing manure (i.e . 0.28 lbs a.i/ A) for land application. 

### In general, application rate of manure recommendation is based on nutrients (i .e. nitrogen, phosphorus and potassium) requirement for crops. For this assessment, application rate for manure applied to pasture and rangeland are based on 250 lb total nitrogen/acre per year requirement for growing warm season perennial grass in Texas. It 

### is also assumed that there is no surface water and groundwater intakes adjacent to CAFOs, therefore, runoff from CAFOs is not cons idered for drinking water assessment. Detailed descriptions and calculations of applicat ion ra tes for coumaphos were al so provide in 

### Appendix A . Table 1. Estimated Coumaphos Application Rates for Various Scenarios Sources of a.i. Wash
- Off Maximum Single Number of Maximum Annual from Application Fraction Application Rate Applications/Year Application Rate Scenario (lb/A) (lb/A) Spray Application (3 applications (ti 0.02llb/AU) Manure applied to crop 0.38 0 .28 1" 0 .28 land 0.21 0 .1 6 1 0.16 0.02 0.015 1 0.015 Runoff from range land 0.38 0.0024 3 0.0072 0.21 0.0013 3 0.004 0.02 0.00013 3 0.0004 AU= animal unit a Application rate can be split based on Total Nitrogen requirement during the growing season . 

### The residues of concern (ROC) for human health risk assessment and for tolerance expression are coumaphos and its oxygen analog coumaphoxon (U S EPA, 2007). A maximum conversion efficiency ofcoumaphos to coumaphoxon of 10.2% was derived from availab le data on photodegradation in water. This conversion efficiency was used to estimate a coumaphoxon application rate of 0.0285 lbs ai/A for drinking water modeling. The EDWCs of coumaphos and coumaphoxon were generated using Tier II PRZM/EXAMS model for surface water and T ier I 2

### SCIGROW (Screening Concentration in Ground Water Program). Pesticide Root Zone ModelGround Water model (PRZM-GW) was also used for ground water based on recent EFED guidance document dated ' (US EPA, 2012a). The recommended EDWCs for surface water and groundwater are listed in 

### Table 1 . PRZM/EXAMS model pred icted total coumaphos residue concentration (coumaphos 

### + coumaphoxon) in s urface water are not likely to exceed 2.38 J..tg/L coumaphos equivalent/L for the maximum peak concentration (acute) and 1.62 J..tg coumaphos equival ent/L for the average concentration (chronic). SCI-GROW and PRZM_ GW modeli ng res ults are listed in Table I. 

### PRZM
- GW pred icted total coumaphos residue concentration in groundwater used as drinking water is not likely to exceed 2 . 81 J..tg coumaphos equivalent/L for the maximum peak concentration (acute) and 1.22 Jlg coumaphos equivalent/L for the average concentration (chronic). 

### Table 1. 

### Recommended EDWCs for Drinking Water risk assessment for Coumaphos and Coumaphoxon Source of Drinking Estimated Drinking Water concentration (J.tg/L) Water Acute Chronic Average chronic Co umaphos Surface Water ' 2.38 1.62 1.06 Groundwater· 2.81 

### - 1.22 Coumaphoxon Surface Water 0.001 0.0001 3.52E-5 Groundwater1 ' J 0.002 

# - 0.0007 Coumaphos E quivalents (Coumaphos+Coumaphoxon) Surface Water 2.38 1.62 1.06 Groundwater• 2.81 

### - 1.22

EDWC s based on PRZM/ E XAMS model 2 EDWCs based on PRZM-GW mode l 3 Highest EDWCs derived from NC Cotton scenario 4 Highest concentrations of coumaphos oxon for acute and chronic are 0.02 fl g/ L and 0.006 fl g/L respectively for the WI Corn scenario. Since coumaphos concentrations are the highest in NC Cotton scenario, for highest additive concentrations of coumaphos and coumaphos oxon were estimated from NC Cotton. 

### In addition, PRZM-GW modeling was also performed with the estimated DTs o of2761 days based on NAFT A Kinetic modeling procedure (US EPA, 20 12b) and yielded maximum concentrations of 14.0 J..tg/L and 5 . 5 J..tg/L for acute and chronic values re spectively for groundwater using extended (100 yrs) weather data for NC Cotton scenario. These concentrations are approximately two to three orders of magnitude higher tha n the estimated acute (0 .07 J..tg/L) and chronic (0.006 J..tg/L) concentrations using 30 year weather data for the NC Cotton scenario. In addition , there is an uncertainty related to the estimated DTso value , which is approxima tely 7X hi gher than duratio n of aerobic soi l metabolism study and 15 to 23X high er than the reported field dissipation half-lives. Th erefore, recommended groundwater concentrations based on 3X of duration of aerobic soil metabolism study provide reasonab le 

## concentrations in groundwater. 3

### Modeling Approach and Input Parameters The current supported uses for coumaphos include direct application to animals, including dairy cattle, beef cattle, swine and bedding, and horses , for the control arthropod pests including ticks , scabies mites , lice , flies , fleece wonns and screw worms. Coumaphos can be applied by dip vats , aerosol can, dustbags, hand-held dusters , hand-held sprayers , backrubber oiler, mechanical dusters , shaker can, and squeeze applicator. Based on the above understand ing ofthe uses and methods of application on animals, there is a potential for indirect exposure of coumaphos in the environment via dislodging of applied chemical from animal hides. The indo or u se of coumaphos (e.g., 

### to treat swine bedding) and the placement of coumaphos-treated strips in bee hives would not be considered in the drinking water assessment becaus e they do not provide complete routes of exposure to surface waters or groundwater. Therefore, EFED believes that the application of coumaphos containing manure on agricultural land would b e a major exposure route for drinking water sources. A limited environmental fate database for coumaphos indicates that it i s a persistent (DT5

### oof> 1 year in aerobic soil) chemical and slightly mobile to hardly mobile (Koc = 1874 to 10297 Llkg) in soil according to FAO classification of mobility in soi l (FAO, 2000). The major pathway of coumaphos degradation appears to be photodegradation in water (DT5

### oof33 hours). A major degradate, oxygen analog, coumaphoxon, was detected in an aqueous photodegradation study at a maximum of 10.2% of applied chemical. Limited environmental fate data are available for coumaphoxon, which suggests that it is not a pers i stent compound in the terrestrial environment (DT

### so of 0.49 to 2.27 day s) and mobile (Koc= 198.4 L/kg) in soil according to FAO classification of mobility in soil (FAO , 2000). Since the environmental fate data suggest that the fate behavior of coumaphos and coumaphoxon differ in the envi ronment , EDWCs were estimated independently for these chemicals. 

### Residues of Concern The residues of concern (ROC) for human health risk assessment and for tolerance expression are coumaphos and its oxygen analog coumaphoxon (US EPA, 2007). 

