Paulina Toribio
Polychlorinated biphenyls are mixtures of 209 individual chlorinated compounds, also known as congeners. PCBs are man-made and are not found naturally in the Earth.
PCBs vary in consistency from thin and light colored to yellow-black waxy. Some PCBs can exist as a vapor in air. PCBs have no known smell or taste and range in toxicity.
PCBs were used as coolants and lubricants in transformers, capacitors, and other electrical equipment. This is because of their non-flammability, high boiling point and being extremely good insulators. PCBs were domestically manufactured in 1929 until their manufacture was banned in 1979. This was because of evidence that was build up in the environment and the realization that they can cause harmful health effects.
PCBs are still be released to the environment from hazardous waste sites to illegal or improper disposal of and consumer products. PCBs do not break down in the environment, which means they will remain there for long periods of time. In water, PCBs stick to organic particles and bottom sediments.
PCBs are taken up by small organisms and fish in water. They are also taken up by other animals that eat these aquatic animals as food. PCBs accumulate in fish and marine mammals, reaching levels that may be many thousands of times higher than in water.
Exposure to Polychlorinated Biphenyls may be by the use of old fluorescent lighting and electrical appliances older than 30 years. These items leak small amounts of PCBs into the air when they get hot during operation, and could be a source of skin exposure. Also, eating contaminated food can exposure humans to high levels of PCBs. The main dietary sources of PCBs are fish, meat, and dairy products. Breathing air near hazardous waste sites and drinking contaminated well water can expose humans to PCBs as well.
When exposed to large amounts of PCBs, the most commonly observed health effects are skin conditions such as acne and rashes. Studies in exposed workers have shown changes in blood and urine that may indicate liver damage. PCB exposures in the general population are not likely to result in skin and liver effects. Few studies of workers indicate that PCBs were associated with certain kinds of cancer in humans, such as cancer of the liver. To avoid exposure to PCBs, children should be told not play with old appliances, electrical equipment, or transformers, since they may contain PCBs and should be

discouraged from