Occurrence of estrogenic activities in second-grade surface water and ground water in the Yangtze River Delta, China

•Estrogenic activities were present in second-grade surface water and ground water.•Most of the detected equivalents were higher than the predicted no-effect-concentration of E2.•ER-EQ20-80 ranges showed that samples in Huaihe River and Yangtze River posed the highest toxicity.•Bisphenol A contributes to most of the instrumentally derived equivalents in surface water.

Second-grade surface water and ground water are considered as the commonly used cleanest water in the Yangtze River Delta, which supplies centralized drinking water and contains rare species. However, some synthetic chemicals with estrogenic disrupting activities are detectable. Estrogenic activities in the second-grade surface water and ground water were surveyed by a green monkey kidney fibroblast (CV-1) cell line based ER reporter gene assay. Qualitative and quantitative analysis were further conducted to identify the responsible compounds. Estrogen receptor (ER) agonist activities were present in 7 out of 16 surface water and all the ground water samples. Huaihe River and Yangtze River posed the highest toxicity potential. The highest equivalent (2.2 ng E2/L) is higher than the predicted no-effect-concentration (PNEC). Bisphenol A (BPA) contributes to greater than 50% of the total derived equivalents in surface water, and the risk potential in this region deserves more attention and further research.