PCB's include any of a group of toxic, chlorinated aromatic hydrocarbons used in a variety of commercial applications, including paints, inks, adhesives, electrical condensers, batteries, and lubricants; known to cause skin diseases and suspected of causing birth defects and cancer. (An acronym for polychlorinated biphenyl.) (1996, Academic Press, Inc.) http://www.academicpress.com.
PCBs form a group of compounds which were developed in the 1930s and were mainly used in the electricity supply industry and mining. Due to their accumulation in the food chain, production of PCBs was halted world-wide at the beginning of the 1980s and in 1996 an EC Directive was agreed requiring a phase-out of continuing uses (mainly in ageing electrical equipment). PCBs are, however, still found in trace concentrations in the sea and in the fatty tissue of marine animals.