### Models

### Surface Water The EDWCs were generated using EFED 's standard suite of models. Pe sticide Root Zone Model (PRZM v3.12.2, May 12, 2005) and Exposure Analysis Modeling System (EXAMS v2.98.04.06, Apr. 25, 2005). PRZM and EXAMS are simulation model s coupled with the i nput shell PRZM/EXAMS (PE v5.0, Nov. 15, 2006) to generate EDWCs of coumaphos and its major degradate, coumaphoxon , that may occur in surface water used as drinking water. The PRZM model simulates pesticide movement and transformation from crop application through soil residue processes. The EXAMS model simulates pesticide loading via runoff and erosion assuming a standard watershed of 172.8 ha that drains into an adjacent standard drinking water index reservoir with surface area of5.26 ha and an average depth of2.74 m. A more detailed description of the index reservoir watershed can be found in Jones 

### eta!., 1998. Standard percent 4

### cropped areas (PCA) were used for proposed uses as estimates of the extent of watershed on which crops are grown. The national default for non-agricultural use (PCA of 1.0) was applied in this assessment accord ing to the current PCA guidance (US EPA 20 12b). 

### Ground water Screening Concentration in Ground Water (SCI-GROW v2.3 , Jul. 29 , 2003) is a regression model used as a screening tool to estimate pesticide concentrations found in ground water used as drinking water. The SCI-GROW model and user ' s manual may also be downloaded from the EPA Water Models web-page (http: //www.epa.gov/oppefed1 /model s/ water /# scigrow). PCAs are not used with the SCI-GROW model. In addition, Tier 1 groundwater EDWCs for coumaphos and coumaphoxon, resulting from use as land farming were also derived using the PRZM-GW model (Pesticide Root Zone Model for Groundwater, vers ion 1.0, August 31, 20 12), with the G W-GUI (Graphical User Interface, version 1.0, August 31, 2012). PRZM-GW is a one-dimensional , finjte-difference model that estimates the concentrations ofpesticides in groundwater. It accounts for pesticide fate in the crop root zone by s imulating pesticide transport and degradation through the soil profile after a pesticide is applied to an agricultural field. PRZM-GW permits the assessment ofmultiple years ofpesticide app lication (up to 100 years) on a single site. S ix standard scenarios , each representing a different region known to be vulnerable to groundwater contamina tions , are available for use with PRZM-GW for risk assessment purposes. In PRZM-GW simulations, each ofthese standard scenarios was used. PRZM-GW output values represent pesticide concentrat ions in a vulnerable groundwater supply that is located directly beneath a rural agricultura l field following many years of pesticide application. Descriptions of all executable versions ofcurrent models used in drinking water exposure can be obtained from URL link (http: //www.epa.gov/oppefedl /models/water D. Input Parameters 

### A summary of the model input parameter values used in PRZM/EXAMS, SCI-GROW, and the PRZM_OW Models are in Table 2, Table 3, and Table 4, 

### respectively. Input parameters were selected in accordance with EFED's "Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides," 

### Version 2 .1 (USEPA, 2009). Sample model output files are located in Appendix 

### C. PRZMIEXAMS Time series for coumaphos and coumaphoxon for PA Turf scenario were also attached in Appendix C.

Table 2. PRZMIEXAMS input parameters for coumaphos and coumaphoxon Parameter Value 

### Data Source Comments 

### Coumaphos Maximum application See Appendix A

Rate lb a. i./ A (kg 0.28 (0.31) E stimated a . i./ha)



### 5

### Table 2. PRZMIEXAMS input parameters for coumaphos and coumaphoxon Parameter Value Data Source Comments Assumed , however , application r ate Number of Applications I can be split based on Total Nitrogen requirement during the growing season . Depth of Incorporation 0 Assumed (inches) Method of Application Ground spray common pract ice for application of manure Spray Drift 

### 0 Applied as manure Application Efficiency 1.0 Assumed Applied with manure spreader Scenario and PA Turf , 15-10 Based on Assumed manure applied during Application Date FL Turf, 15-10 PRZMIEXAMS dormant season

(da y-month) BSS Turf, 15-1 0 Scenarios Molecular Mass (g/mol) 362.5 US EPA2007 

# ---

Vapor Pressure (Torr) l.OE-07 US EPA2007 

# -- - Henry 's Law Constant 2 .62E
- 07 Estimated - (atm m3 /mol) Solubility in Water 20 US EPA 2007 

### --- (mg/L) Hydrolysis t 112 at pH 7.0 0 Not Available Considered stable to hydro l ysis 

### @ (days) pH 7.0 Aquatic Photolysis t 1 n 1.38 MRID 42764101 Coumaphoxon is a major degradate (days) MRID 4310390 I (10 .2%) Aerobic Soil 0 MRID 40518701 Considered stable Metabolism t1n (d)

Aerobic Aquatic 0 

# --- Inpu t parameter guidance (USEP A, Meta bol ism t 1 n (d) 2009) So il P artitioning 5904 MRID 45721401 Represent average Kroc from 4 so ils Coefficient (Koc; ml/ g 0 ) Wetted in? No 

### -- Assumed Percent Crop Area US EPA 2012c Recommended PCA for non 1.0 agricultural uses (Dec imal) 

### Coumaphoxon Maximum application Ra te lb a.i./ A (kg 0.0285 (0.031) Est imated•


### --- a.i./ha) 

### 6

### Table 2. PRZMIEXAMS input parameters for coumaphos and coumaphoxon Parameter Value Data Source Comments Number of Applications 1 Assumed Based on application rate of coumaphos Depth oflncorporation 0 Assumed __, _ (inches) Method of Application Not applicable 

# -- Degradation product of coumaphos PA Turf, 15-10 Based on Scenario and FL Turf, 15-10 PRZM/EXAMS Assumed manure applied during Application Date BSS Turf , 15-10 Scenarios dormant season Molecular Mass (glmol) 346.7 EPISUITE Estimated value

Vapor Pressure (Torr) 7.68E
- 08 EPISUITE Estimated value Henry's Law Constant 1.10E-09 EPISUITE Estimated value (atm m3 /mol) Solubility in Water 31.6 EPISUITE 4. I Estimated value (mg!L) Hydrolysis t 112 at pH 7.0 0 (days) Not available Assumed stable Aquatic Photoly sis t 112 0 Not available Assumed stable (days) Aerobic Soil 90th percentile upper confidence Metabolism DT5o (d) 4.1 MRID 48705501 bound on the mean half-life of coumaphoxon Aerobic Aquatic**8.i ~**  

### --- 2X of Aerobic Soil Metabolism Metabolism t 112 (d) 

### DTso (days)

Soil Partitioning 198.4 Coefficient 

### (Ko.;**mV~)** EPISUITE 4.1 Estimated value Percent Crop Area 1.0 US EPA 2012c Recommended PCA for non (Decimal) agricultural uses • Coumaphos application rate (0.28 lb a.i/A) x [(0.1 02 , the maximum conversion rate from aquatic photolytic degradation of coumaphos to coumaphoxon in laboratory studies) x (0.96 , the molecular weight ratio of coumaphos to coumaphoxon)] b In absence of aerobic aquatic metabolism study, 2X of aerobic soil metabolism DT 50 value was multiplied by 2 according to Guidance for selecting input parameters in modeling for environmental fate and transport of pesticides. Version 2.1 October 22, 2009. 

