Variations of Pesticide Residues in Arizona Milk

Abstract

Information concerning the extent and nature of pesticide residue contamination in milk, produced under Arizona conditions, was obtained in a survey conducted over a period of 4 years and 3 months. The residue level exhibited a seasonal cycle, with a maximum in the fall and a minimum in the late spring or early summer. This cyclic pattern could be correlated with practices in pesticide application and the harvesting, storage, and feeding of drift-contaminated forage. Educational and regulatory efforts gave response in reduced Insecticide contamination, with the latter apparently being more effective. DDT [dichlorodlphenyl trichloroethane] and its metabolites DDE [l,l-dichloro-2,2-bis(p-chlorophenyljethylene] and DDD [dichloro-diphenyl-dichloroethane] were the major compounds found. The metabolite DDE occurred in concentrations 6 to 12 times higher than DDT.