Browsing by Subject "Taking Stock - Pollution & Contamination"

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Duluth Parks and Recreation Master Plan: Principles and Objectives
(2010) Duluth, Minnesota Parks and Recreation
12 slide Powerpoint presentation. Principles, listed below, in addition to specific objectives for each are included. Principle 1: Provide Safe, Clean, Fun and Beautiful Parks Principle 2: Ensure Adequate and Stable Funding Principle 3. Build Partnerships Principle 4: Ensure equitable access Principle 5: Connect the community Principle 6: Connect with Nature Principle 7: Continue to meet evolving natural resource needs Principle 8: Be sustainable Not much reference is made about water resources in the master plan files available on the city website; most of the survey pertains to non-water recreational park use.
Fond du Lac Resource Management: 2008 Integrated Resource Management Plan
(2008) Fond du Lac Band of Lake Superior Chippewa
This very comprehensive document was reviewed and is felt to have significant content and analysis relevant to Minnesota’s coastal area and water resources. It also contains biophysical and watershed-related content directly relevant to Native communities in Minnesota’s coastal communities. Key content is reproduced below: Executive summary: “This Integrated Resource Management Plan contains information about the Band’s past and current management activities and identifies resources that need additional management. The Integrated Resource Management Plan contains alternatives to resource management, as required by the National Environmental Policy Act, which are based on the management objectives. Management activities range from no action to full implementation, and the alternatives presented reflect that range. The objectives that can be completed under each alternative are displayed in a table located at the end of discussion on alternatives. Public input was solicited on the draft document, which included a variety of management alternatives. Comments obtained from the community and tribal government were incorporated into the final document, and the hearing process provided a basis for the formulation and selection of the preferred alternative. The preferred alternative is officially approved by Resolution # 1183/08. Each resource is described in a narrative that was developed in the following format: o Description of the affected environment o Background for that resource o Issues, concerns, and opportunities for that resource o Goals and objectives for that program, with different management alternatives The final chapter is a summary of the alternatives. The preferred alternative is identified for each resource.” Approximately 15 pages of this report are dedicated specifically to water-based resources, including chapters on wild rice, wetlands and water, and fisheries. Some sections are reproduced below. Wild Rice There are five primary wild rice lakes on the Fond du Lac Reservation. The total area on which wild rice is currently present on these lakes is 843 acres. The wild rice areas on the individual lakes are: Perch Lake, 411 acres; Mud Lake, 151 acres; Rice Portage Lake, 131 acres; Jaskari Lake, 79 acres; and Deadfish Lake, 71 acres. These lakes are all within the Stoney Brook Watershed, which is tributary to the St. Louis River. Wild rice is also present in Side Lake, Cedar Lake, Wild Rice Lake, Simian Lake, and Hardwood Lake. Side Lake and Hardwood Lake are within the Stoney Brook Watershed. Cedar Lake and Simian Lake are within the Simian Creek Watershed. Wild Rice Lake is the headwaters of the Moosehorn River, a tributary of the Kettle River. The density of mature wild rice varies from season to season, as the ecology of wild rice growth is related to cycles of plant decomposition, the number of growing days, and available nutrients. In addition, wild rice is easily lost as a result of natural events, such as high winds, flooding, and hail. The majority of the wild rice resource on the Fond du Lac Reservation is in the Stoney Brook Watershed. Beginning in 1916, the Stoney Brook Watershed was adversely affected by the creation of a network of judicial ditches. These judicial ditches drastically altered the hydrology of the watershed, resulting in the loss of over 500 acres of wild rice habitat. The lower water levels that resulted from the judicial ditching allowed competing vegetation to encroach on areas that at one time supported wild rice. Besides the Stoney Brook Watershed, wild rice resources in other areas of the Fond du Lac Reservation are in decline as well. The reason for this decline is primarily due to higher water levels, caused by road building and beaver activity. The Fond du Lac Natural Resources Program is responsible for the wild rice management and restoration activities on the Fond du Lac Reservation. The primary method of wild rice lake management consists of utilizing water control structures (dams) to stabilize water levels, ditch maintenance, and beaver dam management. The restoration of the major wild rice lakes on Fond du Lac is dependent on restoring the lakes to their historical elevation and a more natural annual hydrological cycle. The implementation of the Rice Portage Wild Rice and Wetland Restoration Project resulted in the construction of four water control structures. These four structures are located at the outlet of Perch Lake, the outlet of Rice Portage Lake, an impoundment that is upstream of Deadfish Lake (commonly known as “Upper Deadfish”), and at the outlet of Deadfish Lake. These structures are used to restore the lake elevations and improve hydrologic function. Issues: The ineffectiveness of current mechanical methods for the restoration project on Rice Portage Lake. Mud Lake continues to produce a thin crop of wild rice, despite its potential for higher yields. Concerns: Invasive species–both invasive and exotic plant species–are of great concern due to their persistence once introduced. While there are no know exotic species in our wild rice lakes, the risk is high given the uses of these lakes by waterfowl hunters and wild rice harvesters. Climate change–weather pattern changes, annual precipitation, and temperature changes–all may impact the viability of our wild rice lakes. Opportunities The Stoney Brook Watershed Study will provide a model that will allow for more effective water level management, and identify opportunities for restoration of the original river system, and abandonment of unnecessary ditch segments. The current trend of land purchasing, land use planning, and increased resource management capabilities affords long term protection for portions of the wild rice lake watershed that were unavailable in the past. Increased Resource Management Division staff and capabilities may allow for opportunities to partner with other agencies and organizations to restore, protect, and enhance wild rice growth throughout the Ceded Territories. Goals & Objectives At a minimum, maintain the current program and management. Increase vegetation treatment acreage per annum. Surface water resources The Fond du Lac Reservation includes abundant freshwater resources, with over 3,000 acres of lakes (828 acres of wild rice waters), nearly 44,000 acres of wetlands, and 96 miles of rivers and streams. The St. Louis River, the largest U.S. tributary to Lake Superior, borders the Reservation to the north and east, and approximately 95% of the waters of the Reservation lie within its watershed. All of the waters within the Reservation are believed to be relatively pristine. There are no known or permitted industrial or municipal discharges to the waters, except to the St. Louis River. Historical hydrological modifications to many of the Reservation’s wild rice lakes occurred with the development of the judicial ditch drainage system early in the twentieth century. Currently, a restoration project is underway to gradually restore Rice Portage Lake, one of the most productive rice lakes, to its historical water levels, and to minimize water level fluctuations on Deadfish Lake, thereby enhancing its stands of rice. Shoreline development and the accompanying potential for increased nutrient inputs (septic discharge and lawn chemicals) and erosion are factors that could affect the water quality of several Reservation lakes. By 1998, the Fond du Lac Environmental Program developed and the Reservation Business Committee adopted a set of Water Quality Standards for the surface water resources of the Reservation, setting contaminant criteria and designating uses for 24 lakes and eight streams within the boundaries, and identifying Outstanding Reservation Resource Waters. More recently, the Band has been granted “Treatment as a State” authority by the U.S. Environmental