Between the time of initial (1929) and final production (1977) the USA produced an estimated 0,54 billion kg of PCB's. They were widely used in transformers and capacitors, lubricants, fire retardants, plastics and other materials. PCBs can enter the marine environment by adsorption to particals and admosferic transport. PCBs have been shown to cause reproductive abnormalities in marine mammals, chronic diseases in humans. Furthermore they are suspected to be carcinogenic. Like other organochlorine compounds they are a hazard to marine ecosystems because of their extreme stability, low biodegradability and lipid solubility, which causes them to bioaccumulate.
There are 209 different forms of PCBs. Therefore, to asses the risk of PCB exposure, the sum of all these forms needs to be taken into account. 
- Lawrence E (ed.), 2000. Henderson’s Dictionary of Biological Terms. 12th edition. Prentice Hall, Pearson Education Limited. Harlow, Great Britain. Cite error: Invalid
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- ↑ Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp