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fenhexamid NYSDEC-New Active Ingredient Registration 5/00



New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
50 Wolf Road, Albany, New York 12233-7254
Phone: (518) 457-6934 FAX: (518) 457-0629


May 5, 2000


CERTIFIED MAIL
RETURN RECEIPT REQUESTED

Mr. Desmond Byrne
Tomen Agro, Inc.
100 First Street, Suite 1700
San Francisco, CA 94105

Dear Mr. Byrne:

Re: Registration of the New Active Ingredient - Fenhexamid Contained in the Pesticide Product - Elevate 50 WDG Fungicide (EPA Reg. 66330-35)

    The New York State Department of Environmental Conservation has completed its review of the application and supporting data received from Tomen Agro, Inc. on October 1, 1999 for the referenced pesticide product. Elevate 50 WDG Fungicide contains 50.0% fenhexamid, an active ingredient never before registered for use in New York State. The United States Environmental Protection Agency (USEPA) granted conditional registration of fenhexamid on May 21, 1999. As a condition of registration, Tomen Agro, Inc. is required to submit a field dissipation study by June 30, 2001.

    Elevate 50 WDG Fungicide, containing the new fungicide, fenhexamid, is labeled for use as a spray for control of Botrytis diseases of grapes and strawberries in agricultural settings; it is not labeled for homeowner use. It is a water dispersable granule applied by ground equipment only. Fenhexamid is a "protectant" fungicide, in that it does not directly kill the target fungus (Botrytis spp) when applied but binds to the surface of vegetation. When fungus is exposed, it interferes with germ tube and hyphae development. Without hyphae, the fungus dies from lack of nutrients. The half-life of fenhexamid when bound to the surface of foliage is about 28.6 days. Elevate may be applied three times at the rate of 0.5 lbs ai/A for each application to grapes, not to exceed 1.5 lbs ai/A per season. On strawberries four applications of 0.75 lb ai/A for a total of 3.0 lb ai/A/year may be made. Multiple applications should be separated by an interval of 7-14 days. The label requires that not more than two consecutive applications be made before switching to an alternative product with a different mode of action for at least two consecutive applications, to avoid the development of resistance and preserve the usefulness of fenhexamid.

    On November 19, 1999 the application was determined to be incomplete for purposes of review. On December 22, 1999 the Department received additional supporting documentation and the application was considered complete on January 24, 2000 with the registration decision date set for June 22, 2000.

    The available information on fenhexamid and the formulated product indicates that they are not very acutely toxic to laboratory animals, nor are they dermal sensitizers or very irritating to eyes or skin. Although data from chronic studies showed the potential to cause certain hematological and other effects, the expected exposure from using fenhexamid should not pose significant risk to the general public or workers. The USEPA established a reference dose of 0.17 mg/kg/day based on the NOEL from the one-year dog study (17 mg/kg/day) and an uncertainty factor of 100.

    Fenhexamid did not cause ongogenic effects in either rat or mouse chronic feeding studies. It was also negative in a number of genotoxicity tests. The USEPA classified fenhexamid as a 'not likely' human carcinogen.

    The USEPA established tolerances for fenhexamid residues in or on strawberries and grapes at 3.0 parts per million (ppm) and 4.0 ppm, respectively. The USEPA estimated that chronic dietary exposure to these residues would be 1.8 percent of the chronic population adjusted dose (PAD) of 0.057 mg/kg/day for the general U. S. population and 4.8 percent of the chronic PAD for children one to six years old. For non-nursing infants and nursing infants, the chronic dietary exposure was estimated at 2.4 percent and 6.6 percent of the chronic PAD, respectively. This chronic exposure analysis is based on the assumption that 100 percent of crops treated contain tolerance level residues.

    The USEPA conducted a risk assessment for dermal exposure of workers to fenhexamid based on its labeled use in the Elevate 50 WDG Fungicide. For mixer/loader/applicators, margins of exposure (MOEs) were estimated to range from 11,000-17,000. These estimates assume that the workers wore long-sleeved shirts and long pants whereas the label also requires shoes, socks and waterproof gloves. Generally, the USEPA considers MOEs of 100-fold or greater to provide adequate protection.

