Exposure to endocrine-disrupting chemicals (EDCs), such as estrogens, is a growing issue for human and animal health as they have been shown to cause reproductive and developmental abnormalities in wildlife and plants and have been linked to male infertility disorders in humans. Intensive farming and weather events, such as storms, flash flooding, and landslides, contribute estrogen to waterways used to supply drinking water. This paper explores the impact of estrogen exposure on the performance of slow sand filters (SSFs) used for water treatment. The feasibility and efficacy of SSF bioaugmentation with estrogen-degrading bacteria was also investigated, to determine whether removal of natural estrogens (estrone, estradiol, and estriol) and overall SSF performance for drinking water treatment could be improved. Strains for SSF augmentation were isolated from full-scale, municipal SSFs so as to optimize survival in the laboratory-scale SSFs used. Concentrations of the natural estrogens, determined by gas chromatography coupled with mass spectrometry (GC-MS), revealed augmented SSFs reduced the overall estrogenic potency ofthe supplied water by 25% on average and removed significantly moreestrone and estradiol than nonaugmented filters. A negative correlationwas found between coliform removal and estrogen concentration in nonaugmentedfilters. This was due to the toxic inhibition of protozoa, indicatingthat high estrogen concentrations can have functional implicationsfor SSFs (such as impairing coliform removal). Consequently, we suggestthat high estrogen concentrations could impact significantly on waterquality production and, in particular, on pathogen removal in biologicalwater filters.
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