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Biomonitoring Study - Chemical Highlights

Check the menu below to learn about the chemicals involved in the Fond du Lac Biomonitoring Study.


Polychlorinated Biphenyls (PCBs)

PCBs are a group of 209 similar man-made chemicals. PCB mixtures were widely used for decades in many industrial and commercial applications, such as transformer fluids, heat exchange fluids, and paint additives. PCB production and distribution was prohibited in the U.S. in 1978 and they are no longer manufactured or commonly used in North America.

Although the amount of PCBs in the environment is decreasing, they break down slowly and can accumulate in the food chain, especially in older and larger predators. The amount in certain fish can reach levels much higher than in the water. PCBs are still a concern for some fish in Lake Superior and major rivers in Minnesota, but not for inland lakes and small streams in the state.

Most people are mainly exposed to PCBs in food, especially fish. Fluorescent light fixtures and old electrical appliances (e.g., TVs and refrigerators made more than 30 years ago) may leak small amounts of PCBs. Also, people who work on PCB transformers or handle PCB-containing materials may be exposed on the job.

There is some evidence that PCBs can interfere with the body’s hormones and affect the immune system, and may increase the risk of cancer. The most common effects in people exposed to large amounts of PCBs are a severe form of acne (called chloracne), rashes, and changes that may indicate liver damage. These effects are not likely to occur in the general population.

As a general precaution against chemicals such as PCBs that build up in fat, choose low-fat dairy products and lean meats when possible and include a variety of foods in your diet. Fish and other traditional foods should be part of a healthy diet. Fatty fish are an excellent source of healthy fats (like omega-3 fatty acids) and protein. Follow guidelines for eating fish safely for the waters where you fish. Also, when preparing fatty fish, remove the skin, trim the fat, and broil, bake, or grill the fish so that fat drips away.


DDT is the abbreviation for a pesticide that was banned in the U.S. in 1972, but is still used in some parts of the world. Until it was banned, DDT was used widely in the U.S. to control insects in agriculture and insects that carry diseases such as typhus and malaria. DDT remains in the environment for a long time and build up in fish, birds, and other animals. People are mainly exposed by eating foods contaminated with very small amounts of the chemicals. DDT can affect the nervous and endocrine (hormone) systems. DDT and DDE may cause cancer in humans. DDT and DDE from environmental sources can enter people’s bodies through swallowing or breathing them in or through the skin. Since DDT and DDE may cross the placenta and can be in breast milk, fetuses and nursing babies may be exposed to these chemicals if their mothers have been exposed. Most people are regularly exposed to very small amounts of DDT and DDE from eating contaminated foods, such as root and leafy vegetable, but especially meat, fish, poultry and dairy products. People exposed to large amounts of DDT and DDE over a short time might develop nervous system effects such as excitability, tremors and seizures. Human health effects from exposures to low doses of DDT/DDE in the environment or at levels measured in biomonitoring testing are unknown. Studies of animals suggest that long-term exposure to smaller amounts can harm the liver, affect reproduction and other effects, and it is possible that this could happen in people too. Except for people who live near an industrial or waste disposal site that was contaminated with DDT/DDE, the greatest source of exposure to these chemicals is likely to be from food. While it is not possibly to completely avoid DDT/DDE in the diet, there are choices people can make that will help reduce exposure.

Make your meat lean. Choose lean cuts of meat and buy organic meat if possible. Cut off visible fat before cooking meat and choose lower-fat cooking methods: broiling, grilling, roasting or pressure-cooking. Avoid frying meat in lard, bacon grease, or butter.

Limit dairy fat. Opt for low-fat, organic dairy products when possible.

Wash fresh fruit and vegetables. Imported foods may be from areas where DDT is still used. Cleaning fruit and vegetables will help remove DDT/DDE and other contaminants that might be on their surface.

Choose fish wisely. Commercial fish that contain higher levels of pesticides, including DDT, are bluefish, wild striped bass, American eel, and Atlantic salmon. When preparing fish, remove the skin, trim the fat, and broil, bake, or grill the fish so that fat drips away; this will reduce your exposure to DDT/DDE and other chemicals that accumulate in fatty tissue.

Fish are an excellent source of nutrients including protein, omega-3 fatty acids, and vitamin D, so don’t remove fish from your diet—but be selective about the fish you eat.

Mirex, HCB and Toxaphene

We recently highlighted DDT and its breakdown product DDE. DDT is one of the more widely recognized organochlorine pesticides. People who participated in the FDL Community Biomonitoring Study were tested for DDT and DDE, as well as a few other environmental chemicals that are similar to them; namely mirex, HCB (hexachlorobenzene), and toxaphene. These chemicals were widely used (mirex was mainly used in southwest U.S.) historically. Mirex and toxaphene were used mostly to control insects, but they had other uses too. HCB is a fungicide that was mainly used to protect agricultural seeds.

