Origin, Distribution, Fate, and Remediation of Microplastics in Biowastes and Biowaste-Amended Soil

Microplastics are an emerging class of contaminants that are ubiquitous in the environment and have been detected in terrestrial, marine, and freshwater ecosystems, and even at remote locations. These are becoming a huge challenge due to their adverse impact on human health and the 82environment, particularly the marine environment. Biowastes, such as farmyard manure, composts, crop residues, and biosolids are land-applied due to the abundance of carbon and nutrients. However, due to the contamination of microplastics, the land application of biowastes inadvertently adds particulate plastic to agricultural soil, making them available for uptake by soil biota and eventually, the food chain. Due to their fine particle size and large surface area, microplastics (and nanoplastics) adsorb other contaminants on their surface and act as a vector; therefore, uptake of microplastics by soil biota, followed by humans and animals can lead to adverse effects due not only to microplastics but also to the contaminants transported by them. Unfortunately, due to the inherent properties of plastics and polymers, it is difficult to remediate microplastics in the environment, particularly in biowastes and biowaste-amended soil. There are limited physical, chemical, and biological remediation methods available to remove, treat, or degrade microplastics, which are described in this chapter.