Evaluation of hydrogeochemical parameters of groundwater for suitability of domestic and irrigational purposes: a case study from central Ganga Plain, India

The study area is one of the most productive part of central Ganga Plain and fertile tract for sugarcane cultivation. Hydrogeochemical parameters of groundwater of the study area was evaluated to know the suitability of groundwater for domestic and irrigational purposes. Fifty-five groundwater samples from hand pumps in pre-monsoon 2007 were analyzed for physical and chemical groundwater parameters (electrical conductivity, pH, total dissolved solid, Na, K, Ca, Mg, HCO3, Cl, SO4, and NO3). Three major groups of groundwater with distinct chemical compositions had been identified on L-L diagram, i.e., Ca+Mg-HCO3 type, mixed type, and alkali bicarbonate type. All possible species, such as Na-Cl, K-Cl, Na-HCO3, Na-SO4, Ca-HCO3, Mg-HCO3, Ca-SO4, and Mg-SO4 occur in the groundwater system. Groundwater comes under the category of moderately hard to very hard, mildly acidic to slightly alkaline in nature. Majority of the sample are within the permissible limit when compared with drinking water standards in terms of electrical conductivity, pH, total dissolved solid, Na, K, Ca, Mg, HCO3, Cl, SO4, and NO3. According to Gibb's ratio, most of groundwater samples fall in the rock dominance field. Assessing the domestic uses, all the samples are considered fit, as they are neither acidic nor strongly alkaline. Based on analytical results, irrigational quality parameters like sodium adsorption ratio, residual sodium carbonate, and permeability index were calculated which indicate that the groundwater is also suitable for irrigational uses.