"PCBs" - Polychlorinated Biphenyls

PCB Transformers - http://mrg.bz/wrBCzJ

           Have you ever seen one of these old transformers on a pole near your home? Can they be hazardous? Have you heard of PCBs but wanted to know more? Well you've come to the right place!
            Polychlorinated Biphenyls, or PCBs as they are commonly known, are man-made chemicals that have become well known due to the environmental affects caused by bioaccumulation, particularly in Lake Ontario (Glooschenko & Glooschenko, 1975, Oliver & Niimi, 1998). They did not exist in natural environments until they were first made in the 1900’s (Barbalace, 2003). So there off to a rough start.

           PCBs were used in many products prior to the 1960s because of the physical properties of the chemical, which include being: non-flammable, insulating, persistent, and chemically stable (United States Environmental Protection Agency, 2013). However in the early 1970s, the toxic properties of the chemicals were identified which resulted in the reclassification of PCBs to that of a widespread contaminant (Glooschenko & Glooschenko, 1975). Yikes! Following reclassification, landfills and disposal companies had to rethink their use of the chemicals due to greater cost and changes associated with new regulations and handling procedures (Province of Alberta, 1996). This change, and greater awareness of health concerns drove the commercial and consumer use of PCBs down drastically.

           PCBs bio-accumulate in the environment, meaning that once they are present they are very hard to remove. The effect of which is an accumulation of the chemical over time. An example of this seen in Lake Ontario, as the contamination of microscopic organisms in the lake led to the buildup of PCBs in larger bony fish, rendering them unfit for human consumption by Health Canada guidelines (Glooschenko & Glooschenko, 1975, Oliver & Niimi, 1998).

           PCBs are still in use today, particularly for industrial purposes such as transformers (see picture above), and in old commercial products such as light ballasts (United States Environmental Protection Agency, 2013). The case of PCBs should be viewed as a lesson to future generations that will undoubtedly utilize chemical compounds without knowing all of the potential consequences.

References:

Barbalace, R. C. (2003). The chemistry of polychlorinated biphenyls. Accessed on-line: http://EnvironmentalChemistry. com/yogi/chemistry/pcb. html. 

Glooschenko, V., & Glooschenko, W. (1975). Effect of polychlorinated biphenyl compounds on growth of Great Lakes phytoplankton. Canadian Journal of Botany, 53(7),  653-659.

Oliver, B. G., & Niimi, A. J. (1988). Trophodynamic analysis of polychlorinated biphenyl congeners and other chlorinated hydrocarbons in the Lake Ontario ecosystem. Environmental science & technology, 22(4), 388-397.

Province of Alberta. (1996). Waste Control Regulation. Retrieved October 22, 2014 from http://www.qp.alberta.ca/documents/Regs/1996_192.pdf 

United States Environmental Protection Agency. (2013). Polychlorinated Biphenyls (PCBs). Retrieved October 20, 2014 from http://www.epa.gov/wastes/hazard/tsd/pcbs/about.htm