Endocrine disrupting compounds in the middle and lower reaches of the Lhasa River Basin: Occurrence, distribution, and risk assessment

The contamination of endocrine disrupting compounds (EDCs) in frigid alpine areas is poorly understood compared with that in industrialized regions. In this study, the occurrence, distribution, and risk assessment of EDCs were investigated in the middle and lower reaches of the Lhasa River Basin in the Tibetan Plateau. Eight EDCswere analyzed in samples of surfacewater, sediment, natural soils, and farmland soils during the dry season and rainy season. Bisphenol A (BPA) and estriol were the most frequently detected compounds. The EDCs concentrations in the sediment and surface water varied with the rainy and dry seasons. The BPA concentration in the surface water of the lower reaches in the dry season was higher than that in the rainy season, which could be attributed to the low dilution by low water flow in the dry season and high degree of urbanization and industrialization in the lower reaches. The estradiol equivalents of EDCs in the surfacewater were belowthe predicted no-effect concentration (2 ng/L) of 17 beta-estradiol in the two seasons. Compared with other research results in the world, EDCs contamination in the Lhasa River Basin is at relatively lowlevels, and the risk in the middle and lower reaches of the Lhasa River Basin is generally low. (C) 2020 Elsevier B.V. All rights reserved.