Water quality assessment and health risk evaluation in Kushtia Municipality, Bangladesh: A comparative analysis of untreated water, treated water, and public water points

Pipeline water supply, a primary source in urban areas, delivers treated water from water treatment plants (WTPs) directly to consumers. This study comprehensively evaluates water quality in Kushtia Municipality, Bangladesh, focusing on untreated water, treated water, and freely available public water point (PWP) samples. Twelve water samples were collected from March 1 to 7, 2024, and analyzed for physicochemical and microbiological parameters using standard methods. The treatment efficiency, water quality index (WQI), Nemerow pollution index (NPI), and hazard quotient were calculated based on the analytical measurements. Findings indicate that, among the 12 assessed parameters, only three comply with Bangladesh’s water quality standards. The mean cumulative efficiency shows that WTP 2 exhibits the highest treatment efficiency (30.76%), whereas WTP 1 has the lowest (12.34%). While WQI scores classify all treated and PWP samples as “unfit” for consumption, treated water demonstrates comparatively better quality than PWPs. The NPI analysis identifies the primary contributing pollutants in the following order: Biochemical oxygen demand>hardness>alkalinity>iron>temperature>electrical conductivity. The health risk assessment reveals no significant risk of iron ingestion or dermal exposure for adults and children. However, long-term ingestion of arsenic-contaminated water presents a moderate health risk for both groups, while dermal contact poses no risk.