RESUMO
Changes in the endocrine potency of municipal wastewater at 3 wastewater treatment plants (WWTPs) in Australia were investigated using a panel of in vitro receptor-driven transactivation assays. The assays were based on human estrogen receptor α, androgen receptor, progesterone receptor, glucocorticoid receptor, and peroxisome proliferator-activated receptor γ2. Total removal efficiencies for estrogenic activity in the dissolved phase were 79.8% to 99.4%. Chemical analysis of 17ß-estradiol, estrone, and 17α-ethinylestradiol levels showed that they accounted for the majority of the observed in vitro estrogenic activity in the final effluents but only 18% to 70% of estrogenic activity in the influents. Removal efficiency for androgenic activity was 97.5% to 100%. Endocrine activity levels were low in the final effluent of the WWTP with the lowest catchment population, with only estrogenic activity detected. In the final effluent of the WWTP with an intermediate catchment population, estrogenic, glucocorticoid, and peroxisome proliferator activities were detected. Estrogenic, antiandrogenic, progestagenic, glucocorticoid, and peroxisome proliferator activities were detected in the final effluent of the WWTP with the highest catchment population. The present study confirms the efficacy of secondary and tertiary treatment in reducing the concentrations of endocrine-active compounds in municipal wastewater. Further work is required to determine the possible health risks to aquatic biota posed by multiple hormonal activities present at low levels.