August 5, 2009
The Department of Environmental Quality (DEQ) has released a report on selenium issues surrounding Cleveland Cliffs Michigan Operations' Tilden and Empire Mines near Marquette. The report shows that elevated levels of selenium are present below the tailings basins and waste rock piles at the mines, and have accumulated in fish at levels that may impact the survival rate of newly hatched fish.
Cliffs and the DEQ are working together to ensure that the discharges of selenium are properly controlled and the fisheries are protected by developing and implementing a comprehensive program of source identification, control options, and impact determination at Cliffs' operations. In addition, the plan will include sampling below other historic mine sites.
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. Selenium contamination is rare in Michigan surface waters, and the levels found as part of this study are high relative to "normal" levels found in Michigan. The DEQ and Cliffs are conducting additional studies to assess the extent of selenium contamination in the areas surrounding the mines and to evaluate controls for the selenium discharges.
The DEQ has placed selenium limits on process wastewater discharges from the Empire Mine that are effective in December 2011. The Tilden Mine discharge permit currently requires monitoring of selenium in the discharge but is being evaluated to include selenium limits. Cliffs is also developing a control strategy for runoff from the 3,000 acres of waste rock between Palmer and National Mine as part of their Storm Water Pollution Prevention Plan.
The DEQ report found that Warner Creek, Goose Lake Inlet, and several small streams exceeded the state water quality standard for selenium. Selenium has accumulated in the sediments of seven lakes and streams above a risk level for bioaccumulation in aquatic life and water dependent wildlife. Fish have been or will be analyzed for selenium in these waters.
The DEQ also evaluated potential human health issues from consuming fish with elevated selenium levels. Of 64 edible fish that were sampled, 1 brook trout from Warner Creek exceeded the acceptable risk level. The average selenium concentration in Warner Creek brook trout was well below the acceptable risk level for human consumption.
Additional DEQ studies are planned this year to determine the extent of fish contamination and to document dissolved oxygen levels in Goose Lake. In addition, the DEQ will be sampling water and sediments below closed mines with extensive waste rock piles and tailings basins for selenium.
The report can be found at: www.michigan.gov/deqwater.
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Editor's note: DEQ news releases are available on the department's Internet home page at www.michigan.gov/deq.
"Protecting Michigan's Environment, Ensuring Michigan's Future"
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