Bladder cancer deaths continue decades after arsenic exposure

Arsenic exposure appears to continue causing bladder and lung cancer deaths years after exposure ends, according to a study published in the Journal of the National Cancer Institute (2007; 99:905).

Researchers from Pontificia Universidad Católica de Chile in Santiago, and colleagues, including collaborators from the University of California, Berkeley, investigated bladder and lung cancer death rates in northern Chile between 1950 and 2000. (Beginning in 1958, drinking water in the region became contaminated with very high amounts of arsenic before the construction of water treatment plants in the 1970s.) Researchers compared these death rates with those from a similar region farther south where the water was not contaminated.

Bladder and lung cancer mortality rates in the area with arsenic-contaminated drinking water began to rise about 10 years after arsenic levels rose. They then continued to climb, peaking between 10 and 20 years after the arsenic levels dropped. At the peak, bladder cancer deaths were six times higher in men and 14 times higher in women than in the control region, and lung cancer deaths among men and women in the contaminated region were about three times higher.

“The impact of arsenic in drinking water on this large population is without precedent for environmental causes of human cancer, and it points to the public health priority of ensuring that arsenic concentrations in drinking water are controlled worldwide,” wrote the authors, led by Guillermo Marshall, PhD, of Pontificia Universidad Católica.

In an accompanying editorial, Jay H. Lubin, PhD, and colleagues at the National Cancer Institute in Bethesda, MD, noted that many health-related consequences are associated with arsenic exposure and that millions of people in both developed and developing countries rely on water with arsenic levels that exceed the recommended limit of 10 µg/L, and that the public health consequences are not yet clear.