Persistent organochlorine pesticides residues in cow and goat milks collected from different regions of Ethiopia

• Extremely high levels of organochlorines were found in cow and goat milks.
• Regions known for their malaria epidemics were the most contaminated with DDT.
• Environmental contamination prevented distinction of specie effect for contamination.

The present study investigated the bioaccumulation of organochlorines in two milk-producing animals (goats and cows) grazed on the same feed to explore the extent of organochlorines availability in milk and any species effect on the bioaccumulation pattern. Six organochlorine pesticides: aldrin, α-endosulfan, β-endosulfan, p,p′-DDE, o,p′-DDT and p,p′-DDT were determined in samples collected from four regions in Ethiopia. Aldrin (11.6 μg kg−1) was detected only in one cow milk sample and α-endosulfan was detected in one goat milk sample at a level of 142.1 μg kg−1, and in one cow milk sample (47.8 μg kg−1) from the same region. p,p′-DDE was detected in 40% of the milk samples analyzed while o,p′-DDT and p,p′-DDT were found in high amounts in almost all samples. The average total DDT (excluding DDD) in the samples was 328.5 μg kg−1. Regions known for their malaria epidemics were the most contaminated with DDT residue. The accumulation pattern in both species was not clear under natural sampling.