1. Department of Environmental and Molecular Toxicology, Oregon State University, 139 Oak Creek Building, Corvallis, Oregon 97331, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon 97331, Animal Metabolism-Agricultural Chemicals Research Unit, USDA ARS, Fargo, North Dakota 58105-5674, and USDA Environmental Management and By-Product Utilization Laboratory, Building 007, 10300 Baltimore Avenue, BARC-West, Beltsville, Maryland 20705