Microplastics in complex soil matrix: Recovery, identification and removal using micro nano techniques

Abstract

Investigations on microplastic (MPs) particles in soils are extremely rare, and the published results often lack comparability due to different sampling, extracting, and analytical approaches used. The current techniques for examining tiny MPs in soil samples are not particularly effective, but minor adjustments and method combinations should be explored. The complexity of the soil matrix presents challenges in developing a standardized approach for characterizing MPs and removing them effectively, due to the heterogeneity of soil composition, variability in their size/shape, interactions with soil particles, background contamination, and methodological variations. This review focuses on evaluating various methods for sampling, extraction, purification, identification, measurement and removal of tiny MPs in complex soil systems. A recommended methodology for extracting MPs from complex soil samples is proposed, aiming to provide a systematic approach for their recovery and identification. Furthermore, the article discusses sampling plans, drying and sieving techniques, density separation methods, and removal the MPs with special emphasis on photocatalytic removal. The review also addresses the challenges encountered in such analyses and suggests possible solutions, followed by future prospects. Additionally, the importance of removing MPs from the environment is highlighted, underscoring the need for effective methodologies in tackling this pressing issue.