Integrated Multivariate Analysis, Hydrogeochemical Modelling and Speciation Studies to Reveal Geogenic Origins behind Physical Disabilities: A Case Study in Pure Village, Varanasi, India

Abstract

The study aims to discuss elaborately about the origin of physical disabilities amongst the locals of Pure village in Varanasi district, India through proper hydrogeochemical facies, multivariate statistics and correlations, saturation indices of mineral phases, speciation of heavy metals, radiation surveys, and comparing the values of major ions and heavy metals with respect to the permissible limits of USEPA, WHO, ICRP, and BIS standards. The evolution of water is Ca-Mg-HCO₃ type, as evident from Piper trilinear plot, with neutral to feeble alkalinity. From Gibbs’s diagram, origin of major ions in groundwater is found primarily to be chemical weathering of the rock forming minerals as all the samples fall in rock dominance zone. Mineral saturation indices modelling by PHREEQC suggest supersaturation of water with goethite, hematite, Fe(OH)₃(a), and dolomite. Speciation studies of PG-4 having high U concentration (13 μg/l) reveal dominance of U⁴⁺ and Fe²⁺ species, thus confirming reducing environment in aquifer. The high concentration of iron minerals in water promotes adsorption of U⁴⁺ on their matrices thus reducing effective U concentration in water. The U values are higher in most of the drinking water samples as per safe limits indicated by ICRP and WHO suggesting that long-term use for drinking purpose may cause serious health crisis. Higher Sr values (119 ± 39 μg/l) in groundwaters, greater than minimum reporting level, as per USEPA, may be one of the contributing factors for physical disabilities of inhabitants.