| dc.description.abstract | Global concern about microplastic pollution is increasing, with microplastics detected in various environments, including remote areas with minimal human activity. These particles have been found in organisms, human organs, drinking water, and food. Due to their high surface area, microplastics can adsorb environmental pollutants, which may impact health upon ingestion and can transfer up the food chain.
This study represents the first comprehensive investigation of microplastic pollution from upstream catchment areas to downstream drinking water treatment plants (DWTP) in Taiwan. Conducted from August 2023 to June 2024, the research involved collecting microplastic samples from Shimen Reservoir and its downstream DWTP. The reservoir was sampled five times over the study period, while the DWTP was sampled three times. Surface water samples were pre-treated using the Fenton method and density separation, identified with Nile Red staining, and analyzed with μ-Raman spectroscopy. The study assessed microplastic pollution levels in surface and intermediate waters of the reservoir, and evaluated the removal efficiency of various DWTP treatment units using the Hazard Index (H), Pollution Load Index (PLI), and Pollution Risk Index (PRI).
Results revealed microplastic pollution at all sampling points, with surface and intermediate water concentrations of 4.53 ± 2.3 items/L and 4.12 ± 1.86 items/L, respectively. The majority of microplastics were in the 37~300 μm size range, and fragments constituted over 70% of the samples. The primary polymers identified were PP, PE, and PET. The PRI varied from the highest (V) to the lowest (I) pollution levels, with Shimen Reservoir exhibiting relatively minor pollution. In the DWTP, the sedimentation basin demonstrated the highest removal efficiency at 63%, whereas the rapid filtration had the lowest at 11%, and the treated water achieved 46%. Overall, the DWTP reached an 83% removal efficiency, with all sampling points, except raw water, showing the lowest pollution level (I), indicating effective microplastic removal. Statistical analysis indicated a significant positive correlation between microplastic levels and rainfall in the 72 hours preceding sampling, suggesting that rainfall is a major factor influencing microplastic abundance. Additionally, microplastic levels varied significantly with meandering terrain (p < 0.05). | en_US |