### STATES ENVIRONMENTAL PROTECTIOn AGENCY WASHINGTON D.C., 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES 

### DP Barcode: 36823.8 PC Code: 288008 Jaouary 08, 2010 MEMORANDUM SUBJECT: 

### TO:

FROM:

THRU: 

### Drinking water assessment for aminocyclopyrachlor acid and its degradate cyclopropanecarboxylic acid (IN-

### V0977) 

### for non-crop and turf**.use~** 

### Mindy Ondish, Risk Manager Reviewer James Tompkins, Risk Manager Registration Division 

# W Christopher 

# M. Koper, Chemist

# (1/.~~1 . Environmental Risk Branch I

# ~~ Environmental Fate and Effects Division

. Brian Anderson, Acting Branch

# ~,ief 

# t> r 4.)t

# /..~ James Lin, Secondary Reviewer

- Environmental Risk Branch I Environmental Fate and Effects Division CONCLUSIONS This drinking water assessment was conducted on the parent aminocyclopyrachlor acid al)d its degradate cyclopropanecarboxylic acid (IN-V0977). 

### It was decided at the Residues ofConcern KJ10wledgebase Subcommittee (ROCKS) meeting to also assess this degradate in this assessment because oftoxicity concerns. Additional information is described in the decision memorandum 0370638 dated 15 OClober2009. Amincyclopyrachlor acid is used as a systemic herbicide used against a variety ofbroadleaf weeds (dandelion, clover, plantains, wild violet, ground ivy) and turfgrasses. The registrant is seeking registration for non-crop and turfuses. The Estimated Drinking Water Concentrations (EDWCs) for use in the human health risk assessment are based on the maximum proposed application rates specified in the product labels. For aminocyclopyrachlor acid for non-crop use, 1

### a single application of 0.284 lbs. ailacrecan be applied for a yearly maximum application rate of 0.284 lbs. a.i.1acre. For turf use, three applications of 0.108 lbs. ailacrecan be applied with a 30-day application interval for a yearly maximum application rate of 0.324 lbs. a.i./asre. For reference, the product rate table can be found in Appendix 111. The application rate for the degradate can be calculated by multiplying the applicatio6rate of the parent (e.g.: 0.284 lbs. a.i./acre) by the fraction of the maximum detected degradate fqom the submitted fate studies (0.146; MRID 475602

### 11)then multiplied by the ratio ofthe m lecular weights of the degradate to parent (86.091213.62). Following this equation, the maxi 

# k

um single application rate was 0.017 lbs. a.i./acre for non-crop use and 0.006 lbs. a.i./acre for tukf. Soil photolysis of the parent is slow (tliz = 

### 129 days; MRID 47560213) and the primary robe of formation of the degradate is through aqueous photolysis; therefore, exposure of the +gradate is most likely to occur from spray drift in aqueous environments. Based on the proposed application rates and the environmental fate properties of aminocyclopyrachlor acid, surface water and ground water contamination may aminocyclopyrachlor acid as well as its degradate cyclopropanecarboxylic acid 

### (INThe risk ofwater contamination is primarily associated with stability and mobility and toxicity and mobility ofthe degradate. Due to the difference in toxicities, this assesses is the parent and degradate separately. Tier I screening models was employed for this assessment. For surface water, the FI ST (FQPA Index Keservoir Screening Tool) Version1-1.1model was used to estimate drinking ater 

## - 

# ," concentrations. For ground water, the SCI-GROWmodel (Screening Concentration ip Ground Water Program Version 2.3 was used to predfctthe maximum acute and acute concen/trations present in shallow ground water.

