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UVM researcher tells committee PFAS moves from soil into crops, raising food-safety questions
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Summary
Hao Chen, assistant professor at the University of Vermont, told the Agriculture, Food Resiliency, & Forestry committee that PFAS from biosolids, packaging and pesticide surfactants can be taken up by plants and move into milk and other food products; Chen said more targeted study is needed on pesticide chemistries and monitoring gaps.
Hao Chen, an assistant professor at the University of Vermont, told the Agriculture, Food Resiliency, & Forestry committee that per- and polyfluoroalkyl substances, or PFAS, applied to or present in agricultural soil can be taken up by plants and enter the human food chain.
Chen said his team is studying PFAS-contaminated soil from Maine and that contamination from past biosolid applications forced an organic farm to shut down. "PFAS can go to winter triticale, and then it go to the milk, go to the cheese, and to go to the food chain," Chen said during the committee's question-and-answer period.
Why it matters: Chen described PFAS as highly persistent "forever chemicals" that resist chemical breakdown and can persist for decades in soil and organisms. He told lawmakers short-chain and long-chain PFAS behave differently in soil and plants: many short-chain species (roughly four to six carbons) are more likely to translocate from roots into shoots and leaves, while longer-chain PFAS often remain bound in roots but can break down over time into more bioavailable forms.
Evidence and limits: Chen cited lab and field studies showing PFAS in cereals, fruits and vegetables and studies of willow trees and common field weeds that detected shoot and leaf accumulation in short-term experiments. He emphasized the existing research is recent and still evolving and said his winter triticale analysis is ongoing. "Most of those PFAS go to the leafy part of the mustard we actually gonna to consume," Chen said, noting different species show different uptake capacities.
Sources and exposure routes: Committee members and Chen discussed multiple PFAS sources relevant to agriculture, including biosolids spreading, pesticide formulations (where fluorine substitutions may be used as surfactant or stabilizers), packaging and legacy contamination near airports and military sites. Chen identified wastewater treatment plants and improper disposal as potential contributors to environmental PFAS and said groundwater and irrigation can be exposure pathways in rural areas.
Regulatory and monitoring gaps: Committee members noted prior testimony that some EPA-approved pesticides contain fluorinated compounds. Chen said he is not a pesticides chemist but understands some manufacturers substitute fluorine to prolong shelf life and that the complexity and variety of PFAS make simple regulatory lines difficult. He offered to review which EPA-approved pesticide compounds contain PFAS and share findings with committee staff.
Unanswered questions and follow-up: Members asked about PFAS in rainwater and airborne deposition; Chen said airborne PFAS likely exist but concentrations can be below laboratory detection limits, citing a study that used hairbands to sample trace airborne PFAS. Representatives also asked whether PFAS in flowers, pollen or forest leaf litter could affect invertebrates or act as long-term sinks; Chen said the literature on those pathways is limited and that more targeted research would be useful.
The committee took no formal action during the session. Chen said he would share specific compound information with staff and provide results from his triticale analysis when available.
