Polychlorinated biphenyls (PCBs) were widely used as dielectric and coolant fluids in equipment such as transformers, capacitors, and electric motors. In 1881 German chemists synthesized the first PCB in a laboratory. In the US commercial production of PCBs was taken over by the Monsanto Company. From 1930 to 1977, PCBs were marketed under the trade name Aroclor. Manufacturing of PCBs peaked in the 1960’s. Their commercial appeal was primarily based on their chemical stability, low flammability and electrical insulating properties.
In 1966, Dr. Soren Jensen determined PCBs to be an environmental contaminant. In 1979 PCB production in the US was banned. Their chemical and physical stability has been responsible for their continuing persistence in the environment decades after regulations were imposed to control environmental contamination.
One of the most well documented instances of environmental contamination occurred in Anniston Alabama. PCBs which originated from the Monsanto Chemical Company in Anniston were discharged into Snow Creek. The contamination continued downstream to Logan Martin Lake and Lay Reservoir. Today levels of PCBs contamination remain concentrated in Snow and Choccolocco Creeks. Concentrations in fish have declined over time. However rudiment disturbance can resuspend the PCBs into the water column and increase concentrations in aquatic life.
The toxicity of PCBs can vary considerably among the various Aroclors. Individuals can be exposed to PCBs through breathing in contaminated air, consuming contaminated food, or by skin contact with PCB oil. Once in the body PCBs may change to other chemicals. These chemicals or unchanged PCBs may remain stored in the body for extended periods of time. PCBs may be transmitted to infants through breast feeding.
The most commonly observed health effects in people exposed to high levels of PCBs are skin conditions such as chloracne and rashes. Studies in PCB exposed workers show changes in blood and urine which may indicate liver damage. Babies born to women who ate PCB contaminated fish showed abnormal responses in tests of infant behavior. This included problems with motor skills and a decrease in short term memory. Studies examining a possible link between PCBs and cancer have been inconclusive.
The exposure limits for PCBs are set fairly low. The OSHA Permissible Exposure Limit (PEL) and the ACGIH Threshold Limit Value (TLV) for employees is 1mg/m3 for PCBs with 42% chlorine. The OSHA PEL and ACGIH TLV for PCBs with 54% chlorine is 0.5mg/m3. The EPA standard for PCBs in drinking water is 0.5 parts per billion. The FDA has set limits for various foods. FDa limits are 0.2 ppm PCB in infant and junior foods, 0.3 ppm in eggs, 1.5 ppm in milk and dairy products, 2 ppm in fish and shellfish, and 3 ppm in poultry and red meat.
At The University the main effort in controlling PCBs has been directed toward management of the predominant source on campus, transformers and electrical equipment. Beginning in the 1980’s, EHS began testing equipment on campus to determine if PCBs were present. Equipment determined to have PCB or PCB contaminated oil was identified and labeled. As utilities were upgraded equipment determined to have PCBs was removed from service and disposed of. The use and disposal of PCB and PCB contaminated equipment is regulated by the EPA through the Toxic Substances Control Act (TSCA) requirements. At this point there are very few major pieces of equipment on campus which contain PCB oils.