Tuesday, May 21, 2024
40.0°F

Study shows trees contaminated

| May 18, 2005 12:00 AM

By BRENT SHRUM Western News Reporter

Analysis of bark samples from trees near the former W.R. Grace vermiculite mine revealed measurable levels of asbestos, a University of Montana researcher told the Community Advisory Group last week.

Tony Ward of the university's Center for Environmental Health Sciences briefed the CAG on Thursday on preliminary results from a study aimed at determining whether the bark of trees might serve as a reservoir for asbestos fibers. The study is intended to answer questions about potential risks associated with logging in contaminated areas.

Samples were taken from three trees located about 100 yards from the former pump house at the mine site, one tree located farther down the Rainy Creek drainage and one tree just outside the fence near the intersection of Rainy Creek Road and Montana Highway 37.

Two lodgepole pines at the site closest to the mine showed asbestos levels of 530 million and 330 million fibers per gram of bark while a larch tree at the same location showed 140 million fibers per gram, Ward said. A lodgepole farther down the drainage showed 160 million fibers per gram, and a lodgepole near the highway showed 41 million fibers per gram.

Only the bark showed contamination, Ward said; core samples were clean.

The bark contamination is not a surprise, said Jim Christiansen, manager of the Environmental Protection Agency's cleanup program in Libby.

"We expect those trees up around the mine to have some asbestos contamination," he said.

The findings aren't good, Christiansen said, but he suggested that the numbers announced by Ward may make things sound worse than they are. The level of contamination averages out to about .05 percent by weight, which would be classified as "trace" contamination in soil, Christiansen said. The trigger point for soil cleanup is 1 percent.

The decreasing level of contamination as distances from the mine increased is a good sign, Christiansen said. The contamination of trees near the road leading to and from the mine is likely a result of the traffic on the road when the mine was in operation, Christiansen indicated.

"I expect those to be pretty nasty along the road too, with all the dust that was there and all the stuff coming back and forth," he said.

Ward stressed that the findings are preliminary and that additional study is planned. More samples will be collected from around the Libby area and across northwestern Montana, he said.

In other business, Christiansen provided a briefing on recent EPA cleanup activities in the Libby area. So far this year, 40 properties have been cleaned, bringing the total to 390 cleanups to date.

"We're right on pace," Christiansen said. "That's going really well."

Cleanup work was conducted at J. Neils Memorial County Park after visible vermiculite was found late last year at one of the park's ball fields and trace levels were found at another, Christiansen said.

"I think that work is pretty much complete now," he said.

Cleanup work has started in the central maintenance building on the former Stimson mill property, now owned by the Lincoln County Port Authority, Christiansen said. The job of cleaning vermiculite insulation from the walls is moving ahead one bay at time, he said.

"It's been tough," he said. "It's dirty, nasty stuff and old wood, but we're making progress."