Hydrogeochemical delineation of groundwater fitness for drinking and agricultural utilities in Thiruvallur district, South India

Appraisal of groundwater fitness to drinking, agricultural, and domestic purposes was attempted within the Thiruvallur district of South India since groundwater is the significant sources for the above utilities. Groundwater samples collected from a sum of 110 locations have to be analyzed for major concentrations of which higher values of total dissolved solids (TDS), chloride (Cl − ), and sodium (Na + ) ions were noted during pre-monsoon (PRM) specifically besides the east along with the southeastern part of the study region and higher calcium (Ca 2+ ) and nitrate (NO 3 − ) values disseminated besides the central and eastern parts of the study region during the post-monsoon (POM) season. Suitability of water quality depends upon total dissolved solids; Water Quality Index (WQI) suggests 70% and 62% of the study area representing hard and sedimentary formations are appropriate for consumption utilities. Irrigation aptness of water for utility suggests the majority of study area is suitable in view of electrical conductance, sodium adsorption ratio, USSL plot, Na%, Wilcox’s plot, Kelly’s ratio, and Doneen’s plot. Dominant hydrochemical facies were observed to be Na-Cl, mixed Ca-Mg-Cl, and Ca-HCO 3 , and parameters like Na + , Ca 2+ , HCO 3 − , Cl − , and NO 3 − ions have been observed to be higher in the central region next to the east and may be appropriate to influence geogenic, anthropogenic, and seawater encroachment.