Tracking microplastics at the source: a comparative study of fluorescent and FTIR microscopy at a drinking water intake in the Perak River, Malaysia

Asian rivers are significant carriers of microplastics, posing major environmental and health risks. It is critical to understand the quantity and characteristics of MPs in freshwater, particularly river water used as a source of drinking water. Microplastic pollution in freshwater is a serious issue, but there is surprisingly little data on it, especially in Malaysia. This study aims to investigate the presence and characteristics of microplastics in Perak River water, specifically at a water treatment plant point of abstraction, to understand the quantity and features of MPs in river water used as a source of drinking water, and to inform mitigation measures to reduce riverine MP contamination. Water samples were collected in February and July 2023 from the point of abstraction near the Perak River in Malaysia. We analyzed microplastics based on size, shape, and polymer type using fluorescence and FTIR microscopy. Fluorescence microscopy detected more particles on average, while FTIR microscopy identified 12 distinct polymer and semi-synthetic polymers, with Rayon and PE dominating. Most MPs' particle sizes ranged from 1 to 10 µm. MPs in the shape of granules and irregulars were often discovered. Study finds FTIR microscopy a more suitable and accurate method for identifying MPs compared to fluorescence microscopy. Numerous unidentified particles were also detected using FTIR and fluorescence microscopy. This research helps authorities to develop mitigation measures to reduce riverine MP contamination in drinking water.