# DUPONT SULFOMETURON METHYL

EPA FOCUS MEETING

ENVIRONMENTAL FATE AND EFFECTS

AQUATIC AND AVIAN SPECIES TESTING

September 26, 2012

# Guideline 835.6100 Terrestrial Field Dissipation Study: Supporting ECM & ILV

We concur with EPA comment. Separate soil/water analytical methods are available for parent compound and

metabolites IN

- X0993, IN

- D5803 and IN

- 581. If requested, DuPont will refine current methods to single parent + metabolites method, and provide method ILV.

# Guideline 835.4100

– Aerobic Soil Metabolism

Acceptable laboratory data (route and rate of degradation) for aerobic soil metabolism of SMM is available for Keyport soil. DuPont is of the position that additional rate data may be obtained from available field data because for all SUs, field data are very consistent with laboratory data :

SU Lab Rate Range (DegT 50, days) [Number of Soils] Field Rate Range (DT 50, days) [Number of SItes]

Sulfometuron 23, 29 [1] 1 12

– 23 [4] 2

Thifensulfuron 0.5

– 7 [6] 1

– 10 [12]

Metsulfuron 9

– 90 [14] 37

– 68 [4]

Flupyrsulfuron 8

– 22 [6] 8

– 23 [4]

Chlorsulfuron 12

– 71 [5] 3

– 70 [5]

Rimsulfuron 21

– 40 [4] 6

– 18 [8]

1. Two separate studies run on Keyport soil

2. Field soil types characterized as silty clay loam (2 sites), clay (1 site) and sandy loam (1 site)

# Guideline 835.4100

– Aerobic Soil Metabolism (continued)

For sulfometuron methyl, field data on multiple soil types are consistent with laboratory data; overall data set includes 4 distinct soil types

SU Laboratory DegT50 (days); Soil Type Field Data

Field DT 50 (days) Soil Type Soil pH Soil %OC

Sulfometuron 23, 29 1 ; silty loam, pH 6.4, 1.6% OC 12 silty clay loam 6.7 0.6

14 silty clay loam 6.8 1.0

13 clay 7.9 1.3

23 sandy loam 7.8 0.7

1. Two separate studies run on Keyport soil

# Guideline 850.1025

– Acute toxicity estuarine/marine invertebrate (bivalve);

Guideline 850.1035

– Acute toxicity estuarine/marine invertebrate (mysid);

Guideline 850.1075

– Acute toxicity estuarine/marine

fish

We accept that the variability in these studies leads to their classification as supplemental instead of core

# Guideline 850.1350

– Estuarine/marine invertebrate life cycle

We agree with EFED to characterize toxicity to estuarine/ marine invertebrates using toxicity data for freshwater invertebrates

Study Sulfometuron Chlorsulfuron Metsulfuron Rimsulfuron

Acute Daphnia magna (LD50) (freshwater) >150 mg/L >112 mg/L >120 mg/L >243 mg/L

Acute Crassostrea virginica (LD50) (estuarine/marine) >38.2 mg/L 385 mg/L

- >120 mg/L

Acute Mysidopsis

bahia (LD50) (estuarine/marine) >44.8 mg/L 89 mg/L

- >110 mg/L

Chronic Daphnia

magna (NOEC) (freshwater) 97 mg/L 20 mg/L 150 mg/L 26 mg/L

Life Cycle Daphnia

magna (NOEC) (freshwater) - - 100 mg/L

-

# Guideline 850.1400

– Estuarine/marine and freshwater fish early

- life stage

We agree with the suggestion from EFED to characterize toxicity to estuarine/marine and freshwater fish using toxicity data for other sulfonylureas with a similar toxicity profile and the same mode of action Study Sulfometuron Chlorsulfuron Metsulfuron Rimsulfuron

Acute Lepomis

macrochirus (LD50) ( freshwter ) >150 mg/L >128 mg/L >119 mg/L >250 mg/L

Acute Oncorhynchus mykiss (LD50) (freshwater) >148 mg/L >122 mg/L >113 mg/L >180 mg/L

Acute Cyprinodon variegatus (LD50) (saltwater) >45 mg/L >980 mg/L

- >110 mg/L

Early life stage Oncorhynchus mykiss (NOEC) - 32 mg/L 4.5 mg/L 125 mg/L

# Guideline 850.2100

– Avian oral toxicity, passerine species

SMM Mallard Duck Acute Oral Toxicity

– LD50 >5000 mg/kg

SMM Mallard Duck Dietary Toxicity

– LD50 >5000 mg/kg, NOEC

– 5000 mg/kg

SMM Northern Bobwhite Dietary Toxicity

– LD50 >5620 mg/kg, NOEC

– 5620 mg/kg

The maximum dose

- based EEC calculated by T

- REX is 76.88 mg/kg

- bw (small bird with short grass diet)

Passerine species would need to have an LD50 an order of magnitude more sensitive than ducks and quails in order to be of concern



## Sulfometuron Methyl is practically non

- toxic to birds and we request that this study be waived

# Guideline 850.2300

– Avian reproduction, upland game and waterfowl species

We agree with EFED to characterize avian reproduction toxicity using data for other sulfonylureas with a similar toxicity profile and the same mode of action Study Sulfometuron Chlorsulfuron Metsulfuron Rimsulfuron

Acute Mallard (LD50) >5000 mg/kg >5000 mg/kg >2510 mg/kg >2250 mg/kg

Acute Bobwhite (LD50) - >5000 mg/kg

- >2250 mg/kg

Dietary Mallard (LC50) >5000 mg/kg >5000 mg/kg >5620 mg/kg >5620 mg/kg

Dietary Bobwhite (LC50) >5620 mg/kg >5620 mg/kg >5620 mg/kg >5620 mg/kg

Reproduction Mallard (NOEL) - 961 mg/kg 1000 mg/kg 1250 mg/kg

Reproduction

Bobwhite (NOEL) - 907 mg/kg 1000 mg/kg 1250 mg/kgDuPontTM, The DuPont Oval logo, The miracles of scienceTM, [trademark name]TM and [tademark name]® are trademarks or registered trademarks of E. I. du Pont de Nemours and Company or its affiliates.

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### Additional Information: Comparison of SU Aerobic Soil Metabolism