Death from Cancer Remains High Decades after Exposure to Arsenic is Reduced

Allan H. Smith, MD, Ph.D.
University of California Berkeley
R01ES10033 and P42ES004705

Death rates from lung and bladder cancer remain high decades after residents of northern Chile were exposed to high levels of arsenic in their drinking water according to a report in the June 12 issue of the Journal of the National Cancer Institute. The study was conducted by NIEHS-supported researchers at the University of California Berkeley along with their colleagues at the Pontificia Universidad Católica in Chile.

The northern region of Chile draws much of its water supply from arsenic contaminated rivers originating in the Andes. Until 1958 the water supply for the largest city in the region, Antofagasta, contained about 90 micrograms of arsenic per liter. To satisfy the growing population in the region, additional water was drawn from the Toconce and Holajar rivers, which contained much higher levels of arsenic. As a consequence, from 1958-1970, the municipal water supply for this region averaged 870 micrograms arsenic per liter, nearly 90 times the current U.S. EPA standard. The world’s first large-scale arsenic removal plant was opened in Antofagasta in 1971, but by then, residents had been exposed to high levels of arsenic for 13 years.

The researchers analyzed cancer deaths in the high arsenic area region and compared them with another region in Chile with similar demographic characteristics but with low arsenic exposure. They found that lung and bladder cancers mortality rates started to increase in 1968. The mortality continued to rise, peaking between 1986 and 1997 with combined lung and bladder cancer death rates of 153 per 100,000 men and 50 per 100,000 women; rates over 2.5 times higher than in the area of lower arsenic exposure.

This study points out the need for more testing of the world’s water resources. The results show that the health risks of consuming arsenic contaminated drinking water are very high and long lasting.

Citation: Marshall G, Ferreccio C, Yuan Y, Bates MN, Steinmaus C, Selvin S, Liaw J, Smith AH. Fifty-year study of lung and bladder cancer mortality in Chile related to arsenic in drinking water. J Natl Cancer Inst. 2007 Jun 20;99(12):920-8.