Known in the arsenic
By Denis Delbecq • July 15th, 2008 in 10:41 · Category: Actuality
More than hundred million persons ingest too much arsenic, notably in Bengladesh and in India. A team of Eawag, a Swiss research institute on the water, tried to raise a card of risks which covers every the southeast Asia. Published in Nature Geoscience of July 10th, this modelling will allow to target the analyses of the water in the most threatened regions.
In Asia, millions of wells had been dug in the eighties, to struggle against diarrhoeic diseases caused by the bad quality of waters of surface. Often, the water of boring had been analysed but the arsenic had been forgotten. Millions of lives were saved by these virgin waters of bacteria. On the other hand, the arsenic, a true bomb has delaying, progressively polluted dozens million persons. In the long, the métallo¨ïde causes a hyperpigmentation of the skin, serious disturbances of the liver and of the kidney and some cancers.
The researchers of Eawag therefore undertook, on the basis of geological and topological data to identify the regions where the arsenic piled up in a natural way in the course of time and when it is likely to pollute waters in basement. The card shows a ten-kilometre precision. The model was then calibrated by confronting him with the data of 1750 samples of underground waters in the hang gliders of Mekong, of Bengal and of Red river. He gives likelihood, for every region, that the water contains more arsenic than the maximum value pointed out by the World Health Organisation (10 microgrammes by litre).
This cartography should allow big progress in the prevention of diseases linked to the arsenic. In Sumatra, the Swiss team determined a 100 000-kilometre zone of risk square. A hundred of samples performed on place confirmed the reliability of predictions. Concentration from 100 to 3000 microgrammes by litres was raised, ten - three hundred times more than value targets fixed by the WHO.
Two other zones risk of which was unknown were identified and their confirmed pollution: the hang glider of Irrawady (Burma) and the river of Chao Phraya (Thailand).
Picture: Stagnant Water © Denis Delbecq
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