Protection Agency, under the federal Clean Water Act, enabling it to enact and enforce such standards. As a critical tool for implementing these standards, the Environmental Program designed a comprehensive Water Quality Monitoring Plan. Initially a rigorous three-year monitoring project measuring the physical, chemical and biological quality of 24 lakes and eight streams located within the exterior boundaries of the Reservation, it has since been modified to reflect an ongoing status and trends program. This comprehensive database on Fond du Lac surface waters will also permit the Office of Water Protection to develop numerical biocriteria to replace the narrative biocriteria currently in the tribal Water Quality Standards. The data is also utilized to assess and report on the condition of these water bodies and their attainment of designated and aquatic life uses. Protecting human health requires monitoring for indicators that measure the safety of eating fish or other aquatic wildlife, or of swimming and boating. Conserving ecosystems requires indicators of diverse, healthy aquatic plant and animal communities, and indicators are also needed to assure that water quality and sediment conditions can maintain those biological communities. The Water Quality Monitoring Plan was designed to assess indicators for both human health and aquatic life. Atmospheric deposition of mercury is of particular concern in this boreal forest and wetland ecoregion, as biochemical processes enhance mercury availability to the aquatic food chain, bioaccumulating to levels that are hazardous to top predators and humans. Consequently, fish caught in Reservation waters can be dangerously high in tissue mercury content. Criteria for the Water Quality Standards were calculated under an assumed fish consumption rate that is much higher than the state of Minnesota or the Great Lakes region assumes for the general population, as some Band members rely upon fish at a subsistence level in their diet. The Environmental Program has completed several projects that assessed contaminant levels (mercury, PCBs and lead) and characterized sediments of twelve Reservation lakes and the St. Louis River. In 2001, Fond du Lac partnered with the Minnesota Department of Health to collect and analyze fish tissue from lakes and the St. Louis River (preferred fishing waters), using the data to develop specific fish consumption advisories. Groundwater In 2004, Fond du Lac completed its first Nonpoint Source Assessment Report and applied for Treatment as a State for non-point source authority. The Office of Water Protection received its first base program funding in 2005 and is using that support to implement several projects under the following categories: hydro modification, timber harvesting, roads and urban development. The Resource Management Division is also engaged in a major hydrologic study of the Stoney Brook watershed in partnership with Natural Resources Conservation Service and the U.S. Geological Survey. Ultimately, a Stoney Brook Watershed Management Plan will be developed to account for multiple resource management objectives, including wild rice production and stream and wetland restoration. The Office of Water Protection also has identified aquatic invasive species as a major concern for protecting the Reservation’s water resources. The nonpoint source program provides for broad education and outreach to the Reservation community and affected stakeholders, in order to minimize nonpoint source impacts to Fond du Lac water resources. The primary objectives of the Environmental Program are to ensure the protection of valuable ground water resources through the continued closures of abandoned wells, the delineation of protection zones for wells contributing to community water systems, and the development of a wellhead protection plan for the Reservation. The Fond du Lac Reservation boundary encompasses 101,153 acres, of which 43,264 (43%) are wetlands. These wetlands consist of forested (67% – black spruce, tamarack, or black ash dominant; includes bogs), scrub shrub (29% – alder or willow dominant), emergent (3% – sedge, reed canary grass, or cattail dominant; includes wild rice lakes), and open water (< 1% – coontail dominant). Many wetlands on the Reservation have been degraded due to human activities, particularly by ditching, road construction, agricultural and silvicultural runoff, and commercial and residential development. The Environmental Program has a Wetlands Conservation and Protection program that has been active since October of 1998. A Wetlands Protection and Conservation Plan was adopted by the Reservation Business Committee in October 2000. The plan was expanded, updated and adopted by the Reservation Business Committee in February 2006 to become the Fond du Lac Joint Comprehensive Wetlands Protection and Management Plan. The adoption of this plan led to the development and adoption by the Reservation Business Committee of the Fond du Lac Wetlands Protection and Management Ordinance in June 2006. Erosion and sedimentation resulting from storm water can cause significant impact to surface waters. On the Reservation, construction activities have the potential to be a major contributor to these impacts. Since March 2003, the Office of Water Protection has been providing erosion and sedimentation control best management practices oversight of construction projects on the Reservation. This is the result of the Environmental Protection Agency’s National Pollutant Discharge Elimination System Phase II Construction Storm Water regulations as part of Section 402 of the Clean Water Act. In addition to this voluntary oversight, the Office of Water Protection has also entered into a Storm Water Direct Implementation Tribal Cooperative Agreement to conduct inspections of construction sites impacting one acre or more. Two tribal inspectors have been trained and credentialed by Environmental Protection Agency to conduct inspections on the Reservation. More than 13 projects are scheduled for inspection during the construction seasons of 2007 and 2008. In addition, the Office of Water Protection has been developing the required Storm Water Pollution Prevention Plans for nearly all projects conducted by the Reservation, as well as occasional projects conducted by individual Band members.” A long list of concerns and threats to water resources is included in the report. These related to taconite and sulfide mining operations, mercury deposition, nonpoint source pollution and other causes. “Fisheries The majority of the lakes on the Fond du Lac Reservation are small, shallow bodies of water, more suitable for growing wild rice than for the management of any significant fisheries. Many of these lakes do have fish, however, with populations consisting primarily of northern pike), largemouth bass, panfish, yellow perch), and bullhead. Due to relatively shallow water, high abundance of aquatic macrophytes, and substrates composed predominantly of decaying organic matter, many of these Reservation lakes are incapable of supporting any naturally reproducing populations of walleye (Sander vitreus). These lakes are, however, conducive to the production of northern pike, panfish, largemouth bass, and bullhead but are also subject to frequent winterkill. Most of the lakes on the Reservation do have some type of public access, though most are strictly carry-in accesses. The fishery of the St. Louis River is by far the most important one for residents of the Reservation. At least four game fish species can be found in appreciable numbers; northern pike, walleye, smallmouth bass, and channel catfish. The channel catfish fishery remains the highest priority of Fond du Lac Band members who regularly use the St. Louis River’s fishery resources. Much can be done to improve the trout populations on the Reservation. Stream improvements and the removal of beaver and their lodges and dams may improve habitat for resident trout populations. Stocking may need to be a part of future management activity, but shouldn’t be random and haphazard as past stocking activities appear to have been. In addition, regular assessments need to be performed following any stocking efforts. The fisheries in the 1854 and 1837 Ceded Territories are numerous and diverse, from small trout streams in the Superior National Forest, to lakes such as Mille Lacs that are capable of sustaining large walleye populations, to the salmon and trout of Lake Superior. Walleye and northern pike appear to be the most important species to Band members, and are relatively abundant throughout both of the Ceded Territories. A high priority for Band members is a concentrated subsistence harvest at Mille Lacs Lake, where a regular spring harvest season occurs.”
