Widespread microplastic contamination in Australian soils: Sources, pathways, and environmental implications

Microplastics are ubiquitous in the environment, capable of long-range transport via rainfall, waterbodies, wind, and snow, and often carry other emerging contaminants on their surface, as well as additives within their own structure. This makes them persistent, bioaccumulative, and potentially toxic. This study represents the first survey of multiple land use settings in Victoria and New South Wales, Australia. A total of 55 soil samples were analysed for 13 different polymers in the 10-1000 μm size range, using foam fractionation to separate microplastic particles from the soil. The mean abundance was 14,400 ± 20,000 microplastics/kg, with a median of 4200 microplastics/kg (range: 0-90,200 microplastics/kg). Most of the particles were between 10 and 100 μm, with acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyethylene (PE), and polyurethane (PU) being the most prominent polymers. The microplastic particle morphologies were dominated by fragments (38 %) and pellets (27 %), with the remaining consisting of spheres, films, foams and fibres.