Evaluation of groundwater quality and its suitability for drinking and agricultural use in the coastal stretch of Alappuzha District, Kerala, India

Groundwater is an essential and vital component of any life support system. It is not only the basic need for human existence but also a vital input for all development activities. The present hydro-geochemical study was confined to the coastal belt of Alappuzha district, which lies in the coastal lowland division of Kerala. Groundwater quality and its suitability for irrigation and domestic purpose were examined by various physico-chemical parameters such as pH, electrical conductivity, total dissolved solids, total hardness, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, and chloride. These parameters were used to assess the suitability of groundwater for domestic purpose by comparing with the WHO and Indian standards. TDS, sodium adsorption ratio (SAR), and permeability index were used for irrigation suitability assessment. The sample analysis reveals that the groundwater is not entirely fit for drinking with respect to pH, EC, Ca2+, Mg2+, Na+, and Cl−. In some of the collected samples, the concentrations of these parameters exceed the permissible limits of WHO and ISI standards. Based on TDS and SAR almost all samples are suitable for irrigation purpose except a few locations, which show values beyond the permissible limits. Ca–Mg–HCO3 is the dominant water type in the study area. The sequence of the abundance of the major cations and anions is Ca > Na > Mg > K = HCO3 > Cl > SO4. Based on the total hardness and TDS, 96 % of groundwater samples are found suitable for drinking purpose.