Toxicity of polyvinyl chloride microplastics on Brassica rapa

Hao Wu; Beibei He; Bocheng Chen; An Liu

doi:10.1016/j.envpol.2023.122435

Toxicity of polyvinyl chloride microplastics on Brassica rapa

Environ Pollut. 2023 Nov 1:336:122435. doi: 10.1016/j.envpol.2023.122435. Epub 2023 Aug 23.

Authors

Hao Wu¹, Beibei He¹, Bocheng Chen¹, An Liu²

Affiliations

¹ College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
² College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China. Electronic address: liuan@szu.edu.cn.

PMID: 37625773
DOI: 10.1016/j.envpol.2023.122435

Abstract

Microplastics (MPs) can pose high risk to living organisms due to their very small sizes. This study selected polyvinyl chloride MPs (PVC-MPs) which experienced up to 1000 h UV light radiation to investigate the influence of PVC-MPs on Brassica rapa growth. The outcomes showed the presence of PVC-MPs inhibited the plants' growth. The stem length, root length, fresh weight and dry weight of plants exposed to PVC-MPs after 30 days reduced by 45.9%, 35.2%, 26.1% and 5.2%, respectively. The chlorophyll, soluble sugar, malondialdehyde (MDA) and catalase (CAT) concentrations for plants exposed to PVC-MPs after 30 days increased by 25.9%, 135.7%, 88.7% and 47.1% respectively. It was also observed that PVC-MPs blocked the plants' leaf stomata and even entered plants' bodies. This might lead to PVC-MPs movement within the plants and influence plants' growth. The transcriptomic analysis results indicated that exposure to PVC-MPs up-regulated metabolic pathway of plant hormone signal transduction of the plants and down-regulated pathway network of ribosome. However, the research outcomes also showed that the PVC-MPs' locations in soil (located at the upper layers or at lower layers) and the UV light radiation time did not exert significantly different influences on inhibiting plants' growth. This can be attributed to PVC-MPs' small sizes and not much decomposition under light radiation. These imply that longer light radiation time and different particle sizes should be included into future research in order to further explore photodegraded MPs' toxicity effects on plants.

Keywords: Microplastics; Plant growth; Polyvinyl chloride; Toxicity mechanisms.