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      https://www.ias.ac.in/article/fulltext/jess/126/06/0089

    • Keywords

       

      Shallow aquifers; DRASTIC model; hydrochemical signatures; vulnerability assessment; granitic terrain; southern India.

    • Abstract

       

      Shallow aquifer vulnerability has been assessed using GIS-based DRASTIC model by incorporating the major geological and hydrogeological factors that affect and control the groundwater contamination in a granitic terrain. It provides a relative indication of aquifer vulnerability to the contamination. Further, it has been cross-verified with hydrochemical signatures such as total dissolved solids (TDS), $\hbox {Cl}^{-},\, \hbox {HCO}_{3}^{-},\, \hbox {SO}_{4}^{2-}$ and $\hbox {Cl}^{-}/\hbox {HCO}_{3}^{-}$ molar ratios. The results show four zones of aquifer vulnerability (i.e., negligible, low, moderate and high) based on the variation of DRASTIC Vulnerability Index (DVI) between 39 and 132. About 57% area in the central part is found moderately and highly contaminated due to the 80 functional tannery disposals and is more prone to groundwater aquifer vulnerability. The high range values of TDS (2304–39,100 mg/l); Na+(239– 6,046 mg/l) and Cl (532–13,652 mg/l) are well correlated with the observed high vulnerable zones. The values of $\hbox {Cl}^{-}/\hbox {HCO}_{3}^{-}$ (molar ratios: 1.4–106.8) in the high vulnerable zone obviously indicate deterioration of the aquifer due to contamination. Further cumulative probability distributions of these parameters indicate several threshold values which are able to demarcate the diverse vulnerability zones in granitic terrain.

    • Author Affiliations

       

      C Mondal1 S Adike2 V S Singh1 S Ahmed1 K V Jayakumar3

      1. Earth Process Modeling Group, CSIR-National Geophysical Research Institute, Hyderabad 500 007, India.
      2. Rural Water Supply & Sanitation, Mahaboobnagar, Telangana, India.
      3. Water & Environmental Division, Department of Civil Engineering, National Institute of Technology, Warangal 506 004, India.
    • Dates

       
  • Journal of Earth System Science | News

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