    There are no chemical-specific federal or State drinking water/groundwater standards for fenhexamid. Because of its chemical structure, this compound falls under the 50 micrograms per liter New York State drinking water standard for "unspecified organic contaminants" (10 NYCRR Part 5, Public Water Systems).

    The use of this product as labeled is unlikely to have any adverse impact on fish and wildlife. Fenhexamid has a relatively short life in the environment. In water, fenhexamid is photolytically degraded with a half-life of about one hour. The half-life due to microbial degradation in water is about 13 days in the water column and about 40 days in sediment. It has a moderate Kow (3200) and binds to sediments. Fenhexamid has a complex fate on soil. It rapidly degrades via photolysis and microbial transformation while binding to the soil as well. What isnít bound is degraded very rapidly. The bound portion continues to degrade although much more slowly. The bound portion is bound tightly to the soils and is biologically unavailable. The half-life due to microbial degradation is four days. Only one degradate was ever detected at a concentration of greater than 10 % of the applied active ingredient. That degradate was detected at a concentration of about 25 % of the applied active ingredient. It persisted for about five hours and then disappeared.

    When Fenhexamid was modeled for potential impacts to non-target organisms, no toxicity threshold was exceeded in any of the risk assessment models. The direct application of Elevate 50 WDG Fungicide at the labeled rate to an acre of water six inches deep did not exceed the toxicity threshold for any fish or freshwater invertebrate species. Therefore, the use of Elevate 50 WDG Fungicide as labeled is not likely to cause any harm to fish, wildlife or estaurine/marine species.

    The environmental fate review was performed by the Environmental Assessment Division of the Pest Management Regulatory Agency of Health Canada. The Health Canada review stated that fenhexamid is stable to hydrolysis at pHs 5, 7, and 9 and hydolysis is not considered a major route of transformation in the environment. Fenhexamid is soluble in water at 20 mg/l and has a photolysis half-life (DT50) in water of about one hour. Photolysis is considered a major route of transformation for fenhexamid.

    Fenhexamid is non-persistent in surface water and slightly persistent in sediment under aerobic conditions. Fenhexamid is slightly persistent in anaerobic sediment and bound residue formation is a major process. The sediment half-life did not follow major order kinetics, but the DT50 was 87 days. Fenhexamid is moderately persistent in anaerobic sediment, and partitioned more to the sediment as compared to the surface water. The surface water DT50 was 39.9 days. Adsorption/Desorption studies showed that fenhexamid is classified as a medium to low mobility compound with Koc values ranging from 450 to 1025 in loamy sands and clay loam, and with its Kocís not dependent on clay and organic matter content.

    The Canadian terrestrial field dissipation studies have to be repeated (the new study is due June 30, 2001) because the dissipation pathways of fenhexamid were inadequately characterized. However, the first study, done in a silty loam, showed a DT50 of one day. No compound was found below 15 cm for this study and negligible amounts of compound were found at 0-15 cm after one week. The mobility of fenhexamid was also tested in a second study done on bare ground using lysimeters in a sandy loam soil. The DT50 was 44 days with a negligible amount of fenhexamid found below six inches. However, this second study was considered supplemental because typical end use product was not used and replicate samples were not taken to assess experimental error.

    Our computer groundwater modeling predicted that there would be no fenhexamid in the leachate. Because of its short half-life, fenhexamid is not expected to cause an impact to groundwater when used as labeled.

    Therefore, the Department accepts Elevate 50 WDG Fungicide (EPA Reg. No. 66330-35) for registration in New York State as labeled. As a condition of this registration, Tomen Agro, Inc. must provide the Department with a copy of the additional studies required by the USEPA as a condition of federal registration and copies of any subsequent reviews provide by either the USEPA or Health Canada as soon as they become available but no later than December 31, 2001.

    Enclosed are the Certificate of Registration and a stamped-accepted copy of the product label for your records. If you have any questions, please contact Frank Hegener, Acting Chief of our Pesticide Product Registration Section, at (518) 457-7446.

Sincerely,

Stephen Hammond, P.E.
Director
Division of Solid & Hazardous Materials

Enclosure

cc: w/enc.- G. Good/W. Smith, Cornell PMEP
R. Zimmerman/R. Mungari, NYS Dept. of Ag & Mkts.
N. Kim/D. Luttinger, NYS Dept. of Health

BS:scy
(betty\Elevate.sh)