مشخصات پژوهش

Microplastics (MPs) are emerging contaminants increasingly detected in drinking water systems worldwide. However, comparative information on their occurrence and removal in drinking water treatment plants using different source waters remains scarce. This study evaluated the occurrence, characteristics, and removal efficiency of MPs in two drinking water treatment systems in Iran: a conventional freshwater DWTP and a seawater reverse osmosis (SWRO) desalination plant. In the freshwater DWTP, MP concentrations decreased from 118 ± 28 MPs/m³ in raw water to 28 ± 11 MPs/m³ in treated water, corresponding to a 76% removal efficiency. Fragment-shaped MPs in the 100–500 μm size range, predominantly blue in color, were the most abundant particles, while polyethylene terephthalate (PET), polypropylene (PP), and polyvinyl chloride (PVC) were the dominant polymers. In the SWRO desalination plant, MP concentrations declined from 140 ± 53 MPs/m³ in raw seawater to 17.6 ± 12 MPs/m³ after treatment, achieving an 87% removal efficiency. Fiber-shaped MPs measuring 500–1000 μm, mainly white and black, predominated, with polyethylene (PE) and PP identified as the most abundant polymers. The estimated daily intake ranged from 0.0008 to 0.006 items/kg/day. These findings provide practical insights into the occurrence, characteristics, and fate of MPs in freshwater and desalination-based water systems.