Levels of organochlorine pesticides in Mexican butter.
Organochlorine pesticide residues were analyzed in 345 samples of butter purchased from Mexican supermarkets in 1994. Three national brands and one foreign brand were analyzed. Most samples contained residues of gama-HCH (91%), HCB (90%), and p,p'-DDE (88%). Residues of alpha-HCH (63%), p,p'-DDT (42%), beta-HCH (38%), o,p'-DDT (17%), heptachlor epoxide (7%), and endosulfane sulfate (3%) were also detected. Mean values of pesticide residues determined were 0.093 mg/kg fat for total HCH and 0.056 mg/kg for total DDT. Mean values of organochlorine pesticide residues in Mexican butter were comparable with those in a foreign brand.