I 

### Based on FIRST and SCI-GROW modeling, the surface and ground water EDWCs fo/rthe parent aminocyclopyrachlor acid and the degradate cyclopropanecarboxylic acid (IN-V0977) for the use on non-crop applications and turfgrasses are presented in Table 1. ISurface Water

Aminocyclopyrachlor



### Due to the difference in toxicities, individual EDWCs were calculated for theparent aminocyclopyrachlor acid and its degradate cyclopropanecarboxylic acid (IN-V0977),. For drinking water derived from surface water for the parent aminocyclopyrachlor acid, the FIRST model estimated the acute and chronic (annual average) concentrations at 27.487 ug/L and 16.965ug/L, respectively. For drinking water derived from surface water for the degradate cyclopropanecarboxylic acid (IN-V0977), the acute and chronic (annual average) conbentrations are 1.742ug/L and 1.246ug/L, respectively. For drinking water derived from ground water for the parent aminocyclopyrachlor acild, the SCIGROW model estimated the ground water concentration to be 40.2 ug/L, This concelhtration should be used for the acute, chronic and cancer-chronic values. In addition, since the parent is not susceptible to soil photolysis (t 112 = 

### 129 days; MRID 47560213), the degradate isnot an issue for ground water contamination; therefore, no SCI-GROW modeling was performed on the degradate.

### Environmental Fate Summary 

### The risk ofwater contamination is primarily associated with stability and mobility ofthe parent aminocyclopyrachlor acid and toxicity and mobility ofthe degradate cyclopropaneca

# 1 boxylic acid (IN-V0977). In addition, surface and ground water contamination may occur fiqmthe parent; however, since the parent is not susceptible to soil photolysis (t 112 = 

### 129daysj MRID 47560213), the degradate is not an issue for ground water contamination. Mobility 

### Based on the batch equilibrium data, adsorption of aminocyclopyrachlor (Koc =

### 2 to 26 mL/goc; MRID 475602 19) is characterized asbeing highly mobile to mobile in the test soils (QAO Classification; USEPA, 2006). Desorption constants were not provided. However, 13 -

### 39% of non-extractable residues were found in an aerobic soil metabolism study (MRID 4758022 1). Sufficient extraction methods were used and sorption increased throughout the study.1 Aminocyclopyrachlor is non-volatile (4.9 x 10" Pa. at 25OC; 3.7 x mm Hg; MRIP47559818 and 

### KH =

### 3.47 x lo-" atm-m3/mol;

### MRID 47559820) and highly soluble (2810 mg/Lat 20°C; MRID 475598 16)in water. Therefore, dissipation of aminocyclopyrachlor in the envilronment is expected to occurpredominantly via runoff and leaching. Aminocyclopyrachlor was detected at soil depths of 70 -

### 90 cm at 365 days (MRID: 47575 102),indicating that leaching ofkesidues into groundwater may occur. Degradation 

### Considering biodegradation, aminocyclopyrachlor ispersistent in aerobic aquatic (tlnnot determined; observed DTso> 

### 100 days; MRID 475602 16) and aerobic terrestrial envi onments (t1/2 = 

### 315 days; MRID 475602 14). In addition, it is relatively stable in anaerobic aq atic (tin = 

# t 1733 days; MRID 475602 17) and anaerobic terrestrial environments (tin = 

### 6932 daysb MRID 475602 15). Considering abiotic degradation, aqueous photolysis (MRID 475602 1 1)isthe major qoute of degradation and aminocyclopyrachlor is expected to degrade with a half-life of 1.2 days in shallow, clear, and well-lit natural (pH 6.2) water bodies and 7.8 days in pH 4 buffer $elution. 

### However, it is slowly photolyzed on soil (tin = 

### 129 days; MRID 47560213). I 

### Aminocyclopyrachlor is stableto hydrolysis (MRID 47560210) at pH 4 and 7. At p 9, the 

# 4 calculated half-life is 34.7 days; however, it is uncertain ifthe compound degrades befause approximately 10% ofthe applied decrease in the test substance coincided with appro~ximately 10%ofthe applied decrease in the material balance. Dissipation occurred with half-lives ranging from 22 to 126 days in terrestrial field dibsipation studies conducted in the continental United States and Canada (MRID 47575 102,475160222, 47560223, and 47560224).

### Water Resources Summary A. Monitoring: Being a new chemical, currently there is no monitoring data on the concentrations ofXhe parent aminocyclopyrachlor acid and its degradate cyclopropanecarboxylic acid (1~-~0977i in surface or ground water. B. Surface Water: Due to the stability and mobility of the parent aminocyclopyrachlor acid, the compoundmay move from the treated field to surface water through run-off which occurs shortly after application (i.e. rainfall events). Considering aqueous photolysis as the major route of dissipation, the degradate cyclopropanecarboxylic acid (IN-V0977) can form in aqueous environments and may migrate by runoff. Both the parent and degradate are mobile in soil. The tier 1drinking water concentrations derived from surface water for the parent aminocyclopyrachlor and the degradate cyclopropanecarboxylic acid (INV0977) wer? estimated using the FIRST model Version 1.1.1. 

### Input values for the FIRST model are reported,in Table 2. 

### Model outputs are included in Appendix I. Table 2: 

### FIRST Input Parameters for Aminocyclopyrachlor Acid and the Degltadate Cyclopropanecarboxylic Acid (IN-V0977) for Non-Crop and TurfUse I I 

### Parameter: Application Rate (lbs ailacre) 

### Input Value: 0.284 0.108 0.017 0.006 Maximum Number of ApplicationsIYear Application Interval (days) Percent Crop Area (as decimal) 

### Data Source/Rationale:

# ' I EPA Reg. No. 352-TI1(non-crop 

### -

Koc parent 12 Average Koc value: MRID 4756021 Degradate 2.735 Model Estimation (KOCWIN Versio 2.0) using CAS # 1759-53-1 (cyclopropanecarboxylicacid) 1 3 1 3 NA 30 NA 30 0.87 parent) EPA Reg. No. 352-TOT (turf -pareet) EPA Reg.No. 352-TI1(non-crop -degradate) EPA Reg. No. 352-TOT (turf -deghdate) 

# 1 EPA Reg. No. 352-TOT (turf -pare t) 

# 4 EPA Reg. No. 352-TI1(non-crop - EPA Reg.No. 352-TOT (turf - EPA Reg. No. 352-TI1(non-crop - egradate) degrtdate) parent) EPA Reg. No. 352-TOT (turf - EPA Reg. No. 352-TI1 (non-crop 

### -+gadate) EPA Reg. No. 352-TOT (turf

### -degr+date) I I National Default ValueAerobic Soil Metabolism Half-life (days) Parent Degradate Is the pesticide wetted-in? Method ofApplication

MRID 47559816 Model Estimation (WATERNT Vers~ion 1.01) using SMILES string O=C(O)C(Cl) (cyclopropanecarboxylic acid)

MRID 475602 16 suggested by FIRST users manual

MRID 4756021 1

(molecular weight of degradatel molecular weight ofparent) Non-Crop =(0.284 lbs. a.i./acre) x (0.146)x (86.091213.62) =0.017 lbs. a.i.1acre Turf =(0.108 lbs. a.i./acre) x (0,146)x (86.091213.62)= 0.006 Ibs. a.i.1acre Granular methad of application was selected for the degradate (Drift = 0.0% and App. Efficiency = 100%). NA =Not Applicable 373



### 0 (stable) No 

### A and B Parent valuerepresents the upper 90% confidence limit on the mean value (MRID 47560214 and 4756022 1). Degradate value is unavailable; enteqed zero as suggested by FIRST users manual Chemical not known to be activated by water I I Aerial and Ground App. (non-crop 

## - parent)

### B. 

### Ground Water: Due to the stability and mobility ofthe parent aminocyclopyrachlor acid, the compound may move from the treated field to ground water through leaching. Since the parent is not susceptible to soil photolysis (t 1,~ = 

### 129days; MRID 47560213), the degradate is not an issue fof ground water contamination; therefore, no SCI-GROW modeling was performed on the degradate. Table 3 details the input parameters for the screening level groundwater model, SCI-&ROW,for the parent aminocyclopyrachlor acid only. Model outputs are included in Appendix 1k.



