The Impact of Contamination of Groundwater Using Electrical Resistivity Method: A Case Study of Palar River, Ambur
Author : Vangala Satish Kumar and Alwal Narsing Rao
Abstract :
In the present study the effluent discharged from tanneries industries along the Palar River was investigated using an integrated electrical resistivity approach. A of 19 Vertical Electrical Soundings (VES) and 32 Electrical Resistivity Tomography (ERT) were conducted within the study area to delineate subsurface geology and to map the effluent plume. All vertical electrical sounding (VES) and 6 electrical resistivity tomography profiles were considered in the study area. The electrical soundings were carried out with total spreading of 100 and 200 meters whereas 120 to 240 meters was carried for electrical resistivity tomograph. Electrode configuration includes Schlumberger and Wenner array for Sounding and Tomography. The current scenario of pollution was established using parameters such as Longitudinal Conductance (Si), aquifer vulnerability index and overburden protective capacity derived from the VES analysis. The four principal geoelectric layers inferred from the VES data include the topsoil, sand, sandy clay and hard rock. Resistivity values for these layers vary from 4.9 to 310, 4.5 to 659, 4.2 to 1030, and 91.5 to 9000 Ωm with a corresponding thickness of 0.4-8.9, 1.03-24.7, 2.1-33 and 5-24.9 m respectively. The effluent plume occurs to a maximum depth of approx. 15 meters in the 2-D inverse models. The correlation between longitudinal conductance and overburden protective capacity show that aquifer in study area have moderate to good protective capacity and moderate to highly vulnerable to contamination. The pervious topsoil, sand and sandy layers increased the aquifers vulnerable to contamination by failing to act as an efficient barrier against seepage.
Keywords :
Contamination vulnerability, resistivity tomography, vertical electrical soundings, protective capacity, longitudinal conductance, aquifers
