1 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460

OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES

PC Code: 121301 Chemical: Cyromazine
DP Barcode: D358724 July 6, 2009

Drinking Water Assessment

SUBJECT: Drinking Water Asse ssment for New Use of Cyro mazine (Trigard 75WP (75% ai)) on Succulent Beans.

TO: Daniel Rosenblatt, Risk Manager, RM05 Susan Stanton, Risk Manager Reviewer
Insecticide Branch Registration Division (7505C)

FROM: James K. Wolf, Environmental Scientist
Environmental Risk Branch 3

Mark Corbin, Senior Scientist
Environmental Risk Branch 3

Dana Spatz, Branch Chief
Environmental Risk Branch 3
Environmental Fate and Effects Division (7507C)

The Environmental Fate and Effects Division (EFE D) was requested to prepare a drinking water assessment, as part of a Tolerance Petiti on (8E7470), for a new use of the insecticide cyromazine. The proposed new use [Labels [Supplemental 654A-S2-0508 and Technical SCP 632-L (draft use)] is to contro l leafminers on succulent beans 1 . Cyromazine is the active ingredient (ai) in Trigard ® Insecticide (75 WP) [EPA Reg. No. 100-654]. The proposed maximum application rate for this use is 0.125 lb ai/acre, with a maximum number of 6 applications per crop of succulent beans and a mi nimum reapplication interval of 7 days. The
season total is 0.75 lb ai/ acre. (Appendix 2, Table 1).

1 Includes only: Bean ( Phaseolus spp.) succulent broad bean, green lima bean, runner bean, snap bean (green bean), and wax bean; and Bean ( Vigna spp.) asparagus bean, black-eyed pea, Chinese longbean, cowpea, jackbean, moth bean, southern pea, and yardlong bean.2 The Supplemental Label for EPA Reg. No. 100-654 (SCP 654A-S2 0508) and the Technical Label 100-632 (SCP 632A-L (draft use) contain contradictory information. Page 2 of the Supplemental Label indicates that cowpeas are in cluded in the new use, whereas Page 5 of the Technical Label excludes cowpeas. This discrepancy should be clarified.

Previously, EFED prepared a Ti er 1 Drinking Water Assessment for the use of cyromazine on potatoes (D324410 – Appendix 1).The EFED Tier 1 surface water (FIR ST) and ground water (SCI-GROW) models were used. Two application rates were considered in that drinking water assessment, 6 applications @ 0.125 lb ai/acre and 3 applications @ 0.25 lb ai/acre, both with 7- day reapplication intervals. Therefore, the rate proposed for succulent beans was previously assessed (Appendix 1). Three estimates (150, 1 78, and 450 days) of aerobic soil metabolism (ASM) rates were also previously used. It was sh own previously that the half-live value selected
for ASM had little effect on the EDWC estimated with the FIRST model (Appendix 1, Table 1). The recommended EDWCs were based upon the 450 da ys ASM half-life (assumed a single value times 3). Since the last drinking water assessment the submitted environmental fate studies have
been reviewed to ensure that these data wh en used for model inputs following current EFED guidelines (USEPA, 2002). Additionally, aerobi c and anaerobic soil metabolism studies, which are being reviewed, are also cons idered in this assessment. The values used for modeling inputs were adjusted (compare Tables 3 and Appendi x 1, Table 3) to take into account addition information and updated guidance.

The estimated drinking water concentrations (EDW Cs) of cyromazine for the proposed succulent bean use (Table 1) is 47.1 and 15.8 μg/L, for the peak (acute) and annual (chronic and cancer), respectively. The EDWCs from the previ ous assessment (D324410) were 43.9 and 17.8 μg/L. Therefore, the EDWCs for the proposed new use are slightly higher fo r the acute exposure concentration and slightly less the chronic than those from the prior assessment. The increased
acute concentration is due the use of a lower K ads value (i.e., lowest non sand). The lower chronic exposure concentration is due to a decreas e in the aerobic soil metabolism half-life (T 1⁄2 ~ 147.38 days) and the addition of a default (2 times aerobi c soil metabolism) value for the aerobic aquatic metabolism rate (T 1⁄2 ~ 294.76 days) rather than assuming no aquatic metabolism. The primary degradation product of cyromazine is melamine. Th e Health Effects Division has determined that exposure to melamine derived from cyromazine does not exceed the Agencies Level of Concern (FR Vol. 64, No. 178, 09-15-99, 50043).3 Table 1. Estimated Drinking Water Concentratio ns (EDWC) of cyromazine residues for succulent beans using the Tier 1 FIRST applied as 6 applications at (0.125 lb ai/ac) rates, and
a seasonal rate of 0.75 lb ai/acre. The concentr ations have been adjusted with the Percent Crop Area (PCA) of 0.87 for a national assessment.

