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The sustainability of the Lake Superior region is a dynamic interaction between people and the environment. The health of the environment influences the health and well being of the people living here and those who rely on the region's natural resources. Now, and for generations to come.

People are an important part of the equation. Recognizing the interconnectedness of people and the Lake Superior environment, the LaMP for Lake Superior recognizes the threats to human health posed by critical pollutants.

The Lake Superior LaMP seeks to restore the "swimability", "fishability", and "drinkability" of Lake Superior. Swimability means that all beaches are open, safe, and available for public swimming. Fishability means all fish are safe for human consumption. Drinkability mans that treated drinking water is safe of human consumption.

The presence of chemical and microbial pollutants in Lake Superior still keep us from reaching that goal. What are the potential adverse human health effects that could come from exposure to persistent, bioaccumulative, toxic chemicals as well as other contaminants of health concern that are found in the Lake Superior Basin and how can we protect the environment and ourselves?



Understand how humans can be exposed to contaminants found in the Lake Superior environment and the potential human health implications

Understand how to reduce your exposure to environmental contaminants



The World Health Organization defines human health as "a state of complete physical, mental and social well-being, and not merely the absence of disease..." When considering human health, all aspects of well-being need to be considered, including physical, social, emotional, spiritual, and environmental impacts on health.

balanceHuman health is influenced by a range of factors, such as the physical environment (including environmental contaminants that may be present in that), heredity, lifestyle (smoking, drinking, diet and exercise), occupation, the social and economic environment the person lives in, or combinations of these factors.

Exposure to environmental contaminants is one among many factors that contribute to our health. It is important to consider the complete range of factors that influence health, and the complex interactions between these factors, when investigating the role of environmental contaminants as a cause of health issues.

groups of kidsTo investigate human health in the Lake Superior Basin, we need to look more closely at the people who live here.

The Basin's population is made up of a range of cultural groups including aboriginal peoples or "Native Americans.. Each cultural group represent unique heredity, lifestyle, and social characteristics and customs.

Not everyone within a cultural group is the same either. Each person has his or her own individual characteristics that make them more or less susceptible to health problems due to exposure to environmental contaminants.

Recognizing the diversity of people living within the Lake Superior Basin, those who are at greater health risk from environmental contaminants can be identified.



Clear water is not always clean water.

Looking at Lake Superior's crystal clear, cold water; it is hard to believe that its water and sediments contain toxic chemicals that can negatively affect human and environmental health.

Several hundred environmental contaminants are found in the Great Lakes Basin. Eleven of these chemicals are so toxic that they have been designated as "Critical Pollutants"

Nine of these critical pollutants have been found in Lake Superior's water and sediments. They are called the "Nasty Nine" and have been found to cause developmental defects, cancer, and other chronic diseases in laboratory animals, fish, and wildlife. This has raised concern about their effects on human health. These poisons are so nasty; a goal of the United States and Canada is to achieve zero discharge of them into Lake Superior by 2010.

The "Nasty 9" include organochlorines such as PCBs and toxaphene, and metals such as lead and mercury. These chemicals do not break down easily, tend to persist in the environment, and bioaccumulate in the environment and animal and human tissues. Organochlorines tend to accumulate in fat (such as adipose tissue and breast milk), and metals tend to accumulate in organs and flesh. These nasty characteristics have earned them the title of Persistent Bioaccumulative Toxics or PBTs.

Progress continues to be made to reduce the risk to health from exposure to chemical and microbial contaminants in the Lake Superior Basin.

frog ring
Developmental flaws found in frogs exposed to pesticides.

Since the 1970's, there have been steady declines in many PBT chemicals because these substances are banned from manufacture in the United States and Canada. This has lead to decreasing PBT levels in human tissues, lead in blood, and organochlorine contaminants in human breast milk. This means that health risks from these contaminants are declining.

Demonstrating health effects in humans from chronic, low-level exposure to PBT chemicals typically encountered in the Great Lakes region is a challenge for researchers. Human health research is limited because it is difficult to separate health effects that are caused by exposure to contaminants from those related to other known health factors like smoking, drinking alcohol or general health status.

Despite these limits, neurodevelopmental and reproductive effects have been reported in some studies of human populations in the Great Lakes basin. Developmental abnormalities have been observed in wildlife and laboratory studies of PBT chemicals.

These human and wildlife studies are sufficient to suggest that human health is also at risk from exposure to PBT chemicals, and may have profound implications for the Lake Superior Basin's population.


Effects o. PBT Chemicals on Fish and Wildlife in the Great Lakes
Source: U.S. EPA's National Water Quality Inventory. 1992 Report to Congress.
NA= not applicable, NE= not examined, S = suspected

Species Population decrease Effects on Reproduction Eggshell thinning Birth defects Behavioral changes Biochemical changes Mortality
Mink x x NA NE NE NE x
Otter     NA NE NE NE S
Double-crested cormorant x x x x   x S
Black-crowned night heron x x x x   x S
Bald eagle x x x NE   NE NE
Herring gull   x x x x x x
Ring-billed gull       x   NE x
Caspian tern   T   x NE NE  
Common tern   x x x   x  
Forster's tern   x   x x x  
Snapping turtle NE x NA x NE NE NE
Lake trout   x NA     x  
Brown bullhead     NA     x  
White sucker     NA x   x  



old fish photo
Eat fish? Read and heed fish consumption advisories for your area.

How are people exposed to pollutants in the Lake Superior environment.

