Contamination of polychlorinated biphenyls and organochlorine pesticides in breast milk in Korea: Time-course variation, influencing factors, and exposure assessment

•The levels of PCBs and OCPs in breast milk significantly increased within the first month of lactation.•Seafood and noodle consumption was associated with the concentrations of PCBs and OCPs in breast milk.•OC exposure to breast-fed infants was below the thresholds proposed by US EPA and Health Canada.•Chlordane has a potential health risk to Korean infants via breast milk.•This is the first comprehensive study to assess infant exposure to OCs via breast milk in Korea.

Breast milk is a noninvasive specimen to assess maternal and infant exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). In this study, 206 breast milk samples were collected from 87 participants during lactation, at <7, 15, 30, or 90 days postpartum in four cities in Korea. The total concentrations of PCBs (ΣPCB) and OCPs (ΣOCP) ranged from