Concentration and Health Risk Assessment of Organochlorine Pesticide Residues in Breast Milk of Nursing Mothers in Agricultural Communities of Katsina State

Organochlorine pesticides, although banned or restricted in many countries, persist in the Nigerian agricultural environment due to historical use and continued illicit application. Breast milk is a sentinel matrix for biomonitoring lipophilic chemical exposure in nursing mothers and provides direct evidence of neonatal exposure risk. This study determined organochlorine pesticide concentrations in breast milk of nursing mothers from agricultural communities in Katsina State, North West Nigeria, and conducted a health risk assessment for breastfed infants. Sixty breast milk samples were collected from consenting nursing mothers across four farming communities in Dutsinma and Kankia local government areas. Pesticide extraction was performed by liquid-liquid partitioning, and fourteen target organochlorines including DDT metabolites, endosulfan, and lindane were quantified by GC-ECD. Hazard quotient and estimated daily intake were calculated for breastfed infants using FAO/WHO tolerable daily intake values. DDT and its metabolite DDE were detected in 87% of samples, with total DDT concentrations ranging from 8.4 to 312 ng/g lipid weight. Endosulfan was detected in 43% of samples. Infant estimated daily intake of DDT exceeded the tolerable daily intake in 28% of cases. Hazard quotients above 1.0 were calculated for infants in the highest exposure scenarios. These findings indicate ongoing organochlorine exposure in Katsina State agricultural women and highlight the need for biomonitoring integration into maternal and child health programmes. Keywords: organochlorine pesticides, breast milk, health risk assessment, Katsina State, DDT.