Cyanide not detected in well tests
<p>Potman Kenneth Sexton operates a vehicle used to transport alumina from the Anaconda Aluminum Co. storage silos to the reduction cells in February 1957. Mel Ruder photo</p>
Eighteen property owners with wells near the closed Columbia Falls Aluminum Co. smelter recently received letters from the Environmental Protection Agency with results from sampling conducted on April 10.
“Water from your well was tested for contaminants regulated under the National Primary Drinking Water Regulations,” the letters stated. “None of these contaminants were present in your well at or above the ‘Maximum Contaminant Level (MCL),’ which is the maximum amount of a contaminant allowed to be present in a public drinking water system.”
The letters were sent to property owners on the North Fork Road, Aluminum Drive, Florence Street, Dorothy Street and 12th Street by Martin McComb, the on-scene coordinator for the emergency response program at the EPA Region 8 office in Denver, Colo.
“The analytical results were also compared to other benchmarks, including State of Montana Numeric Water Quality Standards and EPA’s Risk Based Screening levels,” the letters said.
According to Rob Parker, the EPA site assessment manager who spoke to Columbia Falls residents at a public meeting on April 15, “these wells were sampled in response to the detections of cyanide in two residential wells during the original sampling event last fall.”
Cyanide is created over time inside the aluminum reduction pots and leaches out of spent potliner that is discarded when the pots are rebuilt. In the past, spent potliner was buried at the CFAC plant in unlined landfills.
Parker said one of the two residential wells that had indicated the presence of cyanide last fall was re-sampled, and samples from the second round of testing were analyzed for similar contaminants as the fall sampling — along list that included polyorganic chemicals and metals.
“Overall, none of the water samples from the domestic wells had any detections of cyanide,” Parker said about the April 10 samples. “While we certainly view this as a good thing, as residential well users that were sampled aren’t being exposed to detectable levels of cyanide, the EPA still believes that further investigation at the site is warranted based on the previous detections of contaminants at elevated concentrations in groundwater at the facility and detections of contaminants in the Flathead River, Cedar Creek and domestic wells.”
Further investigation by the EPA would help investigators “better understand the hydrogeology and the nature and extent of contamination,” Parker said, “and will help determine what, if any, remediation is necessary to protect human health and the environment.”