UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, ,D.C. 20460 OFFICE OF PREVE~TION, PESTICIDES AND TC)XIC SUBSTANCES



### Date: ~ukust 7,2009 MEMORANDUM SUBJECT: 

### Propamocarb hydrochloride: Tier 

### I Drinking Water Estimated Environmental

# ~ Concentrations for use in the Human Health Risk Assessment. I 

### TO: 

### Susan Stanton, Risk Manager Reviewer Barbara Madden, Team Leader Minor Use Team Registration Division (7505P) r.? 

### FROM: 

### Chuck Peck, Environmental Engineer 

# d?/,$ Environmental Risk Branch 

### IV Environmental Fate and Effects Division (7507P) REVIEWED 

### BY: MariettaEcheverria, Environmental Scientist, RAPL 

# m.. &&\~6.cgr 

### %f 

# I {&1 Environmental Risk Branch IV 

### Environmental Fate and Effects Division (7507P) APPROVED BY: 

### Elizabeth Behl, Branch Chief Environmental Risk Branch IV 

### Environmental Fate and Effects Division (7507P) I 

## ~ EXECUTIVE SUMMARY 

### This memo summarizes the Tier I Estimated Drinking Water Concentrations (EPWCs) for propamocarb hydrochloride in support of the proposed new use on lima beans. Propamocarb h4ldrochloride (CAS 25606-41

### -I), a fungicide, is an active ingredientin several registered pesticide products, inclodingBan01 (EPA Reg.No. 432-942), Promess (EPA Reg. No. 55260-lo),Proplant (EPA Reg. No. 55260-9), sindPrevicur Flex (EPA Reg. No. 264-678). The previous drinking water assessment evaluated multiple piopamocarb hydrochloride applicationsto turf;however, a higher rate to ornamentals has been identified,reqviring a new drinking water assessment. , I 

### The assessment is a Tier I 

### screening-level assessment conducted using the models SCI@ROW

### and FIRST with maximum application rates. Additional refinements of the assessment can be dev$loped with higher tier analysis, if requested by HED. 

# ~The maximum proposed application rate for the proposed new use of lima beans consideredfor this assessment is 1.5 lbs ai/acre/application, applied 

### 4 times per year with a 7-day reapplication interval for a maximum total annual application rate of 6.0 1b ai/Alyr. The computer models FIRST (surfacewater) and SCI-GROW (groundwater)were used to develop the EDWCs for use in the human health risk assessment. Because the maximum applicationrates for the new uses assessed here are less than the application rate for container-grown ornamentals in nurseries, the values for container-grown ornamentals are recommended for use in the human health risk assessment. 

### In a previous Tier 1 drinkingwater assessment for propamocarb hydrochloride on turf grass (drinkingwater memo ofNovember 10,2003;DP Barcode 267925), an applicationrate of 8.2 lbs ai/acre applied 3 times with a 7-day retreatment interval was used. The potential label application rate for container-grown ornamentals is 128 lb ai/A (EPA Reg. No. 55260-9). The container-grown ornamentals can be retreated on a 3 week (21 day) interval. The label doesnot indicate the maximum number of applications, nor does it limit the maximum amountapplied. Using the retreatment interval of 3 weeks, over the course of a year (52 weeks), the maximum number oftreatments that are possible is 17. The total maximum annual application rate is 2,176 lbs/A/year. For ground spray applications to container-grown ornamentals, the estimated annual acute concentration ofpropamocarb hydrochloridein surfacewater sources of drinkingwater is 14,568 pg/L (ppb). The estimated chronic concentration is 1,157 pg/L. For comparison purposes, if only one application was made, the estimated annual acute concentration in surface water sources of drinking water would be 7,175 pg/L and the estimated chronic concentrationwould be 566 pg/L. The FlRST output file is attached. As a point ofreference, the previously reported acute and chronic values were 972 and 77 ppb, respectively. The acute and chronic values for lima bean applicationswere 221 and 18ppb, respectively For groundwater sourcesofdrinkingwater, the estimated concentrationofpropamocarbhydrochloride in shallow groundwater is 264 pglL. For comparison purposes, if only one application was performed, the estimated concentrationin shallowgroundwater would be 15.5 pg/L. The SCIGROW output file is attached. As a point ofreference, the previously reported value was 2.99 ppb. The reported value for lima beans is 0.73 PP~. Modeling results for propamocarb hydrochloride in surface water and groundwater are presented below in 

### Table 

### 1. Table 1. Tier I Estimated Drinking Water Concentrations for propamocarb hydrochloride use.


## 1 I Lima beans (1.5 lbs. a.i./A/applic.

### x 4 

## / 

## I a- , 

## I DRINKINGWATER SOURCE (MODELUSED) Groundwater (SCIGROW) USE (rate modeled)



# . vr-,

Surface Water (FIRST) MAXIMUM ESTIMATEDDRINIUNG WATER CONCENTRATION (EDWC) I nnhl Lima beans (1.5 lbs. a.i./A/applic.

