Polychlorinated biphenyls (PCBs)

PCBs are synthetic chemicals banned in the U.S. since the 1970s because of their toxicity. PCBs contaminate water by leaching from landfills and hazardous waste clean-up sites. PCBs increase the risk of cancer. Read More.

Up until the late 1970s, PCBs were used widely as coolants and lubricants in transformers, capacitors and other electrical equipment. Currently, PCBs are widely detected in the general population. They build up and are stored in fatty tissues and fluids such as breast milk, and can be passed on to fetuses and infants during pregnancy and breast-feeding. In human epidemiological studies, PCBs have been associated with an elevated risk of breast and prostate cancers. Infants and children with higher PCB exposures during development score lower on measures of neurological function, ranging from decreased IQ scores to reduced hearing sensitivity. PCBs also affect hormones and damage the immune system.