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Mercury Pollution in the Boundary Waters Region of Minnesota

Curricular materials created for the 2017 SAIL seminar:

Wilderness in the Anthropocene

This module:

  1. Introduces students to the history, politics and science surrounding the issue of sulfide mining near the Boundary Waters Canoe Area and Wilderness (BWCAW) through reading and discussion
  2. Guides students through the process of building a numerical (computer) model of the transport and effects of mercury on a simple lake ecosystem; designed to represent the impacts of a possible leak of contaminated mining waste into the BWCAW
  3. Allows students to use the model as a predictive and hypothesis-testing tool
  4. Allows students to use their experience working with the model as the basis for a brief letter to policymakers regarding the risks and benefits of using predictive scientific models in this area of decision-making


Content/Concept Goals

Upon completing this module, students are expected to be able to:

  • Identify the major issues and actors relevant to the issue of proposed sulfide mining near the BWCAW
  • Use a model to test hypotheses related to ecosystem health as well as human health
  • Analyze and interpret data
  • Appreciate and communicate the challenges of using models as the basis for policy-making

Higher Order Thinking Skills Goals

This module requires students to:

  • Do multidisciplinary work as they consider the issue of sulfide mining from the perspectives of environmental science, ecology and management/policy
  • Consider the use of scientific (modeling) results as the basis for a policy recommendation
  • Understand context about the preferences and needs of different actors in the economic and management spheres


In this class, students are introduced to a new system each week through background readings (e.g. population growth, glacier movement, ocean circulation, lake levels, etc.) and then guided through the process of building a model of that system, and using the model to run experiments and/or test hypotheses.

This module was introduced at the end of the Modeling Earth Systems course, but not necessarily because it was more “advanced.” The only background skills or knowledge students needed from earlier in the course was an introduction to basic population modeling.

This course met T/Th for 90 minutes each day. The project took a week of class time, as well as time outside of class. Students prepared for the Tuesday class by doing assigned readings, and then came to class ready to work on their models. The two class periods consisted entirely of building, troubleshooting and discussing their modeling work. Although given as an individual assignment, it could very easily be a group assignment. This might in fact be preferable for students who aren’t as used to modeling, as they could work together to solve problems.

Dissemination Strategies

The assignment is based entirely in the iconographic box modeling software STELLA. This software is expensive; however, it may be very similar to a free software called Vensim and could likely be easily adapted. There are different options for purchasing student or computer lab licenses of STELLA or for downloading a free trial version. For those learning to use STELLA, I suggest the online “play-along” tutorials from isee systems. Like any software, it has its pros and cons, but its main selling point is the ability to construct relatively complex numerical models without needing to learn a programming language.

Teaching Notes

The pilot version of this module went fairly smoothly; the version here includes some changes I made based on the students’ experience, mostly to make the model a little more accurate. Although my students were pretty used to doing exercises like this by the time of the semester when they encountered it, I think it would work reasonably well outside the context of this course, especially for something like Ecology or Environmental Policy, where students would come in with more background knowledge about the content even if they weren’t experienced modelers.

Resources & Materials

Modeling Answer Key

Contains images of the graphs produced in the various model runs, as well as written answers to questions.

Modeling Earth Systems Site

Provides an overview of the course, which was originally developed as part of the InTeGrate program at the Science Education Resource Center (SERC). It includes some background and context about using models in the classroom, as well as the population exercise referenced in this module. Instructors can register for a free account to access all materials (students can see some things but not the keys, notes, etc.).


Reading List

HIstory of the BWCAW

Provides an historical overview of the Boundary Waters Canoe Area and Wilderness from the 17th century onward. In reality, people have lived and traveled in this area for likely 10,000 years; their descendants are some of the Native American groups (bands of Ojibwe, Chippewa and Sioux people) who were living in the region when French fur traders arrived. Today, the BWCAW is a popular destination for outdoor recreation, including camping, hiking, fishing, and especially canoeing. It provides an important component of the region’s economy, employing residents at resorts, outfitters, restaurants and shops in Ely and other communities near the Wilderness area. Native American groups also still occupy the region and have continued to push for renewed access to various areas of the BWCAW that represent important religious and cultural sites in their community traditions.

