Dr. Alexander Frie

Wet deposition of per- and polyfluoroalkyl substances (PFAS) is a known but unconstrained mechanism of PFAS introduction to hydrologic systems. This project will identify chemical tracers, source regions, and the importance of wet deposited PFAS in target areas of the Great Lakes region. These seemingly expansive goals will be achieved through capitalizing on existing data and applying scalable analytical approaches. Specifically, the researchers will leverage PFAS precipitation, sediment, and runoff data from the National Atmospheric Deposition Program, the Environmental Protection Agency’s Great Lakes Sediment Surveillance Program, and the United States Geological Survey-supported sampling efforts.

The researchers will also collect and comprehensively characterize (total organic fluorine, targeted PFAS analysis, non-targeted PFAS analysis) a smaller, new precipitation, and sediment dataset. They will investigate these datasets for PFAS species or functional classes suitable for use as tracers of wet deposited PFAS. They will then use these tracers to estimate wet deposited PFAS’s importance to PFAS observed in sediment samples from Lake Superior and Lake Huron and runoff samples from tributaries to Lake Superior. Next, they will use airmass back trajectories from precipitation sampling sites in Wisconsin, Minnesota, and Michigan to identify primary source regions for wet deposited PFAS. Lastly, positive matrix factorization will derive chemical profiles of wet deposited PFAS sources from the precipitation datasets. Outputs of this project will include:

• Tracers for wet deposited PFAS
• Assessment of the importance of wet deposited PFAS to sediment and runoff pools in select Great Lakes
• Spatial distribution of point and non-point PFAS wet deposition sources in the western Great Lakes
• Chemical profiles of sources contributing to PFAS wet deposition.

This approach is adaptable and could be applied to help regulators and resource managers identify the sources and importance of wet deposited PFAS in regions outside of the Great Lakes.