The estrogenic activity of influents and effluents of five municipal sewage treatment works(STWs)in Nanjing was investigated.The water samples were enriched by solid phase extraction,then eluted with different polar solvents,and finally three fractionated extracts were obtained.Estrogen receptor recombinant yeast screen was used to evaluate the estrogenic activity of individual fractionated extracts and their mixture.The results show that the influents and effluents of the two STWs mainly receiving industrial wastewater have no obvious estrogenic activity,and the water samples from the other three STWs mainly receiving domestic wastewater show different degrees of estrogenic activity.The total estrogenic concentration ranged from 171.52 ng/L EEQ(E2-equivalent concentration)to 1008.37 ng/L EEQ in the influents,and from ND(not detected)to 36.3 ng/L EEQ in the effluents.By comparing the results of different fractionated extracts,the methanol and dichloromethane extracts of the water samples show higher estrogenic activity,while the hexane extracts very low.The(xeno)estrogens from domestic wastewater could be removed obviously by activated sludge treatment units.However,the effluents of STWs in Nanjing still have chemical contaminants capable of binding to estrogen receptors.
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