Spatiotemporal distribution and human health risks of potential toxic elements in the groundwater of the lower Tista Floodplain, Rangpur, Bangladesh

This study assessed the extent of potential toxic element (PTE) contamination and its associated health risks in groundwater from the Tista Floodplain, Rangpur, northern Bangladesh. A total of 130 groundwater samples (65 from the wet season and 65 from the dry season) were analyzed for six PTEs: As, Al, Cu, Mn, Cr, and B using Atomic Absorption Spectrophotometry (AAS) and VIS Spectrophotometry. The mean concentrations of PTEs followed a decreasing order of B > Mn > Cu > Al > As > Cr in the wet season and Mn > B > Al > Cu > As > Cr in the dry season. Metal evaluation index and degree of contamination indicated minor contamination, while the Nemerow pollution index showed moderate to severe contamination, especially in Nilphamari district. Contamination levels were higher in the dry season compared to the wet season. No individual PTEs posed non-carcinogenic health risks, but combined PTEs presented potential health threats, particularly to infants, with higher severity during the dry season. No dermal health risks were identified. Despite the relatively low contamination levels, monitoring policies for new and existing tubewells should be implemented to ensure sustainable groundwater management and long-term water quality.