Microplastic contamination of agricultural soil in Southern India: a review and PRISMA analysis

The presence of microplastic contamination in agricultural soils represents a growing environmental concern, with significant ramifications for soil health, ecosystem functioning, and food security. While a substantial body of research has focused on marine pollution, the study of terrestrial systems, particularly in the Indian context, remains underdeveloped. The present review examined studies from 2015 to 2025, drawing on sources such as Scopus and Web of Science. A PRISMA-guided systematic qualitative review and narrative synthesis were used, excluding effect-size pooling and publication-bias assessment. Out of 210 records, 35 met the criteria for comprehensive analysis. The findings demonstrate that microplastic levels vary significantly, with concentrations ranging from ~ 45 items/kg in urban agricultural fields to more than ~ 4200 items/kg in mulched and unmulched fields. Fibres and fragments are the most prevalent forms of debris, with polyethene and polypropylene being the predominant polymers. In Southern India, contamination levels are highest at urban dump sites and in agricultural areas that use plastic mulch, apply wastewater or biosolids, or are subject to atmospheric deposition. This region-specific review underscores substantial data deficiencies and calls for standardised monitoring, enhanced policies, and sustainable farming practices to address microplastic pollution in soils.