What comes to mind when you think of arsenic? For most people, it conjures up a deadly poison used by killers in fictional mystery novels and some real-life murderers, too. But the danger of this toxic substance most often comes not from some evil-doer but simply from exposure to it through our environment, including the water we drink. Unwittingly taken into the body over many years, arsenic can result in lung, bladder and skin cancers, as well as heart disease, diabetes and neurological damage.

In the U.S., many locations are known to have groundwater containing arsenic concentrations in excess of the new Environmental Protection Agency (EPA) standard of 10 parts per billion. But now comes research that suggests the EPA's supposedly "safe" level of arsemic allowed in water supplies for public consumption isn't safe at all. In fact, water laced with the federally-approved amount of arsenic could be causing high blood pressure and artery-clogging arhterosclerosis.

According to animal research by University of Pittsburgh scientists set to be published in the December issue of the Journal of Clinical Investigation, and available online now at http://www.jci.org/articles/view/35092, arsenic at EPA-approved levels for drinking water causes pores in liver blood vessels to close, potentially leading to cardiovascular disease and hypertension. This study calls into question whether present Environmental Protection Agency standards (currently based only on the risks of arsenic causing cancer) are stringent enough.

(ARTICLE CONTINUES BELOW)

Aaron Barchowsky, Ph.D., associate professor of environmental and occupational health at the University Of Pittsburgh Graduate School Of Public Health, and his research team studied sinusoidal endothelial cells in the livers of mice. These specialized cells normally remove waste from the blood and allow nutrients to regulate metabolism. But when mice were exposed to ten to 100 parts per billion (ppb) of arsenic over a period of 14 days, the arsenic increased the activity of an enzyme called NADPH oxidase and the levels of oxidants it produces. In turn, the sinusoidal cell functions became less able to remove damaged proteins from the blood. What's more, the cells lost their characteristic pores or "windows". Bottom line: the cells' ability to effectively handle nutrients and waste was extremely compromised.

Although mice are, of course, tiny compared to people, their bodies are known to be far less sensitive to arsenic's effects than humans'. And that makes the study even more worrisome. "These results are important since this type of cellular dysfunction, over time, can impair the body's ability to clear fats and waste proteins that build up in blood vessels and can lead to cardiovascular diseases such as hypertension and atherosclerosis," Dr. Barchowsky said in a statement prepared for the media.

The current federal standard for arsenic in public water systems not only may be too high, but it only applies to drinking water sources that serve more than 20 people. "We are especially concerned about water from individual wells in small, rural and semi-rural communities that are exempt from the EPA requirement and often contain levels of arsenic that exceed the EPA limit," Dr. Barchowsky stated in the press release. "Our findings raise some concerns about whether current EPA-developed standards can effectively protect against cardiovascular risks posed by arsenic in drinking water."

The study is a strong reminder that no one in the U.S. should assume that because their water supply is dubbed "safe" by the EPA that it doesn't contain not only arsenic but other toxins. For example, most public water supplies are known to contain a host of pharmaceutical and pesticide residues,too. Testing your water or finding a proven system of safe water filtration are the only known ways to make sure you are putting pure water into your body.