Microplastics pollution in inland aquatic ecosystems of India with a global perspective on sources, composition, and spatial distribution

Indian inland aquatic ecosystems. Microplastics (MPs) have been identified as emerging contaminants, potentially impacting public and ecosystem health. This comprehensive review discusses the current state of knowledge on MP contamination and mechanistic process understanding in Indian inland aquatic ecosystems. It highlights knowledge gaps regarding current MP data and discusses methodological differences in MP sampling and sample processing that can lead to contrasting results. Most studies reviewed here have provided evidence of MP contamination in water, sediment and certain indicator species of inland aquatic ecosystems at specific locations and times. Significant seasonal variations in MP concentrations have been identified for pre-, during and post-monsoon periods. We found that only a few of the reviewed studies have considered the inherent spatio-temporal variability of MP concentrations, and the intricate interplay with hydrological key parameters has largely been overlooked. However, in order to improve our understanding of how MPs are transported within these aquatic ecosystems (e.g., river networks) and decide on potential pollution mitigation, it is imperative to link data on MP concentration and physico-chemical characteristics with key hydrological information such as flow velocity or discharge. This will provide information on MP loads and help to establish loading functions for these aquatic ecosystems that are needed to better understand the impacts of MP pollution on public and ecosystem health.