Microplastics Monitoring in Environmental Matrices of an Alpine River originating from Hindu Kush Mountain Range

Abstract Microplastics (MPs) are cosmopolitan in distribution and an emerging threat to life and the environment. These particles are not restricted to human-inhabited lands but also found in different mountains and glaciers where the human population is relatively low. These MPs make their way to the river ecosystem from glaciers, rains, and municipal and industrial effluents. The current study was designed to highlight MPs' pollution in water, sediments, and fishes of the Swat River: originating from the Hindu Kush Mountain Range. These samples were collected from eight different sites across the river. The average MPs concentrations were 305.79 ± 289.66 MPs/m 3, 588.29 ± 253.95 MPs/kg, and 12.54 ± 8.02 MPs/individual the water, sediments, and fish samples, respectively. The highest MPs concentrations (753.71 ± 330.08 MPs/m 3 ) in water were recorded near Mingora City, whereas MPs concentrations (834.0 ± 367.21 MPs/kg) were the highest on the same site. Among the selected fish species, the highest number of MPs was observed in Shizothorax plagiostomus. In contrast, the lowest in Wallago attu being 17.08 ± 8.27 Among the selected fish species, the highest number of MPs was observed in Shizothorax plagiostomus, whereas the lowest in Wallago attu being 17.08 ± 8.27 MPs/individual and 5.0 ± 2.36 MPs/individual, respectively. Fibres were the most prevalent MPs in all the matrices representing 80%, 92%, and 85% of the total MPs count in water, sediments, and fish samples. These findings highlighted that the high concentration of MPs prevailing in the river originating from high-altitude freshwater sources and awareness, education, ecotourism, sustainable reduction in plastic use, and strict rules and regulations could be helpful to prevent the anthropogenic menace.