Hydrochemical characterization, ionic composition and seasonal variation in groundwater regime of an alluvial aquifer in parts of Nalagarh valley, Himachal Pradesh, India

Around 72% industries in Nalagarh are processing without effluent treatment plants which is a major threat to groundwater regime. The present study is focused on hydrochemical characterization and seasonal variation of groundwater quality to assess the intensity of pollution in this industrial belt. At some locations the concentration of pH, total hardness and magnesium exceeded the permissible limits and other parameters like electrical conductivity, total dissolved solids, calcium, magnesium and bicarbonate showed above the desirable limit of Bureau of Indian Standard (BIS) that requires precautionary measures. Groundwater of the study area was assessed for irrigation purposes on the basis of Electrical Conductivity, Sodium Adsorption Ratio, Residual Sodium Carbonate, Percent Sodium, Kelley's Ratio and Doneen's Permeability Index all water samples were suitable for irrigation purpose respectively. The value of Magnesium Hazard indicates that 68.75% and 34.38% of water samples fall under “Harmful” class during both seasons respectively. Chadha's diagram for geochemical classification and hydrochemical processes of groundwater for both seasons indicates that all the water samples are Ca²⁺-Mg²⁺-HCO₃-type. The study reveals that the groundwater quality changed due to anthropogenic and natural influence such as industrial, agricultural, natural weathering process.