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With thousands of chemicals in production and very low detection levels allowing for frequent chemical detections in our natural environment, identifying which chemicals are most likely to pose an ecological hazard is challenging. Many chemicals are present as complex mixtures for which the potential biological consequences are difficult to predict. For a sequence of Great Lakes tributary surveillance studies from 2010-2018, chemicals and chemical mixtures of ecological relevance were prioritized based on potential for biological effects. Predictions of cumulative biological effects from chemical mixtures were estimated based on summation of effects from common biological pathways. Collectively, contaminants monitored in these studies included 629 chemicals, including PAHs, flame retardants, components of plastic products, pesticides, pharmaceutical compounds, and others. With this bio-effect-based approach, the number of chemicals targeted for further consideration was reduced by about 90% (to 65 chemicals) from the original list of chemicals analyzed, allowing resource managers to focus on chemicals with the greatest potential for adverse ecological effects.
Steve Corsi is a Research Hydrologist with the U.S. Geological Survey in Madison, Wisconsin. His education included a bachelor’s degree from UW Eau Claire where he studied physics and mathematics, and a master’s degree in Civil and Environmental Engineering from UW Madison where he focused on hydrology. He began his career with the USGS in 1988 as a student and began full time employment in 1989. His career With USGS has focused primarily on water quality studies, including evaluation of agricultural and urban nonpoint-source pollution management practice effectiveness in Wisconsin streams, and assessment of biological impact from toxic chemicals in tributaries of the Great Lakes. Examples of this include long-term trends of chloride in streams resulting from road salt runoff, pesticides in runoff from urban and agricultural streams, microplastics presence in streams with variable land use, and prioritization of several hundred organic contaminants observed in Great Lakes tributaries based on potential for toxicity. He has also studied waterborne pathogens and fecal indicator bacteria in streams and recreational beaches, and dissolved oxygen impact on fish reproduction in urban and agricultural streams. His current career goals are to provide a foundation of information on the “next generation” of environmental contaminants in aquatic systems, to increase awareness of these issues in the scientific community and general public, and to help prepare early-career scientists to address the ongoing challenges of evaluating an ever-growing suite of chemical contaminants in our environment.