Effect of microplastics on soil microbial community and microbial degradation of microplastics in soil: A review

The mass production, continual usage, and improper disposal of plastic products have resulted in significant environmental pollution. The larger plastic polymers gradually break down into smaller particles called microplastics (<5 mm). Existing studies on the occurrence and ecological impact of microplastics have focused on the aquatic ecosystems, with very little attention given to the soil environment. The soil represents a natural sink for microplastics from sources such as sewage sludge, landfills, plastic mulch from agricultural activities, fertilizers, and municipal wastewater effluent. The current study, therefore, provides an overview of existing knowledge on soil microplastic pollution focusing on the impact of microplastics on soil microbial community and microbial degradation of microplastics in soil to systematically identify knowledge gaps to be filled with further research. Future research challenges to be addressed include detailed monitoring of the sources and distribution of microplastics in soil under different land uses, exploring diverse microorganisms in their natural environments for their microplastic biodegradation potential using cultivation-dependent and independent approaches, understanding the mechanism of ecological impacts of microplastics and contributions of microplastic additives, degradation products, and other adsorbed environmental pollutants on soil microbial community.