Assessment of Microplastic Pollution in the Kelani and Gin River Drinking Water Intake Points in Sri Lanka

Microplastic pollution has become a growing concern in freshwater systems that supply drinking water. This study used a quantitative experimental design to assess the occurrence and preliminary characteristics of microplastics in the Kelani and Gin River drinking-water intake points in Sri Lanka. Water and surface sediment samples were collected from upstream, intake, and downstream locations, then processed by filtration, density separation, and phase-contrast microscopy. The observed particles were classified into four main morphologies: fibers, fragments, films, and pellets. In the reported counts, Kelani River water contained 48 fibers, 32 fragments, 25 films, and 34 pellets, while Gin River water contained 39 fibers, 34 fragments, 21 films, and 32 pellets; sediment samples showed lower overall counts but the same dominant morphologies. XRD was used only as a preliminary structural characterization technique; definitive polymer identification requires complementary techniques such as FTIR and SEM, which were not performed in the present study. The study provides baseline evidence of suspected microplastic contamination at both drinking-water intake systems and supports continued monitoring and further polymer-specific characterization in Sri Lanka’s drinking-water sources.