March 11, 2009 CERTIFIED MAIL RETURN RECEIPT REQUESTED

Transcription

1 New York State Department of Environmental Conservation Division of Solid and Hazardous Materials Bureau of Pesticides Management, 11 th Floor 625 Broadway, Albany, New York Phone: (518) Fax: (518) Website: Alexander B. Grannis Commissioner March 11, 2009 CERTIFIED MAIL RETURN RECEIPT REQUESTED Ms. Debra Krueger State Registration Manager Bayer CropScience, LP P.O. Box Research Triangle Park, North Carolina Dear Ms. Krueger: Re: Denial of Application to Register a Major Change in Labeled (MCL) Use Pattern for the Active Ingredient Ethofumesate Contained in the Pesticide Product Nortron 7 SC Herbicide (EPA Reg. No ) The New York State Department of Environmental Conservation (Department) has completed a technical review of the application (received January 28, 2008) and supplemental information (received August 14, 2008) submitted in support of registration of the referenced pesticide product. Nortron 7 SC Herbicide (EPA Reg. No ) contains the active ingredient ethofumesate (2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate) [Chemical Code ] and is labeled for preplant, preemergence and post-emergence application for selective control of broadleaf and grass weeds in sugar beets, garden beets, onions, garlic, shallots (in all states) and carrots (in WA and OR only). Nortron 7 SC Herbicide is also labeled for selective control of weeds in certain grass seed crops and commercial sod production in California, Idaho, Nevada, Oregon, and Washington. The active ingredient ethofumesate is a component of three products currently registered in New York State for use by professional applicators on ornamental turf only. Although the proposed food crop use of Nortron 7 SC Herbicide on sugar beets, garden beets, onions, garlic and shallots has been classified as a major change in labeled (MCL) use pattern, the subject review action represents the initial technical review of ethofumesate in New York State. Nortron 7 SC Herbicide contains 4.0 pounds ethofumesate per gallon. For onions (dry bulb), garlic (bulb) and shallots (bulb) grown on course soils, the maximum use rate is 48 fluid ounces Nortron 7 SC (1.5 lbs ai) per acre per growing season. On medium and fine textured soils, the maximum use rate is 96 fluid ounces Nortron 7 SC (3.0 lbs ai) per acre per growing season. The maximum use rate on table (garden) beets is 96 fluid ounces Nortron 7 SC (3.0 lbs ai)

2 Ms. Debra Krueger 2. per acre per growing season. On sugar beets, no more than a total of one gallon Nortron 7 SC (4.0 lbs ai) can be applied per acre per growing season. The application package was deemed complete for purposes of technical review on October 7, 2008 following one determination of incompleteness (3/28/08). Pursuant to the review time frame specified in Environmental Conservation Law (ECL) , a registration decision date of March 6, 2009 was established. The Department=s completeness letter noted that Bayer CropScience should be prepared to submit any available groundwater monitoring data or other information which may mitigate concerns for leaching. Ethofumesate has a very low K d and long half-life and preliminary groundwater modeling predicted the potential for leaching when used as labeled at the 1.5 lbs ai/acre/year rate on onions, garlic and shallots. Human health, ecological effects and environmental fate risk assessments were conducted for ethofumesate and the Nortron 7 SC Herbicide end-use product. HUMAN HEALTH RISK ASSESSMENT: Neither ethofumesate nor the formulated product Nortron 7 SC Herbicide was very toxic in acute oral, dermal or inhalation exposure studies in laboratory animals. Neither the active ingredient nor the formulated product was very irritating to skin and eyes (tested on rabbits) or sensitizing to guinea pigs. Ethofumesate caused some toxicity in chronic animal feeding studies. In a one-year dog feeding study, ethofumesate caused increased liver weight and circulating levels of alkaline phosphatase and alanine aminotransferase at milligrams per kilogram body weight per day (mg/kg/day) in males and mg/kg/day in females; the no-observed-effect-level (NOEL) was mg/kg/day in males and 109 mg/kg/day in females. In a chronic feeding/oncogenicity study in mice, no effects were reported at dose levels of 1,601 mg/kg/day and 2,145 mg/kg/day in males and females, respectively, the highest doses tested. In a chronic feeding/oncogenicity study in rats, reduced body weight and body weight gain in females and liver cell histopathology in males was observed at 469 mg/kg/day and 1,003 mg/kg/day, respectively. The NOELs were 127 mg/kg/day in females and 332 mg/kg/day in males. The United States Environmental Protection Agency (USEPA), Office of Pesticide Programs (OPP), established a reference dose (RfD) for the general population of 1.3 mg/kg/day based on the NOEL of 127 mg/kg/day from this study and an uncertainty factor of 100. This RfD has not yet been adopted by the USEPA s Integrated Risk Information System (IRIS). Ethofumesate caused some developmental toxicity in the offspring of pregnant rabbits, but not pregnant rats, exposed to this chemical during organogenesis. In the rabbit study, increased resorptions, post-implantation loss and incomplete ossification of the vertebral arches were reported at a maternal dose of 300 mg/kg/day; the NOEL was 30 mg/kg/day. Maternal toxicity consisted of decreased body weights and increased mortality, abortions and complete litter resorptions at a dose of 3,000 mg/kg/day; the NOEL was 300 mg/kg/day. In the rat study, no treatment-related effects were observed in offspring or dams at maternal doses up to 1,000 mg/kg/day, the highest dose tested. In a multigeneration reproduction study in rats, ethofumesate did not cause any parental, developmental or offspring toxicity effects at doses up to mg/kg/day in males and mg/kg/day in females. Due to observed developmental