### Table 3. SCI-GROW (v2.3) Input Parameter Values for Coumaphos and Coumaphoxon Parameter 

# I Value 

# I Data Source 

# I Comments 

### Coumaphos Application Rate (lbs 

# I 0.28 

# I Table2 

# I --- a. i./acre) 

### 7

### Table 3. SCI-GROW (v2.3) Input Parameter Values for Coumaphos and Coumaphoxon Parameter Value Data Source Comments Number of I US EPA, 1998 See Table 2 applications Since there is a threefold difference in KFoc (mL!g) 1870 MRID 45721401 observed values , lowest non - sand KFoc value used. Aerob ic soil MRID45118631 metabolism DT50 0 Stable (days) 

### Coumaphoxon Maximum application Rate lb a.i./A (kg 0.0285 (0.031) Table2 

# --- a.i ./ha) Number of Table 2 applications 

# - - - Koc (mL/g) 198.4 EPISUITE 4 . 1 Estimated value Aerobic soil 4 .1 MRID 48705501 90 01 percentile upper confidence bound metabolism (DT50) d on the mean half-life of coumap_hoxon 

### Table 4. PRZM-GW (vl.O) 

### Input Parameter Values for Coumaphos and Coumaphoxon Data Source Comments Parameters Va lue Application Method Ground Table2 

### --- Application Rate 0 .0285 [0 . 031] Table 2 

# --- (lbs. a.i./acre) [kg/ha] Application 1 Table2 

## --·- Frequency Hydrolysis (DTso) d Stable -- · - No study Aerobic soil 1095 1 MRID 451 1 8631 Stable . Assumed 3X of duration of metabolism (DT 50 ) d study

Koc 2922 L/Kg MRID 4680841 1 Average KFoc 2 

### Coumaphoxon Application Method Ground Table2 

# --- Applica t ion Ra te 0.0285 [0.031] T able2 

# -- - (lbs. a.i./acre) [kg/ha] Application I Table2 

### --- Frequency 

### 8

### Table 

### 4. PRZM-GW 

### (vl.O) Input Parameter Values for Coumaphos and Coumaphoxon Data Source Comments Parameters Value Hydrolysis (DTso) d 0 Not available Assumed stab le 2 Aerobic soil 4.1 2 MRJD 4870550 I 9oth percentile upper confidence bound metabolism (DT so) d on the mean half-life of coumapboxon 

### Koc 198.4 EPISU ITE 4.1 Estimated value 1 Model requires a numerical value other than 0. DT 5 0 was estimated using the NAFT A degradation kinetics procedure and did not have a recommendation for modeling (Figure l, Appendix B). In addition , the estimated Single First Order (SFO) DT 50 of276 1 days is well beyond the duration of study. 2 EFED input parameter guidance: htto: //www.eoa.!wv/oooefedl /models/ water / orzm !?.w / watt orzm ow innut !?.uidance.htm 

### Results Estimated coumaphos concentrations in surface water and ground water used for drinking water are summarized in Table 5 and 6. Sample outputs from model runs are provided 

### in Appendix 

# c. PRZMIEXAMS mode l co ncentrations (f.lg/L) 

### repre sent untreated s urface water**~oncentrations.** 

### The SCIGROW and PRZM-GW concentrations represent groundwater concentration that might be expected in sha ll ow unco n f"med aquifers under sandy soils. All sc enarios run in PRZM-GW requ ired the use of an extended weather file , which allows the user to run the simulation for up to 1 00 year s in 

### o rder to observe breakthrough. The simu lated concentrations prov i ded in this assessment are conservative estimates of concentrations in drinking water. If dietary ri sks require refinement, higher- tiered, crop-specific and location- specific models and modeling scenario s can be used.



### Table 

### 5. PRZMIEXAMS EDWCs Based on Manure Containing Coumaphos and its Degradate Coumapboxon application 1-in-10 year 1-in-10 year I 

### 30- year annual Drinking Water Source Crop Scenario acute chronic average 

## I (f.lg/L) (f.lg/L) (f.lg/L) 

### Coumaphos Surface Water 1 BSS 

### Turr 0.42 0.02 0.01 FL Turf 1.65 0.85 0.64 PA Turf 2.38 1.62 0.64 Ground water NC Cotton 2.81 Not Applicable 1.22 Scenario 2 Generic 3.96 E-02 3.96 E-02 3.96 E-02 Scenario3 

### Coumaphoxon Surface Water BSS Turr 1 o.42 0.02 0.01 

### 9

### Table 5. PRZMIEXAMS EDWCs Based on Manure Containing Coumaphos and its Degradate Coumaphoxon application 1-in-10 year 1 -in-10 year 30
- year annual Drinking Water Source Crop Scenario acute chronic average (p.g/L) (Jtg/L) (Jtg/L) FL Turf l.OE-03 4.48E
- 05 3.52E-05 PA Turf l.49E03 1.33E-04 3.52E-05 Ground water WI Com 0.58 Not Applicable 6.0E-03 Scenario2 GenericScenario5 1.04£04 1 .04£04 1 .04£04 EDWCs generated using PRZM/EXAMS model 2 Highest EDWCs generated using PRZM-GW model, 3 EDWCs generated using SCIGROW model and can be considered for both acute and chronic values 

### Table 6. PRZM-GW EDWCs EDWCs Based on Manure Containing Coumaphos and its**De~radate** 

### Couma >hoxon application Application Rate and Highest Post Average Simulation Scenario 1 Daily Breakthrough Breakth rough Time Frequency Value**(~giL)** Average**(~giL)** (days) 

### Coumaphos FL Citrus 0.45 0.10 Incomplete FL Potato 4.98E
- 05 7.62E-05 Incomplete GA peanut 3.87E-05 2.46E-06 Incomplete NC Cotton 2 . 81 1.22 Incomplete 14.0:l 5.49:l Incomplete D e lmarva sweet com 0.53 0 .08 Incomplete WI com 0 . 58 0 .01 Incomplete 

### Couma >hoxon 0.028 lbs a.i ./ A x FL Citrus 3.3E-04 9 . 81E-05 2464 I applications FL potato l.04E
- 08 1 .28E-09 4574 GA peanut 1.3E-04 6.6E-05 4502 NC cotton 2.7£-03 7.0£-04 2034 Delmarva sweet com 5.0E-03 3.0E-03 1806 WI com 0 .02 6.0E
- 03 2610 These scenarios are regional vulnerable sites for groundwa ter evaluation. 2 These EDWCs are based on aerobic soil metabolism DT 50 of2761 days 

