Long-Term Study Finds Endocrine Disrupting Chemicals in Urban Waterways

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U.S. Geological Survey (USGS) scientists determined that endocrine disrupting chemicals (EDCs) were present in wastewater treatment plant (WWTP) effluent, water, and fish tissue in urban waterways in the Great Lakes and upper Mississippi River Regions (Indiana, Illinois, Michigan, Minnesota, and Ohio) during 1999 through 2009.

Scientists Electrofishing on the North Branch of the Chicago River

For this study scientists collected several fish species from river and lake sites and analyzed them for endocrine disrupting chemicals and biomarkers of endocrine disruption. In this photo the scientists are electrofishing to collect fish from the North Branch of the Chicago River, Chicago, Illinois. Photo credit: Clifford P. Rice, U.S. Department of Agriculture.

Urban waterways provide critical functions, including water supply, wastewater disposal, transportation, and aquatic habitat. Management of these multiple uses requires an understanding of the sources, fates, and effects of chemical contaminants. There are many potential sources of chemicals to urban waterways including discharges from municipal and industrial WWTPs, inputs from land-surface runoff, and wet and dry atmospheric deposition.

Scientists started with a survey of WWTP effluent and stream water at or near some of the major WWTPs in the regions to understand differences among sites and inputs to urban waterways. A focused investigation of the Greater Metropolitan Chicago Area Waterways, Illinois assessed the movement of EDCs from their source within the WWTP sewer collection system, through the major treatment processes, and into the receiving stream. The approach also included the assessment of fish tissue concentrations and fish endocrine disruption responses to understand corresponding environmental health implications.

Scientists measured alklyphenolic EDCs including surfactant degradation products 4-nonylphenol (NP), 4- nonylphenolpolyethoxylates (NPEO), 4-nonylphenolethoxycarboxylic acid (NPEC), 4-tert-octylphenol (OP), 4-tert-octylphenolpolyethoxylates (OPEO), a plastic component (bisphenol A), and an antimicrobial (triclosan). Other non-EDCs (ethylenediaminetetraacetic acid [EDTA] and boron) were measured as tracers of wastewater. Multiple fish species were collected, and their tissues were analyzed for NP, NPEO, NPEC, OP, and OPEO.

This study documented that WWTP effluent discharges can be long-term sources for a diverse group of EDCs that are not removed completely during the treatment process, and once introduced into the receiving stream, the compounds can persist for long distances downstream. All EDCs measured were detected among WWTP effluent samples, with NPEC found most frequently and with the greatest concentrations. The EDCs also were detected in the water and fish tissue of waterways receiving WWTP effluent. Biomarkers of endocrine disruption in fish indicated exposure to EDCs in the WWTP- impacted urban waterways, with a positive correlation between whole-body tissue concentrations of NP and biomarkers of endocrine disruption.

Detailed investigations of the highly engineered Greater Metropolitan Chicago Area Waterways, Illinois, indicated that (1) alkylphenolic EDCs in the sewer systems came from residential, commercial, and industrial sources; (2) although EDCs decreased during wastewater treatment, they were still present in the final WWTP effluent; (3) some EDCs are produced during wastewater treatment as the result of biodegradation of the parent surfactants; and (4) EDCs and other contaminants discharged in the WWTP effluent are transported downstream with little change in concentrations.

Information on contaminants in urban waterways is important to resource managers facing issues including wastewater reclamation and reuse, drinking water quality, aquatic biota health, and impacts of engineering approaches to change flow direction for controlling invasive species.

This study was funded by the USGS Toxic Substances Hydrology Program and the U.S. Environmental Protection Agency.

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