Arsenic Health Effects Research

Studies in a Unique Arsenic-exposed Area of Chile

Our new ecologic evidence from Northern Chile suggests that arsenic exposure in childhood or in utero could cause up to a 10-fold increase in adverse health effects in the lungs in young adults. This may be the first time that early-life exposure to a common environmental agent has been linked to high risks of adverse health effects in adult humans. Importantly, these data are preliminary and need to be confirmed. The highly unique arsenic exposure scenario in Northern Chile offers a rare opportunity to do this. Because almost everyone in Northern Chile obtains their water from large municipal sources, and past arsenic levels in all of these sources are well documented, arsenic carcinogenicity can be studied using exposure data that are much more accurate than anywhere else in the world. In addition, a very distinct 14-year period of high exposure in this area, with low exposure before and after, has created a population where tens of thousands of people were exposed to high arsenic levels only in utero or as young children offering a unique opportunity to study the long-term impacts of an early-life carcinogen with excellent data on past exposure. We propose a case-control study of 675 cases of lung and bladder cancer obtained over a three-year period using a rapid case ascertainment system involving all local pathologists. Controls will be obtained from the Chile electoral register containing 94% of the Chilean population. Dose-response relationships and other aspects of susceptibility will also be investigated. For example, we have found evidence that people producing high levels of monomethylated arsenic (MMA) have 2-5 times higher cancer risks than others, perhaps due to the highly toxic trivalent form (MMA3). Biological samples will be collected on all subjects and susceptibility related to metabolism, diet, genetics, and other factors will be investigated. Millions of people in the US are exposed to drinking water arsenic. But, current US arsenic regulations do not incorporate information on potentially susceptible subgroups despite the fact that cancer risks in these groups could be exceedingly high. The information gained from this project may help to determine if some groups, such as children, those who metabolize arsenic poorly, or those with poor nutrition, may need special consideration in regulatory standard setting. Information on MMA3, diet, and the future genetic and proteomic studies we will plan could add further insight into the co-factors and mechanisms of environmental carcinogenesis.

Chile Research Teams

Antofagasta Team

Arica Team

Iquique Team

Antofagasta Team:

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