1-in-10 year Cyromazine Concentration
Application rate/# number/interval (lbs ai/ac/#/days) Peak ( μ g/L) Annual Mean ( μ g/L)

0.125/6/7/1 47.1 15.8

It was previously noted that (D324410) the selection of an aer obic soil metabolism rate had a greater influence on the cyromazine concentratio ns in ground water as estimated by SCI-GROW. The estimated ground water concentration ranged from 5.35 to 26.6 μ g/L (Appendix 1, Table 2), depending on half-life used. EFED had recomme nded that 6.9 μg/L be used as ground water concentration of cyromazine for human health risk assessment, which corresponded to the 178 day half-life.

EFED recommends that for this new use is that 1.1 μg/l (Table 2.) be used for acute and chronic exposure concentrations of cyromazine in gr ound water which considers the additional fate information (Koc = 99.6 mL/g
oc and mean ASM half-life of 104 days. The SCI-GROW runs are listed in the Appendix 3.

Table 2. SCI-GROW estimates of cyromazine concentrations in ground water.
Application rate/# number/interval
(lbs ai/acre/number/days) Concentration
( μ g/L)

0.125/6/7 1.1

Physical/Chemical Properties

Several physical and chemical prope rties of cyromazine are given below. The chemical structure is shown in Figure 1.

Chemical name: N-cyclopropyl -1,3,5-triazine-2,4,6-triamine Common name: Cyromazine
CAS #: 66215-27-8
Chemical Number: 121301 Empirical Formula: C 6 H 10 N 6 Molecular Weight: 166.19 Solubility in Wate r: 11600 mg/L at 25 ° C Vapor Pressure: 1.13 x 10 -9 mm Hg at 20 ° C4 Figure 1. Cyromazine Structure

Environmental Fate and Transport Characterization

Based on previously submitted data, cyromazine is stable to hydrolysis and photolysis, and is persistent in aerobic soil (T 1⁄2 > 60 days). This was confirmed in the field studies, where dissipation half-lives are as long as 250 days. Freundlic h adsorption coefficients (K ads ) for the
mineral soils are less than 5 mL/ g, and for the organic soil the K ads value was 17 mL/g. The K ads values are not equal to K d , because the slope (1/n) in the adsorption isotherm was less than 1 (0.77 to 0.85). The logarithms (1.6 to 2.3) of the Koc values are generally less than 2, which falls into the “Mobile” category as described by the EF ED Standardized Soil Mobility Classification Guidance (Bradbury, 2006). Cyromazine is also highly soluble (1.16 x 10 4 mg/L). These characteristics would suggest that cyromazine has the potential to leach th rough soils, especially sand, fine sands, and loamy sands, or to be transported in solution in runoff water.

Melamine was identified as the primary cyromazine degradate. In aerobic metabolism studies the melamine levels ranged between 33 and 60 percent of the parent (as applied radioactivity). The persistence (T 1⁄2 ), adsorption (K d ), and dissipation rate of melami ne have not been specified, but in terrestrial field studies, mela mine is shown to be more persistent and mobile than the parent, and may accumulate in soil with repeated uses. Tw o other degradates were also noted, but not
identified.

