It’s been about 10 years since the Environmental Protection Agency started cleaning up heavy metal contamination from a history of mining in the Silver Valley.
Within two years, the EPA expects to be finished up with cleanup within the Bunker Hill Superfund “box,” which is the 21-square-mile site in the immediate vicinity of the old Bunker Hill Mine.
Aside from some continued work on water quality within the box, the EPA will then focus on cleanup of the larger Coeur d’Alene Basin.
A draft review of cleanup activity thus far inside and outside the Superfund “box” and of whether the work is protecting human and environment health has just been released by the EPA.
This week, the agency is holding five open houses on the review findings and recommendations in North Idaho and Spokane. The public has 30 days to comment on the draft.
“The major issues revolve around whether or not certain remediated areas are becoming recontaminated,” said Angela Chung, the EPA’s Coeur d’Alene team leader for cleanup.
Mining in the Silver Valley for silver, lead, zinc and other metals began in 1883. A century’s worth of mine tailings and heavy metals have spread from the mine adits above Wallace all the way downstream along the Spokane River.
An estimated 100 million tons of contaminated sediments and other materials are spread throughout the Coeur d’Alene Basin, according to the EPA. The work in the larger basin area, outside the original Superfund box, is just beginning.
The EPA recommends ongoing monitoring to see if areas are being recontaminated by vehicle traffic or other disturbances within the box. One concern, for instance, is the use of all-terrain vehicles on the hillsides above Kellogg, said Tamara Langton, the report’s lead author.
The concern is that ATV use might tear up the protective layer of soil and vegetation that’s covering the formerly denuded hillsides that were poisoned by emissions from the Bunker Hill smelter.
“We have some suggestions on what we can do, mainly encouraging people to stay off the hillsides,” she said.
The EPA also wants to ensure that certain maintenance activities are carried on into the future, such as the operation of the Central Treatment Plant, a water treatment plant that treats acid mine drainage from the former mine.
The EPA wants the state of Idaho to operate the plant forever, but “because of the cost, the state is having difficulty saying yes,” Langton said.
The EPA issued a previous Five-Year Review in 2000, five years after cleanup began. In this review, the EPA has addressed the remediation efforts downstream for the first time.
Part of the review discusses the conversion of the Union Pacific Railroad line to a trail. The railroad removed 150,000 cubic yards of contaminated soils from the right of way as part of the trail project, and then capped the grade with rock and asphalt.
Many property owners along the railroad grade have complained that the rails-to-trails method of dealing with the contamination was inadequate, but EPA’s Ed Moreen, a project manager based in Coeur d’Alene, said it was designed with the knowledge that the grade would likely be contaminated every time there’s a flood in the basin.
“The logic was there was no reason to do a full cleanup,” he said. “If you clean up this ribbon, you don’t really achieve anything.”
The trail is in its “infancy,” Moreen said, and the review suggests that ongoing monitoring of its use and the effectiveness of the asphalt barrier is necessary.
The review doesn’t address the issue of contamination of Lake Coeur d’Alene, which is to be addressed through a Lake Management Plan developed by the Coeur d’Alene Tribe and the State of Idaho.
Amber Waldref of The Lands Council, a Spokane-based environmental group, said she was pleased with the EPA’s progress, but was worried about downstream issues.
“We’re concerned about the tribe and DEQ getting to an agreement on a lake management plan,” she said. “That continues to be something that’s hanging in the air.”
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