[Evaluation of estrogenicity of sewage samples from Beijing, China]

The recombinant yeast estrogen screen (YES) was used to evaluate the estrogenic activities of sewage samples from every step of three sewage treatment plants (STPs) in Beijing, China. Meanwhile, eight target endocrine-disrupting compounds (EDCs) in corresponding sewage samples were simultaneously analyzed by GC/MS system to further elucidate the variations of their estrogenic activities. The results indicated that estrogenic activities could be considerably reduced by STPs with the rate of 82.2%-97.0%. However,they were still detected in the effluent samples with the values of EEQs (expressed as E2 equivalents) 2.6-16.0 ng/L. In addition,STPs could not completely remove the target EDCs according to GC/MS analysis. The average concentration of 17alpha-E2 in the effluent was the lowest with the value of 13.5 ng/L, and the concentration of BPA (106.4 ng/L) was the largest. The estrogenic activities of effluent samples were mainly composed of steroid estrogens. Consequently, potential environmental risk can be caused by the discharge of effluents from STPs. How to effectively remove steroid estrogens during sewage treatment is, therefore, of a major concern.