Can microplastics threaten plant productivity and fruit quality? Insights from Micro-Tom and Micro-PET/PVC

Solanum lycopersicum L., a crop grown worldwide with a high nutritional value for the human diet, was used to test the impact of microplastics on plant growth, productivity, and fruit quality. Two of the most represented microplastics in soils, polyethylene terephthalate (PET) and polyvinyl chloride (PVC), were tested. Plants were grown in pots with an environmentally realistic concentration of microplastics and, during the whole crop life cycle, photosynthetic parameters, number of flowers and fruits were monitored. At the end of the cultivation, plant biometry and ionome were evaluated, along with fruit production and quality. Both pollutants had negligible effects on shoot traits, with only PVC causing a significant reduction in shoot fresh weight. Despite an apparent low or no toxicity during the vegetative stage, both microplastics decreased the number of fruits and, in the case of PVC, also their fresh weights. The plastic polymer-induced decline in fruit production was coupled with wide variations in fruit ionome, with marked increases in Ni and Cd. By contrast there was a decline in the nutritionally valuable lycopene, total soluble solids, and total phenols. Altogether, our results reveal that microplastics can not only limit crop productivity but also negatively impact fruit quality and enhance the concentration of food safety hazards, thus raising concerns for their potential health risks for humans.