National Academy of Sciences (NAS) panel found that the risk of cancer arsenic in drinking water are even greater that we thought. The panel report, published on 11 September, just six months after the Bush administration shelved the proposal (EPA) Environmental Protection Agency to suppress arsenic, sparking an outcry from environmentalists and some members of Congress ( Science NOW, March 21). EPA Administrator Christie Whitman, who requested the NAS review, now seems to have no choice but to adopt a standard at least as difficult as it was delayed.
People of studies exposed to high levels of arsenic in water linked the metal at high rates of internal cancers. After a review NAS 1999 revealed that the current standard of 50 parts per billion (ppb) was not protective enough, the outgoing Clinton administration proposed tighten to 10 ppb, based on a study of the arsenic and cancer in Taiwan. But the leaders of Western states with naturally high levels of arsenic have protested that the cost of clean water would be overwhelming. In April, the EPA asked the Academy to examine the latest scientific support levels between 3 ppb and 20 ppb.
This new panel concluded that the analysis on which EPA based the proposed 10 ppb had actually underestimated the risks. "Four new epidemiological studies have been key," says the president of the Robert Goyer committee, a retired pathologist from the University of Western Ontario. New studies of Chile and Taiwan counter the suggestion that the previous results had been distorted by the malnutrition. When panel members recalculated the risk of a slightly different way of analyzing the EPA used, they concluded that the risks of lung cancer and bladder cancer were higher. for example, 10 ppb, the study that EPA based on estimates up to 0.8 additional cases per 1,000 people, while the Panel found a risk of about 1.3 to 3.7 additional cases, depending on the background rate of cancer.
An EPA spokesman declined to speculate whether the new standard is 10 ppb or less, but said Whitman is now "more concerned, not less" risk arsenic. Its decision is due by February.
Related Sites
The NAS report is available online
search site Arsenic
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