Influence of polyvinyl chloride microplastic on chromium uptake and toxicity in sweet potato

The extensive use of plastic products and rapid industrialization have created a universal concern about microplastics (MPs). MPs can pose serious environmental risks when combined with heavy metals. However, current research on the combined effects of MPs and hexavalent chromium [Cr(VI)] on plants is insufficient. Herein, a 14-day hydroponic experiment was conducted to investigate the impact of PVC MPs (100 and 200 mg/ L) and Cr(VI) (5, 10, and 20 mu M) alone and in combination on sweet potato. Results showed that combined Cr(VI) and PVC MPs affected plant growth parameters significantly, but PVC MPs alone did not. The combined application of PVC MPs and Cr(VI) resulted in a decrease in plant height (24-65%), fresh biomass per plant (36-71%), and chlorophyll content (16-34%). Cr(VI) bioaccumulation increased with the increase in its doses, with the highest concentration of Cr(VI) in the leaves (16.45 mg/kg), stems (13.81 mg/kg), and roots (236.65 mg/kg). Cr(VI) and PVC MPs-induced inhibition varied with Cr(VI) and PVC MPs doses. Osmolytes and anti-oxidants, lipid peroxidation, and H2O2 contents were significantly increased, while antioxidant enzymes except CAT were decreased with increasing Cr(VI) concentration alone and mixed treatments. The presence of PVC MPs promoted Cr(VI) accumulation in sweet potato plants, which clearly showed severe toxic effects on their physio-biochemical characteristics, as indicated by a negative correlation between Cr(VI) concentration and these pa-rameters. PVC MPs alone did not significantly inhibit these parameters. The findings of this study provide valuable implications for the proper management of PVC MPs and Cr(VI) in sweet potato plants.

Automated summary

The extensive use of plastics and rapid industrialization has raised concerns about microplastics (MPs). MP can pose environmental risks when combined with heavy metals. However, there is insufficient research on the combined effects of MPs and hexavalent chromium (Cr(VI)) on plants. In this study, a 14-day hydroponic experiment was conducted to investigate the impact of PVC MPs and Cr(VI) alone and in combination on sweet potato. The findings show that the combined application of Cr(VI) and PVC MPs significantly affected plant growth parameters, while PVC MPs alone did not have a significant impact. The presence of PVC MPs promoted the accumulation of Cr(VI) in sweet potato plants, leading to severe toxic effects on their physio-biochemical characteristics.