Wednesday, 3 August 2011

After fluoride, it's now uranium in drinking water of Nalgonda district: Uranium dissolved in ground water exceeds maximum permissible limits

By Syed Akbar
Hyderabad: Fluoride in drinking water in Nalgonda district is no more news. The problem of fluoride has been there for ages. But what has now emerged as shocking news is the presence of uranium in Nalgonda waters in limits far exceeding the maximum levels prescribed by international agencies.
The presence of dissolved uranium in ground water in several villages of fluoride-hit Nalgonda has shocked health experts. What doctors so far know is that people in Nalgonda have been drinking water containing high levels of fluoride, and thus, their medical prescription is limited to treatment of health issues related to fluoride contamination. But they are unaware that the water is polluted with uranium too. That dissolved uranium is present in higher concentrations in ground water now warrants a change in doctors'
prescription for thousands of villagers living in this backward district.
Nalgonda is known to contain huge deposits of radioactive element uranium, but what many did not know that it's ground water is polluted by this radioactive element. Researchers in their curiosity to find out whether the presence of uranium deposits has any impact on the ground water, collected a number of samples and analysed them in high-end laboratories. The tests revealed the presence of uranium. Then they selected more areas and repeated the tests. The results were the same: uranium was found dissolved in ground water.
"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 take up studies to find out whether the radioactive element has caused any damage to kidneys, the organs most likely to be poisoned by uranium intake," points out social activist VS Narayana.
Three different teams worked on the water samples. One of the teams was from the Health Physics Unit of Nuclear Fuel Complex in Hyderabad. The other two teams were from the Centre for Environmental Science and Engineering, Indian Institute of Technology, Kanpur, and the department of geology, Anna University, Chennai. The areas surveyed were Devarakonda, Nagarjunasagar reservoir, Peddagattu, Lambapur and Seripalli.
In one test, as many as 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 was found between 0.2 parts per billion (ppb) to 118.4 ppb. One out of five samples had uranium concentration in excess of 30 ppb fixed by the United States Environment Protection Agency.
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. Out of 48 samples analysed 31 per cent had uranium higher than the permissible limit of 30 ppb. Uranium concentration is related to the bicarbonate in ground water.
In Devarkonda and Peddagattu region the teams including from the Environment Assessment Division, Bhabha Atomic Research Centre, Mumbai, found that the average concentration of uranium in these 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, besides a sample from the NS dam. The uranium concentration in ground water varied from 2 ppb to a maximum of 55 ppb. The highest uranium concentration was recorded in Seripalli area. The concentration of uranium in Nagarjunasagar was 4 ppb.
The presence of uranium in Nalgonda water samples may also come in as a surprise to the Bureau of Indian Standards. Perhaps the BIS did not expect the radioactive element to be present in water in the country, as the Indian standards specifications for drinking water fixed by it fails to specify any
maximum permissible limit for uranium.
How does uranium seep into the water table? Senior scientist Dr K Babu Rao says whenever it rains, the rain water carries the uranium with it to the ground water table. The higher the rainfall the higher the contamination. Uranium moves from unsaturated areas and this results in higher concentration of uranium as the water table increases. "Nalgonda has uranium-rich granite rocks and it is from these rocks that uranium seeps into the ground table whenever it rains," he clarifies.
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, which has become a widespread problem at mining and milling sites around the world. The problem will persist in Nalgonda too once the Uranium Corporation of India Limited takes up the mining activity. Already mining is going on in Kadapa district, where largescale ground water studies are yet to be taken up.
"As uranium cannot be detected by taste, sight or smell, it's presence can be found out only through sophisticated laboratory tests, which are not accessible to the general public," observes Dr Babu Rao. The use of fertilisers for agriculture may also lead to uranium concentration in ground water.
The research studies have also shown that uranium contamination in ground water is not a localised problem. Since the ground water has a movement, the uranium concentration also moves along with it. It means if uranium is found in ground water in Nalgonda, it can be found in places far away from it,
where there's no perceptible presence of the nuclear element.
Scientists also developed models to find out whether uranium contamination in Nalgonda can move to the nearby Krishna river. And they found that it's possible, though 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 in and around the proposed uranium mine site at Lambapur-Peddagattu area. They predicted the movement of ground water and particles in the region for the next 15 years.
"Ground water modelling of Nalgonda region indicates that the ground water occurring in the weathered rocks flow towards the Nagarjunasagar reservoir. The simulation carried out until the year 2017 suggests that there is not much change in the ground water flow regime, with the assumed condition of no change in the ground water pumping during mining  activity," BARC scientists said in their study.
As ground water is expected to move towards Nagarjunasagar, it takes more than 15 years for the particles from the proposed mine sites at Peddagattu to reach the water body. And when this happens, the it will be a great catastrophe for the health of millions of people, who source their drinking water from the Nagarjunasagar and the Krishna river downstream. 


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Fact File
==========
* India does not have any standards on dissolved uranium in drinking water. However, the US standards are 30 parts per billion.

* Ground water in many places in Nalgonda district has uranium content in excess of the maximum permissible limits. In some places it goes up to 118 ppb.

* As ground water has a movement, uranium content also moves. Scientists from Department of Atomic Energy have found that the movement of ground water containing uranium in Nalgonda district is
towards the Nagarjunasagar dam, and thus into the river Krishna.

* High content of uranium in drinking water causes damage to kidneys. Since Nalgonda has both fluoride and uranium contamination, doctors need to revise their prescription including uranium detox methods.

* Full fledged scientific studies are yet to be taken up in Nalgonda villages to find out the exact impact of dissolved uranium on people's health. Many villages depend on ground water for their drinking water
needs.

* In one sample analysed from Nagarjunasagar by researchers, it was found that the reservoir water had 4 ppb.

* Uranium content in ground water varies from season to season. As the water table goes up in monsoon, the concentration of uranium also goes up.


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