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Arsenic on tap
Posted: 28 Feb 2003
by Inam Ahmed and Aasha Amin
Arsenic poisoning is contaminating underground water supplies across northern Bangladesh and threatening the lives of millions. (Since this article was written, further evidence of arsenic poisoning further afield in Northern India has come to light - see box below). Inam Ahmed and Aasha Amin report.
There is a cloud of gloom overpowering the otherwise sleepy town of Samta in Jessore, a northern district of Bangladesh. Almost every home you visit there has a child or adult suffering from a mysterious disease. Many have died and the villagers have lost count of the casualties, most of them small children. The symptoms are frightening: watery eyes, chronic indigestion, colds and stomach cramps in the early stages and swollen limbs with bleeding gangrene-like wounds in severe cases. This silent killer is arsenic which has contaminated the drinking water of many villages in northern Bangladesh.
Boy suffering from arsenic poisoning, Bangladesh
© Benagari Chuadanga
Runu, 12, of Samta village, has a strange pigmentation on her skin due to keratosis, a constant runny nose and difficulty in breathing - all tell-tale signs of arsenic poisoning. Within the last five years, it is not only her health that she has lost. Both her parents and two brothers have died from the disease.
“I used to go to school when my parents were alive,” says Runu looking quite lost, “my mother used to dress me, braid my hair and send me to school everyday. I never slept without holding her hand.”
Now, Runu struggles to survive working as a maid for a family which has also been affected by arsenic poisoning: other families refused to employ her. Her parental home is in ruins. Nobody lives there anymore.
In fact, children are the worst victims of arsenic poisoning says Dr Mahmudur Rahman of Community Hospital in Dhaka, the only organisation so far, to carry out an investigative survey of the problem. “Children under 15 constitute 45 per cent of the population,” comments Dr Rahman, “which means that out of the 50 million feared affected almost 20 million are children.”
According to Dr Rahman, those children who are affected, have been consuming arsenic, through water, from a very early age. “Moreover,” he says “in the countryside most children are poor and undernourished, which makes them more vulnerable to poisoning. Those who have reached the keratosis stage of poisoning cannot be saved,” adds Dr Rahman, “fortunately most of the children have not yet reached this stage and there is still time to cure them through proper treatment.”
Black spots on the hand indicate the final fatal stage of the disease
© Benagari Chuadanga
But while early diagnosis and treatment may help the affected children, immediate measures must be taken to stop further contamination. According to the World Health Organization, (WHO), the maximum allowable arsenic content in water is .01mg in every 1000CC of water. In the arsenic hit areas this is as high as 2.7mg for every 1000CC of water. So far, the government has done little to address the problem.
Dr Dipankar Chakravarti, Director of the School of Environmental Studies, Jadavpur University, has done an intensive study of arsenic poisoning both in West Bengal and Bangladesh. He says more than 50 million people across Bangladesh are at risk while thousands already show symptoms of poisoning. In severe cases, victims develop lesions that cause parts of the body to degenerate and break off. Others have cancer or serious liver damage.
Socially, too, the victims suffer. Treated like lepers villagers shun them and prevent them from taking water from uncontaminated tube wells. Says Badsha, 16, who has already developed keratosis, “My friends don’t play with me anymore because they are scared that they may catch the disease.”
In 1993, Dr Chakravarti reported his findings to the Bangladesh government and WHO but his warnings went unheeded. It was only much later when other experts as well as the media brought the horrifying stories to the surface that the government began to take notice.
Some hand tube wells were sealed off but villagers began to re-use them as alternative water sources were too few. Of the 34 districts from where water samples were collected, 22 had high levels of arsenic.
Experts have suggested a three-pronged action plan to address the problem. First of all, arsenic contaminated tube wells must be sealed off, public awareness has to be raised and people have to be persuaded to use alum water to neutralize the effect of arsenic. Secondly, ponds have to be identified and reserved exclusively for drinking water and the wasting of underground water from deep tube wells (one of the causes of rapid spread of contamination), has to be stopped.
Finally, the government will have to initiate watershed management to ensure safe ground water supplies to villages. Comprehensive studies have to be done to find out factors such as why one family is affected while another seems to have developed immunity to the effects of the contamination.
While the government deliberates on checking the contamination, time is running out for the people of the northern districts. Unless something is done right now there will be many more human tragedies.
Inam Ahmed and Aasha Amin are feature writers on the staff of the Daily Star, Bangladesh.
WHO on arsenic in drinking water
Scientists have not been able to decide on the exact cause of arsenic contamination in Bangladesh, West Bengal, and other parts of the subcontinent. New cases of arsenic poisoning in India's Ganges Basin now suggest that the crisis in the sub-continent could extend much farther than previously thought.
According to Dr Atiq Rahman, Director of the Bangladesh Centre for Advanced Studies, some of the geological layers of the soil have minerals containing arsenic. Thus over-irrigation of the deep tube wells may result in soil erosion that exposes the layer to oxygen. When oxygen gets mixed with the arsenic it will enter the water and so contaminate it.
But there are irregularities regarding this theory. It has been found, for example, that while one tubewell’s water has high levels of arsenic, another only 100 yards away is not contaminated. “We do not know enough about the cause,” says Dr Rahman, “the only thing that is certain is that it is geological in nature.”
The simplest method suggested of reducing the arsenic level in drinking water is the age-old use of filtering the water. This method, however, has not proven to be very popular among people because of the time it takes.
The latest surveys estimate that around 36 million people in the Bengal Delta are drinking contaminated water, and 150 million are at risk.
In 2002, arsenic was found in village wells in the Indian state of Bihar, 500 kilometres west of the Bengal delta. Bihar is geologically akin to much of the Ganges Basin. Arsenic-rich deposits could cover much of the Basin, stretching across the foot of the Himalayas from New Delhi to the Bay of Bengal.
Researchers believe that, as in Bengal, hand-pump wells, dug to provide drinking water that is free of waterborne diseases, tap into natural accumulations of arsenic swept down from the Himalayas and deposited in the silty aquifers of the Ganges Basin.
The new finding suggests that the Bengal Delta may be only the tip of the iceberg and that untold numbers of the region's 449 million residents could be exposed to dangerous levels of the element in their drinking water. Arsenic-contaminated groundwater has also been reported in Nepal, some 200 kilometres to the north of Bihar, and there are unconfirmed reports of arsenic in the water in Chandigarh, north of New Delhi.
The new finding suggests that similar arsenic contamination in Vietnam, Thailand and Taiwan could also be more widespread, suggests geochemist Andrew Meharg of the University of Aberdeen, UK. "Wherever people look, they seem to find arsenic elevation in these deltaic aquifers," he says.
See: Chakraborti, D. et al.: Arsenic groundwater contamination in Middle Ganga Plain, Bihar, India: a future danger? in Environmental Health Perspectives Online.