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Fate of Selected EDCs under Redox Conditions Typical of Wastewater and Sediments
Project Purpose:
Research Questions: Determine what are the major sources and environmental fates of EDCs natural and/or pharmaceutical additives. Determine how unreasonable risk can be managed. The overall goal of the project is to characterize the degradability and rates of degradation of selected natural and pharmaceutical hormones and alkylphenols under redox conditions typical of wastewater treatment, receiving waters, and sediments.
Project Description(s):
A number of emerging chemicals being detected in the environment are now gaining attention for having possible endocrine disrupting capabilities. These endocrine disrupting chemicals (EDCs) have been shown to have adverse affects on the endocrine system of fish and wildlife. But not much information is known about the fate of EDCs in the environment, particularly in the anaerobic environment. The primary redox condition for the biodegradation of EDCs is aerobic but little research has been done to look at biodegradation under anaerobic redox conditions.
In particular, we are focusing on selected EDCs, such as natural and pharmaceutical estrogenic and androgenic hormones and degradation by-products from alkylphenol based surfactants. This research is characterizing the biodegradation of these EDCs under different redox conditions, such as, aerobic, nitrate-reducing, sulfate-reducing, iron-reducing, and methanogenic. These redox conditions are commonly found in wastewater treatment, confined animal feeding operations (CAFOs), and sediments.
Research has been completed to determine the biodegradability of nonylphenol (NP) under various redox conditions. It was shown that biodegradation rates differed significantly for certain NP isomers under aerobic conditions but under anaerobic conditions, there was no apparent biodegradation.
Research is ongoing for estrogenic and androgenic hormones to evaluate their degradability under similar redox conditions. This research is being conducted by utilizing enrichment cultures as a positive control and microcosms sampled sacrificially to look at multiple conditions without sampling bias. Cultures are obtained from the anaerobic digester and activated sludge of a local wastewater treatment plant as well as sediments near the outfall of the wastewater treatment plant.
Project Outcomes:
The objective of this research is to determine the degradability of selected EDCs under environmentally relevant redox conditions and concentrations. Characterizing the fate of these EDCs in wastewater treatment plants, sediments, and CAFOs, and at what rate they biodegrade, will help in determining risk management solutions for these EDCs in these environments.
The results of this research will be used to scope out potential operational changes that may be used to increase the removal efficacies of wastewater treatment plants and treatment systems for CAFOs.
Users of this information will include the Office of Water as well as wastewater and CAFO operators.
Contact
Marc Mills at mills.marc@epa.gov