Modeling Inputs

The FIRST and SCI-GROW models were used to estimate surface water and ground water drinking water concentrations, respectively. The ae robic soil [mineral soil] metabolism half-life (t 1⁄2 ) was 142 days for a sandy loam and 107 days for a muck soil (157458, 479168-002), and 62 days for a sandy loam (437679-01). Combining th e half-life values by following EFED Input Guidance, the 90 th percent upper bound on the mean aerobic soil metabolism (ASM) half-life for the three soils is 147.38 days. Because no aerobic aquatic metabolism half-life (AAqM) studies were submitted by the Registrant, the AAqM was estimated as 2 times the ASM half-life as recommended in EFED Input Guidance Docume nt (USEPA, 2002). The lowest non-sand (2.37 mL/g) was used for the mobility input value. Freundlich K ads for mineral soils were less (0.52 to 3.87) than 5 mL/g, for a muck soil the K ads was 17 mL/g). The sorption for the organic soil (muck) was not considered because succulent be ans are not generally grown on organic soils.
The lowest non sand K ads (2.37 mL/g) was used for surface water (FIRST) and the mean Koc5 (99.6 mL/g
oc ) was used for ground water (SCI-GROW), following EFED Model Input Parameter Guidance (USEPA, 2002).

Selected physical/chemical and environmental fate properties for cyromazi ne are summarized in
Table 3.

1 The 90 th percent upper bound of mean of 107, 142, and 62 days is 147.38 days.

2 Aerobic Soil Metabolism half-life times 2, per EFED guidance (USEPA. 2002).

3 K ads 0.52 (sand), 2.37 (sandy clay loam) and 3.87 (silt loam), (not included - organic soil K ads =17.0; Koc = 128)

4 Koc model appears valid Table 3. Select Physical, Chemical, and E nvironment Properties and model input value for Cyromazine.

Parameter Range Value Used Source

Solubility in Water 1.16 x 10 4 mg/L @ 25oC MRID 437679-01

pKa (weak base) 5.22 @ 20oC Not used in FIRST or SCIGROW MRID 103148

Hydrolysis T 1/2 Stable at pH 5, 7, and 9 0 day MRID 103148

Aquatic Photolysis T 1/2 Stable in water at pH 7 0 day MRID 103149

Aerobic Soil Metabolism (ASM) T 1/2 142 days (sandy loam) 104 days (sand-muck) 62 days (sandy loam) 147.38 1 days mean = 103.67, std = 40.10 MRIDs 157458, 470168-02, 437679-01 (in review).

Anaerobic Soil Metabolism

T 1/2 97.6 days Not used 437679-02 (in review).

Aerobic Aquatic Metabolism (AAqM) T 1/2 no data (estimated as 2 times ASM) 294.76 2 days (147.38 x 2) USEPA, 2002

K ads 0.52, 2.37, 3.87 3 mL/g lowest non sand = 2.37 MRIDs 103139, 103150,
103165

Koc 40, 73, 185 mL/g 4 Lowest none sand = 73 Mean = 99.6 mL/g MRIDs 103139, 103150,
1031656 Citations:

U.S. EPA. 2006. Drinking Water Assessment; Ne w Use Rate for Trigard 75WP (75% ai) on potatoes. DP Barcode D324410 [Date: 06- 20-06]. United States Environmental Protection Agency. Office of Pesticide Pr ograms. Environmental Fate and Effects Division. Arlington, VA.

U.S. EPA. 2002. Guidance for Se lecting Input Parameters in M odeling the Environmental Fate and Transport of Pesticides. Version 2. U.S. Environmental Protection Agency. Office of Pesticide Programs. Environmental Fate and Effects Division, Arlington, VA.

cc:/Rebecca Daiss,RRB4/HED, 7509P7 Appendix 1. Previous Tier 1 Drinking Water Assessment for Potatoes (D324410)

Note: The CAS # 131860-33-8 was incorrect in the original document D324410, dated June 20, 2006. The correct CAS # is 66215-27-8.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460

OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES

PC Code: 121301
DP Barcode: D324410 June 20, 2006

Drinking Water Assessment

SUBJECT: New Use Rate for Trigard 75WP (75% ai) on potatoes.

