Science

And this is early days. A report by the World Health Organisation (WHO) predicts that within a few years one in 10 adult deaths across much of southern Bangladesh could be from cancers triggered by arsenic. “Tens of millions of people are at risk,” the World Bank’s local chief, Pierre Mills, said last week.

The international community is gearing up to handle a health crisis that stretches across the border into the Indian state of West Bengal. On Tuesday, British geologists in Dhaka launched a six-month emergency project to uncover how and why the wells are poisoned.

“Within six months I hope we’ll have answers to a lot of questions,” said David Kinniburgh of the British Geological Survey. But much is already clear — and it is deeply embarrassing for Western scientists and engineers. For this crisis is entirely due to their failures.

Until the early 1970s, the 100 million-plus inhabitants of Bangladesh and neighbouring West Bengal drank from shallow hand-dug wells, rivers and ponds. But pollution was causing epidemics of cholera, and this persuaded aid agencies to spend tens of millions of pounds sinking tubewells — steel pipes fitted with simple hand pumps — to tap the plentiful, and apparently clean, water in the sands and silt of the Ganges floodplain. Following their example, villagers sunk many more privately.

Today there are an estimated 3 million tubewells in Bangladesh, providing 95 per cent of the drinking water. But until five years ago there was no record of tests for arsenic on any of those wells.

This was a bad mistake. National surveys unveiled at an international conference on the crisis, held in Dhaka last week, suggest 30 million people are drinking water containing more than 50 parts per billion of arsenic, five times the WHO’s recommended limit. And more than a million may be drinking water with a hundred times the limit.

“It frightens me to think how many people may be suffering,” says Dipankar Chakraborti of the School of Environmental Sciences at Javadpur University, Calcutta, author of the largest study and the man who uncovered the epidemic in India before discovering that its true heart was over the border.

His findings have been confirmed by Bangladeshi government scientists, who estimate that a fifth of the nation’s drinking water has more than 50 ppb of arsenic. Not only that, but arsenic concentrations in many wells is rising year by year, according to Salim Ullah Sayed at the National Institute of Preventive and Social Medicine (Nipsom).

Travel almost anywhere in the lush, heavily populated Bangladeshi countryside and you find victims. I went with doctors from the Dhaka Community Hospital, who first raised the alarm within Bangladesh, to Chandipur, a typical rice-growing village of 5,000 people in the south-eastern district of Laxmipur.

When the doctors checked 800 people here, they found 286 with the classic early symptoms of poisoning: melanomas on chest and hands; white skin blotches known as leukomelanosis; keratosis, painful warts that begin on palms and soles and gradually cover the body; acute conjunctivitis and breathing difficulties.

Here I met Malabar, a 10-year-old boy whose skin is speckled with white blotches. His friend Kawsar was covered in melanomas and keratosis. He appeared mildly deranged and could barely walk. “For these boys the prognosis is dreadful,” said Susan Evans, consultant dermatologist at Broadgreen Hospital, Liverpool, who examined 130 villagers with me in a morning and diagnosed symptoms of arsenic poisoning among most of them.

A woman, Kulsun, showed the ulcers on the soles of her feet. Abdul had sold all his land to buy useless treatment for his wife: “She used to be the most beautiful girl in the village,” he said. Safiq, an elderly man, asked me: “Please come and test my well to see if the water is safe.” But the evidence of his own body, skin blotched and eyes bloodshot and swollen, said it was not.

Several patients told us their relatives had died young showing similar symptoms. And Evans confirmed: “These skin conditions are just the outward and early signs. Many of these people will eventually die of internal cancers. What is most alarming is that, even though this is a cumulative poison, the children seem worse than their parents. ”

Of 166 wells sampled here recently, the average had 30 times the WHO arsenic standard. Six were a hundred times higher. “The people in these villages are very vulnerable,” says Chakraborti. “Working in the fields in hot weather, they drink five litres of water a day. And they consume more through water used to boil their rice.”

Chandipur is one village among thousands with similar stories. In Samta, in the south-western district of Jessore, only five out of 282 wells are safe. So far, 330 people have arsenic poisoning. I visited other villages where a third of the people had symptoms, and met people with amputated legs, gangrenous toes and gruesome melanomas.

Such evidence mocks the government’s claim, repeated by a minister last week, that it knows of only 2,000 cases. Especially when it turns out these are from 152 villages. The World Bank says 43,000 villages “are presently or could be in the future at risk”.

