Dharmapuri district has a high concentration of endemic fluoride and ranks the highest in the State. According to a recent survey by the Tamil Nadu Water and Drainage (TWAD) Board, out of 10,451 handpump sources, 3161 were found highly fluoride contaminated. Sources in the board say “around 30 per cent of the water sources in Dharmapuri and Krishnagiri were found fluoride contaminated when compared with the state average of 6.9 percent.”

Pennagaram and Palacode taluks in Dharmapuri district and Kaveripattinam and Bargur account for the highest concentration in Krishnagiri district. As many as 1,028 identified habitations in Dharmapuri and Krishnagiri have been provided with alternative drinking water supply.

“Failure to conserve rainwater and excessive depletion of groundwater have led to the high concentration of fluoride in the district,” say the sources. While the permissible level in drinking water is 1-1.5 mg per litre, certain habitations have even 9 mg per litre, which causes dental, skeletal and non-skeletal fluorosis.

According to Health department sources, “dental fluorosis occurs mainly due to heavy ingestion of fluoride from the foetal stage up to 12 years.” When pregnant women drink fluoride-infected water, the foetus also gets affected. Skeletal and non-skeletal fluorosis is characterised by pain in bones and joints, stiff back, burning sensation, muscle weakness, chronic fatigue, gastrointestinal disorders and loss of appetite.

Health officials say fluorosis is permanent for life. They have urged the public to drink only boiled water, as fluoride cannot be removed. The TWAD board sources are hopeful of the efficacy of a new process of deflourination of contaminated water through reverse osmosis, by which tiny fluoride particles will get segregated. The project is in initial stages and awaits approval.

As of now, immediate implementation of the Rs.1,100-crore Hogenakkal drinking water scheme is the only option for the residents of Dharmapuri and Krishnagiri, say the sources.