UMD Researchers Found PFAS’s on Farms with No Known Contamination Sources May Be Accumulating from the Atmosphere and Rainwater
UMD graduate assistant Fatemeh Ghezelsofla (Left) and high school senior intern Tanvi Modugula collect water samples on an organic farm.
Image Credit: Edwin Remsberg
University of Maryland researchers found per- and polyfluoroalkyl substances (PFAS), often called “forever chemicals,” in both groundwater and irrigation water at two organic farms in Maryland. Though the farms used no biosolids (such as manure) and no PFAS-containing pesticides, and there were no known industrial sources for those chemicals in the surrounding areas, the study detected multiple PFAS compounds present at low concentrations. The research, published on March 11, 2026, in the journal Toxics, suggests that different types of PFAS compounds can accumulate from the atmosphere and rainwater until the combined effect exceeds EPA safety standards.
“Understanding the impact of PFAS's presence in organic agricultural settings is critical to stakeholders and policy makers as it drives decision making, particularly decisions as to how we manage the presence of PFAS in edible crops,” said Candice Duncan, an assistant professor in the Department of Environmental Science and Technology at UMD and the lead author of the paper. “There is still much to learn about how PFAS accumulates in edible crops and moves up the food chain.”
Although testing for PFAS on farms is encouraged, there are no universally accepted guidelines, in part, because safe limits can be hard to determine, PFAS behavior can change with soil type, and levels don’t directly translate to food safety risk. Farmers don’t have a clear path for determining PFAS exposure risks in their products. The new study suggests the U.S. EPA’s Hazard Index (HI) tool, which combines multiple PFAS into a single measure of potential health risk, could help fill that gap.
Duncan and her colleagues used the tool to evaluate the PFAS contamination at both farms in their study. At one farm, their findings showed that some PFAS were at acceptable levels while others exceeded risk thresholds. At the second farm, PFAS concentrations exceeded recommended thresholds largely because of the presence of newer compounds called GenX, indicating they had accumulated more recently, and were not legacy chemicals residing in the soil from any previous land use.
The findings reveal that PFAS may be more widespread in irrigation water than previously recognized.
This research highlights the value of the Hazard Index as a screening tool for understanding potential health risks from low-level mixtures of PFAS and underscores the need for continued monitoring and research in agricultural settings.
Other study co-authors from UMD include graduate assistants in the Department of Environmental Science & Technology Fatemeh Ghezelsofla and Jazmin Escobar.