Human Influences on Water Quality in Great Lakes Coastal Wetlands
(2008) Morrice, John A; Danz, Nick; Regal, Ronald R; Kelly, John R; Niemi, Gerald J; Reavie, Euan; Hollenhorst, Thomas; Axler, Richard P; Trebitz, Annet; Cotter, Anne C; Peterson, Gregory S
This peer-reviewed article discusses water quality and chemistry issues with anthropogenic causes. Geographically, it covers the US coastal region of the Great Lakes. A map in the article suggests that only one sampling point was within Minnesota’s coastal region. The article focuses on water chemistry in coastal wetlands across the Great Lakes, but not specifically for Minnesota. Key points in the abstract are extracted and reproduced below. A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine stressor-water quality relationships. The sampling captured broad ranges (1.5–2 orders of magnitude) in total phosphorus (TP), total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected, open coastal) and biogeography (two eco-provinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems.
Hydrology and Water Quality of the Copper-Nickel Study Region, Northeastern Minnesota
(1980) Siegel, Donald I; Ericson, Donald W
This 35-year old hydrologic study documents conditions in the Cu-NU region of Minnesota’s Iron Range. It is primarily a technical report, but its main value is the baseline data provided, and that it contains a water budget for the area. It’s primary message for decision-makers is that “the introduction of trace metals from future mining to the ground-water system can be reduced if tailings basins and stockpiles are located on material of low permeability, such as till, peat, or bedrock." Key segments are extracted and reproduced below. Abstract: "Data were collected on the hydrology of the Copper-Nickel study region, to identify the location and nature of ground-water resources, determine the flow characteristics and general quality of the major streams, and determine the potential effects of mining copper and nickel on the hydrologic system. Ground-water investigations indicate that water generally occurs in local flow systems within surficial deposits and in fractures in the upper few hundred feet of bedrock. Availability of ground water is highly variable. Yields commonly range from only 1 to 5 gallons per minute from wells in surficial materials and bedrock, but can be as much as 1,000 gallons per minute from wells in the sand and gravel aquifer underlying the Embarrass River valley. Except over the mineralized zone, ground water in the surficial deposits is a mixed calcium magnesium bicarbonate type. Ground water over the mineralized zone generally has both a greater percentage of sulfate, compared to bicarbonate, and concentrations of copper and nickel greater than 5 micrograms per liter. "Surface-water investigations indicate that the average annual runoff from streams is about 10 inches. Plow characteristics of streams unregulated by industry are similar, with about 60 percent of the annual runoff occurring during snowmelt in April, May, and June. Flood peaks are reduced in the Kawishiwi River and other streams that have surface storage available in onchannel lakes and wetlands. These lakes and wetlands also trap part of the suspended-sediment load. Specific conductance in streams can exceed 250 micromhos per centimeter at 25° Celsius where mine dewatering supplements natural discharge. "Between 85 and 95 percent of the surface water used is for hydroelectric power generation at Winton and thermo-electric power generation at Colby Lakes. Mine dewatering accounts for about 95 percent of the ground-water used. Estimated ground-water discharge to projected copper-nickel mines ranges from less than 25 to about 2,000 gallons per minute, depending on the location and type of mining activity. The introduction of trace metals from future mining to the ground-water system can be reduced if tailings basins and stockpiles are located on material of low permeability, such as till, peat, or bedrock."
An Integrated Approach to Assessing Multiple Stressors for Coastal Lake Superior
(2011) Niemi, Gerald J; Reavie, Euan; Peterson, Gregory S; Kelly, John R; Johnston, Carol A; Johnson, Lucinda B; Howe, Robert W; Host, George; Hollenhorst, Thomas; Danz, Nick; Ciborowski, Jan H; Brown, Terry; Brady, Valerie; Axler, Richard P
This peer-reviewed article summarizes research conducted under the Great Lakes Environmental Indicators (GLEI) project initiated by the authors in 2001. The authors assessed the status of Lake Superior’s coastal ecosystem relative to over 200 environmental variables collected from GIS data sets for the enture US Great Lakes basin. These were assessed using gradients including atmosphereic deposition, agriculture, human population and development, land cover, point source pollution, soils and a cumulative stress index. Relationships of biological assemblages of birds, diatoms, fish and invertebrates, wetland plants, soils and stable isotopes to these gradients were then assessed. Key findings are extracted and reproduced below. Biological indicators can be used both to estimate ecological condition and to suggest plausible causes of ecosystem degradation across the U.S. Great Lakes coastal region. Here we use data on breeding bird, diatom, fish, invertebrate, and wetland plant communities to develop robust indicators of ecological condition of the U.S. Lake Superior coastal zone. Sites were selected as part of a larger, stratified random design for the entire U.S. Great Lakes coastal region, covering gradients of anthropogenic stress defined by over 200 stressor variables (e.g. agriculture, altered land cover, human populations, and point source pollution). A total of 89 locations in Lake Superior were sampled between 2001 and 2004 including 31 sites for stable isotope analysis of benthic macroinvertebrates, 62 sites for birds, 35 for diatoms, 32 for fish and macroinvertebrates, and 26 for wetland vegetation. A relationship between watershed disturbance metrics and 15N levels in coastal macroinvertebrates confirmed that watershed-based stressor gradients are expressed across Lake Superior’s coastal ecosystems, increasing confidence in ascribing causes of biological responses to some landscape activities. Several landscape metrics in particular—agriculture, urbanization, human population density, and road density—strongly influenced the responses of indicator species assemblages. Conditions were generally good in Lake Superior, but in some areas watershed stressors produced degraded conditions that were similar to those in the southern and eastern U.S. Great Lakes. The following indicators were developed based on biotic responses to stress in Lake Superior in the context of all the Great Lakes: (1) an index of ecological condition for breeding bird communities, (2) diatom-based nutrient and solids indicators, (3) fish and macroinvertebrate indicators for coastal wetlands, and (4) a non-metric multidimensional scaling for wetland plants corresponding to a cumulative stress index. These biotic measures serve as useful indicators of the ecological condition of the Lake Superior coast; collectively, they provide a baseline assessment of selected biological conditions for the U.S. Lake Superior coastal region and prescribe a means to detect change over time.” Key points: “In general, the U.S. Great Lakes coastal region of Lake Superior shows greater overall stress in the southern regions compared with relatively low overall stress in the northern regions. These patterns are primarily due to agricultural land use, higher human population densities, and point sources in the eastern and western portions on the south shore, while the north shore at the western end of Lake Superior is primarily forested with relatively sparse human population densities. Coastal regions of Lake Superior can be found at each of the extremes of the disturbance gradients. This includes relatively pristine watersheds in the northern regions with low human population densities and little agriculture that contrast with regions of relatively high populations with industrial activity such as Duluth-Superior in Minnesota-Wisconsin and Sault Ste. Marie Michigan at the other end of the gradient. The U.S. Lake Superior coastal region varies widely in the degree of human-related stress; generally, levels of stress decrease from south to north but with considerable variation, especially along the southern shore due to local agricultural activity and the presence of several population and industrial centers. In spite of a lack of latitudinal variation, there is human-induced, watershed scale variability across the Lake Superior coast. Compared to the other Great Lakes, Lake Superior coastal fish communities had more generally intolerant fish and more turbidity intolerant fish. Coastal fish community composition reflected the higher levels of suspended solids associated with human alteration to watersheds. The most disturbed sites on Lake Superior had greater proportions of non-native species and fewer bottom-feeding taxa.