Like DDT, these chemicals were considered ideal pesticides at one time because they were inexpensive, slow to breakdown, and effective against their targets. Their persistence and ability to dissolve in fat allowed these chemicals to build up in wildlife and people. Unfortunately, it wasn’t recognized that they were not as harmless as believed until huge quantities had been released. All were banned in the U.S. decades ago due to concerns that their continued use was harming the ecosystem.

Because these chemicals have not been made or used on a major scale for many years, the levels present in the environment have gradually declined. Nevertheless, they are very stable and remain in the environment for years, or even decades, before breaking down. They also build up in living organisms and can reach much higher levels in larger and older predator species. As a result, most people have been exposed to extremely small amount of these chemicals—usually in fatty foods.

As a general precaution, people can minimize exposure to contaminants that accumulate in fats by choosing lower-fat dairy products and lean meats when possible. Similarly, when preparing fatty fish, it is generally a good idea to remove skin, trim fat, and broil, bake, or grill the fish so that fat drips away.

Eat traditional foods! Fish, wild game, and other traditional foods should be part of a healthy diet. The many benefits of eating these foods far outweigh the risk from small amounts of historically used pesticides.


Mercury is a metal found in many rocks including coal. When coal is burned, mercury is released into the air. Coal-burning power plants are the largest human-caused source of mercury emissions in the United States. Mining is also a source of mercury in the Lake Superior Basin.

Mercury in the air eventually settles into water or onto land. Some of it eventually runs off into nearby rivers and lakes where, under the right conditions, particular bacteria can change it to methyl mercury – a form readily absorbed in the digestive system of animals. It can bioaccumulate (build up in the tissues of fish and animals) and work its way up the food chain as contaminated fish and animals are eaten by other fish or animals further up the food chain. The methylmercury found in fish, is the form most commonly found in people’s blood.

Most fish are healthy to eat, and fish are an excellent source of low-fat protein. Eating fish may also reduce the risk of heart disease, diabetes and other chronic illnesses. But any fish (store-bought or sport-caught) could contain contaminants such as methylmercury that can harm human health. Methylmercury can harm an unborn child’s developing brain at levels that would not affect an adult. In adults, higher levels can harm the brain, heart, kidneys, lungs, and immune system. By following advice on how often fish can safely be eaten, you can reduce your exposure to the mercury in fish, help reduce your health risks, and still get the benefits of eating fish.

For safe eating guidelines, go to: http://www.fdlrez.com/newnr/environ/water.htm or http://www.health.state.mn.us/divs/eh/fish/eating/index.html


Lead is a natural part of the earth. It is used in many industries and products. Lead lasts forever – it moves around the environment but does not disappear.

People are exposed to lead from:

  • Drinking water: water flows through lead pipes and pipe solder in some older homes.
  • Lead-based paint in homes: contact with chipped or peeling paint and dust in and around homes built before 1978.
  • Diet: eating wild game shot with lead bullets; lead fragments may be too small to see, touch, or notice while chewing.
  • Hobbies: activities such as making stained glass, ceramics, or jewelry; casting bullets or fishing sinkers; or home remodeling and auto repair.
  • Smoking: commercial tobacco.
  • At work: activities such as construction, steel welding, painting, remodeling, foundry work, auto repair, and cable splicing.
  • Personal care products: some hair dyes and cosmetics.

Babies and young children are most sensitive to lead. Lead can affect brain development and contribute to learning problems. Lead can increase blood pressure, decrease kidney function, and cause reproductive problems in adults.

You can take action to lower your level of lead. Once you find and remove the source, the amount of lead in your body will start to decrease. For information about lead, visit these websites:



Cadmium is a metal and a natural part of the Earth. It is used in many industries and products. Cadmium gets into the soil, water, and air from mining, industry, and burning coal and household garbage. Once released to the environment, cadmium does not disappear. Fish, plants, and animals absorb cadmium from the environment.

Cigarette smoking is the biggest source of cadmium for most people. Smokers have twice as much cadmium in their bodies as nonsmokers. In non-smokers, diet is often the biggest source of cadmium. Tiny amounts of cadmium are found in all foods. Some foods, like shellfish, liver or kidney meats, contain higher levels of cadmium. Workplace activities (such as battery manufacturing or metal soldering, plating, and welding) may be a source of cadmium for some people.

Cadmium can damage the kidneys, lungs, and bones; it can cause cancer. It can also affect brain development in babies and young children.

A small amount of cadmium can pass from a pregnant woman’s body into her unborn baby. If you smoke, stopping will help keep cadmium from reaching your unborn baby.

Women who are pregnant or have given birth are often low in calcium and iron. Low iron and calcium increases the amount of cadmium in your body. Eat foods high in iron and calcium if you are pregnant or have given birth.

