Daily Archives: February 3, 2014
By Henry Brean, Las Vegas Review-Journal
Removing asbestos from an old building can be hazardous and expensive. So what happens if the ground outside is covered with the stuff for miles around?
That’s what a team of UNLV geologists is trying to figure out after the surprise discovery of potentially toxic, asbestos-type minerals in rocks and dust from Boulder City to the southeastern edge of the Las Vegas Valley.
University of Nevada, Las Vegas geology professor Brenda Buck said this marks the first discovery of naturally occurring asbestos fibers in Southern Nevada.
A peer-reviewed study detailing the find was published last month in the journal of the Soil Science Society of America.
So how worried should everyone be?
“At this point we know enough to know there is a hazard. We don’t know what the risk is,” Buck told the Las Vegas Review-Journal. “There’s a lot of work that needs to be done. Until we know more, it would be a good idea to avoid dust from those areas.”
That could be a tall order.
The study area takes in all of Boulder City and a wide swath of the Eldorado Valley, with tendrils that reach to the shore of Lake Mead and into the oldest parts of Henderson.
“It’s not everywhere, but I think you’re going to have a hard time not finding it,” Buck said. “In every sample we looked at we found it. We found it pretty easily, too. I didn’t have to look very hard.”
For one test, Buck spent about three hours walking her horse along a dirt road in Boulder City. When she was done, she found asbestos fibers on her pants and her shoes.
“The last thing we want to do is upset people or cause a panic. But on the other side, we don’t want to give people assurances we can’t give,” said UNLV geologist Rodney Metcalf, who partnered with Buck on the study. “We can’t in good conscience say there’s no problem.”
The long, thin minerals were forged roughly 13 million years ago in the roots of volcanoes, also known as plutons. “Boulder City sits on top of one of these plutons,” Metcalf said.
The fibers have been weathering from the ground for the past 12 million years or so, giving them plenty of time to spread out, Buck said.
She specializes in something called medical geology, basically the study of the health impacts of minerals. She was in the midst of sampling arsenic in the dust blowing from Nellis Dunes when she came across a fibrous mineral in one of her samples. She later started talking to Metcalf about the asbestos-like fibers he was studying in northwestern Arizona, and the two decided to go looking for trouble in similar rock deposits in Southern Nevada.
What they mostly found was a mineral called actinolite, one of six types of asbestos regulated as a toxic substance by the U.S. Environmental Protection Agency. Read More