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Arsenic in odd places: Researchers look into toxic metal mysteries

As many as one-fifth of the private wells in New Hampshire may contain arsenic concentrations above a new standard being proposed by the Environmental Protection Agency (EPA)—5 parts per billion (ppb)—and many are above the current standard of 50 ppb. That was the conclusion of a recent Dartmouth study analyzing the state's water records.

"New Hampshire is one of the sites in the country where there is very high arsenic [occurring] naturally in the drinking water," says Joshua Hamilton, Ph.D., an associate professor of pharmacology and toxicology. He is the director of Dartmouth's new Center for Environmental Health Sciences and of its Toxic Metals Research Program. Under the program's aegis, researchers from several DMS and Dartmouth College departments are collaborating with each other —as well as with state and federal agencies—to investigate the problem of arsenic in New Hampshire's drinking water.

Risk: Exposure to high levels of arsenic in drinking water— from 500 to 2,000 ppb—in places like Taiwan, India, and South America has long been linked to an increased risk of skin, lung, and bladder cancer, as well as of cardiovascular disease and diabetes. "What isn't clear yet is whether the slightly lower exposures we have here in the United States, even in places like New Hampshire, are also associated with risk," Hamilton says. Right now, the 50 ppb U.S. standard is five to ten times higher than the standard in most of the Western world.

Epidemiologist Margaret Karagas is one of a number of Dartmouth researchers investigating arsenic; she's looking to see if there's a connection between cancer rates and levels of the toxic metal in drinking water supplies.
Photo by Jon Gilbert Fox

There are several arsenic-related projects under way at Dartmouth:

Model: Hamilton hopes the arsenic initiative will serve as a model within the Center for Environmental Health Sciences for other multidisciplinary efforts. The center also plans to create a training program for undergraduate and graduate students and postdoctoral fellows, in order to "foster training, mentoring, and research opportunities for young scientists who are interested in interdisciplinary studies related to the environment and human health.

"[Students] want to work at these interfaces and do this new kind of science that isn't along traditional boundaries," Hamilton adds. "They want to do something that they feel has an impact on society."

Laura Stephenson Carter

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