### Table 

### 3: SCI-GROW Input Parameters for Aminocyclopyrachlor Acid for ~oln-crop and Turf

### Use 

# ' I I Application Rate (lbs a.i./acre) EPA Reg. No. 352-TI1(non-crop 

### -parent) EPA Reg. No. 352-TOT (turf

### -darent) 

### Parameter:

Maximum Number of ApplicationsIYear EPA Reg. No. 352-TI1(non-cro~ -parent) EPA Reg.No. 352-TOT (turf 

### -garent) 

### Input Value: Data SourceIRationale I

Aerobic Soil Metabolism Half-life (days) Parent

I I 1 Sincetheparent is not susceptibleto soil photolysis (t = 129days;MRID 47560213),the degradpteis not an issue for ground water contamination; therefore,no SCI-GROW modeling was performed.

Input Parameterswere selectedin accordancewith the Guidance for SelectingInput Parameters (Vqrsion 11) dated February 28,2002 

### References

Koc Parent



### USEPA. 2006. 

### Standardized Soil Mobility Classification Guidance. U.S. Environm~ntal Protection Agency, Office of Prevention, Pesticides and Toxic Substances, O&ce of Pesticide Programs, Environmental Fate and Effects Division, Memorandum. April 21, 2006. 373 I Value represents the upper 90% ~onfidence limit on the mean value (MRID47560214 and 475602211).

12 Average Koc value: MRID 475602 19

### Appendix I: FIRST Outputs for Aminocyclopyrachlor Acid and the Degradate Cyclopropanecarboxylic Acid (IN-V0977) for Non-Crop and Turf @se Arninocyclopyrachlor Acid 

## -Non-Crop Use 

## -Aerial Application

RUN No. 1 FORACPAcid ON Non-Crop 

### * INPUT VALUE$ 

### *

....................................................................

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INC~RP

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

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

.................................................................... METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) MIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESEq.)

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

### Aminocyclopyrachlor Acid 

# -Non-Crop Use -

### Ground Application RUN No. 1 FOR ACP Acid ON on-Crop 

### * INPUT VALUES 

### *

RATE (#/Ac) NO.APPS ~c SOIL SOLUBIL APPL TYPE %CROPPED INC~RP

ONE (MULT ) INTERVAL Koc (PPM ) (%DRIFT) AREA (14)

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) -----------------------------------------------------------------4-- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBI~ED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES 

## . -EFF) (RESER. ) (RESE~. )

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

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

### Aminocyclopyrachlor Acid 

## -TurfUse 

## -Granular Application RUN No. 1 FOR ACP Acid ON Turf 

### * INPUT VALUES 

### *

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

ONE (MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN) -----------------------------------------------------------------*-- 0.108 ( 0.307) 3 30 12.0 2810.0 GRANuL( 0.0) 87.0 0.0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) -----------------------------------------------------------------J-- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBI~ED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESE~.)

....................................................................

373.00 2 N/A 7.80- 967.20 0.00 967.20 UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008 -----------------------------------------------------------------+-- PEAK DAY (ACUTE ) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

................................................................. -t 

### - - 27.287 16.965 I 9

### Cyclopropanecarboxylic Acid (IN-V0977) -

### Non-Crop Use 

## -Granular Application RUN No. 4 FOR IN-V0977 ON Non-Crop 

### * INPUT VALUES 

### * -----------------------------------------------------------------*--

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INC~RP

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

.................................................................... I 0.017( 0.017) 1 1 2.735 149,540 GRANUL( 0.0) 87.0 010

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

0.00 2 N/A 0.00- 0.00 0.00 0.do UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, $008

-----------------------------------------------------------------4-- PEAK DAY (ACUTE ) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

.................................................................... 1.515 1.084 

### Cyclopropanecarboxylic Acid (IN-V0977) 

## -Turf Use -

### Granular Application RUN No. 5 FOR IN-V0977 ON Turf 

### * INPUT VALUES 

### *

-----------------------------------------------------------------&--

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

ONE (MULT) INTERVAL Koc (PPM) (%DRIFT) AREA (IN) I .................................................................... 0.006( 0.019) 3 30 2.735 149,540 GRANUL( 0.0) 87.0 0.0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBI&ED (FIELD) RAIN/RUNOFF - (RESERVOIR) (RES.-EFF) (RESER.) (RESE~.)

