Assessment of river contamination by estrogenic compounds in Paris area (France).

Wastewater treatment plants (WWTPs) receive a large spectrum of endocrine disrupting compounds (EDCs) that are partially eliminated during treatment processes and discharged into rivers. Given the lack of information in France about river contamination by EDCs, we chose to examine estrogenic potential of WWTP influents, effluents and receiving waters in Paris and its suburbs. Water samples were analyzed using gas chromatography coupled with mass spectrometry for quantifying natural and synthetic estrogens combined with an in vitro estrogenicity bioassay associated to a high pressure liquid chromatography fractionation. The four estrogens investigated, Estrone (E1), 17beta-Estradiol (E2), Estriol (E3) and 17alpha-Ethinylestradiol (EE2) were found in all WWTP and river samples at concentrations ranging from 2.7 to 17.6 ng/l and 1.0 to 3.2 ng/l, respectively. The synthetic estrogen EE2 seems more resistant to biodegradation in WWTPs and thus accounted for 35-50% of the estimated estrogenic activity in rivers. However, fractionation of samples and differences between concentrations of E1, E2, E3 and EE2 and the estrogenic activity measured by the in vitro bioassay suggested a complexity of mechanisms underlying the biological response that could not be attributed only to the investigated molecules.