Microplastics found to increase uptake of PFAS in vegetables

THE level of PFAS (Polyfluorinated alkyl substances) adsorption in vegetables could be impacted by another contaminant permeating through our soil and farmland, according to a recent study from researchers in China.

A team from the State Key Laboratory of Water Pollution Control and Green Resource Recycling in the School of the Environment at Nanjing University has found that microplastics can affect the adsorption of PFAS in pak choi, a leafy cabbage that has been grown in China for more than a millenia.

Growing research into PFAS and microplastics has found the contaminants to have an overwhelmingly negative impact on agriculture and human health.

Research from the University of South Wales has even found that microplastics specifically hinder photosynthesis in plants and freshwater algae by 7-12%, which could go on to significantly reduce the yields of staple crops including rice, maize and wheat.

Adsoprtion of PFAS

The researchers looked at three types of plastic materials – polyvinyl chloride (PVC), polylactic acid (PLA) and tire wear particles (TWP) – and their influence on the uptake of 10 PFASs in pak choi.

PVC was found to “significantly increase” the total PFAS accumulation in pak choi shoots by 30-70% compared to no presence of PVC. In contrast, TWP reduced PFAS accumulation in pak choi shoots by 37.4-54.1%, partly because it showed the strongest PFAS adsorption capacity and it suppressed plant growth and transpiration. With PLA, the PFAS uptake was mostly unchanged, but it did affect the levels of toxicity, sorption and aquaporin expression in the vegetable.

Different plastics

The researchers said the study points out that the “material identity” of microplastics matters when they interact with crops.

With the difference in adsorption levels dependent on plastic type, the team said that the effects of microplastics cannot effectively be determined from quantity alone, and that factors including polymer type, particle behaviour, plant response and co-existing contaminants must also be considered when evaluating soil safety.