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

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

### Appendix 11: SCI-GROW Outputs for Aminocyclopprachlor Acid for Non-Crop and Turf Use Aminocyclopyrachlor Acid -

### Non-Crop Use 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 chemica1:ACP Acid time is 1/ 5/2010 13:21: 6

Application Number of Total Use Koc Soil Aerobi& rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days) __________-________------------------------------------------------&---- 0.284 1.0 0.284 1.20E+01 373.0 groundwater screening cond (ppb) = 3.523+01 I 

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

### Aminocyclopyrachlor Acid 

## -Turf Use SciGrow version 2.3 chemica1:ACP Acid time is 1/ 5/2010 13:24:15

........................................................................ Application Number of Total Use Koc Soil Aerobif rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (gays) groundwater screening cond (ppb) = 4.02E+01



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

### Appendix 111: 

### Product Rate Table

Herbicide I 352-TOR I GROUND I N A 1 0 268 I 1 I 0 268 TURF: PROFESSIONAL USE PRODUCTS I D~rPo~rt~~ DPX-KJMJ4 80XP Turf Herbicide DitPontT" DPX-MAT28 240SL Tcrrf Herbicide DuPontTM DPX-MAR8 50SG Turf Hembicide

. DclPontw DPX-KJM44 0.0646 Turf Herbicide + Fertilizer DuPontTNDPX-KJM44 0.0536 Turf Herbicide r Fertilize, DuPontTM DPX-KJM44 0.0326 Turf Herl>i~icIe + Fertilizer DuPontT" DPX-MAR8 0.06G Turf Herbicide * Fertilizer DttPontTM DPX-MAT28 0.056 Turf Herbicide r Fertilizer DuPontT" DPX-MAT28 0.036 Turf Herbicide + Fertilizer 352-TOE 352-TOG 352-TOU 352-TOT 352-TO1 352-TOO 352-IRE 352-IRG 352-IRU 0.0686 Lawn Herbicide + Fertilizer Du~ont~'" DPX-KJM14 0.0736 Lawn Herbicide + Fertilizer Dt~Pont~~ DPX-KJM44 0.0656 Lowti Herbidide + Feltilizer DuPontTM DPX-KJM44 0.059G Lawn Herbicide + Fertilizer Dc~Pont~" DPX-KJMJ4 0.0536 Lawn Herbicide + Fettilizer DuPontTM DPX-KJM44 0.0496 Law11Herbicide * Fertilizer DuPontrW DPX-KJM44 0.0396 Lawn Herbicide * Fertilizer DtsPontTNDPX-KJM44 0.0376 Lawn Herbicide + Fertilizer D~rPo~it~~ DPX-KJM14 0.0336 Lawn Herbicide * Fertilizer DuPontT' DPX-KJM44 0.036 Lawn Herl>icicle+ Fertilizer, DuPontT' DPX-KJM44 0.027G Lawn Herbicide r Fertilize, DuPontTM DPX-KJMJ4 0.0246 Lawn Herbicide + Fe~tilizer DuPontTM DPX-KJM44 '0.026 Lawn Herbicide r- ,Fertilize1 GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND

352-IRL 352-INN 352-INR 352-INE 352-ING 352-INU 352-INL 352-INA 352-INT 352-IN1 352-IN0 352-IRN 352-IRR 14 0 094 14 14 30

GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND GROUND 0 094 0 094 0 108

42 42 42 42 42 42 42 42 42 42 42 42 42

12 30 30 30 30 3 3

0 075 0 075 0 075 0 075 0 075 0 050 0 050 0 038 0 038 0 038 0 038 0 025 0 025 30 0 090 0 100 0 036 0 108 0 100 3 

### - 0 0

2 2 2 2 2 2 2 2 2 2 2 2 2 282 282

3 3 3 3 01300 01288 01324 01300

01150

1 I 01150 0) 150 0 150 0 0 150

100 0 100 0 076 CJ 076 I 076 4 

### 2 076

050 Q 050