BANGALORE: For good health, the quality of drinking water is critical. But in Karnataka, where much of groundwater sources are concentrated with fluorides and nitrates, the impact is devastating. Dental and spine-related ailments are showing up in many cities and villages.

In some of the fluoride-endemic districts like Kolar, Chitradurga, Gadag and Bellary, smiles on the faces of young children have vanished as they are afflicted by dental fluorosis.

The Bureau of Indian Standards' permissible limit for fluoride in drinking water is 1.5 mg/litre and for nitrates, the permissible limit is 45 mg/litre. Bagepalli taluk in Kolar has a fluoride concentration of more than 3 mg/litre. In Nellukudiri village of Bellary district, it is 5 mg/litre.

Dean and director, Government Dental College and Research Institute, Dr S S Hiremath, said: "More than 6% of the state's population is afflicted by dental flourosis. Children don't have proper teeth formation."

After years of consuming fluoride, when the spinal cord starts compressing and even before the cause for disability is known, the patient is paralyzed. This is a shocking condition in some fluoride-intense districts like Tumkur, where many people in a few villages have spinal cord-related diseases.

Several villages in Pavagada taluk in Tumkur district have fluoride concentration five times more than the permissible level.

Director of the National Institute of Mental Health and Neurosciences, Dr D Nagaraj, said: "Due to fluoride concentration in water, many people in districts like Dharwad and Tumkur have spinal cord diseases. These are progressive diseases, after decades of consumption. People are battling with permanent disabilities."

Groundwater is a major source of drinking water in rural Karnataka. But, due to lack of monitoring, the population is becoming a victim of water-borne diseases.

According to a mines and geology department study on excess chemicals in the state's groundwater, most districts where drinking water is supplied through borewells have a high concentration of nitrates and fluorides.

CAUSE & EFFECT

The main cause for increase in nitrates in groundwater is open sewage disposal and use of nitrogen fertilizers. Since rural sanitation in Karnataka is in a dismal condition, some districts like Gulbarga, Bijapur, Raichur and Tumkur have sanitation coverage below 20%. The presence of nitrates in water is evidence of such contamination.

Consumption of nitrates beyond the permissible limit is harmful to infants and also affects pregnant women and elderly persons. It causes methemoglobenamia or blue baby syndrome.

As arsenic particles in water cause psychological problems apart from skin diseases, Dr Nagaraj suggests all deep borewells should be systematically studied to tackle psychological diseases in the state.

NITRATES

• Desirable level for consumption is 45 mg/litre

• Majority of villages in state have concentration more than 100 mg/litre

• Some places in Bellary have concentration as high as 1,008 mg/litre