DEER LAKE MERCURY CONTAMINATION A Brief History and Overview of the Amended Consent Judgment Steve Casey DNRE Upper Peninsula District

OVERVIEW  Central Upper Peninsula Impoundment  Hg from Mining, much via Ishpeming WWTP  Complex Environmental Issue  Some sources >100 yrs old  “Yooper” municipal storm water system is part of the problem

MERCURY: AN UNUSUAL ELEMENT Metal that’s liquid at room temperature Direct Toxicity of Ionic Mercury –Drinking water: 2,000 ppt –Aquatic Life: 770 ppt Indirect Toxicity –Protect Wildlife (Fish Consumption): 1.3 ppt Mining Uses –Explosive in blasting caps –Amalgam with gold and silver for processing –Laboratory Assay of Iron Ore

Deer Lake Impoundment Lake Area = 1038 ac Depth = 34 ft Eutrophic anoxic hypolimnia, with excellent walleye fishery Formerly: hypereutrophic excellent pike/perch fishery Ishpeming Wastewater Raw sewage until 1963 Primary treatment until 1987

“Known” Mercury Releases in Deer Lake Watershed Ropes Gold & Silver Co – ,894 tons of ore processed Hg released – 5,000 lbs Hg release to tailings – 900 lbs CCIC – Hg discharged with NO sewage treatment Hg discharged via primary treatment plant Total discharge of Hg = 2,306 lbs Lake sediments contain about 8000 lbs of mercury today

TIMELINE Ropes Environmental Assessment in 1980’s One of 14 IJC “Areas of Concern” in Michigan Consent Judgment with CCI in 1984 Reservoir Drained in mid 1980’s Expectation for mercury levels decline not met Late 1990’s, CCI and DNRE conduct studies Parties Decide to Settle Issue in 2002 Amended Consent Judgment Entered in 2006

Northern Pike in 1984

Mercury Concentrations in Pike before and after stopping CCI Discharge and Draining Lake

Late 1990’s, CCI, UW and DNRE Conduct Parallel Studies Cliffs Focused on: – External Loadings of Methyl and Total Mercury, –In Lake Production of Methyl Mercury –Reference Lakes –Recommended Alternatives to Reduce Water Column Methylation and Increase Fish Growth Rates –Implemented Hypolimnetic Release

DNRE Focused on Mercury in Sediments: How Much Distribution Concentrations in Newly Deposited Sediment Cost to Remove or Cover Sediments ($50- $100M)

DNRE Also Looked at External Sources of Mercury to Deer Lake –Total Loading to DLI = ¾ Pounds per Year (was ~40 lbs/yr) –About 22% from Cliffs Shaft Mine –About 2% from Ishpeming Area WWTP

Parties Decide to Settle Issue in 2002 Technical Issues will not Likely Be Resolved –Sediments a problem? –Drawdown may impact fish 20 to 30+ yrs. –Effectiveness of Dredging is Questionable –Natural Sedimentation Should Cover Contaminated Sediments in ~25 Years

Key Issues Maintain Dam to Keep Sediments in Place and Provide Recreational Value [$750,000 Financial Assurance] Provide the State Mitigation for Damages and Compensation for Taking Responsibility for Liabilities Associated with Mercury in Deer Lake [Cliffs transfers 1500 acres of land with 7 miles of lake frontage, 3 miles of river frontage, 7 lake and 6 river access points to state or local governments] Funding for Improvements as Necessary [$500,000] Control Mercury From Cliffs Shaft Mine [City of Ishpeming is seeking stimulus funding for new storm sewers]

QUESTIONS?