New evidence suggests that arsenic in drinking water could be more hazardous than earlier thought--a finding that could shape new standards for drinking water in California and nationwide.
Even minute amounts of arsenic in drinking water could lead to higher rates of lung and bladder cancer than initial research showed, according to a study released this week by the National Academy of Sciences.
The study provides new ammunition for those opposed to the controversial Bush administration decision in March to delay a more stringent drinking water standard for arsenic, pending further study. Since then, administration officials have tried to find a way out of the public relations disaster caused by that announcement.
The new report "absolutely raised more concern" when U.S. Environmental Protection Agency chief Christine Todd Whitman was briefed on it this week, a spokesman said.
The findings could have an effect in California and other arid Western states where high concentrations of arsenic occur naturally in some ground water.
"They're certainly of great interest to us," said Allan Hirsch, spokesman for the state Office of Environmental Health Hazard Assessment, part of the California Environmental Protection Agency. California is conducting its risk assessment of arsenic and could set a tougher standard for drinking water than that of the federal government.
The study released this week found that people consuming water daily with 3 parts per billion of arsenic have an increased risk of developing bladder or lung cancer. Specifically, 1 in 1,000 such people could be expected to develop one of those cancers in their lifetime because of the arsenic.
The added lifetime risk at 10 parts per billion--the level in the Clinton rule--is greater than 3 in 1,000 people, the study states. It also notes that some studies overseas have linked arsenic exposure to diabetes, respiratory and cardiovascular problems and birth defects. The committee conducting the study recommends more research on arsenic's potential ties to illnesses other than cancer.
Federal EPA standards seek to limit increased lifetime cancer risk to 1 in at least 10,000 people.
California and federal regulations allow arsenic at no more than 50 parts per billion in tap water. After a 1999 National Academy study, the EPA proposed tightening that level to 5 parts per billion, later changing the level to 10 parts per billion, the level adopted by the Clinton administration in its final days.
