Assessment of Potentially Toxic Elements Contamination on the Fertile Agricultural Soils Within Fluoride-Affected Areas of Jamui District, Indo-Gangetic Alluvial Plains, India

Accumulation of excess potentially toxic elements (PTEs) in soils poses a threat to human health as the agricultural ecosystem is closely related to the food chain. Accordingly, soil samples and groundwater samples were collected, and the soil samples were examined for pH, EC, As, Fe, Mn, Co, Cr, Cu, Al, Zn, Ni, Ba, B and F. The mean concentration of As, Co, Cr, Cu, Zn, Ni and Fe exceeded their geochemical background values impacting contamination from these toxic elements in the agricultural soils within study area. The PTEs-based various pollution indices are employed to aggregate and assess the toxic element pollution in the study area which indicates minor enrichment to moderately severe enrichment of Al, Ba, Cu, Zn, Fe, Mn, Ni and As within soils. This could be attributed to the accumulation of these elements from weathering of parent materials such as amphibolite, feldspar, hematite and ilmenite with partial input from the anthropogenic source like pesticides and fertilizers. Similarly, Nemerow comprehensive index also suggests that 60% of locations represent seriously contaminated class (Ps >= 5), due to the elevated concentrations of Cu, As and Zn. Likewise, the potential ecological risk with a mean value of 130.89, appears to be characterized by "considerable (100-200) to high contamination" (> 200) at about 53.33% locations. Hierarchical cluster analysis results also confirm that association of PTEs such as Cr, Ni, Fe, Mn, Zn, Ba and As in a cluster is indicative of anthropogenic source, and on the other hand, weathering of aluminosilicates of parent rock is mainly responsible for contamination of Co, Al, Cu and B. Above all, pH and F in soils have a close association with F in groundwater indicating the influence of soil in enriching F in groundwater, perhaps due to excessive drawdown of groundwater for agricultural activity.