### x 4 auulic,

(SCIGRoW) Surface Water (FIRST) applic) Lima beans (1.5lbs. a.i./Alapplic, x 4 annlicl Acute and Chronic

Container-grown ornamental (128 lbs. a.i./A/applic. x 17 applic ) Container-grown ornamental (128 lbs. a.i./A/applic. x 17 applic) Container-grown ornamental (128 lbs. a.i./A/applic.x 17 applic ) 0.73 Acute Chronic LL 1 17.7 Acute and Chronic Acute Chronic 264 14,568 1,157This assessmentis based on available environmental fate data. There are no significantdata gaps in the environmental fate database submitted by the registrant. Although data are not available fbr anaerobic aquatic metabolism, the anaerobicphase of the anaerobic soil metabolism study indicates that propamocarb hydrochloride is stable under such conditions. 

### PROBLEM FORMULATION 1 This is a Tier 

### I drinking water assessment (DWA) that uses modelingand available monibring data to estimate the groundwater and surfacewater concentrations of pesticides in drinkingwater sourc& water (pretreatment) resulting fiom pesticide use on sites that are vulnerable. Tier 

### I DWAs are designed

# do screen out chemicals with low potential risk for posing a drinking water concern. ,
I 

### ANALYSIS Use Characterization Propamocarb hydrochloride is used to control the plant disease "damping-off' and hais fungicidal activity againstPythium spp. andPhytophthora spp. Propamocarbis a systemicfhgicidepresent yregistered for the followinguses: terrestrialnonfood crops, i.e., ornamentallawns and turf, ornamental sod turffarms), and vines, containerized ornamental plants. 

# I and terrestrial and greenhousenon-food crops, i.e., ornamental herbaceousplants, ornamental wbody shrubs Application information for the proposed new use on lirna beans and the existing use on c4ntainerized ornamentals is presented in 

### Table

### 2. The containerized ornamental rate assumesthat the ornamdntalscan be treated annually 17times. Table 2. Summary use information for propamocarbhydrochlorideproposed new use and containbr-grown ornamentals. I

(EPA Reg. No. 55260-9) I Lima Beans Container-grown ornamentals

Environmental Fate and Transport Characterization Use

Based on the available data, propamocarb hydrochlorideis characterized as a moderate1 persistent, very mobile compound which could be transported to surfacewater bodies andto ground water. Itis extremely soluble in water (700,000 ppm at 25OC) has low volatility and a low adsorption coefficient 

### (Kd $= 0.67 

### - 5.2 mllg), and would be transported in a dissolved phase in runoff. Max. Single Applic. Rate

(Ibs. a.i./A) No, of Applic. 1.5
128 Annual Applic. Rate (Ibs. a.i.IA/yr) 4
17 Interval Between Applic. (days) 6.0 2,176 Applic. 

# 1 Method
I 7 

# I ~tound spray
2 1 I I G ound spray



# tThe main route of dissipationfrom laboratory studies appears to be aerobic soilmetabolism (t% = 12- 30 days). Photolysis on soil is also a possible route of dissipation for propamocarb hydrochloride on the soil surface (t% = 35 days). It is very persistent in soil under anaerobic conditions (t% = 459 days). Propamocarb hydrochloride that reaches surfacewater will degrade slowly, as it is stableto hydrolysis and aqueousphotolysis. It is also moderately persistentin sedimentunder anaerdbicconditions (t%= 100days). However,propamocarb hydrochloridedoesnot accumulate 

### in fish at significant levels (BCFs of 1.5X and 3.OX for edible and nonedibletissues, respectively). 

### Table3 summarizes the physicochemicalproperties ofpropamocarb hydrochloride.A fullassessment of the environmental fate ofpropamocarb hydrochloride can be found in the June 26,2000 memo, Section 3 for propamocarb hydrochloride to control late blight (Phytophthora infestans) on potatoes (DP Barcode 0259522 and others.) Table 3. Physical chemical properties for propamocarb hydrochloride. Parameter 

# I Value 

# I MRID 

# I Molecular Weight (g/mole) Solubility (ppm @ 25°C) Vapor Pressure (mm Hg @ 25°C) Hydrolysis half-life (days) Aquatic photolysis half-life (days) 

