Occurrence, distribution and risk assessment of estrogenic compounds for three source water types in Ningbo City, China

This study evaluated the occurrence, distribution and risk assessment of nine estrogenic compounds found in 29 source water sites in Ningbo City, China. They included 21 reservoirs, five river sites and three wells. The nine estrogenic compounds included estrone (El), 4-n-nonylphenol (NP), 17 alpha-ethynylestradiol (EE2), diethylstilbestrol (DES), estriol (E3), 17 beta-estradiol (E2), 4-toctylphenol (OP), 1713-estradio1-17-valerate (EV), and bisphenol A (BPA). Generally, most of these estrogenic compounds were not detected in samples. Among estrogens detected, we found high concentrations of BPA up to mu g/L levels while NP had the highest detection frequency of all estrogens in all samples. Samples taken from rivers had a higher detection frequency of estrogenic compounds than samples taken from reservoirs and wells. According to risk quotient (RQ) calculations for aquatic organisms living in source water contaminated by estrogenic compounds, the Fenghua and Yao rivers were at high risk. Results from this study can provide insight into selecting appropriate source water based on the accurate identification of compound and/or element contamination through the coupled analysis of their distribution and risk assessment.