Occurrence of contaminants of emerging concern in surface and waste water from the Yangtze River chemical contiguous zone, China: Distribution, sources and ecological risk assessment

Abstract

Limited knowledge exists regarding the occurrence, potential sources, and risks of contaminants of emerging concern (CECs) in surface and waste water from chemical contiguous zones. A total of 136 CECs were detected at 32 sampling sites along the Yangtze River, with concentrations ranging from 0.55 to 4.21 × 104 ng/L. Hydrocortisonacetate, cortisone, prednisone, enalapril and medroxyprogesterone were detected across all sampling sites. Hierarchical cluster analysis based on 47 core CECs yielded similar results compared with principal components analysis and identified two major clusters: wastewater sites and surface water sites. Distinct patterns of CECs were observed in wastewater from three industrial parks owing to variations in the industrial facilities and products within each park. Nineteen CECs were initially classified as presenting a high or medium risk to aquatic organisms. Further quantitative probabilistic risk assessment revealed that caffeine, trenbolone and norethindrone posed a threat to the most vulnerable aquatic species while high-risk sites mainly occurred downstream of the chemical industrial park. The joint ecological risk of high-risk CECs was evaluated using potentially affected fractions, which ranged from 0.44 % to 47.9 % with concentration addition and 0.33 % to 45.1 % with response addition. This suggests the need to consider the joint ecological risk of the detected compounds in future studies.