| Updated at: 1817 PST, Monday, January 17, 2011|
NEW YORK: While arsenic in water and food is a health concern, a new study suggests the levels found in most Americans are too low to raise their risk of high blood pressure.
Earlier research had linked high levels of the chemical to increased blood pressure, lung cancer and other diseases, so the new findings, reported in the journal Epidemiology, offer some reassurance.
A limitation of the study, however, is that it surveyed people at one time point, instead of following them over time to see who developed high blood pressure.
"It's premature to say, 'There's no relationship, you're safe,'" said senior researcher Dr. Ana Navas-Ancien, of the Johns Hopkins School of Public Health in Baltimore.
And even if most Americans' arsenic levels aren't high enough to raise their blood pressure, there could still be other health risks, such as diabetes, she added.
"I think we're learning more and more about the possible health effects of low levels of exposure," Navas-Ancien said. "But we still need to do more risk assessments."
Arsenic is an element found in rock, soil, water and air. It is also released into the environment through industrial activities, and can be found in products like paints, dyes and fertilizers.
Studies from Asia and South America have linked chronic arsenic exposure through drinking water to high blood pressure and lung infections, but the water there had high arsenic concentrations -- upward of 100 micrograms per liter.
In the U.S., the allowable limit is 10 micrograms per liter, and most U.S. drinking-water supplies have levels well below that.
The health effects of such low-to-moderate exposures are not yet clear.
For the current study, Navas-Ancien and her colleagues used data from an ongoing government health survey of a nationally representative sample of U.S. adults. They focused on nearly 4,200 men and women who'd given urine samples for arsenic measurement.
Overall, 36 percent of the study group was found to have high blood pressure. There was no correlation, however, between participants' arsenic levels and their odds of high blood pressure.
But the researchers caution that some Americans are still exposed to relatively high arsenic levels through drinking water -- particularly in certain areas of the West, Midwest and New England where the groundwater contains high concentrations of the toxic chemical.
It is estimated that 13 million Americans live in areas where the public water supply exceeds the threshold of 10 micrograms per liter. And unregulated private wells might also contain too much arsenic.
"Many people who live in areas with high levels of arsenic in the groundwater may have wells," Navas-Ancien said. She recommended that people in these regions have their well water tested.
If the arsenic level exceeds 10 micrograms per liter, the well water can be treated with filtration systems designed to remove the contaminant.