Effects of biochar on the phytotoxicity of polyvinyl chloride microplastics.

Polyvinyl chloride microplastics (PVC-MPs) are toxic to crops, resulting in economic losses during agricultural production. Owing to its strong adsorption capacity, biochar can effectively remove MPs from water. It is presumed that biochar can alleviate the phytotoxicity of PVC-MPs. To verify this hypothesis, the effects of different concentrations of corncob biochar (CCBC) on the phytotoxicity of PVC-MPs were investigated using hydroponic experiments. The results showed that PVC-MPs attached to lettuce roots substantially inhibited the growth and quality of lettuce. The tested CCBC adsorbed the PVC-MPs. At appropriate concentrations, CCBC alleviated the inhibitory effect of PVC-MPs on lettuce yield; however, it decreased some quality indicators. The single PVC-MPs induced oxidative damage to lettuce, as demonstrated by the increased hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA) content. Addition of CCBC considerably decreased the contents of H 2 O 2 and MDA in the lettuce shoots but increased the H 2 O 2 content in the roots. These findings indicate that CCBC may alleviate the adverse effects caused by PVC-MPs to the lettuce shoots but aggravate the toxic effects on the lettuce roots. This study provides a basis for understanding the removal of the phytotoxicity of MPs. [Display omitted] • CCBC can adsorb PVC-MPs. • CCBC alleviated the adverse effect of PVC on lettuce yield but reduced its quality. • In the co-exposed treatments, CCBC reduced ROS and MDA content in the shoots. • CCBC aggravated the toxic effect of PVC on lettuce roots. [ABSTRACT FROM AUTHOR]