Even suspended arsenic standard may be too high for consumer safety

New research has strengthened the link between exposure to low levels of arsenic in drinking water and cancers of the lung and bladder, says a report published by the National Academy of Sciences (NAS).

In January this year, the US EPA, under President Clinton’s administration announced that it would be lowering the permitted levels for arsenic in drinking water from 50 parts per billion (ppb) to 10 ppb, intended to protect 13 million Americans, following a NAS recommendation in March 1999 (see related story). However, in March of this year, the newly appointed EPA Administrator Christie Whitman put the new drinking water standard on hold, saying that there was, as yet, no consensus as to what constituted a safe level for arsenic (see related story), and amid fears from water companies and the mining industry that the costs of reducing arsenic would far out-weigh the benefits.

However, according to the NAS report, even Clinton’s lower arsenic level may be too high. The report reveals that men and women who daily consume drinking water with three parts per billion of arsenic have about a one in 1,000 increased risk of developing bladder or lung cancer during their lifetime, and for those consuming five parts per billion, the risk is 50% higher. At 10 ppb, the risk is three in 1,000, rising to seven in 1,000 at 20 ppb.

“Even very low concentrations of arsenic in drinking water appear to be associated with a higher incidence of cancer,” said Robert Goyer, Chair of the committee that wrote the report and Professor Emeritus of Pathology, at the University of Western Ontario. “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.”

Although the study has shown a link between chronic exposure to arsenic and cancer, the NAS also points out that further work needs to be done to study the extent to which exposure leads to other diseases such as diabetes, respiratory and cardiovascular ailments, and birth defects, all of which have already been linked by other research projects. Research should also encompass vulnerable groups such as children and smokers, and should study the biological mechanisms by which arsenic causes cancer, says the NAS.

The EPA has been reported as stating that it will be lowering the arsenic standard to at least 10 ppb, following this report.

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