No effective treatment for removing cadmium in the body exists. You can take action to lower your level of cadmium by identifying sources of exposure and removing or reducing exposure.

To avoid exposure to cadmium:

  • Do not smoke commercial tobacco. Smoking doubles the amount of cadmium in your body.
  • Avoid eating large amounts of kidney and liver. (Cadmium does not build up in the muscle or meat of wild game.)
  • If you work with cadmium, take precautions to avoid contact. Avoid bringing cadmium-containing dust home to your family on clothing, skin, and hair.

Perfluorinated Chemicals (PFCs)

Perfluorinated chemicals (PFCs) are a group of man-made chemicals used in a wide variety of industrial and consumer products to resist heat, stains, or moisture. There are over 600 different forms of PFCs and much of what is currently known about this chemical group comes from research focused on a few that were made in large amounts.

Because they repel both water and oily substances and also survive intense heat, PFCs have been widely used for several decades in a variety of industrial and commercial applications. Examples include stain-resistant and non-stick products, protective coatings, pesticides, lubricants, grease-resistant packaging and paper products, stain/water/oil-repellents and even specialized fire-fighting foam. Familiar consumer items such as some cookware, all-weather clothing, cleaning products, paints and inks, and many kinds of personal care products are made with PFCs.

Not much is known about how PFCs as a group behave in the environment and how they get into people. In general, many of these chemicals do not break down in the environment, or do so only very slowly. Some PFCs stick to soil and others dissolve readily in water and move into groundwater or surface water. Some also travel long distances and are found in many kinds of animals and people worldwide. PFCs are thought to build up in wildlife and increase through the food chain so that top predators have the greatest amounts.

Most people in the U.S. have small amounts of PFCs in their bodies, regardless of their age. It is believed that most people are exposed through direct skin contact with PFC-containing products and by breathing in and swallowing small amounts in food, water, air, and house dust. It is thought that diet is usually the most important source for adults, and both diet and house dust are major contributors for small children. Since some PFCs resist breaking down in the body, they stay in the body for many years.

One particular chemical (PFOS) is the only PFC that has been shown to reach levels of concern in fish. Although most fish have very low levels of PFOS, certain fish from some Minnesota lakes have amounts that call for more protective consumption advice. For example, the Minnesota Department of Health (MDH) offers advice for some species from Fish Lake Flowage and Wild Rice Lake in St. Louis County due to amounts of PFOS measured in fish. As a general rule though, fish are an excellent source of low-fat protein and most have very little, if any PFCs, and people can safely eat them by following MDH Fish Consumption Advice which is available online at http://www.health.state.mn.us/divs/eh/fish/index.html

The potential effects of PFC exposure for human health are not fully understood at this time. It is possible that some PFCs may increase the risk of some health problems, and studies have shown that large amounts of PFCs may harm research animals, including changes in the function of some organs, increased tumors, and developmental and reproductive effects. What those findings mean for people exposed to small amounts of PFCs is not currently known.

Because there are many sources of PFCs and ways people can be exposed, it is difficult to avoid them completely. Even though it is unknown whether typical use of PFC-containing consumer products poses any health concerns, some people may wish to try to use such items less. If so, they may want to consider the tips below.

  • Decline stain-resistant or water repellent treatments if you buy new furniture or carpets and ask for products that have not been pretreated. Don’t apply such products yourself either.
  • Do not overheat non-stick cookware since PFCs may be released at very high temperatures (above 450°F). Discard items when the non-stick coating is deteriorated or damaged.
  • Avoid personal care products that include the words “fluoro” or “perfluoro” in the names of chemicals listed on the label.
  • Eat less oily packaged foods. Although use of some PFCs in food packaging has been reduced in recent years, grease-proofing coatings on some paper wrappers and containers could contain some PFCs or similar chemicals.


This chemical is one of a large group of over 100 different chemicals called polycyclic aromatic hydrocarbons (or PAHs). PAHs are released into the air when coal, oil and gas, garbage, or any other organic substances are burned. Exposure to PAHs can occur from smoking or chewing tobacco; breathing smoke from grilling, fireplaces, wood stoves, forest fires, and exhaust from vehicles. Grilled and smoked foods also contain PAHs. Historically, PAHs were released into the lower St. Louis River during production of coke from coal. Health concerns include: an increased risk of cancer, reduced fertility, asthma, bronchitis, and other respiratory problems.

You can reduce your exposure to PAHs by limiting your consumption of grilled and smoked foods. Do not smoke or allow others to smoke in your home or car; use exhaust fans or open your windows when cooking indoors; avoid burning wood in poorly ventilated stoves, especially for home heating; and do not idle cars inside your garage. Because PAHs can be in indoor and outdoor dust, wash your hands often, clean your floors regularly, and use a damp cloth to dust.

