MARQUETTE - Selenium: it's found in nature but it can be toxic, and elevated levels of the substance have recently been discovered near Cliffs Natural Resources' Tilden and Empire mines.
Steve Casey, a water official with the Michigan Department of Environmental Quality, said elevated levels of the naturally occurring element selenium have been found in surface waters in a total of seven lakes and streams near the Cliffs mines, including Warner Creek, Goose Lake, Goose Lake Inlet and several small streams. Selenium was also found below the tailings basins and waste rock piles at the mines.
"The effect we're concerned about is on the reproduction of fish and birds that eat the fish," Casey said, cautioning that at this point humans are not in danger of being affected by the contamination. "We sampled about 41 fish. Only one of the fish slightly exceeded the risk level for human consumption."
Casey said it is not known why selenium levels are elevated, but "the two most likely sources are either the ore or, possibly, it's the rock that is above the ore," he said. "Cliffs is doing extensive studies to determine where it's coming from and where it's leaking into the water."
Asked whether mining activity could have produced higher levels of selenium, Casey said that was "probably true."
"Cliffs has been working with DEQ to identify what the potential source of this element is," Cliffs spokesman Dale Hemmila said. "Right now there is no source identified. We believe additional studies have to be done."
He added that it is important to keep in mind that "there is no known impact on the drinking water."
Casey confirmed that the drinking water in the area is not affected, although if there was a new well on Cliffs property, the water would most likely be too contaminated for human consumption, he said.
According to the DEQ, "selenium is a naturally occurring element that can be leached from rock when it is exposed to water and oxygen. It can bioaccumulate in fish and water-dependent wildlife and cause reproductive failures."
Casey said he does not want to draw any conclusions about the selenium source or its effect on wildlife at this time because he and other DEQ personnel are still studying the issue.
"This is the first time we've had a significant issue with selenium in Michigan," Casey said. "The main thing we're doing right now is to fully examine the contamination."
He added that fish from water bodies that receive runoff from Cliffs are being collected and analyzed.
The DEQ has issued selenium limits on process wastewater discharges from the Empire Mine, effective in December 2011. Casey said Cliffs is being given time to clean up the contamination.
"They have to resolve the issue," he said, adding that the Tilden Mine discharge permit currently requires the monitoring of selenium in the discharge and is being evaluated to include selenium limits.
The DEQ and Cliffs are also working together on a program that would identity sources, control options, and determine the contamination impact at Cliffs' operations.
For more information, go to www.michigan.gov/deqwater.
