Microplastics in Indian Freshwater Systems: Current Status and Future Research Needs

Abstract

Microplastic (MP) pollution has emerged as critical environmental issue affecting aquatic ecosystems worldwide. Freshwater systems have received less research attention in the past but have been identified as significant sources and alteration points for MP. The mandate of this review is to bring together the existing information about source, occurrence, distribution, characterization, biological and ecological effects and mitigation measures related to MPs in Indian freshwater environments. Land-based sources such as wastewater effluents, urban runoff, industrial effluents, agricultural activities, and the breakdown of larger plastic waste are main sources of MPs. The prevalence of contamination of river, lake and riverbed sediments and freshwater biota, commonly in the form of micro and macro fibres, is reported from all over the world. Biological and ecological effects encompass ingestion at different levels, physiological stress responses, feeding behaviour changes and possible ecosystem level disturbances. The increasing evidence suggests that consumption of freshwater fish and drinking water may be sources of exposure to humans, which may be of concern for food safety and public health. Microplastics are also a pathway for toxic chemicals and microbial communities, which further contributes to environmental and toxicological hazards. In India, MP contamination has been reported from several freshwater ecosystems, including the Ganga, Yamuna, Gomti, Saryu, Brahmaputra, Mahanadi, Cauvery, Netravathi, Periyar, and Vembanad Lake. MPs have been detected in water, sediments, and freshwater fishes, with fibres and fragments being the dominant particle types and polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) identified as the predominant polymers. The available evidence indicates increasing contamination in highly urbanized and industrialized river stretches, highlighting the urgent need for harmonized monitoring protocols and effective mitigation strategies in Indian freshwater ecosystems. The successful implementation of mitigation measures needs a coordinated approach that involves source reduction, advanced wastewater treatment, implementation of circular economy, policy enforcement, and public participation.