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Uranium in groundwater

Lack of a prescribed limit confusing the public
Dr G.S. Dhillon

http://www.tribuneindia.com/2009/20091030/science.htm#1

For quite some time the print media has been publishing tales of misery caused by high prevalence of cancer cases in the Bathinda district of Punjab. Cancer appears to have ‘spread’ on account of non-availability of clean drinking water. There have been 107 cancer cases in the Talwandi Sabo area and out of these 80 cases were women patients. At Ghari Bhangi village near Bathinda, 35 persons died on account of cancer during past 2.5 year and 20 odd patients are battling for life in the hospitals. Nearly 50 per cent of the patients have no means to support their treatment.


In the case of vi1lage Jaijal the level of uranium in groundwater has been found to be 63 ppb (parts per billion) or microgram per litre. The village pond is filled with filthy water, which is consumed by the cattle. This village used to get ‘filtered canal water’ but that has been badly contaminated by industrial effluent discharged by the infamous Budha nallah of Ludhiana and now contain contaminants like arsenic, selenium, mercury and chromium, which cannot be removed by the filtration process employed earlier.


The proposal to supply the village with clean RO water may not solve the problem because the type of RO unit to be adopted is not capable or removing contaminants like uranium. The water available in the neighbouring villages carry the uranium concentrations varying between 100 ppb to 145 ppb. So, their possibility of getting “clean water” by installing RO System is as bleak as in the case discussed above:


BARC experts tell the villagers and state that there is nothing to worry, even though the level of uranium is “slightly higher” than the permissible level (fixed by BARC) of 60 ppb. Dr, V.D. Puranik, Head of the Environmental Assessment Division Of BARC informed the media sometime back that according to recent tests carried out by BARC of the concentration of uranium in groundwater varied between :2 ppb to 244 ppb.


Dr S.K. Malhotra, Head of” Public Awareness Division of BARC, observed on July 27, 2009 that BARC had no plans to examine the groundwater in Punjab. According to him the Punjab was not the only site with high uranium concentration in groundwater.


What is the level of uranium which can be tolerated without creating any health hazard?’ The US EPA Health Standards for Clean Water fit for drinking purposes has fixed the limit at 20 ppb, which came to be revised upwards to 30 ppb in 2000. The earlier limit of 20 ppb was based on the consideration of preventing toxicity to the human kidney, but as the costs for lowering the levels to 20 ppb involved a price that was considered excessive compared to the health benefits made available, the US EPA stated that even with the raised limit, the safeguard against risk factors involved in the form of kidney toxicity and carcinogen city was still considered ‘adequate’.


Apart from the naturally occurring radionuclide materials (NORMs) in the earth’s surface, the leaching of fly ash deposits in the ash pond leads to elevation of the uranium levels in the groundwater resources. The solubility of uranium from fly ash gets accelerated when pH value of leaching water rises to a value above 8 i.e., alkaline state.


Once the uranium enters groundwater it travels fast from one location to another depending upon the water gradient. This fact is clear from the fact that near the Rajasthan Canal bank, the level of uranium concentration was 2-3 ppb and at some distance far off it rose to a very high value.


The daily intake of coal by two thermal plants is 44,000 tons, which will rise to 1,21,585 tons when the plants at Talwandi Sabo (1980 MW) and Giddarbaha (2640 MW) get going. Unless adequate precautions are taken e.g. fast disposal or fly ash for use by the cement and brick manufacturing, the piling up of the ash will only end up polluting the water in the surrounding regions.


The safe level of uranium in drinking water needs to be carefully fixed so as not to endanger the health of the people. Additionally, safeguards need to be built into our exiting and proposed thermal power plants to reduce the risks of uranium contamination of the ground water resources. Apart from the safe drinking water for human, we also need to consider the safety of the entire food chain involving livestock as well as the food-crops which would be using the pumped-out groundwater.



 

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