3 Ms. Debra Krueger 3. toxicity at ethofumesate doses lower than those that caused maternal toxicity, the USEPA OPP established a separate RfD for females of child bearing age (13-49 years old) of 0.3 mg/kg/day based on the NOEL of 30 mg/kg/day from the developmental study in rabbits study and an uncertainty factor of 100. This RfD also has not yet been adopted by the USEPA s Integrated Risk Information System (IRIS). Ethofumesate did not cause oncogenic effects in rat or mouse chronic feeding studies. This compound was also negative in a number of genotoxicity studies. The USEPA classified ethofumesate as not likely to be carcinogenic to humans. The USEPA established tolerances for ethofumesate residues in or on garlic bulbs, onion bulbs, shallot bulbs and fresh shallot leaves of 0.25 parts per million (ppm), garden beet roots of 0.5 ppm and garden beet tops of 4.0 ppm. The chronic population adjusted dose (cpad) for ethofumesate for the general public is 1.3 mg/kg/day and has the same basis as the RfD. The USEPA estimated that the chronic dietary exposure to ethofumesate residues in food and drinking water would be less than 1% of the cpad for the general population and all population subgroups. The specific cpad and acute population adjusted dose (apad) for ethofumesate for females aged years is 0.3 mg/kg/day and has the same basis as the separate RfD. The USEPA estimated that the chronic and acute dietary exposure to ethofumesate residues would be less than 1% of the cpad and 4% of the apad, respectively, for this specific subpopulation. These exposure analyses are based on the conservative assumptions that 100% of the crops are treated and that these treated crops contain tolerance level residues. Actual residues and resulting exposure levels are expected to be less than this assessment estimates. The USEPA reported the results of an occupational risk assessment for combined dermal and inhalation exposures to ethofumesate from use on garden and sugar beets. For determining margins of exposure (MOEs), the USEPA compared estimated combined short-term and intermediate-term dermal and inhalation exposures to a NOEL of 190 mg/kg/day from the 90- day feeding study in rats. For commercial mixer/loaders and applicators (groundboom sprayer and tractor drawn sprayer), MOEs were estimated to be between 418 and 3,600. A similar assessment was also conducted for the subpopulation females aged years for which exposures were compared to a NOEL of 30 mg/kg/day from the rabbit developmental toxicity study. Estimated MOEs for this subpopulation were between 57 and 490, assuming a dermal absorption of 100%. Using dermal absorption data from a subsequent study in rats (absorption up to 27%) increases the MOEs nearly four-fold. These estimates assumed that workers wore chemical-resistant gloves, long-sleeved shirt and pants and shoes plus socks as per label requirements. Generally, the USEPA considers MOEs of 100-fold or greater to provide adequate worker protection.

4 Ms. Debra Krueger 4. There are no chemical specific federal or New York State drinking water/groundwater standards for ethofumesate. Based on its chemical structure, ethofumesate falls under the 50 microgram per liter (μg/l) general New York State drinking water standard for an unspecified organic contaminant (10 NYCRR Part 5, Public Water Systems). The available data indicate that neither ethofumesate nor the formulated product Nortron 7 SC Herbicide was very toxic, irritating or a sensitizer in acute exposure studies in laboratory animals. Ethofumesate caused some effects in laboratory animals in chronic and developmental toxicity studies, but this chemical was neither carcinogenic, genotoxic nor did it cause reproductive toxicity. Exposure and risk assessments conducted by the USEPA indicate that estimated risks to workers and the general population from the labeled use of Nortron 7 are within the range that is generally considered acceptable. These assessments also took into account the different toxicological and exposure concerns for the subpopulation, females aged years. Given the above, the New York State Department of Health did not object to registration of the Nortron 7 SC Herbicide product in New York State. ECOLOGICAL RISK ASSESSMENT: The Department s Bureau of Habitat had no objection to the registration of Nortron 7 SC Herbicide. A risk assessment was not produced. ENVIRONMENTAL FATE RISK ASSESSMENT: Nortron 7 SC Herbicide contains 42% by weight (4 lbs ai/gal) ethofumesate and is labeled for the selective control of broadleaf weeds in sugar beets, garden beets, onions, garlic, and shallots. The maximum application rate on coarse soils for onions, garlic and shallots is 48 fl oz of product (1.5 lbs ai) per acre per season. On medium and fine soils, the maximum application rate is 96 fl oz of product (3.0 lbs ai) per acre per season. On sugar beets, no more than 1 gallon of product (4 lbs ai) per acre can be applied in a single growing season. The coarse soil application rate is 60 fl oz (1.9 lbs ai) per acre. On garden beets, the maximum application rate is 96 fl oz of product (3.0 lbs ai) per acre per season. The inerts do not appear to be solvent carriers. The technical review follows: 1 Data taken from the EFED Risk assessment (no date on document). Solubility 1 : The solubility of ethofumesate is 500 ppm. Hydrolysis: (MRID acceptable 1 ) Ethofumesate was stable in ph 5, 7, and 9 aqueous buffer solutions. Aqueous Photolysis: (MRID acceptable) Ethofumesate had an environmental phototransformation half-life of approximately 14 days. Soil Photolysis: (MRID acceptable) Ethofumesate had a half-life of approximately 6.9 days. Major transformation product NC 8493 was found at 29.8%. Anaerobic Soil Metabolism: (MRID acceptable 1 ) Ethofumesate had a half-life of

