The spatial distribution, water quality indices, and health risks of trace elements in groundwater in Bogra District, Bangladesh: Implications for sustainable drinking water

Trace element concentrations in aquifers varied significantly. This study was undertaken to evaluate trace element concentrations in groundwater in shallow aquifers in the Bogra district, assessing its drinking suitability and estimating potential health risks. While comprehensive groundwater datasets for this district remain limited, this work provides a novel, district-wide, and subdistrict-resolved integration of trace-element measurements. Specifically, it combines multiple drinking-water quality indices, spatial hotspot mapping, and redundancy analysis (RDA) with age-specific carcinogenic and non-carcinogenic health risk assessments to deliver a robust framework for regional water management. The concentrations of As, Pb, Cd, Cr, Cu, Zn, Ni, Fe, and Mn in 109 groundwater samples were measured by inductively coupled plasma mass spectrometry (ICP-MS). This study revealed that aquifer depths across the 12 subdistricts ranged from 9.14 to 56.4 m. The average contents of As, Pb, Cd, Cr, Cu, Zn, Fe, and Mn were 4.42±10.1, 2.79±3.2, 0.04±0.06, 1.46±0.41, 2.01±2.3, 43.8±259, 3328±2597, and 2706±2454 µg L⁻¹, respectively, while the contents of Ni were below the detectable limit in all samples. The results revealed that all groundwater samples exceeded drinking water standards for Fe, and 97.2% exceeded national standards for Mn. Furthermore, 14% and 4% of samples surpassed WHO guidelines for As and Pb, respectively. The computed water quality indices indicated a widespread, similar trend of contamination, and the spatial distribution identified specific hotspots requiring urgent attention. The calculated hazard quotient (HQ) and hazard index (HI) values for all locations were below the threshold (