Heavy metals may be moving in Lake Coeur d’Alene
COEUR d’ALENE — Some scientists charged with monitoring water quality in Lake Coeur d’Alene say recent preliminary test results could be cause for concern.
Phil Cernera, director of the Coeur d’Alene Tribe’s Lake Management Department, said while the data they gathered from the main stem of the Coeur d’Alene River and some of the chain lakes shows heavy metals could be leaching from the sediment during the summer months, more studies will be needed to determine if it is actually occurring.
“There has been some spot sampling done in some of the lateral lakes and deep pools of the Coeur d’Alene River,” he said, explaining those are the areas where the sediments contain high levels of heavy metals.
He said under certain conditions when the lake level is being held at 2,128 feet, the water appears to be stratifying into horizontal columns and some of the tests indicate there is a lack of oxygen in some of the deeper pools on the river and in some of the chain lakes nearby.
That is a condition scientists call anoxic, and Cernera said that is a problem when heavy metals are present because they start to liquefy and dissolve into the lower water column.
“The river is basically slack water as a result of holding the lake at 2,128,” Cernera said. “Then when the lake is drawn down at the end of summer, it moves the metals into the lake.”
Cernera said he released a limited amount of his data to the Coeur d’Alene Basin Commission, which oversees the state’s lake management plan that was created in 2009 to manage the heavy metals in Lake Coeur d’Alene.
“This is preliminary information, we do not have a very robust data set,” he said. “We are just beginning to look at this phenomenon.”
Cernera said the tribe’s researchers plan to collect more data next month, and they should know more about the potential problem early next year.
Cernera said if their data is correct, the samples they took may reveal unhealthy levels of metal in the water.
“They are definitely exceeding tribal standards, but I am not sure if they are exceeding state standards,” he said.
Thomas Herron, water quality manager for Idaho Department of Environmental Quality, said his agency has not reviewed the data yet.
“I really cannot comment on this until we see the data,” he said. “This is speculative preliminary data.”
Herron said IDEQ staff members are planning to bring the topic up at the next basin coordination meeting for discussion.
Terry Harwood, executive director of the Coeur d’Alene Basin Commission, said they just began talking about the issue when the commission met this week. He said the anoxic condition is a symptom of a larger problem with the lake.
“I’ve got concerns about the whole basin,” he said, adding that nutrients flowing into the lake create a lack of oxygen by increasing plant life in the lake.
Harwood said all the scientists don't necessarily agree that anoxic conditions will cause the metals to leach into the lake water.
“Some scientists say it won't happen,” Harwood said. “It’s kind of like the global warming argument. I really don’t care either way. The bigger issue is what is being done to reduce the big nutrient loaders to the lake.”
Harwood said many agencies are working on stream bank stabilization projects to prevent sediments from washing into the rivers, but more of that needs to be done.
Harwood said the state is limited to regulating “point-source” nutrients such as those found in treated wastewater, but they are very limited in how they can regulate “nonpoint-sources” of nutrients making their way into the lake — especially when those nutrients are coming from private property.
He said the only other agency that may be able to do anything about the nutrients coming from private property is the Environmental Protection Agency, if the lake is deemed an EPA operable unit.
“But people are worried if that happens it would screw up tourism,” he said.
Harwood said if the studies do eventually conclude the water quality is going downhill, that would pose a huge problem for water quality managers.
He said there are very few feasible ways to contain the metals if they are leaching into the water. Dredging was considered when the Superfund was expanded out of Kellogg in the 1990s. He said despite the billions of dollars it would cost to do it, the bigger issue would be finding a place to dispose of the material that is dredged up.
Harwood said entombing the sediments in cobble rock or larger rocks would also work, but that is also very expensive.
“There is no physically practical way to get that stuff out of here,” Harwood said. “My point is people better start caring about this issue.”