Linking field‐based metabolomics and chemical analyses to prioritize contaminants of emerging concern in the Great Lakes basin

John M. Davis, Drew R. Ekman, Quincy Teng, Gerald T. Ankley, Jason P. Berninger, Jenna E. Cavallin, Kathleen M. Jensen, Michael D. Kahl, Anthony L. Schroeder, Daniel L. Villeneuve, Zachary G. Jorgenson, Kathy E. Lee, Timothy W. Collette

The ability to focus on the most biologically relevant contaminants affecting aquatic ecosystems can be challenging because toxicity assessment programs have not kept pace with the growing number of contaminants requiring testing. Because it has proven effective in assessing biological impacts of potentially toxic contaminants, profiling of endogenous metabolites (metabolomics) may help screen out contaminants with a lower likelihood of eliciting biological impacts, thereby prioritizing the most biologically-important contaminants. We present results from a study that utilized cage-deployed fathead minnows (Pimephales promelas) at 18 sites across the Great Lakes basin. We measured water temperature and contaminant concentrations in water samples (132 contaminants targeted; 86 detected), and used (1) H-NMR spectroscopy to measure endogenous metabolites in polar extracts of livers. We used partial least-squares (PLS) regression to compare relative abundances of endogenous metabolites with contaminant concentrations and temperature. Results indicated that profiles of endogenous polar metabolites covaried with at most 49 contaminants. Thus, we identified up to 52% of detected contaminants as not significantly covarying with changes in endogenous metabolites, suggesting they likely were not eliciting measureable impacts at these sites. This represents a first step in screening for the biological-relevance of detected contaminants by shortening lists of contaminants potentially affecting these sites. Such information may allow risk assessors to prioritize contaminants and focus toxicity testing on the most biologically-relevant contaminants. This article is protected by copyright. All rights reserved.