PCB is the abbreviation for a group chemicals called polychlorinated biphenyls. link to.
PCBs are either oily liquids or solids. They are colorless to light yellow. Some PCBs can exist as a vapor in air. They have no known smell or taste so they are difficult to detect by the average person.
PCBs are man-made chemicals. PCBs are also produced as a by-product of as many as 200 different chemical processes. They are not found in nature.
PCBs were invented by scientists to provide a non-flammable material that could be used an insulator in high voltage electrical equipment. PCBs are ideal for this purpose because they do not conduct electricity easily and they do not burn.
These chemical properties make PCBs the perfect choice as coolants and lubricants in electrical transformers, capacitors, and other industrial electrical equipment. PCBs can even be found in electrical devices, microscopes, hydraulic oils, and paints.
HOW TOXIC ARE PCBs?
The federal Environemntal Protection Agency (EPA) has set a limit of 0.0005 milligrams of PCBs per liter of drinking water. The Food and Drug Administration (FDA) requires that infant foods, eggs, milk and other dairy products, fish and shellfish, poultry and red meat contain no more than 0.2-3 parts of PCBs per million of food. Many states have established fish and wildlife consumption advisories for PCBs.
PEOPLE AND PCBS
|Investigate more about the health risks of PCBs.|
PCBs chemical properties seemed great for so many uses, but there were problems.
Exposure to PCBs causes acne-like skin conditions in adults and neurobehavioral and immunological changes in children. PCBs are known cause cancer in animals and are considered probable human carcinogens.
The best way to know whether or not you are regularly exposed to PCBs is through routine evaluation or a blood test that is available to detect recent large exposures. The evaluation only indicates a person's exposure to PCBs and does not predict potential health effects.
PCBs IN THE ENVIRONMENT
The way PCBs function in the environment is a serious problem. Because PCBs are synthetic chemicals, they do not breakdown easily. Once they enter the environment, these toxic chemicals remain there for many years poisoning fish, wildlife, and humans.
PCBs can volatize into a gas; travel long distances in the air, and is deposited in areas far away from where they were originally released. PCBs can remain suspended in water and transported through aquatic ecosystems.
PCBs have been found in human breast milk among Native Peoples in the Artic who live thousands of miles away from industrial sources of PCBs.
PCBs molecules bind strongly to soil particles. In aquatic ecosystems, PCBs stick to organic particles and lake bottom sediments. The greatest concentration of PCBs in the Lake Superior Basin is in the bottom sediments of industrialized harbors areas.
WHAT COMES AROUND GOES AROUND
Perhaps the greatest problem with PCBs, that like many of the critical pollutants, i. bioaccumulates in the food chain.
|Click on the fish to learn about advisories for eating Great Lakes Fish|
In aquatic ecosystems like Lake Superior, small organisms and fish absorb PCB molecules have entered the water. Other animals that eat these smaller organisms as food also eat the PCBs they contain. As they move through the food chain, PCBs accumulate in fish and marine mammals, reaching levels that can be many thousands of times higher than originally was found in the water. When we eat fish or animals that have accumulated levels of PCBs in their tissue, PCBs enter our bodies at these high levels and affect our health.
PCBS ARE BANNED, BUT NOT FORGOTTEN
The good news is that the health effects of PCBs were recognized by 1977 and the new production of PCBs in the United States was banned. The problem is that more than 1.5 billion pounds of PCBs had already been manufactured in the United States by the time it was banned.
Even though PCBs are no longer being produced in the US, older industrial, utility, household electrical equipment still in use within the Lake Superior Basin contain PCBs. Improperly disposing of these items will release PCBs into the environment.
WHERE ARE PCBS COMING FROM NOW?
|An accidental spill of toxic PCBs from electrical equipment into a stream.|
Although PCB production was banned over 20 years ago, these poisons still are entering the Lake Superior ecosystem where their toxicity will remain for many years. In the Lake Superior basin, most continuing PCB releases are thought to be from electrical equipment oil spills. Small amounts could be released from fuel combustion, waste oil combustion, biomedical waste incineration, and wastewater treatment plants.
Even if you do not live near Lake Superior, you may be exposed to PCBs in your community from these sources:
Researchers estimate that 95 percent of the PCB load to the Lake Superior ecosystem comes from the atmosphere.
Because PCBs can easily volatize into a gas, PCBs from sources hundreds of miles away are being deposited into the Lake Superior by the wind or are carried into the Basin on rain or snowfall.
Air deposition sources of PCB contamination may be from other countries where PCBs are still being manufactured and used or through the improper disposal of PCBs in this country or abroad.
|Research what citizens are doing about soil and sediment contamination by PCBs and other toxic chemicals discovered along the Lake Superior waterfront in Ashland, WI.|
Soil & Sediments:
Volatilization of PCBs from soils and sediments is also a significant contributor to PCBs into Lake Superior. PCBs that volatize from soils and sediments enter the air deposition pathway into the Lake.
