UNIVERSITY PARK, Pa. — Samuel Cohen, a graduate student in the Department of Geography at Penn State, saw the real-life impact of his research during a summer internship at the U.S. Environmental Protection Agency (EPA). As a physical science student trainee during the summer of 2023 at EPA’s Athens, Georgia, location, Cohen explored the complexities of per- and polyfluoroalkyl substances (PFAS).
Cohen's thesis research focuses on the biogeochemistry and ecohydrology — or how hydrological processes influence ecosystems — of human-impacted watersheds. Cohen said his goal is to better understand the fate and behavior of pollutants and that the tangible aspects of his internship were pivotal, as they allowed him to witness the real-life applications of his research.
PFAS — known as “forever chemicals” — are a large family of synthetic chemicals characterized by their widespread presence and durability in the environment. Resistant to heat and water, PFAS chemicals have been widely used in industrial and consumer products such as cleaning products, nonstick cookware and personal care products.
According to the EPA, there are thousands of PFAS chemicals found in everyday products and robust information about PFAS is needed to better understand the risks they pose and to be able to take effective actions to protect human health and the environment. According to the Centers for Disease Control and Prevention (CDC), as much as 97% of the country’s population has measurable concentrations of PFAS in their blood.
"There is evidence that PFAS are bad for people's health, but there's still so much that's unknown about what they do on a long-term scale," Cohen said. “During my internship at the EPA, I studied how these chemicals move through the environment, and how they can ultimately end up accumulating in soil, water and animals.”
Through his internship, Cohen explored the technical aspects of extracting PFAS from soil samples. This step is crucial for isolating the chemicals, which are then measured using mass spectrometry. This technique played a key role in Cohen's research, allowing for the identification of PFAS compounds by making educated guesses about their molecular structures and weights.
"Being able to see the implications of what I'm studying really changed my perspective,” Cohen said. “This isn’t just something I’m reading out of a textbook. It is real life. These are threats that are very specific to the local areas where I live and where I'm from.”
Cohen's internship experience was enriched by the expertise of two mentors. He was guided through the intricacies of PFAS research by research chemists Marina Evich and John Washington, who is an alum of Penn State.
“I had a lot of support and help working through this research while at the EPA,” Cohen said. “It was a fun and cool connection to work with someone who went to Penn State. The expertise of the people who work at the EPA is really impressive.”
Cohen said his passion for environmental science was sparked by his love for the outdoors and activities like fishing, a hobby that he says inspired his academic pursuits in geography and environmental science. Prior to attending Penn State, Cohen earned his bachelor’s degree in environmental studies from the University of Pittsburgh.
Cohen is a member of the Department of Geography's Riparia Center, a center specializing in wetlands ecology, landscape hydrology and watershed management. For the 2022-23 academic year, he was an environmental scholar with the Earth and Environmental Systems Institute. He recently won first place for his poster, “Using Herbicide Metabolites as a Novel Tracer of Agricultural Nitrate in U.S. Wetlands,” in the student poster competition at the 2024 Delaware Wetlands Conference. His adviser is Kimberly Van Meter, assistant professor of geography.
Looking ahead, Cohen said he is optimistic about the future applications of his research. He expressed hope that his work will contribute to broader efforts in environmental protection and sustainability.
“I aspire that someday my research can play a key role in the remediation and removal of PFAS chemicals from contaminated sites to protect people and the environment,” Cohen said.