5 Ms. Debra Krueger days when applied to a moist sandy loam soil and incubated under anaerobic conditions. Aerobic Soil/Water Metabolism: (MRID supplemental) In a river water-loamy sand sediment (ph 6.89, %OC 1.15), the half-life in the water was 35.2 days, in the sediment was 169 days and in the total system was 105 days. Major transformation product was unidentified RW1 at 16.5%, 3.3% and 19.7% in the water, sediment and total system, respectively. In a water-clay loam sediment (ph 6.85, %OC 1.36), the half-life in the water was 45.3 days, in the sediment was 258 days and in the total system was 156 days. Aerobic Soil Metabolism: (MRID ) The half-life was 83 days in a silt loam and 122 days in a sandy loam soil when applied to moist soils. When applied to the sandy loam under low moisture conditions, the half-life was 253 days. No major transformation products were identified. Adsorption/Desorption: (MRID ) In a batch equilibrium study, ethofumesate is very mobile in sand with a K d of 0.73, mobile in a sandy loam with a K d of 2.35, mobile in a silty clay loam with a K d of 5.32 and mobile in a clay soil with a K d of Adsorption increased with increasing soil organic matter, clay content and CEC. Terrestrial Field Dissipation: (MRID ) In a supplemental study, ethofumesate residues had a registrant-calculated half-life of 71 days and 120 days in a biphasic study on a sandy loam soil from California. Longer biphasic half-lives of 150 and 95 days were reported for a clay loam in the colder climate of North Dakota. Computer Modeling: Staff ran LEACHM using Riverhead soil, using the lower application rate of 1.5 lb ai/acre/year for onions and garlic, a K oc of 73 (K d divided by 1% organic matter) and an aerobic half-life of 122. Modeling projected cyclical peaks, ranging up to 50 ppb. Environmental Fate Summary: Based on the very low K d s, the long half-life and the fairly high application rate, modeling predicts leaching of ethofumesate at up to 50 ppb per year when used as labeled at the 1.5 lbs ai/acre/year rate on onions, garlic and shallots grown on course soils. TECHNICAL ISSUES SUMMARY: As previously noted, there are three products containing ethofumesate registered for use on ornamental turf and sod farms by professional applicators only. Since these products are classified as State ARestricted Use Pesticide@ products, annual use reports are required under the Pesticide Reporting Law (PRL). The Cornell Pesticide Sales and Use Reporting Database (PSUR) reports the following commercial use of ethofumesate:

6 Ms. Debra Krueger Statewide 1,292 lbs 840 lbs 843 lbs Suffolk 1,187 lbs 660 lbs 727 lbs Nassau 40 lbs 149 lbs 110 lbs Groundwater monitoring data confirms that ethofumesate has the potential to impact groundwater resources in New York State. Suffolk County Department of Health Services (SCDHS) groundwater monitoring data from indicates that ethofumesate was detected in groundwater at levels up to 4 ppb. The detection of ethofumesate in groundwater as a result of foliar application to ornamental turf causes added concern since the predominant use of Nortron 7 SC is preplant and preemergence application to soil. CONCLUSION: When used as labeled, Nortron 7 SC Herbicide has the potential to adversely impact groundwater/drinking water resources of New York State. The Department hereby denies the application to register Nortron 7 SC Herbicide (EPA Reg. No ) in New York State. The Department would consider a Special Local Needs Registration for Nortron 7 SC Herbicide use on table (garden) beets grown on soils which are not susceptible to leaching if it can be demonstrated that there is an existing or imminent pest problem in New York State that cannot be met by an existing federally registered product. However, there are questions regarding the utility of, or need for, Nortron 7 SC Herbicide on onions. Product labeling bears the text Do not use Nortron 7 SC on muck or peat soils. Seventy-five percent (75%) of the onion crop produced in New York State is grown on muck or peat soils. Please contact me, at (518) , if you have any questions regarding this action. Sincerely, Maureen P. Serafini Maureen P. Serafini Director Bureau of Pesticides Management ecc: A. Grey/E. Horn, NYS Dept. of Health R. Mungari, NYS Dept. of Ag. & Markets W. Smith, Cornell University, PSUR