Last year, the WHO sent Allan Smith, epidemiology professor at the University of California, Berkeley, to report on the emerging crisis. He warned that it is only just beginning. Keratosis, the most unambiguous early symptom, takes 10 years to develop. “With large numbers of tubewells dug five to 15 years ago,” he wrote, “a major increase in the number of cases can be projected.” He predicted a doubling in the next two years.

Cancers take longer to emerge. Smith warned that in much of southern Bangladesh, a tenth of all adult deaths could soon be from arsenic poisoning.

The Bangladeshi government and Unicef stand accused of covering up the disaster to protect their tubewell installation programmes. Quazi Quamruzzman of the Dhaka Community Hospital, convenor of last week’s conference, says the government was told in 1985 that Bangladeshis crossing the border to India for treatment for skin complaints were being diagnosed with arsenic poisoning. A scientist at Nipsom told me the arsenic problem was known about in government circles in 1990.

Some foreign water engineers are contrite, though they stand to gain new contracts as aid pours in to alleviate the problem. Peter Ravenscroft of British consultants Mott MacDonald, who has spent 10 years installing tubewells here, admitted: “I’ve asked myself many times why I never thought to check the water for heavy metals. But you associate them with industrial pollution, not rural Bangladesh. And we knew of nothing like it elsewhere.”

“They damn well should have,” responded one geologist. “There are plenty of precedents if the engineers would read the literature. And don’t these guys ever do impact assessments on their projects? ”

Meanwhile the installation of wells goes on. Last Saturday, the Department of Public Health Engineering announced 286 new tubewells over the past six months in Munshiganj just south of Dhaka — a district where surveys suggest 80 per cent of well water is unsafe.

There is no effective treatment for arsenic poisoning, though doses of vitamins can relieve symptoms a little. For most Bangladeshis, the only chance of remission lies in finding alternative sources of clean drinking water. Late last year, the World Bank e armarked $50 million. The first task is to identify which wells are clean and which poisonous. But with roughly one tubewell for every four rural households that is a huge undertaking.

The Dhaka Community Hospital advises people to switch to surface water sources — the very sources abandoned a generation ago to halt cholera. Oxfam’s Enamul Haque says most of the hand-dug wells are abandoned and full of rubbish. But he says old technologies could be revived and improved, with simple sand filters to remove bacteria. And in a country with nine months rain a year, “harvesting” of rain falling on roofs could meet the drinking water needs of many households.

Many water engineers want to sink yet more tubewells, this time tapping deeper alluvium, which is currently arsenic free. But Chakraborti fears this will simply draw the arsenic down to the new wells. The arsenic content of water from one deep well in Samta village increased fivefold in six months.

In the 1960s, when foreign engineers came here to sink the first tubewells, villagers warned that this was “the devil’s water”. They did not know how right they were.

UNDERGROUND RIVERS OF ARSENIC

The arsenic currently poisoning Bangladeshis lurks in the fine alluvial sediments of the Ganges delta. It is tapped by tubewells sunk to depths of 20 to 100 metres — the great majority. Arsenic concentrations in well water vary widely even between adjacent wells. But geologists hope that if they can understand the chemistry that releases the arsenic from the sediments into the water, they may be able to advise on how to sink safe tubewells.

Dipankar Chakraborti of the School of Environmental Sciences at Javadpur University, Calcutta, believes much of the arsenic is bound up in pyrite minerals in the alluvium. He says heavy pumping lowers the water table and allows the depletion of oxygen, which oxidises the pyrites and releases arsenic into the water. “It’s a reasonable theory,” says David Kinniburgh of the British Geological Survey, except that most of the arsenic seems to come from layers that contain little oxygen. “It’s a reducing environment down there, not an oxidising one,” he says.

Even so, he agrees that pumping causes seasonal fluctuations in the water tables, and that that could be a factor in whatever chemical changes release the arsenic into the water.

Water movement underground could turn out to be the key. Hiroshi Yokota, geoengineering professor at Miyazaki University, Japan, believes arsenic poisoning is worst in wells sunk into ancient buried river channels, where there are often fast flows of underground water. He found one such underground “river of arsenic” beneath the worst affected part of Samta village.

[Next week: On the road with the arsenic taskforce]