FROM: James K. Wolf, Environmental Scientist
Environmental Risk Branch 3

THRU: Mary Frankenberr y, Senior Scientist
Environmental Risk Branch 3

Daniel Rieder, Branch Chief
Environmental Risk Branch 3
Environmental Fate and Effects Division (7507C)

TO: George Larocca, RM13
Insecticide Branch Registration Division (7505C)

The Environmental Fate and Effects Division (EFED) has been requested to prepare a drinking water assessment for cyromazine for a new use rate of Trigard (75 WP) to control Colorado potato beetles (DP 324410) on potatoes. The EFED Tier 1 surf ace water (FIRST) and ground water (SCI-GROW) models we re used in this assessment. The Registratio n Division also inquired whether additional ground water monitoring and mobility data were needed.

The registrant has requested, in th is action (D324410), an alternative cyromazine (Trigard 75W) application schedule for the pot ato use. The proposed alternative is for a8 maximum of 3 applications per season at a rate of 0.25 lbs ai/acre per season to control the Colorado potato beetle. The reappl ication interval is 7 to 14 da ys. Previously, EFED estimated drinking water concentrations (E DWCs) for a number of crops, incl uding potatoes. Cyromazine was applied six times at maximum applicati on rate of 0.125 lbs ai/acre, with a 7 day reapplication interval (D271623, D236191). The total for both ra tes is 0.75 lbs ai/acre.

The EDWCs for the potato use, with the proposed new applicati on rate, is given in Table 1. The recommended peak concentration is 43.3 μg/L and the long term average is 17.8 μg/L as this represent the most conservative concentrations for the peak concentration. The reduction in the number of applications (6 to 3) with the corresponding incr eased application rate (0.125 to 0.25 lbs ai/acre) had (Table 1) a limited influence on the initial concentration (peak).

A range (150 to 450 days) of aerobic soil metabolism rate values was considered because there was some uncertainty associated with prepar ing the aerobic soil metabolism rate data as an input to the EFED screening models. This di scussed in detail in the Environmental Fate Properties. The aerobic soil metabol ism half-life had a small influenced on the peak cyromazine
concentration. Aerobic soil metabolism ha s no effect on the estimated cyromazine concentrations once in the surface water (annua l mean) body. The EDWCs for existing rate (0.125 lb ai/ac and 6 applications ) are shown for comparison. The FIRST runs are provided in the Appendix.

Table 1. Estimated Drinking Water Concentratio ns (EDWC) of cyromazine residues for potatoes using the Tier 1 FIRST model with three half-lives (150, 178, 450 day) and applied as 3 applications (0.25 lbs ai/ac) or 6 applications at (0.125 lb ai/ac) rates, and a seasonal rate of
0.75 lb ai/ac. The concentrations have been adjusted with the Percent Crop Area (PCA) of
0.87 for a national assessment. The bold values represent the recommended EDWCs to be used in the drinking water assessment. 1-in-10 year Cyromazine Concentration Application rate/# number/interval/asm 1 (lbs ai/ac/#/days/days) Peak ( μ g/L) Annual Mean ( μ g/L)
0.250/3/7/150 42.8 17.3
0.125/6/7/150 41.0 16.6
0.250/3/7/178 43.1 17.4
0.250/3/7/450 43.9 17.8
0.125/6/7/450 43.3 17.5

1 asm is aerobic soil metabolism half-life in days.

. The selection of an aerobic soil metabo lism rate had a greater influence on the cyromazine concentrations in ground water as estimated by SCI-GROW. The estimated ground water concentrations ranged from 5.35 to 26.6 μ g/L (Table 2) for the 150 and 450 day half-life, respectively. Previous assessments used the 150 day half-life for ground water. EFED
recommends that 6.9 μ g/L be used as ground water concen tration of cyromazine for human health risk assessment, which corresponds to th e 178 day half-life. The SCI-GROW runs are9 listed in the APPENDIX.

Table 2. SCI-GROW estimates of cyromazine concentrations in ground water. Application rate/# number/interval/asm 2
(lbs ai/acre/number/days/days) Concentration ( μ g/L) 0.250/3/7/150 5.3
0.0250/3/7/178 6.9
0.125/6/7/450 26.6
The bold value is the recommended EDWCs to be used in the drinking water assessment.

In addition to the preparing the water asse ssment for proposed new uses, the Registration Division (RD) included several specific (D324410) questions for EFED concerning monitoring and need for additional mobility data:

1) Will additional ground water monitoring and ecol ogical effects data be required to add potatoes to the label? Does the risk mitigation (label language) overcome the need for the ground water study?

