Chlorinated Paraffin Levels in Relation to Other Persistent Organic Pollutants Found in Pooled Human Milk Samples from Primiparous Mothers in 53 Countries

BACKGROUND: The current production and use of chlorinated paraffins (CPs) at [Formula: see text] likely exceeds the lifetime production of polychlorinated biphenyls (PCBs). These persistent organic pollutants (POPs) are a concern to human health. OBJECTIVES: The United Nations Environment Programme conducts global surveys of human milk samples from individual countries as a noninvasive method of investigating levels and trends in human exposures to POPs such as CPs. We measured CP concentrations and assessed their relation to other POPs in pooled samples collected during 2012–2019. METHODS: We analyzed 57 official nationwide pooled milk samples from 53 countries on five continents (Africa, Central/South America, Asia, Europe, and Australia/Oceania). CP concentrations were further characterized by subgroups and compared with concentrations of 19 other POPs, including PCBs and a variety of pesticides. RESULTS: CPs were detected in pooled samples from all 53 countries, with concentrations of [Formula: see text] lipid. CPs accounted for 18–46% of the total summed POPs in human milk, second only to dichlorodiphenyltrichloroethane (DDT). CP concentrations exceeded PCB concentrations in pooled samples from most countries. DISCUSSION: The presence of CPs in all samples, including samples from isolated locations (e.g., Pacific Island countries), emphasizes the ubiquitous presence of these compounds, whereas differences in subgroup ratios indicate a delay in the shift toward nonregulated medium-chain CPs (MCCPs) for these regions. The predominance of MCCPs in samples from many countries suggests a need for regulation and research on health effects. https://doi.org/10.1289/EHP7696