Soil Pollution with Microplastic in the Impact Area of a Plant Producing Expanded Polystyrene

Data on soil pollution with microplastic in the impact zone of a plant producing expanded polystyrene insulation boards (Minsk, Belarus) are discussed. The industrial site and a site on the floodplain of a small river at a distance of 500-600 m from the source of pollution have been studied; alluvial soil (Fluvisol), bottom sediments, and the technogenic deposits at the industrial site have been sampled. The content of microplastic particles in the samples has been determined using drying, sieving, and flotation in distilled water (with heating for the fractions of 1-2 mm and <1 mm). The natural organic substances have been removed with 30% hydrogen peroxide solution. The content of microplastic particles has been visually assessed in the fractions of 3-5, 2-3, 1-2, and <1 mm. Polystyrene particles have been detected in all the samples of soils, bottom sediments, and technogenic deposits. The content of the particles with a size of <5 mm in the soil of industrial site varies from 31 to 175 particles/kg soil; and in the alluvial soil, from 94 to 8864 particles/kg soil. In most cases, the fractions of <1 mm are prevalent followed by the fractions of 1-2 mm. Microplastic is present in the upper horizon (0-5 cm) and in the deeper soil horizons, to a depth of 15-20 cm. As is shown, the granules of the raw material (expanded polystyrene) and waste (foamed beads and polystyrene fragments) are mainly transported by the surface runoff.