Follow these tips to reduce your exposure to contaminants in fish:

The three major routes that chemical and microbial pollutants enter the human body are by:

Ingestion: eating or drinking contaminated water, food, and also soil - particularly in the case of children
Inhalation: breathing airborne contaminants,
Dermal contact: contact with the skin.

Food, especially the consumption of Lake Superior fish, is the primary route of human exposure to these PBT chemicals found in the Lake.

While the average person within the Lake Superior basin does not eat enough fish and wildlife to pose a risk to their health, there are some people who do.

People who eat a lot of fish, regularly eat large predator fish, eat fish from highly contaminated waters, or eat a lot of fish over a short period of time are at increased risk of exposure and health effects.

The developing fetus and young children are at greater risk to PBT exposure than adults. Women of childbearing age, who are pregnant or expect to get pregnant or families with young children, should investigate the fish consumption advisories for their area and the fish species they eat. Although fish consumption programs are well established in the Basin, studies show that only half of the population are aware of these warnings.

Other subpopulations, such as the elderly, nursing infants, children, and those whose immune systems are compromised, may be more susceptible to the effects of persistent bioaccumulative chemicals.

natives in fieldsThe Native American populations in the Lake Superior Basin represents an important population at increased risk of exposure to environmental contaminants, and therefore may be at increased risk of suffering adverse effects.

Harvesting manomin or "wild rice" is an important part of Ojibwa culture. Investigate more about the relationship of the Ojibwa people and the environment.

Native people tend to have higher exposures to PBTs as a result of their strong cultural ties with their environment. Spiritual, medicinal, hunting, gathering and fishing traditions increase the number of ways Native Americans can be exposed to environmental contaminants.

Native Americans in the Great Lakes have much higher fish consumption the general population. Also, Native Americans in the region harvest other natural resources that are potential sources of exposure to critical pollutants, including the consumption of deer livers and wild rice. Both of these represent additional routes of exposure to trace heavy metals (such as cadmium) that are known to accumulate in wild rice and livers of deer.

nettingOther subgroups have increased expose to potentially harmful environmental pollutants. People who have high levels of fish consumption, may have higher exposures to persistent toxic chemicals than the general population, and therefore may be at increased risk of suffering adverse health effects.

The atmospheric deposition PBT chemicals are a major source of deposition to the Lake Superior basin. Although it is not a pathway of direct human exposure, it is a significant source for contaminants that accumulate and magnify in the Lake Superior basin food chain.


Access to clean drinking water is essential to good health. The waters of Lake Superior and surrounding areas are a primary source of drinking water for the people who live in the Lake Superior basin.

While there has been an overall reduction of contaminants in the Great Lakes basin since the 1970s, contamination of the lakes through human activity continues to be a concern. The most common way for people to be exposed to contaminants in water is through the drinking water supply.

Drinking water within the Lake Superior Basin is generally of good quality.
In Canada and the U.S., community water suppliers deliver high quality drinking water to millions of people every day, and a network of government agencies are in place to ensure the safety of public drinking water supplies. Although our drinking water is safer today than ever, problems can, and do, occur, although they are relatively rare. Localized outbreaks of water­borne disease have been linked to contamination by bacteria or viruses, probably from human or animal waste.

unsafeMicrobial contamination of drinking water can pose another potential public health risk in terms of acute outbreaks of disease. Gastro-intestinal disorders and minor skin, eye, ear, nose and throat infections have been associated with microbial contamination of recreational waters. The greatest risk of health concern is accidental ingestion of contaminated water while swimming and drinking from contaminated water sources.

How's the water at your favorite beach and what can you do to keep it safe?



Even though PBTs are no longer being manufactured in the United States or Canada, these toxic chemicals can find their way into Lake Superior. To protect human health, we must continue to reduce sources of PBTs and monitor of contaminant levels in environmental and in humans.

cloudsThey can be carried through the atmosphere from countries where their use has not yet been banned and deposited on water and land through atmospheric deposition.


pbt chemicalsPBT chemicals still remain stored in businesses, industries, homes, and farms throughout the Basin. These are hazardous wastes. These toxic chemicals must be properly disposed of through a certified hazardous waste collection program, like a Clean Sweep Program. If they are disposed of in the garbage, landfilled, or dumped on the ground or in the water; they can enter the environment to poison wildlife and people.

What you can do to protect your health by sweeping your home free of toxic chemical?


One of the greatest sources of PBTs may be right in your backyard if you use a burning barrel. Burning waste and garbage in burning barrels and home incinerators releases mercury and other critical pollutants into the atmosphere where we can directly inhale these poisonous chemicals. Once in the atmosphere, they can be deposited on Lake Superior through precipitation. If you have a burning barrel in your backyard and use it, it is creating more airborne pollution for its size than modern industrial smokestacks! Burning barrels make a poison linked to cancer and hormone disruption.





Levels of persistent organic chemicals, such as PCB's, bioaccumulate in Lake Superior's food chain. Human's are at the top of the food chain!





man on beach CREATE... your own service learning experience to protect and restore aquatic communities. This section provides you with a template to get started in developing your own service learning project.
girl with net ACT... Take action to help restore and sustain aquatic communities and learn about what others are doing in the Lake Superior Basin and your community. This section will give you hands-on things you can do to help!
group reflects REFLECT.... Share and celebrate your experiences with others. This section lets you share what you learned with others.


Copyright 2007 - University of Wisconsin Extension
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