School sampling turns up traces of asbestos
Tests show contamination levels ‘right at the detection limit’ says EPA toxicologist
by Brent Shrum, Kootenai Valley Record
February 18, 2010
Air and soil samples taken at local schools over the past year turned up handful of low-level detections of Libby amphibole asbestos fibers, but the results aren’t cause for alarm among parents, according to an Environmental Protection Agency toxicologist.
All of the hits were "right at the detection limit," said Dr. David Berry during the EPA’s annual update town meeting last Monday night/
As to the issue of whether it’s safe to send children to school, "I think the answer to that is yes," Berry said.
Indoor air samples, soil samples, and activity-based samples were taken at Kootenai Valley Head Start (formerly Plummer Elementary), Asa Wood Elementary, Libby Middle School and Libby High School along with the school administration building. The indoor air samples were taken using stationary detectors over two days while students were in the building. The activity-based samples were collected by workers wearing protective gear and simulating outdoor activities by both students – such as playing on athletic fields and playgrounds – and maintenance workers, such as mowing lawns, raking and sweeping.
Out of 51 samples, one indoor detection occurred in a classroom at Asa Wood, and one occurred in a hallway at Libby Middle School.
"Both of these detections were right at the detection limit, so they were very small detections," Berry said.
Berry attributed the indoor detections to "track-in" of contamination from outside the school.
"That is people bringing the material in on there shoes or on their clothing," he said.
Out of 41 soil samples, six had visible vermiculite detections. Analysis by polarized light microscopy picked up trace levels of Libby amphibole in samples from all five locations. Levels were much lower than those detected in 2001, prior to cleanup of heavily contaminated areas, Berry noted. In those samples, levels as high as 15 percent Libby amphibole were detected.
Better sampling methods in use today could account for trace levels being detected where a few years ago samples would have come back "non-detect," Berry said.
Out of 63 activity-based samples, five detections occurred at three schools. One groundskeeping activity turned up a hit at the Head Start center, one detection occurred on a playground at Asa Wood, there was one groundskeeping detection and one student activity detection at the Libby Middle School soccer field, and there was one detection for simulated football activity at Libby High School.
Ambient air sampling in downtown Libby indicates a "very significant decrease" in fiber levels, Berry said. An average of 2008 samples showed a concentration of .0000056 fibers per cubic centimeter, compared to .0001 to .00086 fibers per cc in 2002 and .59 fibers per cc before W.R. Grace closed its vermiculite mining and milling operations in 1990. Federal workplace standards for asbestos – but not specifically Libby amphibole, which is believed by many to be more toxic – allow a maximum concentration of .1 fibers per cc, Berry noted.
Berry said he expects "sporadic detections" to occur both indoors and outdoors for the foreseeable future.
"Libby amphibole will remain at low levels in the Libby valley for a long time," he said.
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Editor’s Note: See the February 16, 2010 edition of the Kootenai Valley Record for the printed version of this story. The Kootenai Valley Record publishes once a week, on Tuesdays, in Libby, Montana. They are a locally owned community newspaper, located at 403 Mineral Avenue in Libby. For in-county and out-of-county subscription information, call 406-293-2424, or e-mail kvrecord@gmail.com.
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