Spatio-temporal variations of tanning industries induced river water quality in a developing country: Entropy-based water quality, pollution source tracing, and health risk appraisals

Surface water pollution through uncontrolled industrial discharge is a global concern. In this study, 50 water samples from Dhaleshwari River (Bangladesh) were collected and analyzed for 27 water quality parameters (temperature, DO, BOD, pH, EC, TDS, alkalinity, hardness, Pb, Cd, Cr, As, Hg, Ag, Mn, Co, Fe, Ni, Zn, Cu, Mg, F⁻, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, and SO₄^2-) in wet and dry seasons. The aim of this study was to delineate seasonal river water quality, trace pollutants source, and evaluate public health risks through exposure, for environmental sustainability. Water physicochemical properties were measured using a Multimeter. Toxic metals were determined using an atomic absorption spectrophotometer while anions were estimated using the ion chromatography. Spatial and seasonal variation of the parameters were evaluated through GIS and statistically. Several indices were used for water quality and health risk evaluations. Investigation revealed Cr, Mn, Fe, Ni, and Hg were the most prevalent pollutants in this river in both wet and dry seasons, while temperature, DO, BOD, EC, TDS, Cl⁻, and NO₃⁻ were the most concerning parameters in the dry season. One-way ANOVA indicates significant (p < 0.05) variations in concentration for most of the parameters over the studied region in both seasons. Water quality indices indicate severe heavy metal pollution in the river water. Discharged pollutants have changed the water physicochemical parameters significantly. Principal component analysis revealed significant anthropogenic elemental (Cr, Pb, Cd, As, Hg, Ag, Mn, Co, Ni, Zn, and Cu) contributions to the river water. Health risk assessment suggests that Mn, Cr, Co, Hg, and As in the river water could cause adverse effects on human health. Therefore, effective legislative and administrative measures should be implemented for the regulated discharge of industrial effluents in the area to ensure a safe and sustainable environment for aquatic organisms and human beings. Copyright © 2025 Informa UK Limited, trading as Taylor & Francis Group.