Microplastics in Freshwater Ecosystems

Globally, an estimated 12.5 million tons of plastic waste enter aquatic systems annually, with a significant proportion, up to 92%, degrading into microplastics (MPs), which has become a growing environmental concern. These MPs primarily originate from synthetic textiles, cosmetics, industrial materials, and plastic waste. This review identifies polyethylene (PE), polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (PET) as the prevalent polymers in freshwater MPs. This review explores the mechanisms governing the transport of MPs in freshwater systems, categorizing them by size, structure, buoyancy, and interactions. Our review elucidates that horizontal transport primarily occurs via surface water currents, while vertical transport is influenced by settling or resuspension processes. The accumulation of MPs in freshwater ecosystems poses significant risks to both biotic and abiotic components, affecting the food chain, nutrient cycling, and water quality. Furthermore, MPs inflict ecotoxicological damage through various transport pathways, including sedimentation, resuspension, adsorption, and biodegradation. The authors also evaluate current analytical methods for MP detection and quantification, such as microscopy, spectroscopy, and chromatography. This review identifies gaps in our understanding of the long-term ecological impacts of MPs, necessitating further research in areas like bioaccumulation and trophic transfer. Moreover, studies assessing the efficacy of natural degradation processes and microbial interactions with MPs could provide innovative solutions for MP remediation. Finally, the authors recommend the adoption of a multi-tiered approach, including stricter regulations on plastic production and waste disposal, the development of biodegradable plastic alternatives, and community-driven clean-up initiatives. Public awareness campaigns can also play a pivotal role in mitigating MP pollution.