Spatiotemporal heterogeneity and source apportionment of endocrine disrupting compounds and antibiotics in the Erhai Lake basin

Endocrine-disrupting chemicals and antibiotics are prevalent in aquatic environments, where they accumulate persistently, posing significant ecological risks that have become a topic of active research worldwide. Previous studies of such emerging contaminants have mostly involved short-term monitoring without considering the watershed as a whole. This study was designed to establish a sink-source-interception system framework for Erhai Lake basin. Historical data were exploited to investigate the sources, fate, removal and ecological risks of endocrine disrupter chemicals and antibiotics in the lake’s basin. The data show that the levels of endocrine-disrupting chemicals have decreased markedly in a decade, while the detected categories of antibiotics remained consistent with those five years ago. This finding was closely linked to the interception efficiency. Contaminant concentrations are shown to be driven by livestock breeding, urban sewage, and agricultural non-point source pollution. Source analysis identified industrial and domestic wastewater as the primary source of endocrine-disrupting chemicals, while effluent from wastewater treatment plants and farm runoff are the main sources of antibiotics. Ecological risk assessments indicated that estrogens, sulfonamides and quinolone antibiotics present the high ecological risks (RQ > 1). These findings provide a scientific foundation for targeted pollution prevention and control of emerging contaminants at the plateau lake watershed scale.