Microplastics transport in soils: A critical review

Microplastics (MPs) in terrestrial environments are an emerging contaminant of huge concern<br/>to ecosystems and human health. However, our understanding of the MPs fate, particularly their <br/>transport mechanisms, remains elusive. This knowledge gap arises from the multiplicity of <br/>coupled physical, chemical and biological processes and parameters affecting MPs transport, <br/>together with scarcity of systematic studies that aim to isolate their individual effects. In this <br/>paper, we provide a critical review of the state-of-the-art in our understanding of MPs transport, <br/>highlight knowledge gaps, and suggest future research to bridge them. We classify the <br/>governing factors into four main categories: (i) MPs properties; (ii) soil properties; (iii) <br/>hydrological conditions; and (iv) biological activity. Our analysis highlights the intricacy of <br/>MPs transport, showing that seemingly non-monotonic trends and even complete lack of <br/>correlation between some parameters and MPs transport could be explained by the interference <br/>(co-effects) with other parameters and processes