Mercury in Streams at Grand Portage National Monument: Evidence of Ecosystem Sensitivity and Ecological Risk
(2012) Wiener, James G
This is a 4-page pdf, which apparently has not been published although the paper reviewers are named. The origin of the paper is unclear, and it should be regarded as “gray” literature. Key points are extracted and reproduced below. “In 2008, the University of Wisconsin-La Crosse began quantifying mercury in aquatic food webs in six national park units in the western Great Lakes region, including Grand Portage National Monument (GRPO). Principal objectives are (1) to identify parks and water bodies where concentrations of methylmercury are high enough to adversely affect fish and wildlife, and (2) to assess spatiotemporal patterns in methylmercury contamination of aquatic food webs. Methylmercury is a highly toxic compound that readily bioaccumulates in exposed organisms and can biomagnify to harmful concentrations in organisms in upper trophic levels of aquatic food webs. Study sites at GRPO include Snow Creek (beaver pond in upper reaches and lower reaches), Poplar Creek (south branch), and Grand Portage Creek (lower reach). Analytical results reveal elevated concentrations of both total mercury and methylmercury in these stream systems... Concentrations of total mercury and methylmercury in streamwater from GRPO are substantially higher than concentrations typically found in lakes and streams in the western Great Lakes region. “Bioaccumulation and ecological risk. In 2010, prey fish were sampled from three streams in the park and analyzed whole for total mercury, which accumulates in fish as methylmercury. Mean concentrations were highest, exceeding 100 ng/g wet weight (nanograms per gram, equivalent to parts per billion) in blacknose dace (Rhinichthys atratulus) and longnose dace (Rhinichthys cataractae) from Poplar Creek. These mean concentrations in dace substantially exceed the estimated dietary threshold (40 ng/g wet weight in prey fish) associated with reproductive effects of mercury on piscivorous fish that feed on prey fish (Depew et al. in press). Mean concentrations of mercury in most of the other prey fishes analyzed also exceeded the 40 ng/g threshold for reproductive effects on piscivorous fish; these included creek chub (43 ng/g) and central mudminnow (56 ng/g) from Poplar Creek, fathead minnow (58 ng/g) and central mudminnow (55 ng/g) from Snow Creek, and longnose dace from Grand Portage Creek (67 ng/g). The maximal concentrations in individual fish were 242 ng/g in blacknose dace and 211 ng/g in longnose dace. These maximal values exceed dietary thresholds associated with adverse effects of methylmercury on the health and reproduction of fish-eating birds. “The high concentrations of methylmercury in larval dragonflies may indicate significant risks for insectivorous songbirds that forage and nest near streams at GRPO. Studies in eastern North America have documented unexpectedly high concentrations of mercury (present as methylmercury) in certain terrestrial invertivores, including passerine songbirds. Most songbirds with elevated concentrations of mercury are linked trophically to mercury-methylating environments—such as wetlands, streams, or lakes—and feed on spiders or emergent insects with aquatic larval stages. Methylmercury in the diet of reproducing female birds is transferred rapidly to the developing egg, and the embryo is the most sensitive life stage. Methylmercury exposure and its potential effects on reproductive success of invertivorous songbirds at GRPO has not been assessed but merits critical evaluation.”
