Assessment of organochlorine pesticide residues in cows’ fresh and pasteurized milk sold from Kampala markets, Uganda

Abstract

Concentrations of organochlorine pesticides (Lindane, Aldrin, Dieldrin, Endosulfan, p, p’- DDT, o, p’-DDT and p, p’-DDE) residues in cows’ fresh and pasteurized milk samples from Uganda were determined using a gas chromatograph with an electron capture detector and confirmed with a gas chromatograph equipped with a mass spectrometer [GC-MS]. 54 fresh milk samples and 47 pasteurized milk samples were analyzed for organochlorine pesticides. Five organochlorine pesticides were detected in the milk samples; namely Aldrin, Dieldrin, Endosulfan, DDT and its metabolites and Lindane. The average concentration of lindane was 26 ± 1.7 μg/kg in fresh milk samples (n=54) and 22 ± 1.5 μg/kg in pasteurized milk (n=47). Endosulfan concentration was 4 ± 0.3 μg/kg in the fresh milk samples and 3 ±1.0 μg/kg in the pasteurized milk samples. p,p’-DDE contained mean concentrations of 9.5 ± 2.0 μg/kg in fresh milk and 8 ±1.0 μg/kg in the pasteurized milk samples. p, p’-DDT recorded an average concentration of 33 ± 6.9 μg/kg in fresh milk samples and 25 ±5.0 μg/kg in pasteurized milk samples. The average concentration of o, p’-DDT in fresh milk was 9 ± 2.0 μg/kg and in pasteurized milk it was 7 ± 4.0 μg/kg. The mean concentration of aldrin was 9 ± 0.7 μg/kg kg in fresh milk samples and 6 ±1.0 μg/kg in pasteurized milk samples. Dieldrin was 7 ± 4μg/kg in the fresh milk samples and 5 ± 5 μg/kg in the pasteurized milk. The concentration of sum-DDT was 52 μg/kg and was found to range from 3 μg/kg to 33 μg/kg in the fresh milk and was 41 μg/kg in pasteurized milk with the range of 7 μg/kg to 25 μg/kg. Although, most of the organochlorine residues detected were below the maximum limits set by the FAO/WHO, bioaccumulation of these residues is likely to pose health problems in higher organisms like human beings.