Arsenic in New England Well Water Suspected Root of 50-Year Bladder Cancer Rise

More than half a million people in the United States are living with bladder cancer, many of them in northern New England. Specifically, residents of Maine, New Hampshire and Vermont have seen an elevated prevalence over the past 50 years. A new study published in the Journal of the National Cancer Institute (NCI) is now shedding light on why the risk for bladder cancer is 20 percent higher in those states than any other part of the country. It appears to all boil down to private wells and arsenic levels found in its water supply.

“Heavy consumption of drinking water from private dug wells, the shallow ones that were really common during the first half of the 20th century, may have contributed to this longstanding bladder cancer,” says Debra Silverman, chief of the Occupational and Environmental Epidemiology Branch, NCI, and senior author of the study.

Private wells are not maintained by municipalities or regulated by the federal government, so there is no way for a person to know how much arsenic is present, unless that person has his or her water tested.

While it is widely known that high levels of arsenic can cause bladder cancer, not much research has been done regarding low to moderate levels of the element.

Researchers at the NCI, part of the National Institutes of Health, and colleagues at the Geisel School of Medicine at Dartmouth; the departments of health for Maine, New Hampshire and Vermont; and the U.S. Geological Survey compared 1,213 people newly diagnosed with bladder cancer living in Maine, New Hampshire and Vermont with 1,418 people without bladder cancer who lived in the same geographic areas.

A significant find in the study was that those who drank the most water from private wells had almost twice the risk of bladder cancer than those who drank the least. This association was stronger if dug wells had been used. “When the levels are low, like in the northern New England population, the water intake, an individual’s water intake becomes very important in estimating their exposure accurately,” says Silverman.

“We have no water measurements from the first half of the 20th century, so we can only piece together what we think may have happened. No one was concerned about arsenic in the well water in the first half of the 20th century in Northern New England.”

Researchers explained in the study that there are two possible sources of arsenic in the well water in that region. The first is it can be released naturally from rock deep in the earth. The second could be contamination from arsenic-based pesticides, which were commonly used in the 1920s until about 1960. The pesticides were used extensively on crops such as blueberries, apples and potatoes.

In addition to arsenic, there are several other risks for bladder cancer that individuals can avoid. The first is to not smoke cigarettes, which is the no. 1 cause of bladder cancer. Individuals can also limit themselves to workplace exposures and by drinking enough fluids to flush out their bodies. However, age, gender and family history can’t be changed. Silverman explains that smoking and workplace factors in the studied northern New England population were similar to those in other populations, meaning there was another reason for the rise in bladder cancer — leading the authors to their findings on the low to moderate levels of arsenic in the private well water. There is hope for those diagnosed with bladder cancer, but Silverman says they have to be vigilant and regularly checked by a physician.

“A lot of people with bladder cancer are living with it because it has a good survival rate, 74 percent for 10 years. The thing is they need to be seen over and over again for surveillance because it has such a high probability of recurrence,” explains Silverman.

Silverman also advises that everyone who drinks from private wells should get their water tested by a state-accredited lab — if they have elevated arsenic in the water, they should have a filter installed.