Researchers from the National Cancer Institute warn that drinking water from older wells in New England appear to carry a higher risk of bladder cancer due to arsenic exposure.
In a study published this week in the Journal of the National Cancer Institute, researchers sought to explain why bladder cancer mortality rates have been elevated in New England over the last half century. The region, including Maine, New Hampshire and Vermont, has faced a 20% higher incident rate of bladder cancer than the rest of the U.S. over that time.
Researchers looked at 1,213 bladder cancer case patients from that region and compared them to 1,418 control subjects, looking at suspected risk factors. They estimated arsenic concentrations based on measurements from water samples from current and former homes.
According to the findings, the risk of bladder cancer increased with water intake, particularly from private, shallow, wells dug before 1960.
“If dug wells were used pre-1960, when arsenical pesticides were widely used in the region, heavier water consumers had double the risk of light users,” the researchers found. Our findings support an association between low-to-moderate levels of arsenic in drinking water and bladder cancer risk in New England. In addition, historical consumption of water from private wells, particularly dug wells in an era where arsenical pesticides were widely used, was associated with increased bladder cancer risk and may have contributed to the New England excess.”
The link between arsenic exposure and bladder cancer has been well-established. Arsenic is a known carcinogen that has also been associated with other harmful side effects such as skin lesions, developmental effects, cardiovascular disease, and diabetes.
“Arsenic is an established cause of bladder cancer, largely based on observations from earlier studies in highly exposed populations,” study author Debra Silverman, chief of the Occupational and Environmental Epidemiology Branch of the National Cancer Institute, said in a press release. “However, emerging evidence suggests that low to moderate levels of exposure may also increase risk.”
The researchers noted that the risk of exposure to arsenic from dug wells has decreased in recent years with the abolishment of arsenic-based pesticides.
The U.S. Environmental Protection Agency has set a maximum allowed arsenic level of 10 micrograms per liter for drinking water in the U.S.