The Minnesota Regional Copper-Nickel Study 1976-1979, Volume 1: Executive Summary
(1979) Minnesota Environmental Quality Board
This is a comprehensive, clearly-written document summarizing potential biophysical and socioeconomic impacts of copper-nickel mining in Minnesota. Special attention is paid to impacts on water resources. Relevant sections are reproduced in their entirely below, not only for historical interest but because of predictive power. Summary: "The Minnesota Environmental Quality Board's Regional Copper-Nickel Study is a comprehensive technical examination of the environmental, social, and economic impacts associated with the potential development of copper-nickel sulfide mineral resources of the Duluth Complex in northeastern Minnesota. This executive summary of the 5 volume, 36 chapter report presents some of the major findings of the Study, but in order to get a complete picture of the complex issues associated with exploiting this valuable mineral resource, the entire document should be examined. In addition to this report over 180 technical reports, extensive environmental monitoring data files, special sample collections, and other information resources were compiled by the Study" (n.b. these documents were not reviewed as part of this current desk review). Consistent with directions from the Minnesota Legislature, the Regional Copper-Nickel Study presents technical findings but does not make policy recommendations based on these findings." "To allow for a discussion of the potential environmental and socio-economic effects of copper-nickel development, an area of approximately 2100 square miles was designated as the Regional Copper-Nickel Study Area (or simply, the Study Area). This area contains Virginia in the southwest corner and Ely in the northeast corner. The major copper-nickel deposits of interest occur along the Duluth Gabbro Contact, in a band three miles wide and fifty miles long (the Resource Area); however, additional deposits may extend beyond this band. The Water Quality Research Area, which includes the complete watersheds of 14 streams of interest, is shown in Figure 2. Waters north of the Laurentian Divide are part of the Rainey River Watershed, which includes a portion of the Boundary Waters Canoe Area, and whose waters eventually drain into Hudson Bay and the North Atlantic. Waters south of the Divide are a part of the St. Louis River Watershed which drains into Lake Superior and eventually into the Atlantic Ocean via the St. Lawrence River.” "Historically, the exploitation of base metal sulfide resources (such as copper-nickel resources) throughout the world has been accompanied by the significant degradation of the quality of water resources and the destruction of aquatic and terrestrial biota m the vicinity of such developments. Acid mine drainage, toxic heavy metals contamination, erosion, sedimentation, increased salinity, and other water pollution problems associated with mining were common. The nonferrous minerals smelting industry (principally copper, lead, and zinc) has also been a major source of manmade air pollutants. Until new technology has been developed to minimize many of these impacts, adverse impacts of past practices continue to cause close scrutiny of new mining proposals.” Water Quantity (Volume 3-Chapter 4). "Surface water is abundant in the Water Research Study Area due to high surface runoff. Average annual runoff in the region is about 10 inches. The Water Research Study Area includes 360 lakes larger than 10 acres, in addition to 14 small rivers and streams. Nearly 75 percent of the Water Research Study Area, and an even larger proportion of the surface water is north of the Laurentian Divide. North of the Divide, lakes are more numerous and larger, and the volume of stream flow is greater because a larger area is being drained. Because some of these waters are inside the BWCA, not all of the water north of the Divide is directly available for use. Annual average flow for 12 streams studied by the U.S. Geological Survey for the Study ranged from 23 to 1,027 cubic feet per second (cfs). High flow generally occurs after heavy precipitation and following the spring snowmelt. Average low flow for seven days is 2 to 186 cfs compared to an average high flow of 87 to 4,763 cfs. Ground water yield is generally low, limited by the low permeability of the Area's bedrock and the often shallow overlaying glacial deposits. Yields generally average less than 5 gallons/minute. Three relatively small areas have high volume aquifers yielding up to 1,000 gallons/minute: the Embarrass Sand Plain, the Dunka River Sand Plain, and the local fractured and leached bedrock areas in the Biwabik Iron Formation.” "Current industrial use of surface water is primarily for electric power generation. Mine-pit dewatering is the greatest groundwater use. At current levels, water use does not cause significant impacts on the region's water resources, although withdrawal from some streams must be reduced during low flow. Surface water, including some of the large on-channel lakes (e.g. Birch Lake), could supply large water users, al though storage may be required for certain streams. The Embarrass River Valley aquifer is the only identified groundwater source in surficial materials that could supply large water users.” Water Quality (Volume 3-Chapter 4). "Because of the large number of streams and lakes in the Study Area, the value of high quality water which supports a significant recreational and wilderness resource of the state and the nation, and the recognized historic relationship between base-metal mining and water pollution, a major responsibility of the Regional Copper-Nickel Study was the collection of baseline surface and ground water quality data (note: data tables and figures and not reproduced). "The quality of the region's water resources is generally very good except for several streams with watersheds affected by extensive taconite mining activities, and for groundwater either from glacial till or wells near the Duluth Gabbro Complex sulfide mineralization. Streams draining largely undisturbed watersheds can be described as containing soft water, having low alkalinity, low total dissolved solids, low nutrients, high color, very low trace metals concentrations, and low fecal coliform counts.” "Streams draining disturbed watersheds (Partridge, Embarrass, Upper St. Louis rivers south of the Laurentian Divide, and the lower Dunka River and Unnamed Creek north of the Divide) would be considered to contain moderately hard to hard waters, with elevated dissolved solids, nutrients, and trace metals concentrations relative to undisturbed watersheds. Color and fecal coliform concentrations are not significantly different in the two watershed classifications. Most water quality parameters tend to be much less variable in undisturbed streams as compared to disturbed streams. The quality of the lakes studied is variable though similar to the quality of undisturbed streams. However, lake values may be less meaningful for determining baseline concentrations than values in streams because of the limited number of samples.” "In general, concentrations of most chemical constituents are higher in the groundwater than in streams and lakes of the area. Groundwater from wells proximate to the Duluth Gabbro contact were found to have higher levels of trace metals and sulfate than wells located at a distance from the contact. Phosphorus and nitrogen are the major nutrients in aquatic systems. Concentrations of both nutrients in study streams are at the low end of the range of values for U.S. streams. Variations in nutrient levels exhibited no clear trends between headwater and downstream stations or between small and large watersheds. Highest concentrations of nitrogen were found downstream from mining operations where blasting compounds containing nitrogen are used. In lakes, nutrient parameters are closely associated with the activities of aquatic organisms. Higher levels of available nutrients encourage greater biological productivity. The ratio of nitrogen (N) to phosphorus (p) can be used to evaluate which of these nutrients limits algal productivity. Lakes with a N:P ratio greater than 14 are considered to be limited by phosphorus. Within the Study Area, median N:P ratios ranged from 14 to 60, and half the lakes studied had ratios greater than 25. Overall concentrations of both nutrients were at the low end. Median values for both nutrients were higher south of the Laurentian Divide than north of it. The most productive lakes were all headwater lakes, usually shallow, and surrounded by extensive bog and marsh areas.” "A major concern related to copper-nickel development is levels of heavy metals in surface waters. At background stream stations, copper, nickel, and zinc levels are generally very low, with median concentrations of copper and zinc in the range of 1-2 ug/liter and nickel around 1 ug/liter. Other trace