Unseen and untold: the mass-poisoning of an entire nation

Mohammed Yahia Khan wears a charm on his upper arm, and he will need all the powers it may possess to get through the weeks and months ahead.

Mohammed Yahia Khan wears a charm on his upper arm, and he will need all the powers it may possess to get through the weeks and months ahead.

Twenty-eight years old, formerly a student, Mr Khan comes from a village close to the Bay of Bengal in the far south of Bangladesh. He has been fighting cancer for five years. The disease was caused by naturally occurring arsenic in the ground water, pumped up through the tube well in his backyard at home.

Mr Khan is the face of Bangladesh's future. This tragic country, beset by famine and disease ever since its fiery birth less than 30 years ago, is confronting its biggest crisis ever: the accidental poisoning of as many as 85 million of its 125 million people with arsenic-contaminated drinking water.

In a new report, the World Health Organisation describes the crisis as "the largest mass poisoning of a population in history". "The scale of the environmental disaster", the report goes on, "is greater than any seen before; it is beyond the accidents in Bhopal, India, in 1984, and Chernobyl, Ukraine, in 1986."

For 30 years, following the lead of Unicef, the United Nations' children's fund, Bangladesh has sunk millions of tube wells all over the country, providing the mass of the people with a convenient supply of drinking water free from the bacterial contamination of the surface water that was killing one-quarter of a million children a year. Unfortunately, the water from the wells was never tested for arsenic contamination, which occurs naturally in the ground water, and for many years it was believed to be completely safe.

Only the fringes of the country are spared - the hilly areas of the north-west and Chittagong in the far south-east. Dhaka, too, its geology different from the surrounding areas, is unaffected.

One in ten people who drink the water containing arsenic will ultimately die of lung, bladder or skin cancer.

In a cramped research laboratory behind the ward where Mr Khan is being treated, a map shows in red the parts of Bangladesh where arsenic is a menace. Almost the entire country is coloured red. This does not mean that all tube wells in the danger areas are poisoned: in many villages, safe and toxic wells are found in close proximity.

Arsenic is tasteless, odourless, colourless, and taken in small doses in water has no immediate ill-effects. Like tens of millions of his countrymen, Mr Khan has been drinking the water and unwittingly ingesting arsenic for years.

Colin Davis, the Birmingham-born chief of Unicef in Bangladesh, said, "Twenty or 30 years ago, people were not looking for arsenic in ground water. It was something no one knew anything about. By sinking tube wells to enable people to drink ground water we were merely doing what everybody was doing, but we were better at it."

The first cases of arsenic-induced skin lesions were identified across the border in West Bengal, India, in 1983. The Bangladesh government and many international agencies have known the approximate size of the disaster for three years. Two years ago, the World Bank and others gave the government an interest-free loan of $44m (£30m) to begin tackling the crisis in the most urgent, simple manner - by providing an arsenic-free water supply to affected communities.

Yet two years on, the $44m remains unspent, while officials haggle over how to use it. In Dhaka there is no feeling that the government is gearing up to tackle a disaster. "There are 80,000 villages in the country," said a World Bank official. "So far the government has covered only 1,000. If they go on at this pace, it will take hundreds of years before they reach all the villages."

Arsenic poisoning is a slow-ticking time bomb. Skin cancer typically occurs 20 years after people start ingesting the poison. Caught early enough, skin cancer is treatable. The real danger is internal cancers, especially of the bladder and lung cancer, which are usually fatal. Dr Rahman said: "We have been told to expect an epidemic of cancers in the next 10 years. The victims will be people in their thirties and forties who have been drinking the water all their lives - people in their most productive years."

In the tree-shaded backyard of a corrugated iron shack in the district of Bera, five hours north-west of Dhaka, stands a prototype for a solution to the arsenic problem: a hulking cylindrical concrete water butt collecting rainwater by a pipe from the shack's gutters. Bangladesh's monsoon provides massive amounts of rain which has not traditionally been harvested for drinking. Slowly, in pilot programmes such as this, the long overdue effort is beginning.

Other possible solutions being tried out include a simple filter using three ceramic pots suspended above each other, and a pump set up by a pond or river in which the pumped-up ground water is filtered before emerging through a tap.

But not one of the solutions being implemented experimentally is half as convenient as the tube wells it is designed to replace. The government says there are four million tube wells in the country; the World Bank says there are "at least twice that number". They are easy to sink in this delta country's soft alluvial soil, and for tens of millions of peasants the wells have revolutionised access to water. Many households have several, as a Western house has taps in several different rooms. More are being sunk all the time - despite the looming disaster, the government has yet to declare a moratorium on new ones. Three-quarters of those in existence have been sunk by private enterprise. So popular have they become that a tube well is a common item in a bride's dowry.

The Bangladeshi government's task is now to stage a counter-revolution - to wean the people away from the most convenient innovation they have ever encountered. It is a disagreeable challenge, and the government has yet to show any appetite for it.

But unless they rise to the challenge soon, a disaster to dwarf Bangladeshi disasters past will become unavoidable.