http://www.sciencedirect.com/science/article/pii/S0380133099707641
By way of background, the BWC system is composed of softwater lakes with a very low carbonate:bicarbonate buffering capacity and consequent low carbonate hardness. These aquatic systems don't possess any resilience to acid mine drainage.
This is a bit difficult to read, but I opted to include it because it underscores the wealth of data that documents in the impacts and pathways of mercury release from its existence as an amalgam in copper, nickel, and gold ores in the upper Midwest igneous rock formations.
Dr. Charles Kerfoot has a dual appointment at MTU, conducting research in both biology and mineral science at Michigan Technological University. The upshot of his research on non-ferrous mining activity consequences indicate that the wetland complexes that exist in this area are near-optimal methylation sites, converting inorganic mercury that enters them via runoff and atmospheric fallout to methyl-mercury; the organic form that can be absorbed by fish, fowl, and mammals.
This is his presentation transcript from a Mining Impacts Symposium held here in Marquette several years ago.
Presentation Transcript

A Rare Glimpse Into The Past: Lake Sediments Reveal Long-term Methyl Mercury Records From Mining:
A Rare Glimpse Into The Past: Lake Sediments Reveal Long-term Methyl Mercury Records From Mining W. Charles Kerfoot 1* , Noel R. Urban 2 , Cory P. McDonald 2 , Ron Rossmann 3 , Ramakrishna Wusirika 1 1 Dept. Biological Sciences, Michigan Technological University, Houghton, MI 49931 2 Dept. Civil & Environmental Engineering, Michigan Technological University, Houghton, MI 49931 3 U.S. EPA, Mid-Continent Ecology Division, Large Lakes Research Station, Grosse Ile, MI 48138
Funding And Important Data Sources:
Funding And Important Data Sources NOAA/NSF KITES Project (NSF OCE) U.S. EPA Region V Grant to Baraga Tribal Council Michigan Department of Environmental Quality (MDEQ); Portage & Torch Lake Joseph Bohr, MDNRE Fish Hg Data Set (2011)
Sources For Atmospheric Hg Discharges (2000 Environment Canada vs 1997 U.S. EPA Report To Congress):
Sources For Atmospheric Hg Discharges (2000 Environment Canada vs 1997 U.S. EPA Report To Congress)
Mercury In Gold Ore Samples: Geographic Comparisons:
Mercury In Gold Ore Samples: Geographic Comparisons
On Site Mercury Releases (atmospheric): EPA Toxic Release Inventory 2001 Region #9 :
On Site Mercury Releases (atmospheric): EPA Toxic Release Inventory 2001 Region #9
Lake Superior Watershed: Precious And Base Metal Mining:
Lake Superior Watershed: Precious And Base Metal Mining
FLUX:
FLUX The amount of mercury (µg) deposited per unit area (m 2 ) per unit time (yr) From atmosphere onto land From water onto lake bottom
Lake Superior Watershed: Cinnabar And Hg-rich Deposits:
Lake Superior Watershed: Cinnabar And Hg-rich Deposits Hemlo Gold Deposit near Marathon:Williams, Golden Giant, David Bell Mines (Michibayashi 1995; Powell and Pattison 1997; Tomkins et al. 2004): Hg 6% in ore samples, 6.7% in concentrates In Some Massive Sulfide Deposits, includes Flambeau Mine, Ladysmith, Ws (Motti et al. 1999): 0.11% Hg in Cu, 1.13% in Ag Huron River, Baraga Co., Mi Cinnabar/Metacinnabar Deposits (Carlson et al. 2007; Olds 2012)
1994 Estimate Of Hg atmospheric Release (kg/yr) by mining operations:
1994 Estimate Of Hg atmospheric Release (kg/yr) by mining operations
Keweenaw Peninsula: Smelter, Mine, Mill Sites:
Keweenaw Peninsula: Smelter, Mine, Mill Sites Stamp Mills
Mercury In Keweenaw Native Copper (ppm):
Mercury In Keweenaw Native Copper (ppm)
Mercury In Keweenaw Native Silver (ppm):
Mercury In Keweenaw Native Silver (ppm)
Keweenaw Waterway Coring Locations:
Keweenaw Waterway Coring Locations
Establishing Chronology: Radioisotope Dating Of Portage Sediment Core:
Establishing Chronology: Radioisotope Dating Of Portage Sediment Core
Portage Lake MeHg Record:
Portage Lake MeHg Record
Industrial Mercury Discharge To Fish:
Industrial Mercury Discharge To Fish
Torch Lake 210Pb Model:
Torch Lake 210 Pb Model Unsupported 210 Pb profile (20m site) CIC-CRS model Modified CRS model
Torch Lake MeHg Record:
Torch Lake MeHg Record
What are regional implications of smelter/tailing discharges to entire watersheds?:
What are regional implications of smelter/tailing discharges to entire watersheds?
