Impacts of soil microplastics on crops: A review

Microplastics (MPs) are plastic particles with lesser than 5 mm in size, and in recent years their accumulation in the soil has given rise to a critical global environmental issue that poses significant consequences for both organisms and ecosystems. This study reviews the available works of literature on the direct and indirect impacts of MPs on crops, as well as their amalgamated impacts when combined with other pollutants to identify their common toxicities. Specifically, we focus on both the direct ecotoxic aspects and the indirect abiotic and biotic ecological aspects of soil MPs, as well as their effects on crops when combined with other pollutants. This study highlights that (1) MPs in the soil were adsorbed onto the crop seeds and root surface or accumulated in their vascular system, consequently inhibiting the uptake of water and nutrients; (2) MPs caused oxidative damage to the crops and disrupt metabolic activities; (3) chemical additives released from MPs induce cytotoxicity and genotoxicity in crops; (4) MPs altered soil biotic and abiotic environments, thereby impacting the availability of soil water and nutrients to crops; and lastly (5) the combined toxicity of MPs and other common farmland soil pollutants adversely affected crops. In conclusion, this review showcases the consequences of soil MPs on crops and advocates, through recommendations, for more research on their impact on the natural environment and human life.