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Endocrine Disrupting Chemicals Persist Downstream from the Source

Spirit Creek, Georgia
USGS scientists measured the concentrations of select endocrine disrupting chemicals (EDCs) in Spirit Creek, Georgia, as part of an assessment of the effects of the closure of a wastewater treatment plant. Sprit Creek is typical of a stream in coastal environments. Photo credit: Tom Abrahamsen, USGS.

Endocrine disrupting chemicals (EDCs) were transported 2 kilometers downstream of a wastewater treatment plant (WWTP) outfall in a coastal plain stream. EDCs persisted downstream of the outfall with little change in the numbers of EDCs and limited decreases in EDC concentrations.

U.S. Geological Survey (USGS) scientists measured concentrations of select EDCs approximately 10 times in water and sediment from 2009 to 2011, at five sites in the Spirit Creek watershed near Fort Gordon, Georgia, as part of an assessment of the effects of the closure of a WWTP on EDC persistence.

Sites included a control site upstream of the WWTP outfall and four other sites in the 2–kilometer reach extending downstream to Spirit Lake, into which Spirit Creek flows. A site located at the outfall of Spirit Lake was sampled once to assess the potential for EDC transport through the lake.

A modest decline (less than 20 percent in all cases) in surface-water detections of EDCs was observed with increasing distance downstream of the WWTP and was attributed to the chemicals attaching (partitioning) to the sediment. The EDCs focused on in this study included natural estrogens (estrone, 17β–estradiol, and estriol) and detergent metabolites, which exhibit estrogenic properties. Concentrations of estrogens and detergent metabolites downstream of the WWTP remained elevated above levels observed at the upstream control site, indicating that the WWTP was the prominent source of these chemicals to the stream. The mean estrogen concentrations observed downstream of the WWTP were 5 nanograms per liter and higher, a level indicative of the potential for endocrine disruption in native fish.

Estrogens were not detected in the outflow of Spirit Lake, indicating that they were diluted, partitioned to lake sediments, or were degraded within the lake through a combination of microbial processes and/or photolysis. However, detergent metabolites were detected in the outflow of Spirit Lake, indicating the potential for EDC transport downstream.

The ongoing post–closure assessment at the Fort Gordon WWTP will provide more insight into the environmental persistence of EDCs over time and the potential for stream and lake bed sediment to serve as a long–term source of EDCs in stream ecosystems.

The Fort Gordon Environmental and Natural Resources Management Office of the U.S. Army and the USGS Toxic Substances Hydrology Program provided the funding for this work.

Reference

Assessment of endocrine–disrupting chemicals attenuation in a coastal Plain stream prior to wastewater treatment plant closure: Journal of the American Water Resources Association, 2014, v. 50, no. 2, p. 388-400, doi:10.1111/jawr.12165.

More Information

GeoHeatlh
This article was featured as an article in the USGS GeoHealth Newsletter, Vol. 12, No. 1, 2015

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