Microplastics build-up in soils - spatial distribution patterns across different land uses and associated health risks

Abstract Microplastics (MPs) pollution in soil is a growing concern due to extensive plastic use and its persistence in soil, which degrade soil health, and can enter human body through ingestion, however its extent and effects in soil are largely unknown. This study aimed to assess the extent, composition, distribution patterns and potential hazards of MPs in major land use and soils to build knowledge of MPs as emerging containment when designing policy for environmental sustainability. MPs levels ranged from 120 to 4500 MPs/kg, while highest in greenhouse soil (3350 MPs/kg), followed by residential areas (2341 MPs/kg), and lowest in fish farm soil (128 MPs/kg). The geo-accumulation index in residential and greenhouse soils was extremely contaminated (Igeo ~ 4.7). Estimated Daily Intake shows infants have ~ 20 times higher exposure than adults in highly contaminated sites. Polymer types varied by land use types as HDPE dominated roadside (30%) and greenhouse soils (26%), while polyethylene (PE) in sewage-irrigated and PVC peaked in landfill (26%). White, fiber-shaped MPs sized 1–5 mm was most common. This study confirmed the abundance and spatial variability of MPs across various land uses indicating the potential risks of MPs pollution, especially the residential and agricultural soils which act both source and sink of MPs pollution. It also highlights the need for further comprehensive research on implications of MPs contamination on soil ecology under different land use, environmental conditions, and agricultural practices.