A new study from Nanjing University reveals that microplastics in agricultural soil can significantly alter how vegetables absorb per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals.” The research, published in Eco-Environment & Health, shows that the type of microplastic matters: polyvinyl chloride (PVC) increases PFAS uptake in edible plant parts, while tire wear particles reduce it but cause other ecological harm.
PFAS are persistent synthetic chemicals used in countless products for their water- and oil-resistant properties. They enter farmland through various routes, including wastewater irrigation and biosolid application, and can accumulate in crops, posing a risk to human health. Microplastics, defined as plastic particles smaller than 5 millimeters, are also ubiquitous in agricultural soils from sources like plastic mulch, tire wear, and atmospheric deposition. Until now, it was unclear how different microplastic types influence PFAS bioaccumulation in vegetables.
The research team, led by scientists from the State Key Laboratory of Water Pollution Control and Green Resource Recycling, examined the effects of three microplastic types—PVC, polylactic acid (PLA), and tire wear particles (TWP)—on the uptake of 10 PFAS compounds by pak choi (Brassica chinensis L.). The findings were striking: PVC significantly increased total PFAS accumulation in pak choi shoots by 1.31- to 1.70-fold across all tested doses, including at a low concentration of 0.01%, which is comparable to upper levels found in real farmland soils. This increase was not due to simple adsorption but rather to plant physiological changes. PVC exposure upregulated aquaporin-related genes, including PIP1-1, TIP1-1, and TIP1-2 in shoots and NIP5-1 in roots, which enhance water transport and likely facilitate PFAS movement into edible tissues.
In contrast, tire wear particles reduced PFAS accumulation in shoots by 37.4%–54.1%. This reduction was partly due to TWP’s strong adsorption capacity, which bound PFAS and made them less available to plants, and partly because TWP suppressed plant growth and transpiration. At the highest dose, transpiration rate dropped to 73% of the control, and the plants showed signs of oxidative stress, indicated by changes in malondialdehyde (MDA), superoxide dismutase (SOD), and peroxidase (POD). PLA, a biodegradable plastic, inhibited growth and metabolism but had mixed effects on toxicity, sorption, and aquaporin expression, resulting in little overall change in PFAS uptake.
The authors emphasize that microplastic pollution cannot be treated as a single, uniform risk. “The material identity of microplastics matters,” they write. “Risk assessment should move beyond total microplastic abundance and consider polymer type, particle behavior, plant response, and co-existing contaminants when evaluating agricultural soil safety.” PVC’s ability to increase PFAS accumulation even at environmentally relevant levels suggests that farmland contaminated with both plastic residues and PFAS may require closer monitoring. TWP, common in roadside and industrial soils, deserves attention for its potential to damage crops. The findings also caution against assuming biodegradable plastics like PLA are risk-free.
The study has significant implications for food safety, soil management, and regulation of emerging contaminants. Future research should test more crop species, field conditions, and mixed plastic pollution scenarios to develop strategies to prevent PFAS and microplastics from entering the food chain. The full study is available at DOI: 10.1016/j.eehl.2026.100216.
