Fluoride in drinking water in Nalgonda district is no longer news. It’s been a problem for ages. What is news is the presence of uranium in the water far beyond maximum permissible levels as prescribed by international agencies. The presence of dissolved uranium in ground water in several villages of fluoride-hit Nalgonda has come as a shock to health experts who are aware of drinking water containing high levels of fluoride, and have thus treated people for fluoride contamination. They now have to take into account the fact that people living in this backward district have also been drinking water with dangerous levels of uranium.

Nalgonda is known to contain huge deposits of radioactive uranium. Three different research teams collected and tested the ground water samples: the Health Physics Unit of Nuclear Fuel Complex in Hyderabad, the Centre for Environmental Science and Engineering of the Indian Institute of Technology, Kanpur, and the Department of Geology of Anna University, Chennai. The areas surveyed were Devarakonda, Nagarjunasagar reservoir, Peddagattu, Lambapur and Seripalli.

“Most of the villages in Nalgonda district depend on ground water for their drinking water needs. Though the ill-effects of fluoride have been manifest in the form of crippled limbs and bent backbones, it’s not clear what harm the dissolved uranium has caused to these poor villagers. Now that dissolved uranium has been discovered in ground water, health experts will be forced to undertake studies to find out whether the radioactive element has caused damage to the kidneys, the organ most likely to be poisoned by uranium intake,” said social activist Mr V.S. Narayana.

In one test, 456 water samples were collected from 45 wells in Peddagattu and Seripalli villages by the NFC team. The samples were checked for uranium concentration using laser fluorimeter. Uranium of between 0.2 parts per billion (ppb) to 118.4 ppb was found in the samples. One out of five samples had uranium concentration in excess of 30 ppb, the limit fixed by the United States Environment Protection Agency. The highest uranium concentration was recorded in Seripalli area.

In Lambapur, ground water samples were collected from 14 wells including a dug well and a bore well, by the team from Anna University.

At another place uranium concentration in ground water ranged from 0.1 to 82 ppb. Thirty-one per cent of 48 samples analysed, contained uranium higher than the permissible limit of 30 ppb.

In Devarkonda and Peddagattu region, the teams, including one from the Environment Assessment Division of the Bhabha Atomic Research Centre, Mumbai, found that the average concentration of uranium in the rocks was 0.044 per cent.

It is the dissolution of uranium from these rocks that has resulted in ground water contamination. Ground water samples were collected from 42 wells, and one from the Nagarajunasagar dam. The uranium concentration in the samples varied from 2 ppb to 55 ppb, with Nagarjunasagar recording 4 ppb. The Bureau of Indian Standards’s specifications for drinking water do not mention uranium. Perhaps the BIS did not expect the radioactive element to be present in water in the country.

Uranium seeps into the water table with rain water that conveys it from uranium-rich granite rocks. The senior scientist Dr K. Babu Rao, said, “Nalgonda has uranium-rich granite rocks and it is from these rocks that uranium seeps into the ground table whenever it rains.”

According to the research teams, uranium is one of the most common radionuclides in soils, sediments, and ground water at radionuclides-contaminated sites. At these contaminated sites, uranium leaches into the ground water. This has become a widespread problem at mining and milling sites around the world. The problem will worsen in Nalgonda once the Uranium Corporation of India Ltd begins mining activity here. Uranium is already being mined in Kadapa district where large-scale ground water studies are yet to be taken up. “Uranium cannot be detected by taste, sight or smell, so its presence can be detected only through sophisticated laboratory tests, which are not accessible to the general public,” observes Dr Babu Rao. Fertilisers used in agriculture may also lead to uranium concentration in ground water.

An alarming fact is that uranium contamination in ground water is not a localised problem. As ground water flows, so does the uranium it contains. It means that if uranium is found in ground water in Nalgonda, it can be found in places far away from it that may not themselves have uranium rich deposits.

Scientists developed models to find out whether uranium contamination in Nalgonda could move to the nearby Krishna river. And they found that it is possible over a period of time. The process can also be stopped through certain effective preventive measures. BARC scientists proposed a ground water modelling to understand the ground water flow regime around the proposed uranium mine site at Lambapur-Peddagattu. They predicted the movement of ground water and particles in the region for the next 15 years.

Their report concluded: “According to the simulation model, it will take more than 15 years for the particles from the proposed mine sites at Peddagattu to reach the Nagarjunasagar. And when this happens, it will be catastrophic for the health of millions of people.