WHO- and UNEP-Coordinated Exposure Studies 2000–2019: Findings of Organochlorine Pesticides and Industrial Chemicals

Abstract

AbstractThe concentrations of a number of organochlorine pesticides and related chemicals and two organochlorine industrial chemicals were determined in 163 pooled human milk samples from 82 countries from all United Nations regions. These countries participated in one or more of the five exposure studies on persistent organic pollutants coordinated by the World Health Organization and the United Nations Environment Programme between 2000 and 2019. The compounds included were aldrin, chlordane, chlordecone, DDT, dicofol, dieldrin, endosulfan, endrin, heptachlor, hexachlorobenzene, hexachlorobutadiene, hexachlorocyclohexanes, mirex, pentachlorobenzene, pentachlorophenol/pentachloroanisole, and toxaphene.Large differences were found for DDT with the highest concentrations found in Africa. However, the median levels of the DDT concentrations of all samples show a decrease of 72% from the 2000–2003 period to the 2016–2019 period, with considerable differences between regions. Due to metabolization of hexachlorocyclohexanes (HCH) in humans, the concentrations of alpha-HCH and gamma-HCH were below the limit of quantification in most human milk samples. The ranges of beta-HCH found in the five periods varied considerably among UN regions, with a maximum found in 2002 in the Asia subgroup of the Asia-Pacific region. A decrease of the median concentrations of all samples of 91% was found from the 2000–2003 period to the 2016–2019 period. In comparison with DDT and beta-HCH, the ranges for hexachlorobenzene (HCB) were much lower with a maximum found in the samples from Eastern Europe. Other organochlorine pesticides and contaminants and their metabolites were found mostly in ranges of low background contamination; some were below the limits of quantification.