Seasonal Variation of Fe, Mn, and Pb in Groundwater of Northwestern Bangladesh

Abstract

Groundwater is one of the most significant natural resources on earth and also stands as the largest source of all-purpose water in Bangladesh. The higher concentrations of iron (Fe), manganese (Mn), and lead (Pb) in water constitute a threat to human health and the environment. The research aimed to assess the seasonal variations of heavy metal concentrations, including Fe, Mn, and Pb, and the water type controlling the geochemistry of groundwater. A total of sixty groundwater samples were collected over a year in three seasons and analyzed for several physicochemical parameters using the standard analysis methods The highest concentrations of Fe, Mn, and Pb in investigated groundwater samples were found to be 3.69, 2.50, and 0.17 mg/L, respectively. The study observed that the higher concentrations of Fe and Mn were in the pre-monsoon but Pb was in the post-monsoon. The contaminations of Fe, Mn, and Pb in the groundwater follows the order Fe > Mn > Pb in three seasons, and their concentrations of abundance follow the seasons: PRM > POM > MON. The groundwater samples showed the dominance of Ca⁺⁺, Mg⁺⁺, and HCO₃^-, indicating temporary hardness and the Ca-Mg-HCO₃, hydrochemical  facies, controlling the groundwater geochemistry in the study area. These findings would provide an in-depth understanding of water quality, potential risks to human health, and coping mechanisms for sustainable drinking water management.