EFED recommends that the monitoring study (prospective ground water monitoring or ground water well monitoring or surface water monitoring) be placed in reserve. The concentrations necessary to reach HED’s level of concern are unlikely, for the currently registered crops. The label language about the potential to contaminate ground water should remain

.

There is no ecological effects data required at this time.

2) The mobility data for the degradate melamine has not been submitted. Is it still needed?

It is also recommended that the requirement for the registrant to provide mobility data on melamine degradate be placed in reserved. This recommendation is made because toxicity is not
a concern at this time.

Environmental Fate and Transport Characterization

Physical/Chemical Properties

Chemical name: N-cyclopropyl -1,3,5-triazine-2,4,6-triamine Common name: Cyromazine
CAS #: 131860-33-8 Empirical Formula: C 6 H 10 N 6 Molecular Weight: 166.1910 Solubility in Wate r: 1100 mg/L at 20 ° C (pH 7.5) Vapor Pressure: 3.36 x 10 -9 mm Hg at 20 ° C
Chemical Number: 121301

Environmental Fate Assessment

Based on previously submitted data, cyromazine is stable to hydrolysis and photolysis, and is quite persistent in aerobic soil (t 1⁄2 ≈ 150 days or more). This was c onfirmed in the field studies, where dissipation half-lives were more than 250 days. Under anaerobic conditions cyromazine may be more persistent. Soil adsorption coe fficients are generally low with Freundlich adsorption coefficients (K f-ads ) less than 20. Cyromazine is also highly soluble (1.36 x 10 5 mg/L). This would suggest that cyromazine has the potential to leach through soils, especially sand, fine sands, and loamy sands, or to be transp orted in solution in runoff water. Melamine was identified as the primary cyromazine degradate. The persistence (t 1⁄2 ), adsorption (K d ), and dissipation rate of melamine have not been specified, but in terrestr ial field studies, melamine is shown to be more persistent and mobile than the parent, and may accumulate in soil with repeated uses. Two other degradates were also noted, but not identified.

Environmental Fate Properties

Selected physical/chemical and environmen tal fate properties for cyromazine are summarized in Table 3. Cyromazine is stable to hydrolys is and photolysis.

Cyromazine is persistent in soil. The aer obic soil [mineral soil] metabolism half-life (t 1⁄2 ) was 142 days for a sandy loam and 107 days for a muck soil (EFGWB #90679, 1990). It is
unclear whether it is valid to combine results of a mineral soil (sandy loam ) with an organic soil (muck). Combining the half-life values by following EFED Input Guidance, the 90 th percent upper bound on the mean aerobic soil metabolism half-life for the two soils is 178.3 days. Earlier EFED assessments used the 150 day ha lf-life, which was based upon information available at that time. When only one aerobic me tabolism half-life is available, it should be multiplied by 3 [3 x 150 = 450 days; EFED Input Guidance]. The 178.3 day upper bound of the mean falls within the range of half-lives used in this assessment 150 to 450. For this assessment, the half-life of 450 days was used for to estimate cyromazine in surface water. Guidance for the SCI-GROW recommends using the average half-l ife value as an input parameter. EFED believes that the 178 day half-life value would be a better estimate of the mean than 450 days.

Because the FIRST model simulates a rainfall event two days after the last application, thus, it is not very sensitive to a long half-life. Th e aerobic soil metabolism has essentially no
influence on the estimated surface water concentra tions when the half-life value is long. Under anaerobic conditions it may even be more persistent (Cargile, 1986) . Field dissipation half-lives are variable, ranging from 75 days to more th an 250 days. (Cargile, 1986; after CDPR, 1993).
The half-life selected showed more of a differe nce in SCI-GROW (Table 2) as estimates 5.3 and
26.6 μ g/L when the half-life is 150 or 450 days, resp ectively. When the half-life is assumed to be 178 days, the estimated ground water concentration is 6.9 μ g/L.11 Soil adsorption coefficients are genera lly quite low, with Freundlich adsorption coefficients (K ads ) less than 20. The K ads values are not equal to K d , because the slope (1/n) in the adsorption isotherm was less than 1 (0.77 to 0.85). The logari thm of the Kocs are generally less than 2, which falls into the “Mobile” categor y as described by the EFED Standardized Soil Mobility Classification Gu idance (Bradbury, 2006).