Sulfide-ore copper mining threatens the Boundary Waters

Part of the site for Save the Boundary Waters, a nonprofit advocacy organization that opposes the proposed mining development. Read the overview here, and feel free to look at some of the other information on the site. Much/all of the science (see links under the “The Issue” tab) comes from reputable sources, such as environmental impact statements, or independent academic analyses; however, keep in mind that this group has a specific agenda, and therefore they have likely not included all available information on their site.

Science Desk: How Sulfide-Ore Copper Mines Pollute

This page, also from Save the Boundary Waters, gives a brief description of the process involved in copper-sulfide mining. Unlike taconite mining, the primary type of mining that has been conducted in the Iron Range for decades (see optional readings). This kind of mining presents the risk of acid mine drainage leaking from the site. The level of risk is debated of course; the two mining companies proposing these projects claim that they can conduct the projects with appropriate and sufficient safeguards such as liners on tailing ponds. Conservation groups such as this one say that no such mine has ever been free of environmental contamination problems.

Minnesota Issues Resource Guides: Copper-Nickel Studies and Non-ferrous Mining

Maintained by the Minnesota state legislature as a brief history of metal mining in the state, and as a repository for reports, studies and impact statements. Read the top two sections (“Copper-Nickel Studies” and “History in Minnesota”), and skim through the list of reports to get a sense of the types of information that are available.

Minneapolis Star-Tribune: Iron Range mine could pollute water for up to 500 years

Provides an overview of the most recent large development in this issue, the release of the Draft Supplemental Environmental Impact Statement (DSEIS) in 2013.

Government of Canada: Mercury in the food chain

Provides background information about how mercury moves through a food web, including bioaccumulation and biomagnification.


The New York Times Magazine: In Northern Minnesota, Two Economies Square off: Mining vs. Wilderness

Does a nice job summarizing the economic arguments for and against copper-nickel mining near the BWCAW.

MNOpedia: Opening of the Mesabi Iron Range

Gives the history of mining in northern Minnesota, leading up to the growth of the taconite industry.

MNOpedia: United States of America v. Reserve Mining Company

Tells how a lawsuit changed the way taconite tailings were dealt with, and gave increased regulatory power to the EPA.

Environment & Society: Taconite Mining in Silver Bay: A Tale of Extraction and Accumulation

Provides a slightly different take on the same lawsuit above, including a little additional context.

TC Daily Planet: Iron Range 101: What is taconite?

Gives an overview of taconite, the most common product of mining in northern Minnesota in the last several decades.

Outcomes and Significance

I assessed the learning goals by evaluating students’ models and responses to questions in the exercise. For the former, I compared them to my own model; for the latter, I used the instructor key (.STMX files not included here). In addition, I included the following questions in a post-project survey administered within the course management software. I provide some sample responses:

1. Considering both the reading and the model exercise, how well did this assignment help you understand the scientific, social, and economic issues related to proposed sulfide mining near the BWCAW? In what way(s)?

“This assignment helped me realize how environmental issues have a wide impact, on the economy and social issues. The exercise itself only looked at the environmental impact sulfide mining could have, but the results from the models reflected the concerns from the readings about the impact of sulfide mining on the economy and public health. Although the mining industry is lucrative, the potential impact of spills from sulfide mining would devastate the Boundary Waters system. Additionally, the increased levels of mercury in fish is a risk to people consuming fish, as levels above 0.5 µg/g can cause adverse affects on people’s health, including birth defects.”

2. What are the barriers to using numerical models as the basis for policy-making related to this issue? Consider both scientific or technical problems as well as social/communication issues.

“Numerical models cannot take into account every factor that impacts a system, so the models can be unreliable. Additionally, only scientists can interpret the results of numerical models, so they are inaccessible to policy makers. Scientists can interpret the results in a way that can help one side of an issue or another, which also impacts the reliability of the results.”

3. Consider the resources you used as background research and describe why it is important to consider this problem in a multidisciplinary way.

“Environmental degradation and pollution affect the economy, which in turn affect people’s livelihoods. To get a more holistic view of the impact of this problem on the system, considering this problem in a multidisciplinary way is very important.”

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