### Monitoring Data There was no national-scale or state monitoring data available for this assessment. Drinking Water Treatment There is no available information on the drinking water treatment effects on coumaphos and coumaphoxon. Uncertainties The main uncertainty as sociated with this drinking water assessment is the lack of acceptable environmental fate data for coumaphos and its degradate coumaphoxon. Limited da ta available 10

### for coumaphos and it's degradate, coumaphoxon. Supplemental photodegradation in water data (MRID 42764101 and 4276410 2) indicate that the maximum coumaphoxon concentration at any sampling time was 10.2% of cou m aphos application rate. This conversion rate was used to estimate a coumaphoxon a pplication rate of 0.0285 lb s ai/ A. In addition, there is an additional uncertainty related to the estimated DT 5

### o

### value,**whi~h** 

### is approximately 7X higher than duration of aerobic soil metabolism study and 15 to 23X higher than the reported fie ld dissipation half-lives. Groundwater concentration s were based on 3X of duration of aerobic soil metabolism study . In this drinking water assessment, EFED has attempted to locate the best available da ta regarding how to estimate coumaphos embedded in manure and potential run off fraction fro m pastures and rangeland s . Frequently, s uch information i s b etter expre ss ed as ranges rather than points , and when this is the case , EFED typically opts to use the end of rang e which would res ult in the high end es tima te ofEDWCs in order to ensure protection of human health risk from drinking water.



### 11

### References ASAE. 2005. Manure Production and Characteristics. ASAE Standard D384 . 1 FEB 03.Arnerican Society of Agricultural Engineers. St. Joseph, MI FAO 2000. Appendix 2. Parameters ofpesticides that influence processes in the soil. In FAO Information Division Editorial Group (Ed.), Pesticide Disposal Series 8. Assessing Soil Contamination. A reference Manual, Rome: Food andAgricultural Organization of the United Nations. 

### Available at http: / /www.fao.org/DOCREP/003/X2570E/X2570E06 .htm (Accessed Apri l I 0, 20 13). USDA. 2008. Agricultural Waste Management Field Handbook, Part 651. Natural Resources Conservation Services, U.S. Department of Agriculture, Washington, D.C . US EPA. 2008 . Memorandum: EFED Response to Comments for Coumaphos Registration Review Regarding Data Needed to Refine Ecological Risk Assessment Environmental Fate and Effects Division, Office of Chemical Safety and Pollution Prevention. U. S. Environmental Protection Agency (DP Barcode D347373) . US EPA. 2012a. Memorandum: Approval ofPRZM
- GW for use ofDrinking Water Exposure Assessment. Environmental Fate and Effects Division, Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. US EPA. 20 12a. Memorandum: NAFTA Guidance for Evaluating and Calculating Degradation Kinetics in Environmenta l Media. Environmental Fate and Effects Division, Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. US EPA. 20 1 2b. Development and Use of Percent Cropped Area and Percent TurfArea Adjustment Factors in Drinking Water Exposure Assessments: 2012 Update http: //www.epa. gov

### Ioppefed 1 /models/water /pea adjustment dwa.html U S EPA, 2009 . Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version II. 

### U.S . Environmental Protection Agency. Washington, D . C. http: // www.epa. govI

### oppefed 1 /models/water / US EPA. 2007. Coumaphos: Human Health Risk Assessment for Proposed Use on Honey and Honeycomb. PC Code: 036501; Petition Number: 2E6504; DP Number: D315769. US EPA, 2000 . Reregistration Eligibility Decision Addendum and FQPA Tolerance Reassessment Progress Report : Coumaphos . Office of Prevention, Pesticiqes, and Toxic Substances. United States Environmental Protection Agency. EPA 738-R-00-010. US EPA. 1998. Coumaphos -EFED Reply to Registrant's Rebuttal. Office ofPrevention, Pesticides and Toxic Substances, DP Barcodes D230394 and D239676
12

### US EPA. 1994. Coumaphos (3650 1) Reregistration Case No. 0018. Product and Residue Chemistry Chapters for the Coumaphos Reregistration Eligibility Decision · (RED) Document. DP Barcode D207 352.

13

### Appendix A In registrant-submitted wash-off studies, fresh cow hides were treated with either Co-Ral® 11.6% emulsifiable liquid (MRID 42512601) or Co-Ra l® 25% wettable powder (MRID 42512602) and then dried for 0.5, 3, or 24 hours . The wash-off fraction was measured after hides had been soaked in water for 0.5, 1, 1, or 4 hours. Results of these studies indicate that wash
- off fraction is inversely related to drying times and dependent upon the formulation 

### (Table A-1) but not affected by soaking time (data not shown) . Wash-off fractions for the wettable powder!flowable concentrate are used in the assessment since they are generall y more conservative than tho se for the emulsifiable powder/concentrate. 

### Table A-1. Percent Wash-Off for Different Formulations of Coumaphos at Different Dryin g Times (MRIDs 42512601 and 42512602) Formulation(%) Drying Time (brs) Wash
- Off Fraction• Emulsifiable powder /concentrate 0.5 0.116 3 0.046 ( 11.6) 24 0.027 Wettable powderlflowable 0.5 0.38 .., 0.21 concentrate (42) .) 24 0.20 • used m the aquatic exposure assessment 

### To accurately characterize the potential environmental exposure pa thways, select ing the appropriate livestock management system and various exposure pathway scenarios is necessary. Two scenarios were considered to estimate the application rate of coumaphos for drinking water assessment. The following scenarios and example calculations of app lication rate s are based on spray application on cattle . 

### Table A-2 provides application rates for various scenarios. 

### T bl A 2 E .

a e 

# - 

# . shmatedC 

### h A 

# r oumap os ppi lcahon R**~** 

## v . ates or anous 

# s cenar10s Sources of a.i. Wash-Off Maximum Single Number of from Applica tion Fraction Application Rate Applications/Year Scenario (lb/A) Spray Application (3 ap])lications @0.02llb/AU} Manure applied to crop 0.38 0.28 1" land 0.21 0.16 1 0.02 0.015 I Runoff from range land 0.38 0.0024 3 0.21 0.0013 3 0.02 0.00013 3 Dip Vat Application (2 applications@ 0.027 lb/AU) Manure applied to crop 0.38 0.24 I land 0.21 0.13 1 0.02 0 . 013 1 Runoff from range land 0.38 0.0031 2 0.21 0.0017 2 0.02 0.0002 2 AU = anunal umt a Appl ication rate can be split based on TN requirement during the growing season. b Three or two app lications/stocking period; maximum four stocking periods based on http: //www.epa.gov/ agriculture/agl 0 I/beefuroducts.html 

### 14 Maximum Annual Application Rate (lb/A) 0.28 0.16 0.015 0.0072 0.004 0.0004 0.024 0.0130 0.0013 0.0062 0.0034 0.0004

### Example Calculation: Manure from CAFOs (Concentrated Animal Feeding Operation) Manure i s a valuabl e soil amendment/organic fertilizer for any farming operation and has been used for centuries to supply needed nutrients for crop growth. Manure not only supplies many beneficial nutrients for crop production, but could also be a potential source for pesticides that are embedded into manure from wash-off from treated livestock. Application rate of coumaphos was estimated based on dry weight of manure application for crop production. The following steps were used to calculate the application rate of coumaphos. 

