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Prioritization of contaminants of emerging concern in wastewater treatment plant discharges using chemical: Gene interactions in caged fish
Perkins, E., T. Habib, B. Escalon, J. Cavallin, L. Thomas, M. Weberg, M. Hughes, K. Jensen, M. Kahl, Dan Villeneuve, G. Ankley, AND N. Garcia-Reyero. Prioritization of contaminants of emerging concern in wastewater treatment plant discharges using chemical: Gene interactions in caged fish. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 51(15):8701-8712, (2017).
Under Annex 3 of the Great Lakes Water Quality Agreement and Action Plan II of the Great Lakes Restoration Initiative, the Great Lakes National Program Office is interested in the development of approaches and tools to increase knowledge about contaminants in Great Lakes fish, identify emerging contaminants, and assess their impacts on Great Lakes fish and wildlife. The present paper reports on a case study in which an integrated set of pathway-based environmental monitoring, surveillance, and prioritization tools were employed to identify contaminants present in waste water impacted surface waters within a Great Lakes Area of Concern and associate specific contaminants with biological responses observed in fish caged at those same sites. The results demonstrate how different types of data streams (i.e., chemical monitoring data, literature derived databases of chemical:gene or chemical:pathway interactions, in vivo responses in caged fish, and multi-variate statistical approaches) can be used to assemble weight of evidence to guide prioritization of chemicals, sites, and/or biological effects on which to focus monitoring or management activities. The case study demonstrates the role that various pathway-based approaches under development in the CSS program can be employed to aid practical decision making by the regions, states, and local communities faced with the challenge of assessing potential ecological impacts of complex mixtures of emerging contaminants.
We examined whether contaminants present in surface waters could be prioritized for further assessment by linking the presence of specific chemicals to gene expression changes in exposed fish. Fathead minnows were deployed in cages for 2, 4, or 8 days at three locations near two different waste water treatment plant discharge sites in the Saint Louis Bay, Duluth, MN and one upstream control site. The biological impact of 51 chemicals detected in the surface water was determined using biochemical endpoints, exposure activity ratios for biological and estrogenic responses; known chemical:gene interactions from biological pathways and knowledge bases, and analysis of the co-variance of ovary gene expression with surface water chemistry. Thirty-two chemicals were significantly linked by co-variance with expressed genes. No estrogenic impact on biochemical endpoints was observed in male or female minnows. However, bisphenol A was identified by chemical:gene co-variation as the most impactful chemical across the exposure sites. This was consistent with identification of estrogenic effects on gene expression, high exposure activity ratios across all test sites, and historical analysis of the area. Overall, this approach appears useful in examining the impacts of complex mixtures on fish and offers a potential route in linking chemical exposure to adverse outcomes that reduce population sustainability.