PCBs are found in Lake Superior sediments, particularly in harbor areas, industrial sites and contaminated landfills. These sites have been designated Lake Superior Areas of Concern. (link to map at top of this section.
The total amount of PCBs in contaminated soils and landfills around the Lake Superior Basin is still unknown. We can be exposed to PCBs by breathing air near these hazardous waste sites or drinking well water contaminated with PCBs that has leached into the groundwater.
Industrial Electrical Equipment
Most of the PCBs in the Lake Superior Basin are still in storageor use within the municipal, utility, mining and industrial sectors.
Major utilities and some industrial facilities in the U.S. portion of the Lake Superior Basin have made good progress in replacing and disposing of their PCB-contaminated transformers and capacitors.
Small utilities and other industrial facilities need to do more to identify and decommission their PCB-contaminated equipment. PCBs can enter the environment when old electrical transformers and electrical equipment that contain PCBs are not properly repaired or maintained. Accidents, such as fires involving electrical transformers or spills of the PCB laden liquid they contain, can introduce PCBs into the environment. Improper disposal of older PCB containing equipment is another source of environmental contamination.
A PCB Industry Success Story in 2001 Murphy Oil and the City of Superior entered into a voluntarypartnership to develop a pollution prevention guidebook for reducing use of mercury and PCBs. Investigate how this partnership worked towards the elimination of devices containing mercury and PCBs.
Older Household Electrical Lighting Fixtures and Appliances
PCBs are not just found in industries. If your home or school has old fluorescent lighting fixtures or old electrical devices and appliances (such as television sets and refrigerators that were made 30 years ago or more) they may contain small amounts of PCBs. When these appliances get hot during use, PCBs can leak out into the air, exposing you and the environment to PCBs.
Older electrical appliances must be properly disposed of through a community Clean Sweep Program or a household appliance collection program.
|Household appliances dumped near a Lake Superior Basin stream|
If old appliances are burned, dumped, or landfilled, the PCBs they contain may enter the environment.
|Sportfish, like walleye and lake trout, can accumulate toxic chemicals in their tissues. Investigate the risk for eating fish in your area and what to do to reduce your exposure to toxic chemicals.|
PCBs bioaccumulate (glossary link) in the food chain. Smaller aquatic organisms, like zooplankton, are food for fish. If PCBs are present in water, they can be absorbed by zooplankton. As zooplankton are eaten by fish, the fish take in the PCBs.
The amount of PCBs in the fish adds up as they eat more of these food sources. Smaller fish are eaten by larger fish and the levels PCBs continue to build up in the fish meat.
Humans share the top spot at the top of the food chain. When we eat fish contaminated with PCBs, we consume the amount of PCBs that have been building up through the food chain. Like humans, animals at the top of the food chain are exposed to the highest levels of PCBs that have been accumulating in the food chain.
The main human food sources of PCBs are fish (especially sport fish caught in contaminated lakes or rivers), meat, and dairy products.
Learn how to clean fish to remove PCBs and other tips for safe fish consumption.
Lake Superior's fish are fun to catch and great to eat. Because PCBs and many other contaminants accumulate in a fish's fatty areas, by learning how to prepare fish properly we can reduce our exposure to these toxins and still enjoy eating them.
In 2000, Lake Superior top predator fish, like Walleye and lake trout, were deemed unsafe for consumption by other wildlife by the US Environmental Protection Agency. Learn more
GOAL. TOTAL ELIMINATION OF PCBS
|Is Lake Superior recylcing its PCBs? Investigate the latest research.|
The good news is that PCBs are not being made anymore. The problem is that even if PCBs are completely eliminated from the Basin today, volatilization (glossary) of PCBs from old sources, release of PCBs from sediments and soils, improper disposal of PCB containing equipment still in use, and eventual atmospheric deposition from these sources, remain significant pathways for PCBs to enter Lake Superior.
We need to prevent release of existing PCBs and safely get rid of PCBs in that are still in use or are in storage. This also means cleaning up and destroying PCB contaminated soils and sediment, wherever possible.
Th. goal is to:
- Eliminate any new sources of PCBs entering the Lake Superior Basin
- Properly dispose or and destroy any sources of PCBs to achieve a 100% destruction of PCBs in the Lake Superior Basin by 2020.
Here's the progress report and what needs to be done.
1990: Baseline Year. Research estimated that 917,609 liters of PCBs were in use in the United States and Canadian sides of the Lake Superior Basin.
2000: Goal: Reduce PCBs by 33% of 1990 baseline amounts.
2005: Goal: Reduce PCBs by 60%
2010: Goal: Reduce PCBs by 95%
2020: Goal. Achieve 100% destruction of in-use and stored PCBs % to achieve a goal of Zero Discharge (link to glossary) of mercury into the Lake Superior Basin.
TAKE THE NEXT STEPS...to eliminate PCBs
|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.|
|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!|
|REFLECT.... Share and celebrate your experiences with others. This section lets you share what you learned with others.|