Effects of different sizes of polystyrene micro(nano)plastics on soil microbial communities

• Published in: NanoImpact 2023-04, Vol.30, p.100460-100460, Article 100460
• Main Authors: Ko, Kwanyoung, Chung, Haegeun, Kim, Woong, Kim, Min-Ji
• Format: Article
• Language: English
• Subjects: Biomass; Microbial biomass; Microbiota; Microplastics; Nanoplastics; Nitrification; Plastics; Polystyrenes; Size effect; Soil; Soil microbial communities
• ISSN: 2452-0748; 2452-0748
• DOI: 10.1016/j.impact.2023.100460

Micro(nano)plastic (MNP) pollution in soil environments is a major concern, but the effects of different sizes of MNPs on soil microbial communities, which are crucial in nutrient cycling, has not been well investigated. In this study, we aimed to determine the effects of polystyrene (PS) MNPs of different sizes (0.05-, 0.5-, and 5-μm) on soil microbial activity and community composition. Changes in inorganic N concentration, microbial biomass, and extracellular enzyme activities were determined in soils treated with 100 and 1000 μg PS MNPs g−1 soil during a 40-d incubation experiment. Soil microbial biomass was significantly lowered when soils were treated with 0.5- or 5-μm MNPs at 100 and 1000 μg PS MNPs g−1 soil. NH4+ concentration was higher in soils treated with 5-μm MNPs at 100 and 1000 μg g−1 soil than in the control soils at day 1, suggesting that MNPs inhibited the soil nitrification in short term. In contrast, extracellular enzyme activity was not altered by MNPs. The composition of microbial communities analyzed by Illumina MiSeq sequencing changed; particularly, the relative abundance of several bacteria related to N cycling, such as the genus Rhizomicrobium belonging to Alphaproteobacteria was decreased by 0.5- and 5-μm MNPs. Our study shows that the size of MNPs is an important factor that can determine their effects on soil microbial communities. Therefore, the size effects need to be considered in assessing the environmental impacts of MNPs. [Display omitted] •Effects of PS MNPs of different sizes on soil microbial communities were determined.•Soil microbial biomass was lowered by 0.5- and 5-μm PS MNPs.•5-μm PS MNPs lowered soil nitrification in short term.•0.5-μm PS MNPs increased the relative abundance of Proteobacteria.•PS MNPs may lower soil microbial activities and alter bacterial community composition.