ELECTRICAL IMAGING TECHNIQUES FOR GROUNDWATER POLLUTION STUDIES: A CASE STUDY FROM TAMIL NADU STATE, SOUTH INDIA

an attempt was made to identify the extent of pollution in the aquifer matrix of tirupur, a highly industrialized zone of tamilnadu state, south india. electrical imaging techniques were adopted with a syscal pro-96 system, for measuring apparent resistivity values using different electrodes separation. the first profile conducted at valipalayam recorded a resistivity range of <10 ？？a？￠ m at a depth of 8 m, which indicates contamination of top soil due to discharge of effluents. an increase in resistivity >45.5 ？？a？￠mwas observed at a depth of 27 to 47 m indicating the possibility of contamination. the second profile conducted at pethichettipuram indicates source of contamination at left end corner with a drop in resistivity <46.5 ？？a？￠ m at a depth of 7.91 m. a drop in resistivity <21.6 ？？a？￠ m was also observed at a depth of 11.5 m indicating a contaminated zone in deeper regolith. the third survey conducted in palayakadu indicates contamination of regolith at a depth of 0 to 20 m with a resistivity less than 40 ？？a？￠m. the fourth survey at chellapuram indicates contamination of overburden with resistivity >11.5 ？？a？￠m, to a depth of about 10 m. five imaging surveys conducted across the contaminated sites reveals that shallower regoliths are highly contaminated and deeper aquifers are free from contamination except a few locations.