is particularly prevalent in Region II, a province in the north of Chile and one of the driest places on earth. In 1958, the cities there of Antofagasta and neighboring Mejillones tapped into arsenic-laden rivers to supply their growing populations with water. For the next 13 years, until an expensive arsenic removal plant was installed, the water supply for all residents in the cities was laced with an average of 860 micrograms per liter of arsenic. In contrast, the standard for arsenic in drinking water in the United States was recently dropped from 50 micrograms per liter to 10 micrograms per liter, with compliance required in 2006. (A microgram is a millionth of a gram.)
With such clear-cut exposure to arsenic, the unfortunate Chilean cities became a tragic natural experiment for studying the effects of arsenic on humans.
From earlier work he and others conducted in India, Smith knew that arsenic is associated with bronchiectasis, a rare lung disease that causes distortion and dilation of the bronchi, eventually leading to chronic infections. A study involving death certificates for young adults in Antofagasta and Mejillones, Smith realized, would reveal whether lung cancer and bronchiectasis could also occur as a result of childhood exposure to arsenic.
Working with colleagues Guillermo Marshall and Catterina Ferreccio from the Pontificia Universidad Catlica de Chile in Santiago, Smith compared the death rates from 1989 to 2000 of young adults in the two cities with the rates in the rest of Chile, outside of Region II. The team focused on two groups: those born between 1951 and 1958, when the water supply to the cities had relatively low arsenic concentrations, and those born during the high-exposure period of 1958 to 1971.
Both groups, they reasoned, would have been exposed to high levels of arsenic throughout some or most of their childhoods, but the second group would also have been exposed in utero, that is, while in the womb. Exposure Page: 1 2 3 Related medicine news :1
Contact: Liese Greensfelder
University of California - Berkeley
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