Analysis identifies inflow rivers as primary sources of organochlorine pesticides in a plateau lake, suggesting significant bioaccumulation risks.
Abstract Sources apportionment and clarification of migration pathways of organochlorine pesticides (OCPs) are critical yet unsolved scientific issues for sustainable development of plateau lakes. Here, we integrated the distribution pattern, sources analysis and bioaccumulation process of OCPs in a typical semi-enclosed plateau lake, representative aquatic ecosystem of the Tibetan and Yunnan-Guizhou plateau, to address these scientific issues. The δ-hexachlorocyclohexane (δ-HCH), α-hexachlorocyclohexane (α-HCH) and endrin aldehyde were the predominant OCPs in sediments, with their contents ranging from nd (not detectable) to 459.89 ng∙g⁻ ¹ (δ-HCH), nd to 450.87 ng∙g⁻ ¹ (endrin aldehyde) and 11.00 to 236.95 ng∙g⁻ ¹ (α-HCH) respectively. Notably, the main OCPs in lake sediments were linearly related to total organic carbon (TOC), indicating the homologous relationship between OCPs and TOC. Moreover, the behaviors of OCPs were governed by partitioning process regulated by TOC and pH of sediments. Integrating the OCPs distribution, stable carbon isotope (δ¹³C) mixing model and geo-graphical features, we identified inflow rivers (87.1%) and farmland (6.3%) as the main sources. While the bioaccumulation of OCPs in fish was moderate, long-term hjkealth risks of OCPs by consumption of fish were considerable. The findings of this study highlight the priority of basin-wide source control method for sustainable management of such semi-enclosed environment.
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Qiu et al. (2025) studied this question.