The company tasked with investigating the extent of environmental contamination at the Columbia Falls Aluminum Co. Superfund site on Thursday released its first round of test results for soil and water samples collected from the property.
The Environmental Protection Agency assumed oversight of cleanup operations when it officially added the 960-acre site to the National Priorities List last year. Under an administrative order of consent, the agency has authorized Roux, Inc., an environmental company contracted by CFAC, to determine the extent of contamination and develop a range of possible cleanup strategies.
“The results of the evaluation confirm site groundwater issues are caused by closed landfills located on the site and indicate the groundwater is not flowing toward Aluminum City,” the company stated in a Thursday press release, referring to a residential neighborhood located near the property.
The federal agency’s local project manager, Mike Cirian, said Thursday that EPA officials are still reviewing the more than 7,000-page report, but hope to have it complete by April 17 when they meet with the Columbia Falls City Council to discuss the initial findings. Based on the agency’s initial evaluation of the findings, he said the report appeared consistent with previous sampling at the site.
“This data summary report is only based on the first round of sampling that’s done. We’ve done one round of sampling since then and still have two more to go, so there’s still a lot to do until we have a good picture of what’s out there,” Cirian said.
He added, “Nothing that we’ve seen has left the site into the drinking water.”
The report includes analysis of more than 700 samples of soils, sediments, groundwater and surface water. Beginning in January 2016, Roux established the scope of work for the site investigation, which included drilling 44 new monitoring wells and identifying high-risk areas based on the now-shuttered aluminum reduction plant’s history of land use.
The report concludes that cyanide and fluoride are the primary “chemicals of potential concern” in groundwater underlying the Superfund site — mainly at the West Landfill, Wet Scrubber Sludge Pond and former Drum Storage areas. Groundwater studies indicate the contamination generally flows south toward the Flathead River and away from Aluminum City, according to the report.
It also notes that concentrations for those chemicals are below reporting limits in the north, west and southwest portions of the site.
Elevated concentrations of some potentially toxic metals were also found in some of the monitoring wells, but most samples indicated low levels of metals, according to the report. High levels of arsenic in soil samples appeared consistent with the area’s naturally high concentration of the metal, it stated.
The report states that cyanide and fluoride contamination detected in some samples from the site are within the Flathead River’s 100-year flood plain, and could potentially impact sediments, surface water and aquatic life in the river. But it notes that water samples taken from nine locations along the river indicated that the river has not yet been impacted by on-site contamination.
Once the results from the remaining three rounds of sampling have been analyzed, the company will work with the EPA to evaluate risks to human and ecological health and determine what additional sampling needs to be conducted.
The four-year process will culminate in the development of a feasibility study to outline options for remediation of the Superfund site. Cirian said the company is on track to complete the study in 2021.
The data summary from the first round of sampling can be found online at bit.ly/2nt6KKh.
The EPA will meet with the Columbia Falls City Council to discuss the findings on April 17, and will be present at the April 19 public meeting of CFAC’s Community Liaison Panel.
Reporter Sam Wilson can be reached at 758-4407 or by email at email@example.com.