Organochlorine pesticides in placenta, blood and breast milk of mothers in Uganda: Concentrations and health risks to breast fed infants

• First assessment of OCPs in maternal blood, milk, and placenta in Uganda. • ∑DDTs were 63.0, 27.1, 35.0 ng g -1 l.w in blood, milk, and placenta, respectively. • p,p′- DDE and o,p′- DDE were the dominant DDT metabolites across all samples. • OCP levels were significantly higher in rural Kanungu than urban Kampala. • All hazard quotients were <1, suggesting negligible health risks to breast fed infants. Exposure to organochlorine pesticides (OCPs) remains a major public health concern in low-income countries, where historical usage and poor regulation continue to result in maternal and early-life exposures. This study assessed concentration profiles of selected OCPs, namely; p,p′ -DDT, p,p′ -DDE, o,p′ -DDE, p,p′ -DDD, o,p′ -DDD, aldrin, dieldrin, lindane, α-endosulfan, β-endosulfan, and endosulfan-sulfate in maternal blood, breast milk, and placenta samples collected from 52 healthy mothers residing in the rural Kanungu District and urban Kampala District in Uganda. Analytical quantification was performed using gas chromatography-electron capture detection (GC-ECD), and compound identity was confirmed by gas chromatography–mass spectrometry (GC-MS). Concentrations of total DDTs (∑DDTs) were 63.0, 27.1, and 35.0 ng g -1 lipid weight (l.w) in blood, breast milk, and placenta, respectively. o,p′ -DDE was the predominant metabolite in blood (67% of ∑DDTs), while p,p′ -DDE dominated in placenta and milk (34% and 70%, respectively), possibly due to degradation of technical DDT applied in past decades. Other OCPs were generally low (<Limit of detection, LOD to 88.4 ng g -1 l.w), except for dieldrin, which reached 130 ng g -1 l.w in breast milk. OCP levels were significantly higher in Kanungu than Kampala, attributable to ongoing informal pesticide use in agriculture. In general, the estimated hazard quotients were <1, which indicated that the health risks posed to infants due to ingestion of OCPs in breast milk was negligible. Our findings underscore the need for rural pesticide regulation and continuous maternal exposure monitoring.