Impact of Tanning Industries on Groundwater Quality near a Metropolitan City in India

The present study was carried out with the objective of determining the extent of groundwater pollution caused by tanning industries in Chromepet area located south of Chennai, Tamil Nadu, India. Groundwater samples were collected during January and March 2008 from 36 wells and were analysed for the concentration of various major ions and chromium. Na-Cl was the dominant water type found in this area. Groundwater in this area is not suitable for drinking as it contains elevated concentration of most major ions and chromium. This is due to the recharge of partially treated effluent discharged by tanning industries into open drains. The concentration of chromium was above the permissible limit (0.05 mg/l) in 86% of the groundwater samples. The use of chemicals, such as sodium chloride, sodium sulphate, chromium sulphate etc. during the tanning processes is the major reason for the high concentration of major ions and chromium in groundwater. Hence it is important to regulate the industries and also take measures to reduce the total dissolved solids in the treated effluent before disposal. The groundwater quality of this region can also be improved by adopting rainwater harvesting thereby increasing groundwater recharge.