1 The 90 th percent upper bound of mean of 107 and 142 days is 178.3 days.

2 The 150 days represents half-life information previously used.
3 The EFED Guidance recommends multiply a single aerobic soil metabolism half-life value by 3.

4 Kads 0.52 (sand), 2.37 (sand), 3.87 (silt loam), 17 (clay loam)

Melamine is identified as the primary cyromazine degradate. Aerobic metabolism
studies indicated that melamine levels could be as much 33 percent of the parent. Two other degradates were also noted.

Based on the above environmental fate info rmation, EFED concluded that under certain conditions (e.g., sandy soils) cyromazine is both mob ile and persistent, and has potential to move in soil or be transported off site in runoff water. Table 3. Select Physical, Chemical, and E nvironment Properties and model input value for Cyromazine. Parameter Range Value Used Source Solubility (water) (technical) 1.36 x 10 5 mg/L
1.16 x 10 4 mg/L 1.36 x 105 mg/L @ 25° C EFED One-Liner Database (12/2/94)

pKa (weak base) 5.22 Hydrolysis t1/2 Stable at pH 5, 7, and 9 0 day EFED One-Liner Database (12/2/94) Aquatic Photolysis t1/2 Stable in water at pH 7 0 day EFED One-Liner Database (12/2/94)
Aerobic Soil Metabolism
t1/2 ~150 days 178.3 1 days
150 2 days 150 x 3 = 450 days 3 (EFED Guidance) EFED One-Liner Database (12/2/94)

Anaerobic Soil Metabolism
t1/2 no data not considered Aerobic Aquatic
Metabolism t1/2 no data not considered

K ads 0.52 – 17 4 (5.94) mL/g see Koc values
lowest non sand = 3.9 EFED One-Liner Database (12/2/94)

Koc

Log(Koc) 40 – 127 (106) mL/g [40, 73, 185, 127]

106 mL/g ( Koc model appears valid)

1.6 to 2.1 (2.06)
1 to 2 = mobile in
Standardized Soil Mobility Lowest none sand = 40 EFED One-Liner Database (12/2/94)

Mobility Classification Guidance, April 18,
200612 GROUND WATER MONITORING DATA

Prospective Ground Water Monitoring Study

The registrant conducted a small-scale prospective ground-water monitoring study on tomatoes in Florida (D178192, D199290). This study was conducted where leaching was unlikely due to a high water table and high ev apotranspiration. There were no cyromazine residues detected in ground wate r during this study. Low levels of melamine were found in ground water, after irrigation was discontinued. The agronomic prac tices used at this study site resulted in applied irrigation water running off the treated field. The runoff water from the
treated field was not assessed for cyromazine residues. The cyromazine degradate melamine was detected at levels ranging from 0.10 to 0.21 μ g/L in shallow ground water at the study site in Florida. The overall study results and conclusion s were limited, due to the fact that the study
was conducted at one site and reflects only the conditions of the one site.

There were no reported detecti ons of cyromazine residues in ground water at the time that
the Pesticides in Ground Water Data Base was published, in 1992 (USEPA, 1992). This may be because very few ground-water samples have be en analyzed for cyromazine (and melamine)
residues in the United States and because it ha s limited usage areas and crops. Cyromazine and
melamine were not included in the suite of an alyses conducted in the USEPA's National Survey of Pesticides in Drinking Water Wells (U SEPA, 1990, 1992). Cyromazine and melamine are
also not included in the USGS NAQWA program. No surface water monitoring was located.

Previous Recommendations

Several specific recommendations were previ ously made (D199290) (t wo are cited below):

1) The registrant should conduct one or more well-water monitoring surveys in a cyromazine use area, such as lettuce and celery ra ther than retrospective studies as previously stated in earlier reviews (memos C. Eiden, 7/26 /89; Hutton, 1/4/90). The registrant could also consider conducting a prospective study in a use area in AZ, CA, or TX.

2) The potential for surface water contamina tion should be addressed by the registrant through surface water monitoring

3) The registrant should provide mobility data for the cyromazine degradate melamine.

