, f5 56 United States Office of Pesticides and Toxic Substances Environmental Protection Office of Pesticide Programs (TS-766C) Ag«icy Washinqio n,DC 20460 SEPA Pesticide Fact Sheet Name of Chemical: alachlor Reason for Issuance: special review Date Issued: DEC I 4 1987 Fact Sheet Number: g7il Description of the Chemical Chemical name: 2-chloro-2'-6'-diethy1-N-(methoxymethy1)- acetani1ide Common name: Alachlor Trade names: Lasso®, Pillarzo®, Alanex® EPA Shaughnessy number: 090501 Chemical abstracts service (CAS) number: 15972-60-8 Year of initial registration: 1969 Pesticide type: Herbicide Chemical Family: Acetanilide Use Patterns and Formulations Application sites: preemergent use on field corn (including sweet corn, popcorn), soybeans, peanuts, dry beans, lima beans, green peas, cotton, grain sorghum, sunflowers, ornamental plants. Types of formulations: emulsifiable concentrate, granular, microencapsulate Types and methods of application: ground or aerial methods Application rates: rate and frequency vary according to site application; typically 1 to 4 pounds of active ingredient per acre. ------- Science Findings: Physical and Chemical Properties Color Whi te Melting Point 40 to 41°C Speci fic Gravi ty 1.133 (25/15.6°C) Solubility Soluble in ether, acetone, benzene, alcohol (unspecified) and ethyl acetate; slightly soluble in hexane; solubility in water - 24 0 ppm Physical and Chemical Properties; Octanol/Water Partition Coefficient 434 Stability Stable (first detectable heat evolution at 105°C) Appearance at room temperature White, crystalline solid at 2 3°C Tolerance Assessment; Tolerances were established in 40 CFR 180.249 for residues of alachlor and its metabolites. Toxicology Summary; Acute toxicity - Technical alachlor is not an acutely toxic product by any route of exposure. The acute oral LD50 in rats is .93 g/kg (Category III), the acute dermal LD50 in rabbits is 13.3 g/kg (Category III), and alachlor does not cause significant eye or skin irritation in rabbits (Category IV). Chronic Toxicity - Alachlor is oncogenic in both mice and rats. In mice, alachlor causes a statistically significant increase in lung bronchioalveolar tumors in females at 260 mg/kg/day (Highest Dose Tested). In rats, alachlor causes statistically significant increases at 42 mg/kg/day and above in nasal turbinate and stomach tumors in both sexes and thyroid follicular tumors in males. The following No Observed Effect Levels (NOELS) have been established for non-oncogenic effects; 1 mg/kg/day for liver and kidney effects; 2.5 mg/kg/day for uveal degeneration syndrome (UDS) of the eyes; 10 mg/kg/day for reproductive effects to kidneys of offspring. No birth defects were seen in highest dose tested for rats (400 mg/kg /day), but an additional teratogenicity study in rabbits is pending completion in 1988. ------- -3- 4• Summary of Agency's Regulatory Position The Agency position is tiat current registrations for the use of alachlor on agricultural and nonfood crops will be allowed to continue provided the following conditions and label modifications are met to reduce applicator exposure: a. Reclassification as restricted use pesticide. The application of alachlor is restricted to use by certified applicators or persons under their direct supervis ion. b. Continue use of tumor warning on label. The following tuaor warning statement imposed in the alachlor Registration Standard must remain on the label: "The use of this product may be hazardous to your health. This product contains alachlor which has been determined to cause tumors in laboratory animals." c. Require the use of mechanical transfer devices by all mixer/loaders and/or applicators who treat 300 acres or more annually with alachlor. d. Reinstate aerial application on the alachlor label with the following additional label restriction: "Human flacgers prohibited. Aerial application may be performed using mechanical flaggers only." The Agency has determined that the upper bound U.S. dietary risk from alachlor residues on food crops is in the range of 10~6 (approximately one increased tumor case per million persons exposed) based on the actual percent of crops treated with alachlor. The Agency believes this risk is reasonable given the benefits of continued use. The Agency has determined that the risks associated with alachlor exposure through ground water cannot be adequately assessed at this time. The true extent of alachlor occurrence in ground water is not known and cannot be properly estimated for most areas of the country. Further monitoring will be necessary considering the large volume, multiregional use of alachlor, and the lack of statistically representative data from the available studies. The Agency's final evaluation of the ------- -4- potential for alachlor contamination of ground water is being deferred, pending receipt of required monitoring data being generated by the registrant under an EPA-approved p-otocol. This study is scheduled for completion in late 1989, and the results will be evaluated by EPA in early 1990. Existing data on alachlor residues in surface water indicate that the risk from drinking water sources supplied by surface water will generally not exceed a range of 10"^. The Agency believes this level of risk is reasonable given the benefits of continued use of alachlor products, and is not proposing regulatory act ion under FIFRA on alachlor residues in surface water. The Agency plans to promulgate regulations establishing a Maximum Contaminant Level (MCL) for alachlor under the Safe Drinking Water Act in the near future. These regulations would require the treatment of drinking water which contains alachlor residues in excess of the MCL, thereby maintaining the level of risk from exposure at reasonable levels. 5. Contact person: James V. Roelofs Review Manager Special Review Branch Registration Division (TS-767C) Office of Pesticide Programs U.S. Environmental Protection Agency Washington, D.C. 20460 (703)-557-0064 DISCLAIMER: The information in this Chemical Information Sheet is for informational purposes only, and may not be used to fulfill data requirements for pesticide registration or reregistration. ------- |