WASHINGTON (Reuters) – The National Academies of Science said Thursday new studies show a higher risk of lung or bladder cancer from arsenic than previously thought, bolstering the arguments of green groups who have demanded the Bush administration adopt stricter limits.

The report by the prestigious panel of scientists was requested by the Bush administration, which in March halted a Clinton-era plan to slash dramatically the amount of arsenic permitted in tap water.

The Environment Protection Agency said at the time that more studies were needed to help decide the appropriate limit. The suspension of the rule was applauded by many business and mining groups, which feared tighter arsenic limits would be costly.

“Even very low concentrations of arsenic in drinking water appear to be associated with a higher incidence of cancer,” said Robert Goyer, chairman of the National Academies of Science committee that wrote the report,

“We estimated the risk of developing cancer at various arsenic concentrations, and now it is up to the federal government to determine an acceptable level to allow in drinking-water supplies,” added Goyer, a retired pathology professor at the University of Western Ontario.

Arsenic naturally occurs in groundwater as a result of minerals dissolving over time from rocks and soil and from industrial run-off. Arsenic concentrations in water are generally highest in the West and some parts of the Midwest.

SHOULD ARSENIC LIMIT BE 10 PPB?

Goyer said the report bolstered a 1999 study by the National Academies of Science that found a high risk of cancer at the current limit of 50 parts per billion (ppb). No other developed nation allows that much arsenic in drinking water.

Days before President Bill Clinton left office in January, his government announced a plan to lower the limit to 10 ppb, but the incoming Bush administration put that rule on hold and asked for another study by the National Academies of Science.

The scientists found that men and women who daily consume water containing 20 ppb — less than half the current limit — have a 7 in 1,000 risk of developing bladder or lung cancer during their lifetime.

That risk declines to 3 in 1,000 at a level of 10 ppb and to 1.5 in 1,000 at 5 ppb, the panel said.

EPA officials privately said that the new information raised questions whether the 10 ppb limit proposed by the Clinton administration was low enough. The agency has long held that the maximum acceptable cancer risk for various substances regulated by the EPA was 1 in 10,000.

“The administrator has been briefed by the National Academies of Science and the briefing raises more concerns with her, not less,” an EPA spokesman said. “She is still on track to make a final decision on the level by February.”

LINK TO OTHER DISEASES?

The science panel said its new risk estimates were greater than those on which EPA based its rule in January because the committee used different assumptions based mostly on Taiwanese cancer rates and arsenic in water.

New data collected since 1999 from Bangladesh, Chile, China and Finland show a stronger link between arsenic and cancer, the panel said.

“What the academy is saying is that even at 3 ppb, the risk would be several times higher than the EPA’s maximum acceptable cancer risk,” said Erik Olson, senior attorney with the Natural Resources Defense Council.

“This study forecloses any possibility of the EPA going above the 10 ppb limit and we believe it points in the direction of going well below 10 ppb,” he added.

The green group has long advocated a ceiling of 3 ppb for arsenic in drinking water. The Natural Resources Defense Council sued the government several months ago over suspending the proposed rule, and a U.S. Court of Appeals is expected to soon set a hearing schedule in the case.

Arsenic may also increase the chance of other diseases, but more study is needed to pinpoint the exposure risk, the science panel said. Some foreign researchers have linked arsenic exposure to diabetes, respiratory and cardiovascular ailments, and birth defects.

The panel of nine chemists, toxicologists and epidemiologists were drawn from the National Cancer Institute, Harvard University, the University of Washington, Sweden’s Karolinska Institute and other universities.

The Democratic-led Senate and the Republican House of Representatives each passed legislation recently to force the Bush administration to tighten arsenic limits to at least 10 ppb.

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