Many estrogenic chemicals are released into the surface waters by municipal wastewater treatment plants (WWTPs) and livestock farms. Estrogenic chemicals are a sub-class of the chemicals collectively called the endocrine disruption chemicals (EDCs), which are able to bind with the estrogenic receptor and cause adverse health effects to aquatic species. The objectives of this study were: (a) to use the in vitro Yeast Estrogen Screen (YES) bioassay in determining the total estrogenic activities in effluent/biosolid samples from the WWTPs across Canada, and (b) to identify the most efficient treatment method(s) of removing estrogenic chemicals from the raw influents of the WWTPs. Results of our study showed that the estrogenic activities in the final effluents ranged from 0.00057 to 0.390 ng estradiol equivalents (EEQs)/ml whereas the estrogenic activities in the biosolids ranged from 3.6 to 24.6 ng EEQs/g dry weight. The advanced biological nutrient removal method appeared to be the most efficient procedure in removing the estrogenic chemicals from the raw influents; it could reduce the EDC contents in the raw influents by >30 folds. This is the first survey study in which the estrogenic activities in raw influents, final effluents and biosolids of the different WWTPs in Canada are monitored. Future studies should focus on the chemical identities of the estrogenic compounds in the sample extracts and the improvement of treatment methods use in removing the estrogenic chemicals from the raw influents.
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