For more information on PAHs, see the CDC fact sheet: http://www.atsdr.cdc.gov/tfacts69.pdf

Bisphenol A (BPA)

Bisphenol A -- BPA for short -- is the common name for the chemical 4,4'-methylethylidenebisphenol. For over 50 years, BPA has been used for making a variety of industrial materials and consumer products.

Many people became aware of BPA in recent years due to media attention on efforts to ban its use in products such as baby bottles. There continues to be controversy and uncertainty about whether children might be affected by small amounts of BPA since it can act like a hormone and may interfere with the endocrine system. Scientists generally agree that some of the effects on reproduction and normal development seen in research animals could also happen if people are exposed to high doses. However, it is currently unknown whether these or any effects would occur at low doses that people typically experience.

The main way people are exposed to this chemical is by consuming food or drinks that have been in contact with BPA–containing plastics or packaging. For example, BPA can be found in some plastic dinnerware, the lining used to protect the inside of some food and beverage cans, and reusable bottles and food storage containers. These materials can release BPA, especially if they are heated or damaged.

Many common items contain plastics and resins made from BPA. Examples include artificial teeth, eyeglass lenses, toys, and many other rigid, impact-resistant plastics. BPA is also used in some coatings (such as paints, enamels, varnishes), adhesives, and even some cash register and credit card receipts. People may absorb BPA if they touch or put such items in their mouths. People can also be exposed to BPA in the environment since small amounts are in indoor and outdoor air, surface water, and house dust.

It is difficult to avoid BPA completely. Nevertheless, people who may want to lower the amount of BPA in their body can consider taking the following steps:

  • Choose BPA-free plastics (numbers 1, 2, 4 and 5) or non-plastic alternatives. Items with the recycling symbol number 7 may contain BPA. Polycarbonate plastics, those that have the letters ‘PC’ under the recycling triangle, do have BPA. There are also many alternatives for food/beverage containers and tableware such as glass, aluminum or unlined stainless steel.
  • If hard plastic containers are used for food and drinks, avoiding those with scratched or worn out surfaces and not using abrasives and harsh detergents may help. It is a good idea to refrain from heating food or liquid in such containers or putting hot items directly into them.
  • Because BPA is used on the inside of some metal food and beverage cans, limiting canned foods and drinks may reduce BPA intake.
  • Wet mopping and dusting may capture and remove contaminants, including BPA, that are often present in household dust.
  • If you need dental sealants or fillings, see if your dentist offers alternatives that do not contain BPA or another chemical called BADGE.


Triclosan is an antibacterial chemical found in many household items, the environment and people.

Triclosan has been used for more than 30 years as a preservative and a broad-spectrum antimicrobial agent. It is added to many common household and personal care items to kill germs, and resist mildew and odors, as well as extend products’ shelf life. Examples of products that contain triclosan are: liquid soap, mouthwash, acne medication, cosmetics, deodorant, lotion, toothpaste, dish-washing liquids, plastics, and textiles.

Triclosan can get into a person’s body. When they use products with triclosan, small amounts can be absorbed through the skin or mouth. Triclosan usually does not stay in a person’s body very long. A urine test can estimate the amount of triclosan a person has been exposed to recently from all sources they have contacted. Many people have triclosan in their bodies. Scientists found triclosan in the urine of nearly 75 percent of people six years and older who took part in the National Health and Nutrition Examination Survey (NHANES) in 2003–2004.

Simply finding triclosan in a person doesn’t mean that they will get sick from it. The effects on human health from small amounts of triclosan (such as those in the environment) are unknown at this time. Some products containing triclosan have caused skin irritation, but this has been rare. Because recent scientific studies have raised questions about whether triclosan might pose hazards to human health, more research is needed.

Current regulations allow companies to use triclosan in their products. However, it isn't a necessary ingredient in many products. There is no evidence that triclosan in most household items provides extra benefits. For example, anti-bacterial soaps and hand sanitizers use triclosan as the active ingredient to kill bacteria and other germs – which “plain” soap and water can also do.

Other studies have raised the possibility that triclosan may contribute to making bacteria resistant to antibiotics. Increasingly widespread use of triclosan in common household products may encourage growth and greater numbers of germs that can resist antibiotics.

Triclosan can also affect the natural environment. It mainly enters the aquatic environment in wastewater because water treatment does not remove all of it. This means it can end up in lakes, rivers and water sources where it potentially may harm fish and other organisms. You can read about a University of Minnesota study that found triclosan in Minnesota waters at: http://www.mndaily.com/2013/01/23/u-research-finds-antibacterial-ingredient-minnesota-lakes.

The Minnesota Department of Health’s recommendation is to avoid the use of products containing triclosan at home because of possible risks and few benefits. Anyone who is concerned can choose items that don't contain triclosan. To avoid triclosan, read product labels and ingredient lists before buying.