Organochlorine pesticide residues in cow's milk from a tropical region of Mexico

Abstract

A monitoring study was conducted to assess the magnitude of DDT [(1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane)] and HCH (hexachlorocyclohexane) contamination of bovine milk from the central tropical region of Mexico as the chemicals are extensively used in livestock and public-health programmes. Among pesticide residues analysed, the milk samples collected from Tlalixcoyan showed a mean level of γ-HCH (0.128 mg kg^-1), which was significantly higher than residues in milk samples from Medellin (0.049 mg kg^-1) and Paso San Juan (0.022 mg kg^-1). The mean level of pp'-DDE in Medellin samples (0.039 mg kg^-1) was significantly higher than in Paso San Juan (0.018 mg kg^-1) and Tlalixcoyan (0.024 mg kg^-1) milk samples. The pp '-DDT mean level from Medellin milk samples (0.089 mg kg^-1) was significantly higher than the levels detected in the other two areas. The highest mean Σ-DDT level detected in Medellin samples (0.146 mg kg^-1) was three times the FAO/WHO tolerance level. The highest acceptable daily intakes calculated for Σ-DDT were 0.017 μg kg^-1 bw day^-1 for adults and 0.530 μg kg^-1 bw day^-1 for infants; for γ-HCH residues, they were 0.021 μg kg^-1 bw day^-1 for adults and 0.666 μg kg^-1 bw day^-1 for infants, indicating that infants are more exposed to pesticide residues. Results indicate that cattle exposure to HCH and DDT results in high levels in dairy milk and a potential health risk for consumers.

Keywords:

• Organochlorine Pesticide Residues
• Bovine Milk
• Tropical Region