Atmospheric Deposition of PFAS: Connecting Wet Deposited PFAS to Observations in Lake Sediments
Samantha McClung1, 2, 3, *, Bridget Ulrich1, 2, Martin Shafer4, Quinn Whiting1, 2, Timothy Griffis5, Euan D. Reavie2, Tiffany Sprague2, and Alexander Frie3
Per- and polyfluoroalkyl substances (PFAS) are a large family of persistent contaminants with diverse and poorly characterized sources. Our understanding of their environmental cycling is improving, but is still quite limited. The presence of PFAS in environmental media (e.g., sediments, surface water, ice) found in remote areas emphasizes the significant gaps in our understanding of their sources, fate, and transport. In particular, the importance of atmospheric transport, transformation, and deposition of PFAS as a pathway into surface hydrologic systems is poorly understood. To investigate the magnitude, seasonal differences, and profile (fingerprint) of PFAS characteristic of atmospheric deposition, wet deposition (rain and snow) samples were collected from a suite of National Atmospheric Deposition - National Trends Network (NADP-NTN) precipitation monitoring sites around the upper Great Lakes, and analyzed for 33 PFAS compounds. To investigate the role of atmospheric deposition as a source of PFAS to terrestrial and aquatic ecosystems in the western Great Lakes region, a sediment core from Loaine lake, a remote Minnesota seepage lake with primarily atmospheric inputs was age-dated and analyzed for 37 PFAS. The wet deposition and seepage lake datasets have similar profiles of PFAS, with over 70% of observed PFAS mass being perfluorocarboxylic acids,
but the annual PFAS precipitation fluxes were an order of magnitude larger than PFAS sediment accumulation rates. This suggests that in this seepage lake, only a small fraction of precipitation deposited PFAS are accumulated in sediments. The lake sediment core and wet deposition datasets will also be compared to sediment PFAS concentrations measured in the Great Lake sediments by the US Environmental Protection Agency Great Lakes Sediment Surveillance Program (US EPA GLSSP). These preliminary data sets are just one component of a larger effort to constrain PFAS wet deposition across the Great Lakes.
1 Water Resources Science Graduate Program, University of Minnesota-Duluth, Duluth, MN
2 Natural Resources Research Institute, University of Minnesota-Duluth Duluth, MN
3 University of Minnesota Sea Grant Program, Duluth, MN
4 Wisconsin State Laboratory of Hygiene, University of Wisconsin-Madison, Madison, WI
5 Department of Soil, Water, and Climate, University of Minnesota-Twin Cities, St. Paul, MN
* Corresponding Author: mcclu348@d.umn.edu