Modeling the loading and fate of estrogens in wastewater treatment plants

Endocrine-disrupting compounds may produce infertility, nervous system disorders, and improper functioning of the immune system in humans and wildlife. Estrogens are classified as the most potent and common endocrine-disrupting compounds and the major point source for estrogen is municipal wastewater. Monitoring of estrogen is challenging, expensive, and intermittent; and therefore, the focus of this work is modeling estrone, 17 beta-estradiol, and 17 alpha-ethynylestradiol concentrations from wastewater treatment plants in Calgary and Edmonton, Alberta, and Brandon, Manitoba. Demographic groups, excretion rates, population estimates, average daily flows, calculated estrogen transformation, calibration, calculated influent-to-effluent reduction percentages, and a treatment unit removal matrix are used to determine loading estimations of estrogen. Predicted average concentrations for EE2 and E2 in all the study sites exceed the threshold concentrations that could induce vitellogenin production by order of 13 and 2.3, respectively. The results demonstrate reasonable accuracy against previous measurements with r(2) values ranging from 0.79 to 0.99 and RMSE values ranging from 0.5 to 9.4 ng/l and findings are consistent with concentrations reported in the literature. Upon further calibration with additional local data, the model may be used as a risk assessment analysis tool for these contaminants of concern.