Polychlorinated Biphenals (PCBs)
Polychlorinated Biphenyls (PCBs) are synthetic chemicals that were first manufactured in 1929 and used in many industrial materials including coolants and lubricants for transformers until 1977 when a ban was placed on manufacturing and importing PCBs. The ban did not include PCBs already in use however these are being phased out and there are strict regulations for the handling, storage and disposal of PCBs.
PCBs are toxic and classified as a probable human carcinogen however they are not known to cause birth defects. PCBs may affect infant behavior or the immune system in children born to mothers who were exposed to high levels of PCBs.
Health Risks Of PCBs
PCBs do not easily break down and are very persistent, that is they last for many years and they are hard to destroy. Trace levels of PCBs in the air and water are found all over the world, even in remote areas as a result of long-range transport of PCBs by global air currents, and as a result can be found in food. This means that everyone is exposed to low levels of PCBs.
PCBs accumulate in the cells of animals and people with the highest concentrations at the top of the food chain. Everyone is exposed to very small amounts of PCBs in food and even smaller amounts in air, soil and water. These low levels are unlikely to cause adverse health effects.
Most of what is known about the health effects of exposure to PCBs is a result of occupational exposures or accidental releases. The current research suggests that low-level exposures to PCBs are not likely to cause adverse health effects however those people who consume large amounts of certain sport fish, wild game and marine animals may be at higher risk as fish consumption appears to be the major pathway of exposure. Exposure from drinking water is less than from food. In water, a small amount of PCBs may remain dissolved, but most stick to organic particles and bottom sediments. PCBs bind strongly to soil and can be found around the world.