Microplastics in Soils and Sediments: a Review of Characterization, Quantitation, and Ecological Risk Assessment

This study presents a comprehensive review of the characterization, quantification, and ecological risk assessment of microplastics (MPs) in soils and sediments. MPs, defined as plastic particles of size smaller than 5 mm, have been less studied in these environments compared to aquatic ecosystems. Broadly, all analytical methods include the following steps: sampling, extraction, polymer identification, and quantitation/particle counting. This review highlights the variation in current methodologies for sampling, extraction, and quantification of MPs, which hinders data comparison across studies. This poses a real challenge to compare the data of various studies. Hence, there is an urgency to develop standardized methodologies for analyzing MPs in different environmental matrices. Spectroscopic techniques such as FT-IR and Raman are the most widely used techniques for polymer identification. Adopting proper quality control and quality assurance measures will improve the reproducibility and comparability of results. This review calls for further research on MPs' effects on soil and sediment environments to inform standardization efforts and improve our understanding of MPs pollution.