Environmental Fate and Biological Effects of Polychlorinated Biphenyls (PCBs). Gretchen DeBaun. General Information. Highly toxic persistent organic pollutants (POPs) Found world-wide Used predominantly as dielectric fluids in capacitors and transformers
· (AFSME)Degree of concentration in each level of the Great Lakes aquatic food chain for PCBs (in parts per million, ppm). The highest concentrations are found in the eggs of fish-eating birds.