In the village of Chiladi in rural Bangladesh, the people draw their drinking water from wells instead of murky rivers and ponds. Health workers taught them that well water would keep them healthy, preventing them from getting cholera, diarrhea, and other water-borne illnesses. Instead, the well water may be killing them.

Three years ago the people of Bangladesh found out that much of the nation’s well water is contaminated with arsenic. While arsenic is a naturally occurring element found in the earth’s crust, if it gets into drinking water it causes several kinds of cancer; at high levels it causes blood- and nervous system— related illnesses. Suddenly, the world’s most densely populated nation found itself immersed in an environmental tragedy of mind-boggling proportions.

The arsenic crisis in Bangladesh is being called the worst case of mass poisoning the world has ever known. About 97 percent of the nation’s population--116 out of 120 million people--are drinking water from more than four million shallow "tube" wells installed by the World Bank, UNICEF, and other aid organizations in the 1970s and ’80s. Now it appears that up to 40 percent of these wells may be contaminated with arsenic, according to a recent United Nations Development Program survey. Therefore, anywhere from 20 to 60 million Bangladeshis could be drinking arsenic-tainted water; the estimates vary widely depending on the survey. Also, most of the surveys use the arsenic limit set by Bangladesh and the United States, which is 50 parts per billion (or .05 milligrams of arsenic per liter of water). If the World Health Organization limit of 10 parts per billion were used, the estimated number of Bangladeshis drinking poisoned water would be even higher.

When Richard Wilson, a physics professor at the School of Arts and Sciences, became aware of the arsenic problem in Bangladesh, he thought Harvard could help. Wilson contacted David Christiani and John D. Spengler, professors in the School’s Department of Environmental Health. In 1998 the Arsenic Project at Harvard took shape.

Christiani had the CV necessary to take the lead. He had spent years studying arsenic contamination in what became known as the "black foot" region of Taiwan (arsenic poisoning can cause black skin lesions). There he set up long- and short-term health studies and developed a reliable method of using toenails to measure arsenic exposure. Christiani had also conducted occupational health research in China, Africa, and Central America. So he came to the Arsenic Project with a sense of what kind of research would be most helpful to Bangladeshi and international health workers.

Envisioning a multidisciplinary approach, Christiani called on environmental health scientists, epidemiologists, and statisticians from the School; policy experts from the Kennedy School; physicians from Harvard Medical School; and engineers and geologists from Harvard, MIT, and the University of Connecticut. Right now, members of the Arsenic Project are working with their existing resources, but they’ve applied for a $10 million share of the $38 million the World Bank has allocated to address the arsenic contamination problem in Bangladesh.

Christiani has not yet been to Bangladesh, but he has a videotape produced by Dhaka Community Hospital that shows researchers traveling from village to village looking for telltale brown and white spots on the skin--the first signs of arsenic poisoning. When they get to the village of Chiladi, researchers find that "in every house, in every family, there are some arsenic patients." A young woman in a sari steps out of the gathered crowd and opens her palms to reveal brown spots. She tells the health workers that her family refused to take food from her hands. Finally, her husband left her, she said. The video also shows villagers with more advanced cases of poisoning, marked by rotten skin on the fingers, feet, and toes. Long-term exposure to arsenic can lead to bladder, skin, kidney, lung, and liver cancer, says Christiani. In Chiladi the villagers report that early death is common.

The challenge for the Harvard team has been to figure out exactly where their expertise is most needed. "We’re not a public health agency--we’re a research institution," says Christiani. "The questions were: what are our strengths, and what can we do best?"

With these questions in mind, the team has decided to work on several aspects of the problem. First they will use data from earlier arsenic studies to determine more precisely the level at which arsenic exposure triggers human health problems. This figure will help the Bangladeshi government decide which wells to shut down. Because preliminary data indicate that a diet rich in protein and vitamins can reduce arsenic levels in the body, Christiani is also proposing a clinical trial to test the impact of improved nutrition. In addition, the team is planning a longer term epidemiologic study looking at the incidence of hyperpigmentation (dark spots), hypopigmentation (white spots), and keratoses (skin lesions characteristic of arsenic poisoning) that are already evident; the skin cancers that are expected within a few years; and the bladder, lung, kidney, and other internal cancers that are anticipated after a 20-year latency period.

Timothy Ford, associate professor in the Department of Environmental Health, is the director of the Arsenic Project’s Program on Water and Health. Working with MIT researchers, he is studying the geochemistry of the area to collect information on ground water supplies. Nicholas P. Nikolaidis, an environmental engineer from the University of Connecticut, will be evaluating the technology available to remove arsenic from the water. Finally, Wilson and Bangladeshi staff member Tania Hakim will be coordinating a database of information on arsenic contamination and a Web site about the Arsenic Project: http://phys4.harvard.edu/~wilson/arsenic.html.

Hindsight tells Christiani that the crisis in Bangladesh might have been avoided. When the nation’s tube wells were first being drilled, the well water was tested for bacteria but not metals. And according to Christiani, the aid groups drilling the wells ignored a study published in the Lancet in July of 1976 ("Failure of Sanitary Wells to Protect Against Cholera and Other Diarrhoeas in Bangladesh") that called into question the effectiveness of wells in addressing the nation’s diarrhea problem--one of the major health concerns prompting the switch from polluted surface water to "clean" ground water. The data showed that oral rehydration programs were in fact having a far greater health impact. [See A Not-So-Simple Solution.] "They proceeded with the tube well program despite early studies that suggested it wasn’t necessary," he says.

So one of the hot-button issues likely to come up is whether Bangladeshis should begin using surface water again and fight diarrhea and cholera in other ways. According to Christiani, data collected by the Harvard Arsenic Project may help answer that question.

-- Tinker Ready