Per- and Polyfluoroalkyl Substances (PFAS) Abstract

Aquatic resource managers are faced with the dual challenge of protecting natural resources while also ensuring acceptable access and risk to humans who utilize those resources. Our research will provide managers with new information on PFAS levels and trophic transfer in Great Lakes fisheries exploited by commercial, recreational, and tribal entities. This research will produce relevant and timely data to assist managers and officials in assessing the extent of PFAS pollution for prevention or amelioration. Currently, most fish consumption guidelines are informed by legacy contaminants (e.g., heavy metals, PCBs) that are well monitored in fish. However, mounting evidence suggests that current fish consumption guidelines should also consider emerging contaminants such as PFAS if warranted by quantitative information. A thorough study of Great Lakes sport fish would be prohibitively expensive with traditional methods of PFAS analysis (LC-MS/MS), but our novel screening method (PIGE) will allow the first study of its kind on predator and prey fish in Lake Michigan. Our specific aims are to: (1) determine the concentrations and speciation of PFAS in important Lake Michigan sportfish, (2) evaluate dietary routes for PFAS exposure from prey to predator fish using δ15N and δ13C stable isotopes along with PFAS speciation, (3) assess the relationship between total fluorine and PFAS concentrations to determine the full extent of the PFAS problem, and (4) compare observed PFAS concentrations in fish from Lake Michigan to other areas including known areas of PFAS contamination in the upper Great Lakes region. In coordination with the Cooperative Science and Monitoring Initiative (CSMI) sampling efforts planned for Lake Michigan in 2020, we will obtain fish samples from across Lake Michigan supplemented with fish collected at known PFAS ‘hotspots’ in Lake Huron and the Detroit corridor. Tissue samples will be obtained from approximately 500 individual fish (250 sportfish and 250 prey fish) along with fish identity and biometric information (i.e., length, mass, sex, age, location/depth collected). First, we will assay all individual fish using Particle-Induced Gamma-ray Emission (PIGE) spectroscopy developed by our research team (and only existing at Notre Dame), which rapidly and accurately quantifies total fluorine concentrations in a sample as a surrogate measure of PFAS. Second, sportfish and prey fish with the highest total fluorine concentrations (n=100) will be sent to collaborating laboratories (Carleton University and Trident Laboratories) for detailed analysis of specific PFAS using LC-MS/MS. Finally, stable isotopes of C and N will be analyzed for all individual fish using isotope-ratio mass spectrometry (IRMS, located at Notre Dame). Stable isotope mixing models (e.g., MixSIAR) will allow us to infer putative diets of sportfish to trace dietary transfer of PFAS. In aggregate, these studies will provide the first picture of the extent and severity of the PFAS load in important Lake Michigan sportfish as a model for the Great Lakes, potential pathways of food web transferal, and implications for human health. This research will be facilitated by collaborations with USGS scientists engaged in ecotoxicology and fish ecology at three different USGS laboratories.