Occurrence and Control of Microplastics and Emerging Technological Solutions for Their Removal in Freshwaters: A Comprehensive Review

Abstract

Plastic remains a cheap material for numerous uses in households, industries, and engineering; however, it disintegrates in aquatic ecosystems to form smaller particles termed microplastics. Microplastics (MPs) have become a cause for concern due to their persistence and potential effects on freshwater ecosystems. Moreover, the toxicity of microplastics can be achieved through different mechanisms, including physical blockage and additive leaching, or they can function as vectors for other chemical pollutants. Microplastics were found to provide a growing surface for microbial communities, forming a biofilm termed the plastisphere. Microplastic pollution seems to need urgent attention globally; however, the comparability of results becomes a challenge due to the different techniques employed by different researchers. Moreover, the complete removal of MPs has proven to be an impossible task. This review explored MP occurrence in freshwater ecosystems, the role of microbial communities in the dynamics of microplastics, removal techniques, strategies for reduction in the environment, and their effect on freshwater ecosystems. Moreover, techniques to reduce microplastic release, such as recycling, plastic–fuel conversion, and biodegradable plastics, are explored. The review provides recommendations for reducing microplastic release and removal in freshwater ecosystems. This review stresses existing gaps to explore going forward in addressing microplastic pollution and possible removal techniques.