A study by the Central Groundwater Board has detected the presence of heavy metals in the groundwater of five districts of Tamil Nadu.
The study has revealed that the presence of metals like cadmium, lead and chromium in the groundwater was much beyond the limits permitted by the Bureau of Indian Standards (BIS).
The study says that groundwater in Dindigul, Tiruvallur and Kancheepuram have a lead content of more than 0.01 mg per litre.
Additionally, the chromium content in the water was also found to be above 0.05 mg per litre, according to a TNIE report. This is above the levels permitted by the BIS and amounts to contamination.
Cuddalore and Erode are two other districts where groundwater was found to be contaminated with chromium.
Dindigul is a district with a thriving tanning industry. Tanning or leader manufacturing factories are often said to release toxic effluents. One among the toxic effluents released by these factories is chromium which is produced as a result of the oxidation process used in the tanning industry.
The study reveals that groundwater in Tiruvallur is polluted by cadmium, another effluent produced by tanning factories.
Tiruvallur is a district in the suburbs of Chennai, 8.7 kms away from the city, and Dindigul is a mere 5 kms from the state capital.
Besides the fact that the study has found the presence of heavy metals, the water in several districts of Tamil Nadu is also highly saline (which is again not as per the permissible BIS limits).
Groundwater in 19 districts also contains fluoride levels of 1.5 mg per litre, according to the report.
Water in nine districts was found to be contaminated with arsenic and nitrate contamination was found in 27 districts of Tamil Nadu. Arsenic in water was found be above 0.01 mg/litre.