metals of biological importance (As, Cd, Co, Hg, and Pb) have median concentrations significantly below 1 ug/liter. There is little variability in the levels of arsenic, cobalt, cadmium, mercury, titanium, selenium, and silver across almost all surface waters monitored. As expected, iron, manganese, copper, nickel, zinc, lead, fluoride, and chromium concentrations in streams are significantly higher in disturbed watersheds than in undisturbed areas. The dynamics of metals in lakes are somewhat different from those in streams because the large surface area of bottom sediments with their varying oxidation reduction potentials complicates the picture. Lakes can act as sinks for metals (as is the case with iron at Colby Lake) so that the chemistry of out flowing waters is different from that of inflowing waters. Large lakes may exhibit variability in the concentration of metals within the lake itself (as is the case with nickel in Birch Lake). Similar to streams, iron,' aluminum, and manganese were the most elevated metals in the Study Area lakes. Copper, nickel, and zinc have median levels between 1 and 2 ug/l, whereas arsenic, cobalt, and lead have median levels of 0.6,0.4, and 0.4 ug/l, respectively. Cadmium levels were an order of magnitude (10 times) lower than those for arsenic, cobalt, and lead. The greatest variabilities in concentrations were exhibited by manganese, zinc, cadmium, and aluminum, with arsenic the least variable metal.” "Water quality standards and criteria for many parameters have been adopted or are proposed for adoption by the Minnesota Pollution Control Agency or the U.S. Environmental Protection Agency (EPA). Recommended levels for cadmium, color, copper, iron, lead, manganese, mercury, nickel, nitrogen (as N02 + N03), pH, specific conductance, sulfate, and zinc were exceeded in one or more of the streams monitored. In most cases, these elevated levels occurred in Unnamed Creek, which is affected by mining (see discussion of Unnamed Creek below). The region's streams and lakes have naturally high color levels.” "All streams which were monitored exceeded the EPA water quality criteria for mercury (0.05 ug/liter). The median concentration of mercury for all streams monitored was 0.08 ug/liter with a range of 0.01-0.6 ug/liter. Standards for mercury are based on U.S. Food and Drug Administration guidelines for edible fish. High mercury levels have been found in fish from some of the area's lakes and streams. Because acid precipitation is a potential problem, the quality of precipitation in the Study Area was monitored at several sites. Seventy-seven percent of the samples (41) had a pH less than 5.7, which means that most of the precipitation measured can be considered acidic. Fifty percent of the samples had a pH of 3.6 to 4.4. The geometric mean pH of samples collected in the area was 4.6. These values are comparable to, or even less than values measured in areas of the world where ecological damage has already occurred. Measurements by the Regional Study indicate that the present annual sulfate deposition rate (wet plus dry) across the Study Area is from 10 to 20 kg/ha/yr (9 to 18 lbs/ acre/yr). Atmospheric dispersion modeling indicates that regional sources of S02 are not major contributors to depressed acidity of precipitation and suIfate deposition in the region. This in turn indicates that out-state and out-of-state sources, possibly as far away as St. Louis, Chicago, and Ohio Valley areas, are likely the major cause of acid rain and sulfate deposition in northeastern Minnesota.” "If the patterns of increasingly acidic precipitation continue, it is likely that many of the poorly buffered small streams will have noticeable decreases in aquatic populations (such as fish) during and following spring melt.” "Stream systems are very sensitive because the flush of water from spring snowmelt can represent a majority of the water that the stream may carry through the whole year. Recovery from these episodes may be expected to be fairly rapid (i.e. within months) unless or until the sources of recolonizing organisms are themselves affected (i.e. well buffered lakes or large unaffected streams). Recovery would be very slow once the source areas are affected. The effects of acid precipitation on vegetation range from damage to leaves to increased susceptibility to disease and death (see Volume 4-Chapter 2). A direct causal relationship between acid precipitat ion and reduced forest productivity measured by growth remains to be demonstrated. However, research suggests that acid precipitation is probably a cause of reduced forest growth. Because acidic precipitation and sulfate deposition are primarily related to air pollution sources outside the region and are projected to increase significantly over the next 10-20 years, acidification may represent a serious threat to the ecosystems of northeastern Minnesota, even if copper-nickel development does not occur. Long-term changes in the aquatic communities are probably already underway due to the general decrease in the pH of precipitation and thereby of surface waters in the Study Area. Because the decrease in pH will likely be slow, measurement of biological effects would require intensive long-term monitoring. During this period of decreasing pH, the overall productivity and diversity of the aquatic communities can be expected to decrease.” "One crucial parameter that was monitored is the water's buffering capacity-- its ability to regulate pH changes due to acid inputs from atmospheric deposition or leaching. The resistance to pH change is a function of the type of acid input (i.e. strong or weak acids) and the type of chemical components in the receiving water which can assimilate or bind the hydrogen ions. Calcite saturation indices (csr) were calculated for all study lakes and 30 lakes in the BWCA to measure this buffering capacity. Lakes with a csr less than 3.0 are well buffered; lakes with an index between 3.0 and 5.0 are poorly buffered with the possibility that acidification may already be occurring; and an index over 5.0 indicates lakes with little or no buffering ability and a strong possibility that severe acidification has already occurred.” "The poorly buffered lakes in the region are with few exceptions headwater lakes. This may be explained by the fact that buffering is a function not only of atmospheric processes, but also of watershed geology. The chemistry of headwater lakes often reflects that of precipitation, with watershed contributions to lake chemistry assuming secondary importance. As one proceeds from headwater to downstream lakes 1.U the Study Area, the ability of the lakes to assimilate hydrogen ions generally increases. Headwater areas of the region (which include half the BWCA lakes studied) are generally not well buffered and have limited capacities to assimilate existing acid loadings. Some of the lakes sampled during the study which may be the earliest to be affected by acidic precipitation include: Clearwater, August, Turtle, One, Greenwood, Perch, and Long lakes. These lakes have Calcite Saturation Indices above 3.0. Headwater streams are generally poorly buffered, in part because their water quality is also dependent upon the quality of precipitation.” "Two unique water quality conditions have been identified in the Study Area which are directly related to the presence of copper-nickel sulfide mineralization. In one of these cases, human disturbance of this mineralization has accelerated the chemical/physical weathering (leaching) of this material. Filson Creek, located in the northeastern part of the Study Area adjacent to the BWCA, flows naturally over exposed mineralized gabbro. Within the Filson Creek watershed, total concentrations of copper and nickel 10 the year 1977 generally increased from headwater locations to Filson's point of discharge into the South Kawishiwi River. Total nickel concentrations measured in Filson's headwaters were, except for one sample, less than 1 ug/liter, while the mean nickel concentration near the mouth of the watershed was 3 to 5 ug/liter. The smaller copper and nickel concentrations at Filson Creek headwater locations reflect the smaller percentage of sulfide bearing material in the till and the greater distance from the mineralized contact zone. The elevated metal values measured in Filson Creek may not be completely due to natural weathering of sulfide minerals. Prior to 1977, considerable mineral exploration activities occurred, including the taking of a bulk surface mineral sample. Subsequently, a small volume surface discharge was discovered at the foot of the bulk sample site with elevated metals levels (10,000 to 13,000 ug/l Ni, 360 to 1,000 ug/l Cu, and 190 to 5300 ug/l 2n). This discharge enters a small tributary of Filson Creek and raises the nickel and copper concentrations by about 9 ug/l and 5 ug/l, respectively. This change in trace metal concentrations is not sufficient to result in measureable