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

Christopher

Registration

M.

Division

Koper, Chemist (1/.~~1W. 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 of broadleaf

weeds (dandelion, clover, plantains, wild violet, ground ivy) and turfgrasses. The registrant is

seeking registration for non-crop and turf uses. 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. ailacre can be applied for a yearly maximum application rate 

of 0.284 lbs. a.i.1acre. For turf use, three applications of 0.108 lbs. ailacre can 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 applicatio6 rate 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 1 1) then multiplied by the ratio of the 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 of water contamination is primarily associated with stability and mobility 

and toxicity and mobility of the 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 -1.1 model was used to estimate drinking ater ," concentrations. For ground water, the SCI-GROW model (Screening Concentration ip Ground 

Water Program Version 2.3 was used to predfct the 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/r the parent 

aminocyclopyrachlor acid and the degradate cyclopropanecarboxylic acid (IN-V0977) for the 

use on non-crop applications and turfgrasses are presented in Table 1. I 
Surface Water 

Aminocyclopyrachlor 

Due to the difference in toxicities, individual EDWCs were calculated for the parent 

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 16.965 ug/L, respectively. For drinking water derived from surface water for the degradate 

cyclopropanecarboxylic acid (IN-V0977), the acute and chronic (annual average) conbentrations 

are 1.742 ug/L and 1.246 ug/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 of water contamination is primarily associated with stability and mobility of the parent 

aminocyclopyrachlor acid and toxicity and mobility of the degradate cyclopropaneca 1 boxylic 

acid (IN-V0977). In addition, surface and ground water contamination may occur fiqm the 

parent; however, since the parent is not susceptible to soil photolysis (t 112 = 129 daysj 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 as being 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; MRIP 47559818 

and KH = 3.47 x lo-" atm-m3/mol; MRID 47559820) and highly soluble (2810 mg/L at 20°C; 

MRID 475598 16) in water. Therefore, dissipation of aminocyclopyrachlor in the envilronment is 

expected to occur predominantly via runoff and leaching. Aminocyclopyrachlor was detected at 

soil depths of 70 - 90 cm at 365 days (MRID: 47575 102), indicating that leaching of kesidues 

into groundwater may occur. 

Degradation 

Considering biodegradation, aminocyclopyrachlor is persistent in aerobic aquatic (tlnnot 

determined; observed DTso > 100 days; MRID 475602 16) and aerobic terrestrial envi onments 

(t1/2 = 3 15 days; MRID 475602 14). In addition, it is relatively stable in anaerobic aq atic t (tin = 

1733 days; MRID 475602 17) and anaerobic terrestrial environments (tin = 6932 daysb MRID 

475602 15). 

Considering abiotic degradation, aqueous photolysis (MRID 475602 1 1) is the 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 stable to hydrolysis (MRID 47560210) at pH 4 and 7. At p 9, the 4 calculated half-life is 34.7 days; however, it is uncertain if the compound degrades befause 

approximately 10% of the applied decrease in the test substance coincided with appro~ximately 

10% of the 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 of Xhe 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 compound may 

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 1 drinking 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 Turf Use 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 475602 1 

Degradate 2.735 Model Estimation (KOCWIN Versio 2.0) using 

CAS # 1759-53-1 (cyclopropanecarboxylic acid) 

1 

3 

1 

3 

NA 

3 0 

NA 

30 

0.87 

parent) 

EPA Reg. No. 352-TOT (turf - pareet) 

EPA Reg. No. 352-TI1 (non-crop - degradate) 

1 

EPA Reg. No. 352-TOT (turf - deghdate) 

EPA Reg. No. 352-TOT (turf - pare 4 t) 

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 Value 
Aerobic Soil Metabolism Half-life 

(days) 

Parent 

Degradate 

Is the pesticide wetted-in? 

Method of Application 

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 of parent) 

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 value represents 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 of the 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,~ = 129 days; 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 Since the parent is not susceptible to soil photolysis (t = 129 days; MRID 47560213), the degradpte is not an 

issue for ground water contamination; therefore, no SCI-GROW modeling was performed. 

Input Parameters were selected in accordance with the Guidance for Selecting Input 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 2 1, 

2006. 

373 

I 

Value represents the upper 90% ~onfidence 

limit on the mean value 

(MRID 47560214 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 - Turf Use - 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 

DuPontTN DPX-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 Law11 Herbicide 

* Fertilizer 

DuPontrW DPX-KJM44 

0.0396 Lawn Herbicide 

* Fertilizer 

DtsPontTN DPX-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