Arsenic

Arsenic standards too lax, Federal advisory group says some drinking water is unsafe
Medical Tribune News Service, by Dan Vergano

Citing cancer risks, a government advisory committee recommended Tuesday that the Environmental Protection Agency tighten its standards on the amount of arsenic allowed in drinking water. The EPA established the current maximum level of arsenic in drinking water, 50 micrograms per liter, in 1975, based on then-current knowledge of skin-cancer risk from the chemical. Long known as a poison, arsenic occurs naturally in the soil, where it can contaminate water, plants and animals. “The risk of cancer at presently allowed levels is alarming, and the standard should be lower,” said Dr. Robert Goyer, an emeritus professor of pathology with the University of Western Ontario in London, Ontario. He chaired the National Research Council committee that released a new report which found “a combined cancer risk of one in 100” from drinking water with the currently allowed maximum level of arsenic. Two of the 16 committee members dissented from that finding.

Goyer noted that very few water supplies nationwide contain the chemical in dangerous concentrations. Well owners who do have concerns might want to test their water, said Brian Folk, owner of Fresh Water Systems in San Diego. While carbon filters will not take help, distillation effectively removes the chemical, and some reverse-osmosis filters are also effective, he said. The NRC is a branch of the National Academy of Sciences, a non-profit group that provides independent advice on scientific issues to Congress.

New data from Bangladesh and the Bengal region of India linking arsenic to lung and bladder cancers led the EPA to request the report. In those areas, residents have dug wells deep into the ground, where arsenic levels are higher, according to Goyer. There, men who consume the EPA’s maximum-allowed levels of arsenic in drinking water face a bladder cancer risk of one in 1,000, far above the EPA goal of limiting risk to one in 10,000. In the United States, some residents of Western regions with little rainfall have used very deep, or “artesian,” wells for decades, but arsenic levels are not thought to be excessive there, said Goyer.

Less than 1 percent of all public water systems contain even 20 micrograms of arsenic per liter, according to the EPA. “It’s not a widespread problem but certainly a serious one where it occurs,” said Robin Woods, an agency spokesperson. Combining the risk for skin cancer, bladder cancer and lung cancer suggested by various studies led to the one in 100 cancer risk assessment, said R. Julian Preston, director of the Environmental Carcinogen division at EPA in Research Triangle Park, N.C., who served as a committee member prior to joining the agency. One problem the committee faced was a lack of data on the effects of low levels of arsenic on people. Some studies indicate that humans handle toxins like arsenic very well in small amounts, according to the report. At high levels, the chemical causes skin lesions and rashes, as well as possibly promoting cancer.