biological changes in the Creek.” "In the other unique case, a small watershed (Unnamed Creek) which drains into Birch Lake at Bob Bay contains several wastepiles containing mineralized gabbro from a nearby taconite mining operation (Erie Mining Company's Dunka Pit). The large surface area of the waste rock facilitates the chemical weathering process. Surface seeps containing elevated concentrations of sulfates and trace metals (especially nickel) are present. The seeps flow into Unnamed Creek where the influence of this disturbance on water quality is obvious. Median nickel levels in Unnamed Creek were 85 ug/l, compared to 1 ug/l in undisturbed streams (Table 4). Extensive field studies conducted in this watershed have demonstrated that extensive disturbance of the mineralized gabbro without corrective mitigation can result in significant water quality degradation. The magnitude of the potential impacts in this specific case is largely mitigated by natural chemical processes involving adsorption, chemical complexation, and precipitation due largely to the presence of a bog in the watershed. The metal concentrations measured at Bob Bay would be significantly higher if not for the effect of the bog. However, the bog is showing some signs of stress and its beneficial effect on water quality may not continue for long.” Environmental Impact Assessment: Water Use "Water is required in significant quantities as a transport medium for the ore during concentration and for tailing disposal. Additional water is required in the smelting and refining phase for cooling and other purposes. Precipitation partially offsets the major water losses coming from evaporation losses coming from evaporation from tailing basins and water trapped between particles in tailing basins. However, fresh makeup water (estimated to average 0.76-1 b ill ion gallons per year) will be required for all three integrated copper-nickel development models (Volume 2-Chapter 5). Water requirements will vary significantly on a seasonal and annual basis.” "A good water management system is designed to manage and store runoff and seepage on the site (around waste piles, tailing basins, and elsewhere). The specific site and the design of the system will determine whether periodic discharges of waste water will be necessary during periods of above average precipitation. Because of the fairly continuous demand for water and the varying supply of water in lakes and streams in the area, it is estimated that significant water storage (10,000 to 15,000 acre-feet) will be necessary for use during dry periods. This water storage could be supplied by the tailing basin and/or reservoirs. Storage requirements for makeup water supply and containment of polluted water could increase land requirements by 2,000 to 3,000 acres.” "Increased demand for water could become a source of conflict if waters tributary to the BWCA are appropriated for copper-nickel development and if the waters are also diverted for taconite development, such as the Upper St. Louis and Partridge river watersheds. These issues could be considered prior to issuance of a DNR permit which s required for water appropriation. However, if both taconite expansion and copper-nickel development proceed in northeastern Minnesota, a regional comprehensive water management plan and perhaps a cooperative industrial water supply system may need to be considered.” "Quality of tailing water during the operating phase 1S primarily controlled by the concentrating process water. This water is largely recycled and should not be a significant heavy metal pollution source. Seepage can also be collected and recycled if necessary. Elevated levels could occur during the post-operating phase or if more sulfides are deposited in the basin than projected. Local variation in ore mineralogy could result in pockets of tailing having much higher sulfide concentrations which could cause localized leaching problems. Due to limited research on tailing water quality, the unknowns involving the quality of runoff and seepage from a tailing basin are greater than those associated with waste rock piles and create another source of significant risk involving future copper-nickel water management decisions.” "Mine dewatering can also contribute heavy metals, the amount depending upon the quantity of water from precipitation and groundwater sources that must be removed and the metal sulfide content of the mine. No precise conclusions can be made about expected levels of heavy metal release from this source. Smelter and refinery waste water 1S not as significant an issue as waste piles. Production of these waste waters 1S dependent on facility design and operation, and there appears to be no significant post-operational concerns.” "Treatment methods are available to reduce heavy metal concentrations in these waste waters to levels where biological impacts are not expected. Effluent water quality models for impact assessment purposes were developed (Volume 3-Chapter 4) based on the best data available from field and laboratory results, but this information is not sufficient to allow precise statements on the quality of water produced from copper-nickel water pollution sources or on the effectiveness of reclamation practices for specific effluent parameters (e.g. suIfates, trace metaIs, processing reagents). For example, information strongly suggests that runoff from waste piles will contain elevated heavy metals and dissolved solids concentrations as compared to background surface water quality. Heavy metals could be 500 to several thousand times higher than natural water quality levels and sulfates could be ten to several hundred times higher.” "These models reflect an assumption that acid mine drainage problems will not occur because of the natural buffering capacity of the waste materials. If this assumption IS wrong and acid conditions do occur, then projections of water pollution will be significantly underestimated because, as the pH becomes acid, there are dramatic increases in the amount of heavy metals leached from the waste significantly affects whether a metal will be in an aqueous phase (and highly mobile) or in a solid phase.” "Treatment of large amounts of runoff to remove heavy metals to existing background levels may be prohibitively expensive. Additional research is necessary in order to make accurate predictions about effluent quality and the effectiveness of various controls. Cost and time constraints will likely require that the first mining activities proceed without this predictive capability.” Heavy metals have adverse effects on aquatic organisms, the extent depending upon the type of metal (or combination of metals), organism tolerance, and water chemistry (Volume 4-Chapter 1). For example, cold water fisheries are generally more susceptible to heavy metal pollution than warm water fisheries." No mention is made of impacts on wild rice stands.
Public Comment Form about Mining in the Lake Superior Basin
(2013-12) Lake Superior Binational Program
This is a 291-page raw data summary of comments downloaded from Survey Monkey, and published on the LSBF website. The pdf is undated. The LSBF website contains a short article about the survey, noting that the survey was open for public commentary from March 15 to July 31 2013, and that nearly 1,600 individuals provided comments. There were 45 questions posed to respondents. Some key findings relevant to mining and water resources are extracted and reproduced below. “When asked if there should be specific criteria to prohibit mining activities in environmentally or culturally sensitive areas, 64.9 % said yes, 18.8% said mining should not be restricted in any areas. “When asked ‘Which of the following statements best describes your opinion about mining operations in the Lake Superior basin?’ the most picked response was ‘I do not support any new mines in the Lake Superior basin,’ (38.8% response rate) followed by ‘I support mining operations that can be done using proven responsible management practices that minimize environmental damages’ (25.8% response rate). “When asked is there should there be a moratorium on new mining activity in the Lake Superior basin until it can be proven that new mines won’t pollute surface and groundwater, 63.4% said yes, and 31.8% said no.” Among other results, 68% felt that mining should be restricted in areas where culturally significant food is harvested or grown. 76% felt that mining should be restricted where wetlands have international significance or in locations with endangered plants or animals. 70% felt that mining should be restricted in areas with historic importance. 96% disagreed that taxpayers should pay for clean-up and restoration of damages; while 95% felt that mining companies should pay for these costs. 91% felt that open public meetings should be held to inform the public about mining company compliance. 89% want disclosure of chemicals used in the mining process.”
