[Pesticide residues in feed-stuffs in Sweden (author's transl)].

The occurrence of pesticide residues was studied in samples of feed-stuffs produced in Sweden or imported to Sweden during the years 1972--1976. In all, 278 samples representing 37 types of feed-stuffs (components, as well as finished feeds) and 18 countries were analyzed. Residues of chlorinated hydrocarbon pesticides and PCBs were looked for in 224 samples, mostly feed components. The analytical method used involved solvent extraction, florisil-column clean-up, thinlayer chromatographic separation and gas-chromatographic determination. Chlorinated hydrocarbons were found in several samples. DDT and its transformation products were detected in 66 samples (29.5%), lindane in 44 (19.5%), PCBs in 25 (11.2%), alpha-BHC in 22 (9.8%), beta-BHC in 11 (4.9%) and dieldrin in 9 (4.0%). The levels were usually low (Table I). The chloropesticides occurred most frequently and at the highest levels in feed-stuffs of animal origin and in imported oil-feeds. In 25 of the samples the contents of sigmaDDT exceeded the maximum limit accepted by the National (Swedish) Food Administration for grain and bran intended for human consumption (0.05 mg/kg, Talbe IV). The highest residue level of sigmaDDT (0.66 mg/kg) was encountered in a sample of fish meal. The PCB levels found did not exceed the temporary tolerance established by FDA (1973) for finished animal feeds (0.2 mg/kg). One hundred and seven samples were analyzed for phenoxy acid residues using a thin-layer chromatographic and gas-chromatographic technique. Phenoxy acids were detected in only 2 of 62 randomly selected feed samples (0.05 and 0.2 mg/kg, respectively). The residue limit established by the National Food Administration for 2,4-D and MCPA in grain and bran intended for human consumption is 0.1 mg/kg. Fortyfour samples of feeds were submitted because of suspected phenoxy acid contamination. In 12 of the samples phenoxy acid residues were found. The highest level (3.5 mg/kg, MCPA) was observed in a sample of accidentally contaminated molasses. Considering the apparently low level of contamination of Swedish grain with chloropesticides, PCBs and phenoxy acids and the dilution on compounding feed-stuffs of animal origin and oil-feeds, only very low pesticide residue levels can be expected in Swedish finished animal feeds.