Developing water quality and land use surrogates to predict endocrine-disrupting chemical profiles in a highly urbanized river basin.

This study investigated geospatial distributions of endocrine-disrupting chemicals (EDCs) in the waters of the Dongjiang River and their associations with anthropogenic activities. Fifteen EDCs, with total concentrations in the river water of 149-2525 ng/L were detected, with bisphenol-A, 4-nonylphenol, 4-tert-octylphenol, p-hydroxybenzoic acid, and methylparaben being the five predominant EDCs. The total estrogen concentration was high downstream and significantly correlated with the spatial distribution of urban land use, wastewater discharge, population, and gross domestic product, indicating human activities have increased estrogen levels and threatened ecological health. The total risk quotient indicated a high ecological risk of estrogens to fish and a moderate to high ecological risk of personal care products to algae. Estrone, triclosan, bisphenol-A, 4-nonylphenol, and 4-tert-octylphenol were categorized as priority pollutants, which required special concern. Triclosan and triclocarban can serve as reliable chemical indicators for predicting EDC levels based on correlation analysis. The crucial factors affecting EDC levels were identified through the Mantel test and predictor importance was quantified using a multiple regression model, which can help predict occurrences and geospatial distributions of EDCs. Total phosphorus and electrical conductivity were the major predictors of EDC levels, providing promising indicators for monitoring EDCs in river water. Urban land proportion significantly affected phenolic environmental estrogens, natural estrogens, and disinfectants. In the main stream, urban population, urbanization rate, and gross domestic product influenced phenolic environmental estrogen levels. A mini-review of the global distribution of EDCs in river water revealed that income and population differences among countries affect their occurrence, suggesting socioeconomic factors should be considered to mitigate EDC pollution.