# I Aerobic soil metabolism half-life (days) 

# 1 12, 13, 13, 14, 14,30 

# 1 41278125 th 41278128 

# 1 Soil photolysis half-life (days) 224.7 700,000 6.0 x Stable @ pH=5,7, and 9 Stable 00071297 0007 1296 3 5 Anaerobic soil metabolism half-life (days) 4 1834608

Freudlich Soil Partition Coefficient (ml/g) (Ka)

Drinking Water Exposure Modeling I I 459

Organic Carbon-Normalized Soil Partition Coefficient (mL/g,,) (KO,)



### Models 41278129 Oh7 tsand) 0.85 (loamy sand) 5.2 (sandy loam)

An Estimated Drinking Water Concentration(EDWC) in groundwater was estimated using EFED's Tier 

### I aquatic model SCIGROW (Screening concentration in Ground Water, version 2.3; 8/8/2003). SCIGROW is a regression model used as a screening toolto estimate pesticide concentrations found in ground water used as drinking water. SCIGROW was developed by fitting a linear model to groundwater concentrations with the Relative Index ofLeaching Potential

### (RILP) as the independentvariable. Groundwater concentrationswere taken from 90-day average high concentrationsfrom Prospective GroundWater studies; the RILP is a function of aerobic soil metabolism and the soil-water partition coefficient. The output of SCIGROW represents the concentrations that might be expected in shallow unconfined aquifersunder sandy 41278130
140 (sand) 4 1 (loamy sand) 359 (sandy loam) 41278130

### soils,which is representativeofthe ground water most vulnerableto pesticide contaminationlikqlyto serve

### as a drinkingwater source. (Ref. 

### 1) An Estimated Drinking Water Concentration(EDWC) in surfacewater was estimated uding EFED's Tier I aquaticmodel FIRST (vl. 

### 1 .O; 1/1/07). FIRST (FQPA IndexReservoir ScreeningTool) is vetamode1 of PRZM and EXAMS used as a screening tool to estimate pesticide concentrations found in sprface water used as drinking water. FIRST was developed by making multiple runs of PRZM using 

### varying sorption coefficients and determining the concentration in the EXAMS indexreservoir scenario after atwb-inch single storm event. The Index Reservoir is a standardwater body used by the Office of PesticideProgramsto assess drinking water exposure (Office of Pesticide Programs, 2002). It is based on a real reservoik (albeit not currently in active use as 

### a drinking water supply), Shipman City Lake in Illinois, that is Mown to be vulnerable to pesticide contamination). The single runoff event moves a maximum of 8% oflthe applied pesticide into the reservoir. This amount can be reduced by degradation or effects of binding soil in the field. Additionally, FIRST can account for spray drift and adjusts for the area within a wate shed that is planted with the modeled crop (Percent Cropped Area). Spray drift (modeled as direct depo ition of the pesticide into the reservoir)is assumed to be 16%ofthe applied active ingredient for aerial appli ation, 6.3% for orchard air blast application, and 6.4% for other ground spray application. Despite being a

# 1 ingle event model, FIRST can account for spray drift from multiple applications. The non-agriculturalPerc$nt Cropped Area (PCA) of 100% was used in the assessment for ornamental use, while a PCA of 87% was psed for the lima bean new use. The PRZM scenarioused for FIRST developmentwas among the most vul erable, and 

# t thus resulting surface water concentrationsrepresent the upper bound values on the concentratio sthatmight be found in drinkingwater from the use of a pesticide. (Ref. 

### 2 and 3) 

# 7 I I 

### Modeling Approach and Input Parameters I , 

### Tier I modeling forthe EDWC in surfacewater and groundwater frompropamocarb hydrobhloride use on container-grown ornamentals was conducted using the maximum labeled application rate of 128 lbs a.i./A/applicationapplied seventeentimes a year for a total applicationrate of 2,176 lb ai/A/yr. 4dditionally, Tier I modeling forthe EDWC in surfacewater and groundwater from propamocarbhydrochloridtjnew use on lirnabeans was conducted using the maximum labeled applicationrate of 1.5lbs a.i./A/application pplied four times a year for a total application rate of 6 lb ai/A/yr. Physicalkhemical properties and enviro mental fate source data (from submitted studies)were presented in Table3. 

