A recent study published in Eco-Environment & Health has uncovered that microplastics can significantly influence how plants absorb per- and polyfluoroalkyl substances (PFAS), commonly known as 'forever chemicals'. The research, conducted by scientists at Nanjing University, demonstrates that the type of microplastic present in soil plays a critical role in determining the extent to which these persistent contaminants enter edible vegetables, with some polymers enhancing uptake and others suppressing it.
PFAS are synthetic chemicals widely used in industrial and consumer products for their water- and oil-resistant properties. They are persistent in the environment and can accumulate in crops through contaminated soil, posing a direct risk to human health via dietary exposure. Microplastics, defined as plastic particles smaller than 5 millimeters, are also pervasive in agricultural soils, originating from sources such as plastic mulching, wastewater irrigation, sewage sludge, atmospheric deposition, and tire wear. While previous research indicated that microplastics could adsorb pollutants or alter plant processes, the specific effects of different microplastic types on PFAS uptake by vegetables remained unclear.
The study, led by researchers from the State Key Laboratory of Water Pollution Control and Green Resource Recycling at Nanjing University, examined how three types of microplastics—polyvinyl chloride (PVC), polylactic acid (PLA), and tire wear particles (TWP)—influence the uptake of 10 PFASs by pak choi (Brassica chinensis L.). The results 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 an environmentally relevant concentration of 0.01%. This increase was not due to stronger adsorption but 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, suggesting enhanced water transport that facilitates the movement of PFAS from soil into edible tissues.
In contrast, tire wear particles reduced PFAS accumulation in shoots by 37.4% to 54.1%. This reduction was attributed to TWP's strong adsorption capacity and its suppression of plant growth and transpiration. At the highest dose, TWP reduced the transpiration rate to 73% of the control and caused oxidative stress, as indicated by changes in malondialdehyde (MDA), superoxide dismutase (SOD), and peroxidase (POD). PLA, a biodegradable plastic, inhibited growth and metabolism, but its effects on toxicity, sorption, and aquaporin expression offset each other, leaving PFAS uptake largely unchanged.
These findings underscore that microplastic pollution cannot be treated as a uniform risk. The material identity of microplastics matters significantly. PVC may increase the transfer of PFAS into edible vegetables by altering plant water-transport pathways, while TWP may reduce PFAS uptake but introduce a separate ecological concern by damaging plant growth. The authors stress that 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.
The implications for food safety and soil management are profound. Farmland contaminated by both plastic residues and PFAS may require closer monitoring, especially where PVC is present, as it can boost PFAS accumulation at environmentally relevant levels. TWP deserves attention in roadside and industrial soils, where tire-derived particles are abundant and phytotoxicity could affect crop performance. Additionally, biodegradable plastics like PLA should not be assumed risk-free without thorough ecological evaluation.
Future research should test more crop species, realistic field conditions, and mixed plastic pollution scenarios to develop stronger strategies for preventing PFAS and microplastics from entering the food chain. The study was funded by the National Natural Science Foundation of China, the Fundamental Research Funds for Cornell University, and the Yuxiu Young Scholars Program of Nanjing University. The original research article, with DOI 10.1016/j.eehl.2026.100216, is available at https://doi.org/10.1016/j.eehl.2026.100216.
