Residues of HCH isomers and DDT derivatives in Israeli milk and their seasonal fluctuations |
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| Authors: | D Veierov N Aharonson Eugenia Alumot |
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| Institution: | 1. Pesticide Chemistry and Residue Research Laboratory, The Volcani Center, Bet Dagan
2. Div. of Animal Nutrition, ARO, The Volcani Center, Bet Dagan
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| Abstract: | Residue analysis of milk fat from 12 commercial dairies showed that p,p′-DDE, α-HCH and γ-HCH were the major and most frequent contaminants, at 0.15–0.3 ppm. Beta isomer of HCH was found in the milk in much smaller concentrations (less than 0.05 ppm). Further studies showed that the residue levels of α- and γ-HCH in the milk changed considerably during the 18 months of the experiment. The concentrations fluctuated from a maximum of 1.4–1.6 ppm to as low as 5–10% of these values. The variations in concentration for α- and γ-HCH were very similar, and were found to result from commercial spraying of cows with a formulation of HCH. Three days after spraying two groups of cows with HCH, the residue level rose from 0.02–0.05 ppm to 0.18 ppm. During the next 2–3 months, the concentration of these isomers in the milk fat decreased to 0.02–0.04 ppm. A second spray resulted in an even faster accumulation of α and γ isomers in the milk fat, up to 0.38 ppm, three days after treatment. Comparison between the results obtained from the two groups of cows and those obtained from the analysis of 12 cows showed very small individual variations, with a standard deviation of 15–30% of the mean. The results for DDE were different: its concentration in the milk did not fluctuate so much, and it was similar for all the dairies examined. In goat milk, the concentration of HCH isomers was much lower, not exceeding 0.02–0.05 ppm. The level of DDE was also much lower, 0.02–0.07 ppm. |
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