### Input valuesused for surfacewat r rriodeling presented in Table 

### 5. 

# 1
with FIRST are presented in Table 

### 4. Input values used for groundwater modeling with SCI-$~ROW~ are I I 

### ,Inrunning FIRST, the lowest non-sand adsorption coefficient (Kd= 

### 5.2) was used becduse the K, 

### model was not valid for propamocarb. In running SCIGROW, however, a 

### KO, value of 41 (lo est derived 

# t value) was used because there was greater than a three-fold variation in the range of 

### KO, values. 

### In running FIRST, an aerobic soil metabolism half-life of 20.6 days was used, as it represents the goth perc ntile on the mean for 6 available half-lives submitted by the registrants (12, 13, 13, 14, 14 and 30 days). In running SCIGROW, an aerobic soil metabolism half-life of 13.5 days was used, as it represents the medi value for these six half-lives. 

# L ITable 4. Input values for the FIRST model for propamocarb hydrochloride. I I 1 Variable Name 

# I Application Rate (lbs. ailacre) 

# 1 128 (ornamental), 1.5 (lima beans) 

# I Data Value Application Method 

# I Ground (ornamental use), aerial (lirna beans)

Aerobic Soil Metabolism 

# I T1, = 20.6 days (90~ percentile on mean of 6 values) Application Frequency Application Interval (days) Solubility Hydrolysis Photolysis 17 (ornamental), 4 (lima beans) 2 1(ornamental), 7 (lima beans) 700,000 ppm TlIz = stable Tl12 = stable
AerobicAquatic Metabolism Kd TIl2 =41.2 (2x aerobic soil metabolism) 5.2 (lowest non-sand value) Table 5. Input values for the SCI-GROW model for propamocarb hydrochloride.



### Modeling Results Variable Name Application Rate (Ibs. ailacre) Application Frequency Aerobic Soil Metabolism 

### KO,

Tier 

### I surface water and groundwater modeling results for propamocarb hydrochloride for ground spray application to container-grown ornamentals and aerial applicationto lima beans are presented in 

### Table 6. These values are recommended for use in the human health risk assessment. Output values for surface water are not modified for container grown ornamentals using the percentage crop area (PCA) adjustment factor since the value used is 1.0. Output values for surface water are modified for lima beans using the PCA adjustment factor of0.87. Outputvalues for groundwater are not adjusted for a PCA. Additionally, modeling results assume that the ornamental containers are placed directly on the soil surface. Data Value 128 (ornamental), 1.5 (lirna beans) 17 (ornamental), 4 (lima beans) Tliz= 13.5 days (median value, as 6 values available) 4 1 (lowest value; >3-fold variability )

Table 6. Tier I Estimated Drinking Water Concentrations based on propamocarb hydrochloride use on container-grown ornamentals and lima beans.

Surface Water (FIRST)

DRINKINGWATER SOURCE (MODEL USED) Groundwater (SCIGROW) Surface Water (FIRST) USE (ratemodeled) Lima beans (1.5 Ibs. a.i./Ailapplic.

### x 4 aDDlic, MAXIMUM ESTIMATEDDRINKING WATER CONCENTRATION (EDWC) ( PP~)
Lima beans (1.5 lbs. a.i.lA/applic.

### x 4 applic) Lima beans (1.5 Ibs. a.i.lA/applic.

### x 4 applic) Acute and Chronic

A applic) Lima beans (1.5 Ibs. a.i.lA/applic.

### x 4 applic) 0.73 Acute Chronic 22 1 17.7 ZZThe SCIGROW concentration represents the groundwater concentration that might b shallow unconfined aquifers under sandy soils. The output is used for both acute and chronic DRINKING WATER SOURCE (MODELUSED) Groundwater (SCIGRoW) Surface Water (FIRST)

FIRST concentrations (ppb) representuntreated surfacewater concentrations. The one-in-11

# ear peak day concentration is used for acute endpoints and the one-in-10-year annual average concentrati n is used for chronic endpoints. 

# 4
The estimated concentrations provided in this assessmentare conservative estimates ofc ncentrations in drinkingwater. 

### If dietaryrisks requirerefinement, higher tiered crop-specific and location-sp cificmodels and modeling scenarios can be used. 

# 8 USE (rate modeled) Container-grown ornamental (128 lbs. a.i./Napplic.

### x 17 applic ) Container-grown ornamental (128 Ibs. a.i./Napplic. x=-- Container-grown ornamental (128 lbs. a.i./Napplic.

