Integrated assessment of physicochemical, microbial, and heavy metal pollution in theshitalakshya river, bangladesh: implications for water quality, ecological and health risks

Abstract

This study assessed the surface water quality of the river, focusing on physicochemical parameters (pH, DO, EC, TDS, salinity), microbial contamination, and heavy metal pollution, using a combination of water quality indices and ecological risk assessments. Results revealed seasonal fluctuations in water quality, with DO consistently below World Health Organization (WHO) and Environment Conservation Rules (ECR) standards, while TDS and EC frequently approached or exceeded permissible limits. Microbial analysis showed alarmingly high levels of total and faecal coliform counts, far exceeding WHO guidelines. Heavy metal concentrations exceeded permissible limits for Pb, Cd, and As, and Cr contamination was notably high at certain sites. The values of pollution indices, such as the Nemerow Comprehensive Pollution Index, Heavy Metal Pollution Index, Heavy Metal Evaluation Index, and Water Quality Index, indicated that the river was moderately to severely polluted. Ecological risk assessment identified cadmium as the most significant contributor to potential ecological hazards. Arsenic raised non-carcinogenic risk, while Cd showed very high and As, Cr high carcinogenic risks, with children more vulnerable.

J. Bangladesh Acad. Sci.50(2); 299–314: June 2026