SECUNDERABAD:The National Geophysical Research Institute (NGRI) here has come up with a cost-effective way to deal with the fluoride problem in some parts of the state. It has successfully experimented with what is called ‘Artificial recharge through bore hole injection’ for the purpose.
According to Dr T Harinarayana a scientist at NGRI, the experiment has been carried out in Ranga Reddy and Nalgonda districts. The experiment involved digging of bore holes at points close to a well and draining the water, harvested and purified during the monsoons, into the underground water reservoirs. It was noticed that this water successfully diluted the underground fluoride-rich water, bringing it down from five milligram per litre to one milligram per litre.
This dilution effect spread to the surrounding underground water up to a radius of 22 metres in one year, Harinarayana said. Apart from the common dental fluorosis, skeletal fluorosis can also occur if the fluoride content exceeds the safety level of 1.5 milligram per litre of water. Skeletal fluorosis escapes diagnosis until the advanced stage, often too late for the crippled victim.
There are about 100 minerals known to contain fluoride and most are widely present in India. In AP, due to various geological reasons, excessively high fluoride levels have been recorded . In up to 17 districts, wells dug near granite rocks showed a presence of up to 3.1 milligram per litre fluoride.