### x 17 applic )

Uncertaintiesand Data Gaps This assessment is based on available environmental fate data. There are no the environmental fate database submitted by the registrant. Although data are not aquatic metabolism, the anaerobic soil metabolism study indicates that propamocarb under such conditions. (ppb) )

Two major sources of uncertainty and conservatism in this assessment include: Acute and Chronic Acute



# -- Chronic

1) Output values for surfacewater and groundwater for container-grown ornamentals were pot adjusted using a percentage crop area (PCA) factor. This assumes that for container-grown ornmentals

### the entire 178 ha watershed is treated simultaneously with propamacarb hydrochloride. 2) Both SCIGROW and FIRST were designed to model EDWCs from treated agriculturb fields. For propamocarb hydrochloride, the models have been used to estimateEDWCs from contaipers. Unlike an application to crops 

### in soil, containers can provide a barrier that impedes the loss oftpesticide to surfacewaterrunoff and permeation into the soil underneath the containers. As such, themodels may overestimate the EDWCs. I 264 14,568 1,157

References 1. SCIGROW: Users Manual (1 1/01/2001,revised 08/23/2002) 2. FIRST Users Manual (08/01/2001) 3. FIRST: A Screening Model to Estimate Pesticide Concentrations in Drinking Water (0$/01/2001) 4. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and ~rds~ort of Pesticides,Version 11(02/28/2002) 5. Use of the Index Reservoir and Percent Crop Area in EFED Drinking Water ~ssessments (12/01/1999)

I

## Appendix A Chemical Structure 

## -Propamocarb hydrochloride

### Appendix 

### B TIER I SURFACE WATER MODELING OUTPUT FILES I

RUN No. 1 FOR propamocarb ON ornamental 

### * INPUT VALUES 

### *

.................................................................. I- - RATE (#/Ac) NO .APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCO~P

ONE (MULT) INTERVAL ~d (PPM) (%DRIFT) AREA 

# IN^)

.................................................................... 128.000 (252.621) 17 21 5.2******* GROUND ( 6.4) 100.0 

## - 

# p
FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

.................................................................... METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINFD (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESERl.)

.................................................................. 20.60 2 N/A .OO- 

### . 00 41.20 

## t41.20
UNTREATED WATER CONC (MILLIGRAMS/LITER (PPM)) Ver 1.1.0 JAN 1, 2007 PEAK DAY (ACUTE ) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION

RUN No. 2 FOR propamocarb ON ornamental 

### * INPUT VALUES*,

.................................................................... RATE (#/AC) No-APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCOVP

ONE (MULT) INTERVAL ~d (PPM) (%DRIFT) AREA (INJ

.................................................................. T - 128.000 (128.000) 1 1 5.2******* GROUND ( 6.4) 100.0 

### .d I FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) ------------------------------------------------------------------*- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBIN~D (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER,)

.................................................................... 20.60 2 N/A .OO- .OO 41.20 41.2d
UNTREATED WATER CONC (MILLIGRAMS/LITER (PPM)) Ver 1.1.0 JAN 1, 20q7

.................................................................... PEAK DAY (ACUTE ) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

.................................................................. 7 

### - 7.175 ,566 RUN No. 3 FOR propamocarb ON lima beans 

### * INPUT VALUES I* RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP

ONE (MULT) INTERVAL Kd (PPM) ( %DRIFT) AREA 

### IN)^FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

.................................................................... METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RuNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.)

.................................................................... 20.60 2 N/A .oo- .OO 41.20 41.20
UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 JAN 1, 2007

.................................................................... PEAK DAY (ACUTE 1 ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

.................................................................... 214.132 16.928 RUN No. 4 FOR propamocarb ON lima beans 

### * INPUT VALUES 

### * RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP

ONE (MULT) INTERVAL Kd (PPM) ( %DRIFT) AREA (IN)

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES

### .-EFF) (RESER. (RESER.

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 JAN 1, 2007 PEAK DAY (ACUTE ) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION

### TIER I GROUND WATER MODELING OUTPUT FILES SCI-GROW Output SCIGROW VERSION 2.3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U.S. ENVIRONMENTAL PROTECTION AGENCY SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE SciGrow version 2.3 chemical:Propamocarb time is 6/23/2009 10: 4:16

........................................................................ Application Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

........................................................................ 128.000 17.0 2176.000 4.10E+01 13.5

........................................................................ groundwater screening cond (ppb) = 2.643+02



### ........................................................................ SciGrow version 2.3 chemical:Propamocarb time is 6/23/2009 10: 4:26

.................................................................... Application Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (d

.................................................................... 128.000 1.0 128.000 4.10E+01 13.5

.................................................................... groundwater screening cond (ppb) = 1.55E+01



### .................................................................... SciGrow version 2.3 chemical:Propamocarb time is 8/ 7/2009 8:36:12

........................................................................ Application Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (dqys) --------------------------------------------------------------------d--- 1.500 4.0 6.000 4.10E+01 13.5 --------------------------------------------------------------------J--- groundwater screening cond (ppb) = 7.283-01



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