- April 03, 2026
- By Kimbra Cutlip
University of Maryland researchers found so-called “forever chemicals” in groundwater and irrigation water at two organic farms in Maryland.
The study detected low concentrations of multiple per- and polyfluoroalkyl (PFAS) substances, which do not break down in the environment, even though the farms used no biosolids such as manure and no pesticides that contained the chemicals. There were also no known industrial sources of PFAS in the surrounding areas.
The research, published last month in the journal Toxics, suggests that different types of PFAS compounds can accumulate from the atmosphere and rainwater until the combined effect exceeds U.S. Environmental Protection Agency safety standards. The agency says PFAS exposure could contribute to cancer, decreased fertility, impaired immune function and other human harms.
“Understanding the impact of PFAS's presence in organic agricultural settings is critical to stakeholders and policymakers 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 and 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 for a number of reasons: Safe limits can be hard to determine, PFAS behavior can change with soil type, and levels don’t directly translate to food safety risk. Additionally, 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 tool, which combines multiple PFAS into a single measure of potential health risk, could help provide greater understanding of potential health risks from low-level mixtures of the chemicals.
Duncan and her colleagues used the tool to evaluate the PFAS contamination at both farms in their study. At one, they found that some PFAS were at acceptable levels while others exceeded risk thresholds, according to the index. 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, underscoring the need for continued monitoring and research in agricultural settings.
Other study UMD co-authors include Department of Environmental Science and Technology graduate students Fatemeh Ghezelsofla and Jazmin Escobar.
UMD graduate assistant Fatemeh Ghezelsofla (left) and high school senior intern Tanvi Modugula collect water samples on an organic farm. (Photo by Edwin Remsberg)