MAC: Mines and Communities


Published by MAC on 2006-08-15



By Mike Hager (

(17 Juine 2007) A recent study by the University of Talca, "The Geographic Distribution of Cancer Deaths," found that six Chileans die each day of lung and tracheal cancer, and eight die of stomach cancer. And these cancer deaths are spread unevenly throughout the country. Residents of northern Chile are more likely to die from lung cancer, while southerners are at greater risk for stomach cancer.

The study singled out Antofagasta, Tocopilla and Mejillones in Region II as having abnormally high rates of lung cancer deaths. The study noted that cancer rates are high throughout Chile's northern regions, and suggested this may be due to prolonged exposure to arsenic.

Region II, Chile's second most northerly region, has for years been the center of the country's lucrative mining industry. Arsenic--odorless, colorless and poisonous--is both heavily used in mining and also found naturally in the area's soil and rocks.

Another study released this week by the U.S. Journal of the National Cancer Institute concluded that elevated levels of arsenic found in Region II drinking water have greatly increased residents' lung and bladder cancer deaths. The study was headed by the University of California, Berkeley, Professor Allan Smith, who worked with a team of investigators from Santiago's Universidad Catolica.

The region's drinking water saw a marked increase in arsenic concentration beginning in 1958 when residents began taking water from two highly contaminated rivers. The contamination was later much reduced, in large part thanks to water treatment plants built in the 1970s.

Still, the extended period of exposure produced long-term damage to millions of people. Researchers from Smith's report, "Fifty-Year Study of Lung and Bladder Cancer Mortality in Chile Related to Arsenic in Drinking Water," compared death records from 1950-2000 from Region II with Region V, where water was not contaminated. The study found that the rate of bladder cancer deaths were six times greater in men and 14 times higher in the women of the contaminated region. Lung cancer deaths were found to be three times higher in both men and women of Region II.

The researchers point out that the deaths started to increase ten years after the high arsenic exposure began and reached their peak in the mid 1990s nearly 20 years after contamination levels were brought under control.

Another study published in August 2006 by the magazine Environmental Health Perspectives also determined that arsenic found in the drinking water of northern cities in the 1960s is still affecting current residents.

It is too soon to know whether Region II residents will try to seek compensation from the government. In a recent landmark case, Chile's Supreme Court ruled that the state must compensate 356 residents of two slums in the northern mining city of Arica for health problems brought on by years of exposure to toxic waste (ST June 1).

Chile has one of the highest numbers of stomach cancer deaths in the world, surpassed only by Japan, Costa Rica and Singapore. These deaths occur far more frequently in Chile's southern regions. The regions most affected are Maule and Bíobío. Medical studies show that persons most at risk for stomach cancer are those from lower socioeconomic backgrounds, chiefly males and people of indigenous descent. The ingestion of nitrates (like those used in crop fertilizers) or salty and smoked foods greatly increase risk for this cancer.

Gloria Icaza, one of the authors of the University of Talca study, said not much is known about why this cancer is more prevalent in the south and more research is needed. "This is why we created the maps, to identify the problem areas," she said. "Now we have to make the decisions and focus the resources that will help to diminish the huge gap in healthcare that exists in this country."

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