What researchers are finding out about low-level exposure to arsenic
This week, the Environment Report is taking a look at Michigan’s silent poison — arsenic.
Federal standards allow public drinking water supplies to have arsenic levels of up to 10 parts per billion (ppb), but these standards do not apply to private well owners (that's left up to the well owner to determine).
And in counties throughout Michigan, some wells have much higher levels of arsenic than this "maximum contaminant level" set by the EPA.
Higher levels of arsenic in drinking water have been linked to skin cancer, lung cancer, and bladder cancer, among others.
But are lower levels of arsenic a threat to human health?
Jaymie Meliker studies that question. Meliker is an associate professor in the Department of Preventive Medicine and Program in Public Health at Stonybrook University in New York.
“There’s no doubt that arsenic at high levels is associated with a variety of health effects,” he said. “The question is at what levels should we be worried?”
In 2007, Meliker studied the health impacts of lower levels of arsenic in Michigan’s water — between the 10-100 ppb range.
The study discovered that even lower levels of arsenic in drinking water may be associated with mortality from diabetes, kidney disease, and cerebrovascular diseases — diseases that impact blood flow to the brain.
Meliker says there's a growing body of evidence that arsenic at lower doses can cause harmful health effects.
“We’re starting to see more evidence that there is risk in this 20-50 [ppb] range,” Meliker said.
Other studies suggest that low levels of arsenic may be linked to strokes.
A 2010 study from the Journal of the American Heart Association, in which Meliker was an author, looked at low-level arsenic in drinking water in Michigan.
The study concluded "that exposure to even low levels of arsenic in drinking water may be associated with a higher risk of incident stroke."
More recently, a 2014 study by Columbia University's Joseph Graziano found an association between exposure to water tainted with arsenic and lower IQ scores.
From the study:
"..The children who were exposed to greater than 5 parts arsenic per billion of household well water showed reductions in Full Scale, Working Memory, Perceptual Reasoning and Verbal Comprehension scores, losses of 5–6 points, considered a significant decline, that may translate to problems in school."
In David Heath's investigation for the Center for Public Integrity, Graziano compared arsenic to another element we're exposed to:
“I jokingly say that arsenic makes lead look like a vitamin,” said Joseph Graziano, ... “Because the lead effects are limited to just a couple of organ systems — brain, blood, kidney. The arsenic effects just sweep across the body and impact everything that’s going on, every organ system.”
Researchers stress the importance of continuing these studies looking at the links between lower levels of arsenic in drinking water and our health.
Meliker says, in the meantime, it's smart to test your water if you're on a private well. And if your levels are above 10 parts per billion, he says, if you can afford it, it's a good idea to install a reverse osmosis filter.
As scientific study continues on low-level exposure, the EPA has seen enough evidence for the potential of increased cancer risk.
More from Heath's CPI report:
The EPA has been prepared to say since 2008, based on its review of independent science, that arsenic is 17 times more potent as a carcinogen than the agency now reports.
Heath's investigation found that the EPA was forced by one Congressman to hold off on its health assessment. It could be several more years before we see their final analysis.
For more information about testing and treating your water for arsenic, follow this link.
- Melanie Kruvelis, Mark Brush, and Rebecca Williams, Michigan Radio Newsroom.