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Stepping stones: A retrospective on the developments and applications of toxicity testing to effluents and sediments and the importance of SETAC
Citation:
Norberg-King, T. Stepping stones: A retrospective on the developments and applications of toxicity testing to effluents and sediments and the importance of SETAC. SETAC North America, Toronto, ON, CANADA, November 03 - 07, 2019.
Impact/Purpose:
The US Clean Water Act (CWA) authorizes the National Pollution Discharge Elimination System (NPDES) permits and the assessment of the nation’s waters. As such, whole effluent toxicity (WET) methods are used to assess whether chemical mixtures of effluents and ambient waters are causing toxicity to aquatic life, thereby filling a key role in meeting the CWA goal of “no toxics in toxic amounts.” This presentation is an overview of the development of the programs for effluents and sediments, including the methods that have been used to improve water quality and highlight the interactions and role of the Society of Enviornmental Toxicology and Chemistry (SETAC) in vetting the science.
Description:
The Clean Water Act (CWA) establishes the structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. With updates in 1972, the CWA gave EPA the authority to implement pollution control programs such as setting wastewater standards for the industry and water quality standards for contaminants in surface waters. Applying water quality criteria to control the release of chemicals into water bodies was quickly identified as not being able to manage all potentially toxic pollutants in an effluent, nor did it predict biological effects in the receiving waters. Increased production, use, and ultimately, environmental releases of synthetic industrial chemicals and a growing public awareness of environmental issues made the application of aquatic toxicity analyses to discharges a natural step. The updated CWA also stipulated that it is unlawful to discharge any pollutant from a point source into navigable waters unless a permit is obtained through the National Pollutant Discharge Elimination System (NPDES) permit program. And in 1984, EPA issued the Policy for the Development of Water Quality-Based Permit Limitations for Toxic Pollutants that proposed the use of toxicity data to assess and control the discharge of toxic substances to surface waters. With that policy, whole effluent toxicity (WET) testing became a major component of USEPAs Integrated approach to water-qualitybased toxics control and a complement to aquatic-lifechemical-specific criteria and biological assessments. Use of acute toxicity tests for effluents testing became routine as the tests provide a more direct estimate of the safe concentration of effluents in receiving waters. New methods to estimate chronic toxicity were developed for effluent testing and validated with interlaboratory studies and in field studies that demonstrated theconnection between effluent/ambient water toxicity and effects on instream communities. Techniques to identify the cause(s) of toxicity were developed and EPA created a technology transfer center for the water-qualitybased permits, technical assistance, Toxicity Identification Evaluations (TIEs), and training at EPA-Duluth. During this time, we identified many chemicals that were not covered under the chemical-specific limits included in NPDES permits or were not expected to cause toxicity at concentrations present. The sediment program followed the steps of the WET program by developing sediment toxicity methods, methods specific to sediments to address the causes of toxicity and develop numerical criteria for specific sediment toxicants to address the challenge of bioavailability of sediment contaminants. This presentation will provide an overview of thedevelopment of the methods,technical challenges, and scientific accomplishments, as well aslink how the methods and most importantly, how these approaches were vetted through SETAC journals and public meetings, which was essential in for the environmental management decisions within EPA