Persistent Organic Toxicants in Breast Milk of Women From the Sakhalin Region and Health Risk Assessment for Infants

BACKGROUND: According to the World Health Organization, the most reliable indicator of the adverse impact of persistent organic pollutants on human health is their concentration in breast milk. As humans occupy the top of the trophic chain, breast milk analysis provides insights into potential sources of environmental contamination and allows assessment of health risks for newborns. AIM: The work aimed to determine the levels of organochlorine pesticides (hexachlorocyclohexane and dichlorodiphenyltrichloroethane) and polychlorinated biphenyls in breast milk of women from the Sakhalin Region, and to assess the health risks for infants consuming breast milk containing persistent organic pollutants. METHODS: It was a series of cross-sectional studies (in 2022 and 2023). Samples of breast milk from women permanently residing in the Sakhalin Region were analyzed. Sampling was performed by professionals from several healthcare institutions with written informed consent obtained from participants. Concentrations of organochlorine pesticides and polychlorinated biphenyls in breast milk were determined using gas chromatography–mass spectrometry. RESULTS: A total of 57 breast milk samples from women residing in the Sakhalin Region were analyzed: 26 samples in 2022 and 31 samples in 2023. Persistent organic pollutants were detected in all samples. Elevated concentrations of dichlorodiphenyltrichloroethane and hexachlorocyclohexane may be associated with periodic outbreaks of pests and subsequent forest treatment with pesticides. The detection of polychlorinated biphenyls indicates technogenic contamination of the environment, primarily from shipping activities and equipment containing these substances (transformers, capacitors, and other devices). The predominance of β-hexachlorocyclohexane, dichlorodiphenyldichloroethylene metabolites, and polychlorinated biphenyls with medium and high degrees of chlorination suggests active degradation of toxicants in the environment and their long-term presence in the Sakhalin Region. Health risk assessment in infants showed that estimated daily intake did not exceed threshold values, confirming the safety of breastfeeding. Comparison of obtained results with global research indicates the establishment of a worldwide background level of persistent organic pollutants, which can be traced across different regions of the world. CONCLUSION: The total content of persistent organic pollutants in breast milk indicates ongoing degradation processes of parent compounds in the environment and their long-standing presence in the Sakhalin Region. Health risk assessment for infants revealed no exceedance of threshold values, confirming the safety of breastfeeding. At the same time, the findings highlight the need for regular monitoring of persistent organic pollutant concentrations.