Could arsenic be lurking in our drinking water?
11/04/09 by Salisbury Post
EDITOR’S NOTE: This is an edited version of a story by Shavonne Potts which appeared in the October 29, 2009, issue of the Salisbury Post.
There may be something lurking in your drinking water that you can't see, smell or taste, and scientists say it could cause diabetes.
The potential danger is arsenic, a metal that naturally occurs in rocks, soil, plants and animals.
Dr. Miroslav Styblo, an associate nutrition professor at UNC Gillings School of Global Public Health, spoke to a group Oct. 29 at Catawba College's Center for the Environment on the link between arsenic and diabetes.
Styblo, a toxicologist, has been conducting studies in Mexico on whether arsenic in drinking water could be a cause of diabetes.
Exposure to high levels of arsenic in drinking water has been linked to various cancers, including liver and lung, he said.
One of the biggest questions is how does arsenic get into the drinking water?
It can enter drinking water through the ground. For instance, if someone digs a well, it can seep into drinking water through the erosion of the arsenic-rich rocks.
It can also enter the ground through runoff.
Styblo told the group about products that have arsenic in them that can then end up in drinking water. Arsenic can be used in wood preservatives, drugs and in high levels in animal feed and fertilizers. Some common fertilizers used on golf courses can run off into nearby streams or lakes after a hard rain.
The U.S. Environmental Protection Agency's maximum contaminant level is 10 parts per billion.
Most municipalities work hard to remove any harmful levels in drinking water. However, private drinking water wells may cause water levels to drop and can release arsenic from rock formations.
Styblo has conducted studies at Chapel Hill using cell cultures, mice and humans.
Human and animal cells were placed in Petri dishes along with arsenic, and the changes in the cells were studied.
Mice were exposed to high levels of arsenic and one group was given a high-fat diet and another, a low-fat diet. The study showed that the mice fed a high-fat diet developed diabetes.
Since animals are much more resistant to arsenic, they must be given nearly 100 times the amount to produce a desired effect.
The human studies took place in Zimapan, Lagunero and Chihuahua — all in Mexico.
In those cities, arsenic levels in the drinking water reached between 10 parts per billion up to 800 parts per billion.
Through asking the human participants questions about their diet, their water and about arsenic exposure, scientists were able to determine that their risk for developing diabetes increased as their exposure to arsenic increased.
"We hope to get to the point of prevention," Styblo said.
In the United States, people would have to consume higher levels to develop diabetes from arsenic.
The level would have to be somewhere higher than 50 parts per billion.
Someone from the audience asked Styblo about not testing food for high levels of arsenic. He explained that certain foods can change the toxic levels in arsenic.
Drinking water is the best test, he said.
The U.S. Environmental Protection Agency releases a consumer confidence report that details what's in your region's drinking water. Several counties' water quality reports, including Rowan, can be found on the EPA Web site, www.epa.gov.