### Step 1: Total Dry Weight of Manure (DM)/AU(animal unit)lyear OM= 8.5 lb solid in manure [ASAE, 2003] /AU x 365 days= 3103 lb dry manure/AU/year or 1.55 tons/AU/year 

### Step 2: Active Ingredient in manure (AM) 

### lb a.i.!AU AM = (Ax F x S x W x PA) lb a.i ./ AU/year Where: A = application rate: 0.021lb/AU for spray application 

### F =frequency of application: 3/AU /year S = # of stocking/year: 4 (Based on 90-120 days stocking period for cattle in feedlot 1) 

### W 

### =wash-off fraction: 0.02 to 0.38 (MRIDs 42512601 and 42512602) PA =potential adsorption ofcoumaphos in manure: 0.36 (assumed based on EPISUITE est imate for adsorption into sludge) Sample calculation: AM = (0.021 x 

### 3 

### x 4 x 0.38 x 0.36) = 0.034 a.i. lb/AU 

### Step 3: Active ingredient in manure (lb a. i./ton) (0.034 a.i. lb/ 1.55 ton manure) = 0.022 lbs a.i./ton dry manure 

### Step 4: Total Nitrogen Production (TN) per animal (lbs TNIAU/year) TN= (N 

## x L x V x D ) lbs TN /AU/year Where: N =nitrogen content in manure per AU (TN lb/AU) (ASABE , 2003) L = average fraction ofN retained during storage and handl ing: 0.5 (Table 11.5, USDA, 2008) V= Fraction ofN loss due to volatili zation: 0.5 (Table 11.6, US DA , 2006) D = 365 of days /year Sample calculation:

1 http: //www.epa.gov /agriculture/ag I0 I /beefuroducts.htm I 

### 15

### TN= (0.34 x 0.5 x 0.5 x 365) = 31 lbs TN in manure/AU /y ear 

### Step 5: Total N in manure (lblton manure) (31lbs TN/1.55 ton manure) = 20 lb TN /ton manure /AU 

### Step 6: Application Rate of Manure (ton/acre) In general, application rate of manure based TN recommendation for crop types. For example, 250 lb TN/acre per year requires for growing warm season perennial grass in Texas2

. 

### Sample calculation : (250 lbs TN /acre) x (1 ton Manure /20 lbs TN) 12.5 tons manure/acre require for growing perennial grass in Texas 

### Step 7 : Application rate of active ingredient (lblacre) (0.022lbs a.i/ton) x (12.5 tons manure/acre)= 0.28 lbs a.i./acre Therefore, the application rate of0.28lbs a.i/A is based on 38% coumaphos wash-off from treated cattle. Table A-2 provides application rates per acre based on various wash
- off fractions. 

### 1 . 1. 1 Example Calculation: Non-Regulated Small CAFO**~** 

### 300 cattle Runoff of washed-off coumaphos from treated ca ttle could be a major contributor from an open non -regulated feedlot. Application rate was estimated from runoff contr ibution based on was h
off fraction o f coumaphos and animal density per acre. The follow ing equation was used in calculating application rate: Application Rate (AR) of active Ingredient (lb/A) AR (lb a.i ./ A) = (A x F x S 

### x C x W x PR X FF) Where: A = application rate: 0.021 a.i. lb/AU (spray application) F =frequency of app lication: 3 (spray application) S = # of stocking/year: 4 (Based on 90- 1 20 days stocking period for cattle in feedlot 3) 

### C =#of AU in feedlot: 300 (Murphy and Harner, 2006) W =was h- off fraction: 0.02 to 0.38 (MRIDs 42512601 and 42512602) PR =potential remova l through adsorption of coumapho s into manure: 0.64 (1-0.36) (based on EPI SUITE estimate for adsorption of coumaphos into s ludge) FF = fraction of feedlot for 10 

### hectare scenario: 0.1 (based on 3 acres (1 ha) for 300 AU, where density of 1 

### 00 cattle /acre; Murphy and Hamer, 2006) Sample calculation: AR = (0.02 1x 3 X 

### 4 X 

### 300 X 

### 0.38 X 

### 0.64 X 

### 0.1) = 1.82lb a.i ./A

2 St ichles and McFarland , http: //agrilifeextension.tamu.edu/ 3 http: //www.epa.gov/agriculture/ag I0 1/beefuroducts.htmI 

### 16

### 1.1. 2 Example Calculation: Cattle Grazing in Rangeland Runoff o f washed-off couma phos from treated cattle could be major contri butor from treated cattle grazing on rangeland. Application rate was estimated from runo ff contribution based on wash-off of coumaphos and animals stocking rate per acre. Application Rate (AR) of active Ingredient (lbs/Acre) AR = 

### (A X 

### F X 

# c X 

### W) 

### A = a pplication ra te : 0.021 lb/AU ( spray application) F = frequency of application: 3 (spray app lication) C = # ofAU in pasture / land : 0.3 (Pratt and Rasmau ssan , 200 1 ) W =wash-off fraction: 0.0 2 to 0.38 (MRID s 42512601 and 42512602) Sample calculation : AR = (0.021 X 

### 3 X 

### 0.3 X 

### 0.38) = 

### O .OOTi lb/A

17

### Appendix B 

## C oumaphos Ae r obic Soil metabo l ism
Days Percent AR

0 99 .3 0 99 .5 c 0 99 .7**~**

1 96 . 8**~** 1 99 .0 E 1 99 .0 Q) <-> 3 . 98 .0 c 3 98 .9 C) (..) 3 97.0 7 98.9 7 98 .9 7 96 . 1 14 97 . 8 14 97 . 8 14 98.7 30 98.5 60 96.5 90 91.3 120 !1R A 180 DT 60 

### ...,.,,.., FO 2761 

# - . ..... ""' 80 - 60 - 40 

## - 20 

# -

-- SFO 

# I

--- DFOP • • • • • · l ORE 0 0 100 

# ....

200 Time 

# ..

300 1."1. 

