Widespread adverse effects of microplastics in soil

Abstract

Increasing plastic production and its mismanagement have made microplastics (MPs) and nanoplastics (NPs) a major concern for the environment. Plastic use has increased dramatically nowadays, with over 480 million tonnes of plastic produced annually. This plastic does not decompose easily and accumulates in the environment, being a major factor in microplastic contamination everywhere. While marine/aquatic pollution was previously researched more, agricultural soils are also a major source of microplastic pollution. Contamination of these MPs and NPs in agricultural areas poses serious threats to soil health, crop quality, and human health. This article analyzes in detail the sources of MPs/NPs in agricultural soils, their impact on the physical, chemical, and biological properties of the soil, their negative effects on plants, and ultimately their adverse effects on the food chain. The article presents key findings from contemporary research and identifies areas where long-term studies are necessary, particularly on soil fertility, contamination and quality-production in crops, and their long-term risks and toxicological effects on potential human health. Microplastics can also absorb heavy metals and other harmful chemicals as co-contaminants, further increasing the level of pollution in the soil. Agricultural practices such as plastic mulching, irrigation from wastewater, and biosolids-compost are the main causes of collection and 
contamination of microplastics in agricultural soils. These microplastics pose a risk to all agricultural production and food security due to changes in soil physical structure, imbalances in soil microorganisms, and reduced normal plant growth and productivity.