Atmospheric & Lake Surface Deposition:
Atmospheric & Lake Surface Deposition
Distribution Of Mining Shafts:
Distribution Of Mining Shafts
Overview of MDEQ Mercury Water Quality Monitoring, Gary Kohlhepp MDEQ Romulus Workshop 2006:
Overview of MDEQ Mercury Water Quality Monitoring, Gary Kohlhepp MDEQ Romulus Workshop 2006 “ The geographic pattern for mercury in lakes/impoundments was opposite that for rivers/streams, with mercury levels generally higher in the Upper Peninsula. ” - Anomalously high, relative to expected atmospheric deposition (Lower Peninsula 2.1X U.P.) “ Mercury… exceeded the Rule 57 Water Quality Value in 35% of Upper Peninsula Lakes versus 8% of Lower Peninsula lakes. ” 2001-2002 Study: 184 lakes; 84 streams/rivers
Foodweb Indicator Points: “Anomalously High” Hg Concentrations in Western U.P. Fish (Joseph Bohr Data, MDNRE 2011):
Foodweb Indicator Points: “ Anomalously High ” Hg Concentrations in Western U.P. Fish (Joseph Bohr Data, MDNRE 2011) 1) counter to expected atmospheric deposition patterns (2.1X higher in L.P. than in U.P.). 2) Hg concentrations higher in W.U.P. than in N.L.P. fish (Northern Pike, Walleye, Bass) 3) Many fish above 0.5 ppm EPA consumption advisory level
“Anomalously High Mercury Concentrations” In Walleye & Northern Pike: W.U.P. vs N.L.P.:
“ Anomalously High Mercury Concentrations ” In Walleye & Northern Pike: W.U.P. vs N.L.P.
THg & MeHg Profiles (ppm, ppb) Show That Mining-impacted (Tailings & Smelter Plumes) Lake Sediments Have Higher Mercury (MDNRE 2011):
THg & MeHg Profiles (ppm, ppb) Show That Mining-impacted (Tailings & Smelter Plumes) Lake Sediments Have Higher Mercury (MDNRE 2011)
Summary:
Summary 1) Mining is a dominant historic source of mercury inputs to the Lake Superior Basin 2. Mercury is in many metal ores (Cu, Ag, Au, Zn), often as a natural amalgam 3. Smelter & Tailing discharges have contaminated many Lake Superior watersheds (U.S. & Canadian sides) 4. The Keweenaw Waterway suggests that methylation of mercury from mining discharges lingers in watersheds with a time lag of at least 20-40 + years. 5. There are “ anomalously high ” Hg values for fish in U.P. lakes. Does this reflect the abundance of wetlands (methylating environments), carry-over mining effects, or an interaction between both?
Mercury In Lake Sediment (Can. Geol. Survey):
Mercury In Lake Sediment (Can. Geol. Survey)
Keweenaw Peninsula Coring Sites:
Keweenaw Peninsula Coring Sites
Anthropogenic Copper Inventories: Spatial Pattern:
Anthropogenic Copper Inventories: Spatial Pattern
Anthropogenic Mercury Inventories: Spatial Pattern:
Anthropogenic Mercury Inventories: Spatial Pattern
Copper/mercury profiles (NSF/NOAA KITES Project) From Deep Water (LSDH) to L’Anse Bay:
Copper/mercury profiles (NSF/NOAA KITES Project) From Deep Water (LSDH) to L ’ Anse Bay
Copper And Mercury Flux Profiles: Keweenaw Waterway (CG: Near Dollar Bay Smelter):
Copper And Mercury Flux Profiles: Keweenaw Waterway (CG: Near Dollar Bay Smelter)
Mercury Concentrations In Ore Samples:
Mercury Concentrations In Ore Samples A) Keweenaw native copper and silver ores B) World (Cu, Au, Ag) ores and Sphalerite (ZnS) C) Solid solution substitution (native metal-natural amalgamation) or for Zn in Sphalerite
Solid Solution Substitution Of Hg For Zn In Sphalerite (Schwartz 1997) :
Solid Solution Substitution Of Hg For Zn In Sphalerite (Schwartz 1997) Exhalative deposits SEDEX VOLCEX
Most of these mercury release sites are stamp sands near processing sites, as well as old mine sites dating back to aboriginal mining efforts.
Doctor Kerfoot also incorporated methyl mercury tissue concentrations from fish samples in the U.P. into another presentation contrasting accumulation pathways in norhtern and southern Michigan. Essentially, the data his group presented underscored that methyl-mercury entering biota via aquatic pathways resulted in higher fish tissue (analyzed as fillets,not whole fish) concentrations in U.P. sampled fish species when compared to similarly analyzed fish samples taken from aquatic systems in southern Michigan near large industrial areas where the principal mercury release pathway was via atmospheric distribution.
Joseph Bohr works for the Michigan Department of Environmental Quality within the MDNR. He has the data files for the U.P. mercury concentration studies. Note:If you opt to request these data you will need an inbox file size upgrade since these are large files. He also is charged with oversight of the EPA AOC up here Deer Lake, another major site of mercury contaminated biota where mining related release pathways resulted in major issues.
http://www.mdpi.com/2076-3298/2/4/546/htm
I opted to include this data to underscore that methyl-mercury accumulation in fish tissues is of elevated concern because it accumulates in muscle tissue preferentially rather than fat tissue.