Arsenic exposure appears to continue causing lung and bladder cancer deaths years after exposure ends, according to a recent Chilean study [1, 2].

The drinking water in a region of northern Chile became contaminated with very high amounts of arsenic beginning in 1958. In the 1970s, construction of water treatment plants led to a decline in arsenic concentration. This sudden rise and fall of arsenic levels gave researchers the opportunity to investigate the period between first and last exposure to high levels of arsenic and subsequent mortality due to arsenic-related cancers. Bladder and lung cancer death rates were investigated in the region between 1950 and 2000 and compared with data from a similar region farther south, where the water was not contaminated. 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, lung cancer deaths among men and women in the contaminated region were about three times higher than in the control region, while bladder cancer deaths were six times higher in men and 14 times higher in women.

The study is part of the University of California, Berkley's Arsenic Health Effects Research Program, which is conducting research in Argentina, Chile, India and the United States.

[1] Marshall, G. …. [et al.] (2007). Fifty-year study of lung and bladder cancer mortality in Chile related to arsenic in drinking water. Journal of the National Cancer Institute, vol. 99, no. 12, p. 920–928. DOI: 10.1093/jnci/djm004

[2] Lubin, J.H. .... [et al.] (2007). Inorganic arsenic in drinking water : an evolving public health concern. Journal of the National Cancer Institute, vol. 99, no. 12, p. 906–907. DOI: 10.1093/jnci/djm012

Contact: Allan Smith, Director, Arsenic Health Effects Research group, University of California, Berkeley, ahsmith@berkeley.edu, http://sph.berkeley.edu/faculty/smitha.html

Source: Liz Savage, Oxford Journals Jun 2007 ; Will Dunham, Reuters 13 Jun 2007

Tags: water quality, water-related diseases