Review of microplastics in soils: state-of-the-art occurrence, transport, and investigation methods

PurposeA number of studies have been conducted on the occurrence, transport, and fate of microplastics in soil environments. The complexity of matrices presents significant challenges in investigating microplastics in soil, highlighting the need for further research and development in this field. In this review, sampling and pretreatment methods available for detecting and further studying microplastics in soil environments are primarily focused with a minor discussion on their various sources and behavior. Finally, based on the current research findings, the directions of future research are proposed as well.MethodsBased on a comprehensive search of the available database, we provide updated information on the sources and behavior of microplastics in the soil and the analytical techniques available for their study.ResultsPrevious studies have predominantly focused on microplastic contamination and its levels in various environments. We propose that the focus of microplastic research needs to be redirected to allow a better understanding of the behavior and impact of soil microplastics. The novel approach involves modeling the behavior of microplastics in the soil and associated environmental impacts and risks and developing standardized testing methods. These tools will provide a comprehensive strategy for creating a healthy and safe environment.ConclusionsAs plastic production increases worldwide, the accumulation of microplastics in the soil also increases, with potentially adverse implications for food security, human health, and climate change. A comprehensive strategy for rational delineation of microplastic behavior in the soil, as presented here, is needed to counteract and control the environmental impact of microplastics.