Responsible Mining in the Lake Superior Basin
(2013) Lake Superior Binational Program
The Lake Superior Binational Forum drafted a statement on responsible mining, with recommendations for future mining projects, which are summarized in this document. The statement aims at a “zero discharge” principle. The Forum held three public meetings to gather input for the statement. Key excerpts are reproduced below: “Responsible Mining Should: A. Meet or exceed the provisions of the Great Lakes Water Quality Agreement of 2012 between Canada and the United States in: 1. Adopting the goal of zero discharge and zero emission of persistent bioaccumulative toxic substances in the basin, thereby preventing further degradation of the ecosystem. 2. Anticipating and preventing pollution and other threats to water quality in the Great Lakes to reduce overall risks to the environment and human health. 3. Incorporating the precautionary approach, as set forth in the Rio Declaration on Environment and Development, that “Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.” 4. Incorporating the “polluter pays” principle, as set forth in the Rio Declaration on Environment and Development, “that the polluter should bear the cost of pollution.” 5. Applying innovation – considering and applying advanced and environmentally-friendly ideas, methods and efforts to prevent environmental problems. 6. Considering social, economic and environmental factors, including assessment of full life cycle costs and benefits, and incorporating a multi-generational standard of care. B. Be clear and transparent with regulatory agencies, affected communities, and the public, while fostering cooperation with relevant agencies and the greater public. C. Carry out rigorous environmental assessment of all aspects and phases of the mining and milling process, including potential future expansion of mining activities. Public opinion and advice should be incorporated where possible, and the assessment process should explain why other public proposals were not incorporated into the final decision. D. Recognize that short-term mining operations can have long-term legacies, so approved plans should secure funding for staffing, monitoring, prevention, and repair of mining sites after closure. E. Contribute to the local, regional, and national economy through a fair wage, salary, and benefit structure, and in paying all taxes assessed by government agencies in each jurisdiction in which it operates F. Respect private and other land rights and where applicable compensate land owners for losses of value, and land users for losses of opportunity.” The document also contains nine recommendations for future mining operations, briefly summarized as follows: 1. Develop a common set of criteria for use by governments, NGOs and industry to guide the permitting process. Currently public agencies use different criteria in each state. 2. Avoid mining in places with high environmental or social/cultural value. 3. Improve public participation by stakeholders in the environmental assessment process through the collection of adequate baseline data; consideration of potential worst-case scenarios; and independent third-party review processes. 4. Water quality objectives that are consistent with the LAMP should be developed. 5. Overburden and tailings should be discharged into water bodies or wetlands; acid-generating materials should be segregated; and hazardous materials plans should be made public. 6. Companies should make atmospheric emission reports. Environmental assessments should consider greenhouse gas emissions from mining operations. 7. Companies should set aside financial resources for the exploration phase to cover clean-ups, reclamation and long-term monitoring. The public should have the right to comment on the adequacy of these resources and reclamation activities. 8. The public should have the right to access monitoring and periodic technical reports during the life of the mining operation; and to do independent third-party review of the process. 9. Companies should have a reclamation plan with resources set aside for each operation. Mined areas should be re-contoured and stabilized. 10. Citizen participation and oversight are important elements listed under “social impacts and decision making,” including the engagement of Tribal Nations, First Nations and Metis. 11. Research is needed on the cumulative and indirect effects of mining; climate change and mining impacts; and human health research, including impacts on people, fish and wild rice.
Sulfate and Mercury Chemistry of the St. Louis River in Northeastern Minnesota: A Report to the Minerals Coordinating Committee
(2009) Berndt, Michael; Bavin, Travis
This report presents technical data and information on water quality sampling from the St. Louis River related to sulfate and mercury contamination from mining that may affect human health. However the report contains raw data with little interpretation, and gives little guidance as to application of the findings to decision-making. The abstract and key findings are reproduced below. The St. Louis River and its major tributaries were sampled upstream from Cloquet during periods of high, medium, and low flow between September 2007 and October 2008. Special emphasis was placed on measuring sulfate (SO4) and mercury (Hg) distributions as well as other chemical parameters that might help to determine whether SO4 releases from the Iron Range have an impact on Hg speciation in the St. Louis River. These included, but were not limited to, dissolved organic carbon (DOC), dissolved iron (Fe), and the isotopic ratios for sulfur and oxygen atoms in dissolved SO4 (δ34SSO4 and δ18OSO4). Dissolved and particulate fractions of methyl mercury (MeHg), total mercury (THg), and bioavailable mercury (AHg) were additionally determined over a range of hydrologic conditions to identify primary source regions and transport mechanisms for Hg species. Results confirm that the majority of SO4 is derived from the iron mining district, and that SO4 added in the upstream portion of the St. Louis River is generally diluted downstream by waters from larger watersheds containing high percentages of wetlands. SO4, magnesium (Mg), calcium (Ca), sodium (Na), and chloride (Cl) concentrations all increase in the river, especially in the mining region, during periods of low-flow when groundwater inputs dominate chemistry of dissolved components. Variations in the relative concentrations of major elements and inδ34SSO4 and δ18OSO4 among the tributaries provide important clues to specific SO4 sources for each of the individual watersheds under varying flow conditions. Chemical data indicate that most SO4 from the mining region is derived from oxidation of small amounts of iron sulfide minerals present in stock piles, tailings, and pit walls containing Mg-rich carbonate minerals that are common in the Biwabik Iron Formation. Comparison with stream chemistry from 1955 to 1961 indicates SO4 sources were commonly present in the mining region before taconite mining became widespread in the region. Other chemical parameters in these data, particularly Ca and Mg, indicate the primary source for this SO4 was different from today. In contrast to SO4, Hg appears to be derived predominantly from wetlands, and is highest during periods of increased flow in the rivers. THg is well correlated to DOC concentration under most conditions, but quite variable during precipitation events when dissolved AHg and particulate SHg become more abundant in the rivers. MeHg concentrations in the St Louis River and its tributaries are also strongly correlated to DOC. Four sources of DOC are preliminarily inferred to be present in the river depending on the season and watershed characteristics, and it is believed that the relative amounts of DOC from each source may control the MeHg concentrations present in the river. These include: (1) DOC released from surface wetland areas containing low Fe (approximately 0.2 ng/mg Hg and 0.02 ng/mg MeHg in the DOC), (2) DOC containing almost no MeHg that is either produced in-stream or present in small amounts in natural groundwater, (3) DOC released from deep wetland areas following a major summer rain event containing very high MeHg and high Fe, and (4) DOC containing almost no MeHg in waters containing elevated dissolved Fe that seep slowly from deep within wetland areas under dry conditions. MeHg systematics appear to be very similar to those reported in two well-studied low-SO4 tributaries of the Rum River in east-central Minnesota. Additional sampling is planned to verify the above model and to more fully characterize mercury speciation during the warm summer months, particularly during periods when high Fe concentrations are present in the streams.

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