Status of Previous Recommendations

It is recommended that the above monito ring studies and the requirement for the registrant to provide mobility data on mela mine degradate be reserved. This latter
recommendation is made because toxi city is not currently a concern. The label language about the potential to contaminate ground water should remain

.13 Citations

Cargile, N. 1986. Aerobic and Anaerobic soil metabolism of CGA-72662 (cyromazine).

CDPR, 1993. Cyromazine (Larvadex), Risk Characterization Document. Department of Pesticide Regulation, California Envi ronmental Protection Agency. 3-24, 1993

USEPA. 1989. National Survey of Pesticides in Drinking Water Wells (the National Pesticide Survey or NPS). Environmental Protection Agency, Washington D.C.

USEPA. 1992. Pesticides in Ground Water Database. A comp ilation of monitoring studies: 1971 -1991 National Summary. EPA 734-12-92-001. U. S. Environmental Protection Agency: Arlington, VA.

USEPA. 1990, National survey of pesticides in drinking water wells: Ph ase 1 report. EPA 570/9- 90-015. U.S. Environmental Protection Agency. Washington, DC.

USEPA, 1992. Another look: national survey of pesticides in drinking water wells - Phase 2 report. EPA 570/9-91-020

cc:/ Paula Deschamp/HED/REB3/7509C
Demson Fuller SRRD/RRB1/ 7508C14 Appendix 2, Table 1. Calculation of application rates.

Application Product AI (active ingredient) Max # Seasonal Total

oz/acre lbs/acre 1 % lbs ai/acre Appl. lbs ai/acre/season

2.66 0.16625 75.0 0.125 2 6 0.75 3

1 oz/acre * 0.0625 lb/oz = lbs/acre

2 lbs ai/acre = lbs/acre * (75/100)

3 lbs ai/acre/season = lb s ai/acre * Max # Appl.15 Appendix 3.

FIRST OUTPUTS

**RUN No. 1 FOR Cyromazine ON succulent * INPUT VALUES ***

**-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP** 
**ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)**

**-------------------------------------------------------------------- .125( .692) 6 7 2.411600.0 AERIAL(16.0) 87.0 .0** 

**FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)**

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

**-------------------------------------------------------------------- 147.38 2 N/A .00- .00 294.80 294.80** 

**UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 JAN 1, 2007**

**-------------------------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)** 

**CONCENTRATION CONCENTRATION**

**-------------------------------------------------------------------- 47.100 15.745** 

RUN No. 2 FOR cyromazine ON succulent * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .125( .692) 6 7 2.411600.0 AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 147.38 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 JAN 1, 2007

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 47.290 22.88916 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:cyromazine (new fate)**  **time is 7/ 1/2009 14:24:22**

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

**------------------------------------------------------------------------ 0.125 6.0 0.750 9.96E+01 103.7** 

**------------------------------------------------------------------------ groundwater screening cond (ppb) = 1.10E+00** 

****************************************************************************

SciGrow version 2.3 chemical:cyromazine (new fate) time is 7/ 1/2009 14:24:42

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

------------------------------------------------------------------------ 0.125 6.0 0.750 9.96E+01 147.4

------------------------------------------------------------------------ groundwater screening cond (ppb) = 1.72E+00

************************************************************************17 **Previous Assessment (D324410)**

FIRST

SURFACE WATER

RUN No. 1 FOR cyromazine ON potato * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .125( .730) 6 7 3.9 1.36e5 AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 450.00 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 43.269 17.516

RUN No. 2 FOR cyromazine ON potato * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .250( .742) 3 7 3.9 1.36e5 AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 450.00 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 43.903 17.76518 RUN No. 1 FOR cyromazine ON potato * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .250( .726) 3 7 3.9******* AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 150.00 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 42.825 17.342

RUN No. 2 FOR cyromazine ON potato * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .125( .693) 6 7 3.9******* AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 150.00 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 41.031 16.63919 RUN No. 1 FOR cyromazine ON potato * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .250( .730) 3 7 3.9******* AERIAL(16.0) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 178.00 2 N/A .00- .00 .00 .00

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

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

CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- 43.076 17.440