Microplastics in agricultural soils: Evidence from an industrial suburb of Bangladesh

• Status of MP pollution in agricultural soils at an industrial suburb of Bangladesh was evaluated. • MP abundance was significantly higher in surface soils (1309 ± 335 items/kg) than in subsurface soils (660 ± 186 items/kg). • The majority of MPs were <1 mm (78 %), blue in color (37 %), fiber-shaped (54 %), and predominantly polyethylene (PE). • The pollution load index (PLI > 1) classified the soils as polluted with MPs. • MP abundance correlated significantly with soil properties, including pH ( r = −0.37), EC ( r = −0.48), and organic matter ( r = 0.35). ‘Microplastics’ (MPs) are increasingly recognized as emerging soil contaminants, yet their vertical distribution in agricultural systems−particularly in developing regions−remains poorly documented. This study examined MP abundance and characteristics in agricultural soils of central Bangladesh, a rapidly urbanizing agro-industrial zone. Soil samples were collected from 20 agricultural fields adjacent to homesteads, roadways, industries, landfills, and mulches at two depths (0−15 and 15−30 cm). Microplastics were extracted using density separation and wet digestion, identified by stereomicroscopy, and confirmed via ATR-FTIR spectroscopy. Results revealed the widespread presence of microplastics across all sites, with surface soils ranging from 540 to 1926 items/kg and subsurface soils from 253 to 1286 items/kg. Fibers, blue-colored particles, and particles smaller than 1 mm dominated the samples, while common polymer types included polyethylene (PE) and polypropylene (PP). Risk indices indicated moderate to substantial ecological concern, with pollution load values varying by proximity to local sources. As one of the first regional assessments of subsurface MPs in agricultural soils in South Asia, this study establishes critical baseline evidence for terrestrial microplastic transport. These findings highlight agricultural soils as a significant sink of microplastics in Bangladesh and underscore the need for management strategies to mitigate their potential impacts on food security and environmental health.