### Co 1 . 7 98 . 2 

# - · e.t 

## • 

# / 

# •**~** •• 

## ••• 

# .. f • 

## • - 

## •• 

# ...... _ .,...

_ ,,- 

### .. . .........

# - · · 

# • • • 0 100 200 300 Pa r ameters k; 0.000251 4 2 0 ·2 -4 4 0 ·"'.

· 4 4 2 0 ·2 ·4



### =oP NA DT 90 9171

NA 1 . 4 98 . 7 f
- 0 . 479, kg&0 . 0023, k,=
- 0 . 000916 )RE 16 459347678 194832180211 048451 0248402846886 1 . 5 98 . 8 N • 29.7, k • 4 . 82e·61 

### Figure 1. 

### Aero bic Soil Degradation Kinetics (MRID 48705501)



### 1 8

### Appendix C-Model Outputs Surface Water Sample PRZM!EXAMS Output Coumaphos stored as PA

_ M38

_ D .out Chemical: Coumaphos PRZM environment: PAtuifSTD.txt modified Thuday , 23 February 2006 at 18:55:08 EXAMS environment: ir298.exv modified Tueday , 26 August 2008 at 06:14:08 Metfile: w14751.dvfmodified Tueday, 26 August 2008 at 06:15:00 Water segment concentrations (ppb) Year Peak 96hr 21 Day 60Day 90Day Yearly 1961 0.01 0.01 0.01 0.00 0.00 0.00 1962 0.24 0.22 0.17 0.12 0.11 0 . 04 1963 0.37 0.35 0.28 0.25 0 .19 0 . 12 1964 0.33 0.31 0.28 0.24 0.23 0 .21 1965 0.83 0.77 0.59 0.47 0.42 0 .33 1966 1.45 1.34 1.03 0.77 0.71 0 . 52 1967 0.88 0.86 0.77 0.70 0 .68 0 .63 1968 1.47 1. 38 1.13 0.91 0.86 0 .71 1969 2.39 2.21 1.84 1.36 1.22 0.89 1970 1.35 1.30 1.18 1.07 1.04 0.99 197 1 1.46 1.40 1.23 1.12 1.07 1.00 1972 6.01 5.47 3.98 2.74 2.39 1.58 1973 2.16 2.10 1.92 1.78 1.74 1. 70 1974 1.81 1.79 1.75 1.72 1.69 1.63 1975 3.23 3.04 2.51 2.06 1.93 1.60 1976 2.22 2 . 14 1.97 1.78 1.73 1.65 1977 1.81 1.79 1.75 1.69 1.67 1.57 1978 1.64 1.62 1.58 1.55 1.55 1.47 1979 2.33 2.23 1.97 1.77 1.70 1.52 1980 1.79 1.74 1.61 1.51 1.45 1.39 1981 1.65 " 1.62 1.53 1.47 1.46 1.37 1982 1.98 1.90 1.75 1.56 1.48 1.33 1983 2 .04 1.95 1.70 1.37 1.32 1.27 1984 1.56 1.53 1.46 1.38 1.37 1.32 1985 1.48 1.46 1.39 1.31 1.29 1. 23 1986 1.48 1.44 1.34 1.24 1.22 1.19 1987 1.75 1.68 1.49 1.29 1.24 1.16 

### 191988 1.29 1.26 1. 24 1.22 1.21 l.l4 1989 1.47 1 .43 1.32 1.22 1.19 1.13 1990 1.60 1.55 1.42 1.34 1.27 1.19 Sorted results Pro b . Pe ak 96hr 21 Day 60Day 90Day Yearly 0.03 6 . 01 5.47 3 . 98 2.74 2.39 1.70 0.06 3.23 3.04 2.51 2.06 1.93 1.65 0.10 2.39 2.23 1.97 1.78 1.74 1.63 0.13 2.33 2.21 1.97 1.78 1.7 3 1.60 0.16 2.22 2 . 14 1.92 1.77 1.70 1.58 0.19 2 . 16 2 . 10 1.84 1.72 1.69 1.57 0.23 2 .04 1.95 1.75 1.69 1.67 1.52 0.26 1.98 1.90 1.75 1.56 1.55 1.47 0 .29 1.81 1.79 1.75 1.55 1.48 1.39 0 . 32 1.81 1.79 1.70 1.51 1.46 1.37 0.35 1.79 1.74 1.61 1.47 1.45 1.33 0 . 39 1.75 1.68 1.58 1.38 1.37 1.32 0.42 1.65 1.62 1.53 1.37 1.32 1.27 0.45 1.64 1.62 1.49 1.36 1.29 1.23 0.48 1.60 1.55 1.46 1.34 1.27 l.l9 0.52 1.56 1.53 1.42 1.31 1.24 1.19 0.55 1.48 1.46 1.39 1.29 1.22 1.16 0.58 1.48 1.44 1.34 1.24 1.22 1.14 0.61 1.47 1.43 1.32 1.22 1.21 1.13 0 . 65 1.47 1.40 1.24 1.22 1.19 1.00 0 . 68 1.46 1.38 1.23 1.12 1.07 0.99 0 .71 1.45 1.34 1.18 1.07 1.04 0.89 0 . 74 1.35 1.30 1.13 0.91 0.86 0.71 0 .77 1.29 1.26 1.03 0.77 0.71 0.63 0.81 0 . 88 0.86 0.77 0.70 0.68 0 . 52 0.84 0.83 0.77 0 .59 0.47 0.42 0 . 33 0.87 0.37 0 . 35 0.28 0.25 0.23 0.21 0.90 0 .33 0.31 0.28 0.24 0.19 0.12 0 . 94 0.24 0 .22 0.17 0.12 0 . 11 0.04 0 . 97 0.01 0 . 01 0.01 0.00 0.00 0.00 0.10 2.38 2 .23 1.97 1.78 1 .74 1.63 Average 1.06 of yearly averages: Inputs generated by pe5.pl- Novemeber 2006 Data used for this run : 

## 20Output File: PA

_ M38

_ D Metfile: wl475l.dvf PRZM PAturfSTD.txt scenario: EXAMS ir298 .exv environme nt file: Chemical Coumaphos Name: Descriptio Variable Value Units Comments n Name Molecular mwt 362.5 g/mol weight Henr y's henry 2.62E-0 9 atm- m/\3/mol Law Const. Vapor vapr l.OO E- 07 torr Pressure Solubility sol 20 mg/L Kd Kd mg/L Koc Koc 5904 mg!L Photolysis kdp 1.38 days Half-life half-life Aerobic kbacw 0 days Halfife Aquatic Metabolis m Anaerobic kbacs 0 days Hal fife Aquatic Metabolis m Aerobic asm 0 days Hal fife Soil Metabolis m Hydro l ys i pH7 0 days H alf- life s: Method: CAM integer See PRZM manual lncorporat DEPI em ion Depth: Applicatio TAPP 0.31 kg/ha n Rate: Applicatio APPEFF fraction n Efficiency Spra y DRFT 0 fraction of application rate applied to pond Drift Applicatio Date 15-10 dd/mm or dd/mmm or dd-mm or dd-mmm n Date Record FJLTRA 17: IPSCND UPTKF 

### 21R ecord PL VKRT 18 : PLDKRT F EXTRC 0.5 Flag fo r IR Reservoir Ind ex Res. Ru n Fl ag for RUNO F F total non e, monthl y or tot al (ave rage o f e nt ire ru n ) run of f cal c. 

