Methods for separation and classification of microplastics in soil

Abstract: The presence of plastics in the natural environment is widely acknowledged, and despite the efforts of numerous institutions and ecological organizations, the scale of pollution remains high. In recent years, research has primarily focused on aquatic areas, including both coastal and oceanic zones, with less emphasis on freshwater and inland waters. Analyses of soil contamination are still insufficient to provide a comprehensive picture of the current situation. Soil is a highly heterogeneous and dynamic structure, characterised by varying contents of organic matter, mineral salts, and water, making the determination of microplastic content in it a challenge. Additionally, known thermal or reagent-based methods are not always effective, often altering the colour, structure, or properties of plastics, resulting in unreliable outcomes. In this article, the authors describe contemporary methods for the separation and identification of microplastics in soil, as well as sample preparation techniques used by various researchers. By compiling many significant facts, it becomes apparent how challenging the study of soil contaminated with microplastics is and how crucial it is to develop uniform analytical procedures.