Abundance and characteristics of microplastics in a freshwater river in northwestern Himalayas, India - Scenario of riverbank solid waste disposal sites

Microplastics (MPs) are one of the challenging and established contaminants that have adverse implications on human health. The focus of this study was to quantify and analyze the contribution of unscientific municipal solid waste (MSW) disposal sites to the MPs in the Jhelum River and the risk associated with it. Quantitative analysis of our study showed a mean MP concentration of 1474 ± 1026 particles/m for the entire stretch of the river. All the sites confirmed the presence of MPs with the concentration ranging from 600 particles/m to 2500 particles/m. The size distribution of MPs suggested that 34 % of the microplastics ranged between 300 μm to 75 μm while 66 % of the particles varied between 300 μm to 5 mm. The concentrations of MPs downstream of unscientific disposal sites were found to increase threefold to that of upstream. The Fourier Transform Infrared Spectroscopy (FT-IR) confirmed the presence of polyethylene (PE) in the majority followed by polyvinyl chloride (PVC) and polypropylene (PP). The flakes were dominant throughout the river followed by filaments, fragments, and spherules. Count based Pollution level indexing (PLI) estimated 3-14 times MP contamination in the river with respect to contamination in glacial runoffs. The risk assessment study of the MPs indicated an increase of around 10.2 % in ingestion rates of MPs due to the unscientific disposal of MSW on the banks of the freshwater body. The values of polymer hazard index (PHI) and potential ecological risk index (PERI) were in the extreme case of pollution (PHI>1000 and PERI>1200). This study manifests the adversities of unscientific municipal solid waste disposal for timely waste management.