ORGANOHALOGEN AND ORGANOPHOSPHORUS PESTICIDES IN MIXED FEED RATIONS -FINDINGS FROM FDAS DOMESTIC SURVEILLANCE DURING FISCAL YEARS 1989-1994

During Fiscal Years 1989-1994, the U.S. Food and Drug Administration ( FDA) collected and analyzed 545 domestic surveillance samples of mixed feed rations (172 for cattle, 125 for poultry, 83 for swine, 61 for p ets, 56 for fish, and 48 miscellaneous). All samples were analyzed by gas-liquid chromatography for organohalogen and organophosphorus pesti cides. Of the 545 samples, 88 (16.1%) did not contain detectable pesti cide residues. In the 457 samples with detectable pesticide levels, 80 4 residues (654 quantitable and 150 trace) were found. None of these 8 04 residues exceeded regulatory guidance. Malathion, chlorpyrifos-meth yl, diazinon, chlorpyrifos, and pirimiphos-methyl were the most common ly detected pesticides. These 5 organophosphorus pesticides accounted for 93.4% of all pesticide residues detected (malathion, 52.9%; chlorp yrifos-methyl, 25.2%; diazinon, 7.7%; chlorpyrifos, 4.9%; and pirimiph os-methyl, 2.7%). Their median values in samples containing quantitabl e levels ranged from 0.014 to 0.098 ppm. The most commonly detected or ganohalogen compounds were methoxychlor, DDE, PCB, dieldrin, pentachlo ronitrobenzene, and lindane, These 6 compounds combined accounted for only 4.1 of of all residues detected. FDA is continuing its pesticide surveillance of feeds to help ensure animal safety and prevent violati ve residues in food derived from animals.