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The best way to communicate with people in villages in Bangladesh is to hold a fair. So when Columbia researchers and their Bangladeshi colleagues wanted to transmit a critically important message, they followed local custom and organized village festivals, bringing in clowns for the children and folk singers for the adults.

The performers were actually public health educators who used this medium to teach adults and children which village wells contained water safe enough to drink. This public health education effort is only one small part of a multidisciplinary Columbia University project aimed at helping Bangladesh solve, or at least control, its massive water supply contamination problem.

"Bangladesh's drinking water is one of the world's most hazardous because of the presence of arsenic," says Dr. Joseph H. Graziano, professor of environmental health sciences at the Mailman School of Public Health, professor of pharmacology at P&S and associate dean for research at the Mailman School. "An estimated 40 million people, roughly 30 percent of the population, are currently exposed to poisonous levels of arsenic in well water supplied by about 10 million hand pumps."

Arsenic is a carcinogen associated with bladder, lung, and liver cancer and tumors on limbs. People exposed to high levels over time typically develop skin lesions on their hands and feet that, in severe cases, can lead to amputation. It also affects the cardiovascular system and raises the risk of stroke, diabetes, and neurological problems. Arsenic poisoning also stigmatizes people. Some of those affected are shunned by their families because of fear they are contagious or cursed.

Ironically, the current, grave problem in Bangladesh stems from efforts to solve an earlier water pollution problem. In 1970, at the time Bangladesh became independent from Pakistan, Bangladeshis were collecting drinking water from microbially contaminated lakes and rivers. This led to high levels of often-fatal diarrhea, cholera, and typhoid. UNICEF in the early 1970s tried to help Bangladesh by drilling millions of shallow wells, a move that drastically reduced the spread of gastrointestinal diseases. Unbeknownst to UNICEF, however, the groundwater in many places contains naturally occurring high concentrations of arsenic.

Dr. Graziano is leading the six-year, $10.4 million research and intervention project. The effort, now in its fourth year, is part of the U.S. government-funded Superfund Basic Research Program, which supports efforts to study and clean contaminated sites. The collaborative project brings together scientists from the Mailman School, P&S, Columbia's Lamont-Doherty Earth Observatory, and Dhaka University in Bangladesh. Some of the key collaborators are Dr. Habibul Ahsan, associate professor of epidemiology at the Mailman School; Dr. Alexander van Geen, Doherty Senior Research Scientist at Lamont-Doherty; and Dr. Tom Hei, professor of radiation oncology at P&S and environmental health sciences at the Mailman School.

The project includes two public health studies – one that is tracking 12,000 people to define the health effects of arsenic exposure and another that studies the effect of arsenic on pregnancy and child development. The project also has two basic science research studies – one that looks at how much lead and arsenic in soil are absorbed by people and another assessing how arsenic causes genetic damage in mammalian cells.

"We want to determine what dose of arsenic is associated with disease and the biological mechanisms involved that enable arsenic to cause cancer and neurologic disease," Dr. Graziano says. "We are also developing strategies for medical and nutritional intervention."

One of the first things the researchers did in Bangladesh was to select a small but representative section of the country. They chose a 25-square-kilometer area with 6,000 wells that serve 70,000 people. They analyzed samples from each well and mapped their locations and arsenic concentrations using global positioning system (GPS) equipment. They also placed labels on the wells – showing arsenic levels and whether the water is safe to use – and encouraged residents to switch to the safe wells.

But that was just a short-term solution. To make sure communities have access to cleaner water, the researchers are supervising the installation of deep wells that tap safe groundwater. So far, they have completed 50 deep wells and plan to dig more.

"We are finding that by consuming the safer water, especially from the new deeper wells, people have dramatically less arsenic in their bodies, as indicated by lower arsenic levels in their urine," Dr. Graziano says.

Although the health studies are not completed, the researchers are finding that arsenic affects child development, causing cognitive deficits.

Now, the researchers are focusing on helping Bangladesh deal with the problem on a countrywide basis, rather than just in one small section. With encouragement from Dr. Jeffrey Sachs, director of Columbia's Earth Institute, who, along with Lee Bollinger, president, Columbia University, and Dr. Allan Rosenfield, dean of the Mailman School, visited Bangladesh, the researchers have drafted recommendations for a strategic plan to fix the water supply problem across the entire country within five years.

Such efforts are especially important to South Asia because there are high levels of arsenic in groundwater from eastern India to Vietnam. "We hope our findings will help developing countries ensure that their people have water that is safe to drink," Dr. Graziano says. "We also hope the research will assist in U.S. and international policy decisions in protecting water supplies globally."

The research is supported by the NIH's National Institute of Environmental Health Sciences as well as Columbia's Earth Institute, the Mailman School of Public Health, and the Lamont Investment Fund.

—Matthew Dougherty