Investigation of hydrogeochemical processes and groundwater quality in Upper Vellar sub-basin Tamilnadu, India

摘要

An attempt has been made in the Upper Vellar sub-basin to assess the hydrogeochemical processes influencing the water chemistry along with suitability of water for domestic and agricultural utilities. A total of 35 groundwater samples were collected for two different seasons, premonsoon (PRM) and post monsoon (POM), and analyzed for major cations, anions, and trace elements. The obtained results indicate that the dominance of silicate weathering, ion exchange process, and anthropogenic and microbial activities alter the chemistry of groundwater. The Piper plot suggests the facies evolution from Ca-HCO3, Ca-Mg-Cl and mixed Ca-Na-HCO3 and NaCl fluxes influencing the water chemistry. The ionic ratio plots suggest the predominance of Na+, Ca2+, HCO3- and Cl- indicating the silicate minerals dissolution and anthropogenic activities. All the trace elements are within the scale; however, Zn exceeds the WHO standard. The stability plot suggests samples representing kaolinite field during PRM and evolves towards montmorillonite and chloride field during POMinfers the dissolution of silicates minerals and ions from host rocks. According to the WHO standard, 23% of PRM and 6% of POM water samples exceed the maximum permissible limits for drinking purposes.