Elevated Bladder Cancer Risk Tied to Arsenic in Water from Private Wells

Drinking water from private wells may have contributed to the elevated risk of bladder cancer observed in Maine, New Hampshire and Vermont.

A new study has found that drinking water from private wells, particularly dug wells established during the first half of the 20th century, may have contributed to the elevated risk of bladder cancer that has been observed in Maine, New Hampshire and Vermont for more than 50 years. Other risk factors for bladder cancer, such as smoking and occupational exposures, did not explain the excess risk in this region. The study—by researchers at NCI and colleagues at Geisel School of Medicine at Dartmouth; the departments of health for Maine, New Hampshire and Vermont; and the U.S. Geological Survey—appeared May 2 in the Journal of the National Cancer Institute.

Bladder cancer mortality rates have been elevated in northern New England for more than half a century. The incidence of bladder cancer in Maine, New Hampshire and Vermont has been about 20 percent higher than that in the United States overall. Rates are elevated among both men and women. A unique feature of this region is the high proportion of the population using private wells for their drinking water, which are not maintained by municipalities and are not subject to federal regulations. These wells may contain arsenic, generally at low to moderate levels. Previous studies have shown that consumption of water containing high concentrations of arsenic increases the risk of bladder cancer.

There are two possible sources of arsenic in the well water in northern New England. Arsenic can occur naturally, releasing from rock deep in the Earth, and arsenic-based pesticides that were used extensively on crops such as blueberries, apples and potatoes in the 1920s through the 1950s.