Researchers working to improve and simplify models for how PFAS flows through ground
Graphical abstract. Credit: Environmental Science & Technology (2022). DOI: 10.1021/acs.est.2c03962

A key hurdle in addressing this harmful group of chemicals lies in unraveling how they move through a region of the environment called the unsaturated zone.

A new study by the University of Wisconsin–Madison shows a simplified way of understanding the movement of PFAS.

Perfluoroalkyl and polyfluoroalkyl substances are abbreviations. Synthetic chemicals have been used in cookware for decades. There are some chemicals that can persist in the environment indefinitely. It's important to model their flow through the vadose zone because the chemicals can linger there for years or decades, all the while slowly leaking into the water supply.

The complexity of the unsaturated zone and the structure of the PFAS chemicals make it difficult for those tasked with this job.

The study's lead author, Will Gnesda, is a graduate student in the Department of Geoscience at the University of Wisconsin–Madison.

Gnesda says that it's always been a big issue for all types of contaminants. Another layer of complexity is added by the PFAS.

The boundary between air and water is the reason for that.

According to Gnesda, the zone is full of those boundaries.

Modeling the movement of PFAS through the unsaturated zone has traditionally been difficult. Gnesda is trying to improve the work she does in the lab of the professor.

Through a series of lab observations and calculations, Gnesda and his colleagues have produced a simplified framework that holds promise for reducing the computing power. Specific sites can be applied to the framework in order to make it useful to utilities and environmental consultants.

The work was published in a journal.

There are two municipal wells that were found to be contaminated with PFAS in the city of Rhinelander. The site's geology has provided useful data for testing the framework.

There are a number of factors that affect where and how long harmful PFAS chemicals stay in the ground. The amount and location of organic carbon is one of the factors.

The research shows that a more accessible approach is needed to model the flow in the ground. The focus of the project is that. Gnesda and his colleagues are working on a project to track the flow of PFAS molecule through a lab on the University of Wisconsin–Madison's campus.

Gnesda expects the experiments to further refine the modeling framework so they can be applied to more real world scenarios.

William R. Gnesda, et al., Adsorption of PFAAs in the Vadose Zone and Implications for Long-Term Groundwater Contamination, Environmental Science & Technology is available. The book is titled "acs.est.2c03962."

Journal information: Environmental Science & Technology