### Coumaphoxan stored as PA

_Oxon.out Chemical: Coumaphos Oxon PRZM environment : PAturfSTD.txt modified Thuday, 23 February 2006 at 18:55:08 EXAMS environment: pond298.exv modified Tueday, 26 August 2008 at 06:14 : 08 Metfile : w14751.dvf mod i fied Tueday, 26 August 2008 at 06:15:00 Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly 1961 2 . 80E - 04 2.63E-04 2.06E-04 1.16E - 04 8.07E - 05 2.06E - 05 1962 2.91E-05 2.78E-05 2.31E - 05 1.67E - 05 1.24E - 05 3.40E-06 1963 9 . 67E-05 9.17E-05 7.44E-05 4 . 68E-05 3 . 40E - 05 8 . 82E - 06 1964 2 . 62E-05 2.50E-05 2.02E-05 1.58E-05 1.20E-05 3.16E-06 1965 5.26E-04 5.04E-04 4.22E-04 2.81E - 04 2.04E - 04 5.27E-05 1966 1.92E-06 1.92E-06 1.87E-06 1.71E -06 1.53E -06 4.96E - 07 1967 3.51E-04 3.37E - 04 2 .84 E-04 1.85E-04 1.39E-04 3.61E-05 1968 2.33E-04 2.16E - 04 1.57E-04 8.38E-05 5.78E - 05 1.52E - OS 1969 1.82E - 04 1.74E - 04 1.37E-04 7 .8 5E - 05 5.53E - OS 1.43E - OS 1970 2 . 81E - 03 2.62E - 03 1.99E-03 1.12E-03 7 . 80E - 04 1.99E-04 1971 1.58E - 05 1.53E - 05 1.30E-05 9.14E - 06 8.72E - 06 3.34E-06 1972 6 . 3SE - 07 5.75E - 07 3.92E-07 2 .03E - 07 1.60E - 07 7.31E-08 1973 1.97E-04 1.84E-04 1.40E-04 8 . 28E-OS 5 .84E - 05 1.49E - OS 1974 3 . 90E - 04 3.67E-04 3.01E-04 1.69E - 04 1.19E - 04 3.06E-05 1975 2.20E - 04 2.08E - 04 1.57E-04 1.03E - 04 8 . 22E - 05 2 . 18E-05 1976 4 . 16E - 06 3.80E-06 2.66E - 06 1.44E - 06 1.26E - 06 5.36E-07 1977 1.52E - 03 1.44E-03 1.18E-03 7.64E - 04 5 . 65E - 04 1.47E-04 1978 9 . 52E - 04 9.10E -04 7 .16E -04 4.97E - 04 3 . 6SE -04 9.53E - 05 1979 3.70E -06 3 . 70E -06 3.63E-06 3.35E - 06 2.99E -06 1.01E - 06 1980 2 . 13E - 04 2 . 03E - 04 1.63E-04 l.OOE -04 7 . 17E -05 1.84E - 05 1981 8.20E - 07 8.15E - 07 7.88E-07 7 . 05E - 07 6 . 28E - 07 2.01E - 07 1982 8.62E - 05 8.11E -05 6 .36E -05 3.73E-05 2.68E -05 6.91E - 06 

## 221983 1.56E-03 1.46E - 03 1.22E-03 7.32E-04 5 . 13E-04 1.34E - 04 1984 8.23E-04 7 . 74E-04 6.53E-04 4 .25E - 04 3 . 05E-04 7 .97E - OS 1985 9.54E-05 8.64E - 05 6.00E-05 3.14E -05 2 .19E-05 6 .45E - 06 1986 1.1SE - 03 1.09E-03 8.86E - 04 6.53E - 04 4 . 83E - 04 1.2SE-04 1987 5.35E-06 5.33E-06 5.18E - 06 4.73E - 06 4 . 23E -06 1.36E-06 1988 9 .02E -08 8.19E-08 7 . 17E - 08 6 . 57E-08 5 . 90E-08 2 . 3 1 E - 08 1989 1. 9 0E - 04 1.75E - 04 1.24E - 04 7 .00E - OS 5.99E -05 1 .59E - OS 1990 1.06E-05 9 . 69E - 06 6 . 90E-06 3.61E-06 2.SOE-06 8.38 E -07 Sorted results

Pro b . Peak 96 hr 21 Day 60 Day 90 Day Yearly 0 . 03 2.81E-03 2.62E - 03 1.99E-03 1.12 E- 03 7.80E-04 1 . 99E - 04 0.06 1.56E-03 1.46E - 03 1.22E - 03 7.64E - 04 5 . 6SE-04 1.47E-04 0 . 10 1.52E - 03 1.44E - 03 1 . 18E - 03 7.32E-04 5.13E-04 1.34E - 04 0 . 13 1.15E - 03 1.09E -03 8.86E - 04 6.53E-04 4.83E-04 1.25E - 04 0 . 16 9.52E - 04 9.10E - 04 7 . 16E - 04 4.97E-04 3.65E-04 9.53E - OS 0.19 8 . 23E - 04 7 . 74E - 04 6 . 53E-04 4. 2 5E-04 3.05E - 04 7.97E-OS 0.23 5 .2 6E-04 5 . 04E - 04 4 . 22E - 04 2.81E-04 2 . 04E - 04 5.27E-05 0.26 3. 9 0E-04 3.67E -04 3.01E - 04 1 . 8SE-04 1.39E - 04 3.61E-05 0 . 29 3.51E-04 3 . 37E-04 2.84E - 04 1.69E - 04 1.19E - 04 3 . 06E-OS 0.32 2 . 8 0E - 04 2 . 63E-04 2 . 06E - 04 1.16E-04 8.22E - OS 2.18E - OS 0.35 2 . 33E - 04 2 . 16E-04 1 . 63E - 04 1.03E - 04 8 .07E-OS 2.06E-OS 0.39 2 . 20E-04 2 . 08E-04 1 . 57E - 04 1 . 00E - 04 7.17E - OS 1.84E-OS 0.42 2 . 13E - 04 2 . 03E -04 1 . 57E - 04 8.38E - OS 5.99E-OS 1.59E-05 0.45 1.97E - 04 1 . 84E-04 1.40E-04 8.28E-OS 5.84E-05 1 . 52E -05 0.48 1. 9 0E-04 1.7SE-04 1.37E-04 7.85E - 05 5 .78E - OS 1 .49E - 05 0.52 1.82E-04 1.74E-04 1.24E - 04 7.00E - 05 5.53E - OS 1.43E - 05 0.55 9.67E-05 9.17E-OS 7 .44E-05 4.68E -05 3.40E - 05 8 . 82E - 06 0.58 9 . 54E - 05 8.64E - OS 6.36E-OS 3.73E-OS 2.68E-05 6.91E -06 0 . 61 8.62E - 05 8 . 11E - 05 6.00E-05 3.14E-05 2.19E-OS 6 .45E-06 0.65 2.91E-05 2.78E-OS 2 . 31E -05 1.67E - 05 1 . 24E - OS 3.40E -06 0.68 2 . 62E -05 2 . 50E-OS 2.02E - 05 1.58E -OS 1.20E - OS 3.34E-06 0 . 71 1.58E-05 1.53E-OS 1.30E-OS 9.14E-06 8.72E - 06 3 . 16E -06 0.74 1 . 06E - 05 9 . 69E-06 6.90E - 06 4 . 73E-06 4 . 23E-06 1.36E - 06 0 . 77 5 . 35E -06 5.33 E-06 5.18E-06 3 . 61E-06 2 . 99E - 06 1.01E -06 0.81 4.16E - 06 3.80E - 06 3.63E-06 3.35E -06 2.SOE - 06 8 . 38E - 07 0.84 3.70E - 06 3 . 70E - 06 2.66E - 06 1 . 71E -06 1.53E - 06 5.36E-07 0 . 87 1 . 92E - 06 1.92E - 06 1.87E - 06 1 .44E - 06 1 . 26E - 06 4 . 96E - 07 0.90 8.20E - 07 8.15E-07 7 . 88E - 07 7 . 05E-07 6 . 28E - 07 2 .01E -07 0 . 94 6.35E-07 5 . 75E-07 3.92E-07 2 . 03E-07 1.60E-07 7.31E-08 0.97 9. 0 2E -08 8 . 19E-08 7.17E - 08 6.57E - 08 5.90E-08 2.31E -08 0.10 1.49E - 03 1.40E - 03 1. 1 SE - 03 7.24E -04 5.10E - 04 1.33E - 04 Average 3.52E - 05 

