ISTOCK, WOODYUPSTATEEndocrine disrupting compounds (EDCs) are a class of emerging contaminants that potentially pose a threat to aquatic life by mimicking hormones. Steroidal estrogens found in treated municipal wastewaters are of higher concern to aquatic wildlife, and amongst these 17β-estradiol(E2), estrone(E1), and 17α-ethinylestradiol (EE2) have shown to be some of the most potent, with several studies displaying their potential to exert effects at low and environmentally relevant concentrations.
In our recent Nature Geoscience article, we calculated the proportion of stream flow that derives from upstream, publicly owned treatment works and used that to estimate estrogenic compound concentrations during average and low-flow conditions. For this study, we utilized a spatially explicit watershed-scale hydrologic model consisting of more than 14,000 sites in the U.S. where treated wastewater discharges to rivers or lakes to estimate the dilution factor (the ratio of total flow in the stream to the flow of wastewater discharge). We then assessed potential threats to aquatic life by estimating the receiving streams’ abilities to meet or exceed the dilution factor required to meet the hazard quotient (HQ), including a tenfold factor of safety.
We find that lower dilution factors naturally equate to higher ...