### 23Inputs generated by peS.pl - Novemeber 2006 Data used fo r this run: Output File: PA_Oxon Metfile: w14751.dvf PRZM PAturfSTD .txt scenar i o: EXA MS env iron ment fi l e: pond298.exv

Chemica Coumaphos Oxon I Name: Desc ri pti Variable Va lu e on Name U nits Molecu l mwt 346.71 g/mo l ar we i ght Comments

Henry's henry 1.10E-09 atm-mA3/mol L

aw Con st. Vapor Pressure So lubilit y Kd Koc Photolys is halfl i fe Aerobic Aquatic Metabo li sm vapr so l Kd Koc kdp kbacw

Anaerob kbacs ic Aquatic Metaboli sm Aerobic asm Soil Metabo li sm 7.68E-09 torr 31.6 mg/L mg/L 198 mg/L 0 . days Ha lf- l i fe 8.2 days Halfife

0 days Halfife

4.1 days Halfife



## 24 of year ly 

### averagesHydro lys pH 7 0 days H a lf- li fe i s: Met h od: 

### CAM 1 integer See PRZM manua l l ncorpor DE PI em ation Depth : Applicati TAPP 0 . 0006 kg/h a o n Rate: Applica t i APPEFF 1 fraction on E

ffi cienc y: Spray DRFT 0 fract i o n of a p p l icat io n rate app l ied to pond Dr i ft App l i cati Dat e 3-Mar dd/mm or dd/m m m or dd -mm or dd-mmm o n Date Interval in terva l 10 days Set to 0 o r d e l ete li n e fo r sing l e app. 1 ap p. rate apprate kg/h a 1 I nterva l in t erval 10 d ays Set to 0 o r de l ete li n e for single app. 

### 2 ap p . rate a p prate kg/h a 

### 2 I nte rva l i nterva l 10 d ays Set to 0 or d e l ete l i n e fo r single app. 3 a pp . rate ap prate kg/h a 3 I nterval in terva l 10 d ays Set to 0 o r d e l ete l i ne for single app. 4 app. rate a p prate kg/h a 4 Inte rva l i nterva l 10 days Set to 0 or d elete l i ne fo r s i ngle app. 

### 5 app. rate ap prate k g/h a 

### 5 Record FILTRA 17: I PSC N D 1 U P TKF Reco rd PLVKRT 18: PLDKRT FEXTRC 0.5 F

l ag for IR EPA Index Po n d Res. Run 

### 25Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)

Application rate (lb/acre) 0.310 

### PRZM/EXAMS T ime Series PA_Coumaphos

_

TS_ SW.csv

# ~ PA_Courraphos Oxon_TS

_SW.csv 

### Ground water Sample SCIGROW Outputs SciGrow version 2.3 chemical:Coumaphos time is 7/29/2013 8:55:26 Nwnber of applications Total Use (lb/acre/yr) Koc (ml/g) .Soil Aerobic metabolism (days) 1.0 0 . 310 1 . 87E+03 1095 . 0 groundwater screening cond (ppb) = 3.96E-02 *************************** ****************************** ***************

Application rate (lb/acre) 0 . 031 SciGrow version 2.3 chemical:Coumaphos Oxen time is 7/29/2013 8:56:15 Nwnber of applications Total Use (lb/acre/yr) Koc (ml/g) Soil Aerobic metabolism (days) 1.0 0.031 1.98E+02 4.1 groundwater screening cond (ppb) 

## = 1.04E-04 **********************************************************************



## 26

### Sample PRZM-GW Outputs [i;l PIUM-(;W (Venoon 1 01) :::- 

### I'X 1



# ...**--.~..._.**



### ...- s- G ...,.., - s - -.- .H
- ......, - Cot19.<...., 

### s........,.o..- .__ ___ _, NQk· T me...,.. output is delwoed tolhe wM<i'lg drectOIJ Sl>tdied**~**

I 

## ... HighestOaij>Val""[ppb)**~**

SmulationAve<ageV-[ppb)**~**



### I Save Grooh 

### I Average Breal<t1YC119> T mo**)** lncomplele

### Tl·~**~** Post Breal<t!YOI9>A""'IOI [ppb) fl nocmpleee ]**/O F~Fil!** **~-** NC.wlna

_Celt..,.1110j<t**/0W<ri< Diectory**  C**adel&~~\** 

### North Carolina I§ PRZM GW (Vemon 1.01) 

### 1:- !lXI



# ... 

# --**~** 

# ... ------ Pes

bade Seenaritt G enotal Scenario: Hori ""' Ccnligu<ation I Sum,...y Outi>A Nelle. Time,..,.. outi>A is dolivered to the working drectory speclied below H 9>est0aij> V alue[ppb) 

### I0 0027• 

### I Sin<la t ionAveroge V alue[ppb) J o.0006 5S 

### I Ave<oge Break.tl'olavgh T me (days) \§ .7 73 

### I**Tlvo lii1>UII** **~** Poll Br ea!<t

lvavgh AvOfage [ppb ) l

o .000658 

### I 0. 003 .---------- -- ----- --,



### I Save G<aph 

### I I Ccc>loGrac>h l 1/0Fq Fii! Name:**NC Q,..,.** **,** 1/0 Work<1g0r ectory. C.**\Modell~\**


### NC Cotton 27