PCB_Health_Effects

As mentioned in the pathways section, the EPA ruled to stop the commercial manufacturing of PCBs in 1977 because of environmental health impact on both humans and wildlife.

There are various health effects associated with PCBs such as cancer as well as non-carcinogenic effects to the immune, reproductive, endocrine, and nervous systems.

PCBs and Cancer

Animal studies (Kimbrough et al. 1975) as well as workplace surveys have shown evidence of increased mortality due to PCB exposure. In particular, a significant cancer mortality increased was found by Bertazzi et al. (1987) at all locations they studied as they observed in the gastrointestinal tracts of workers exposed to PCBs containing 42 and 54 percent chlorine.

Gallbladder Cancer

Normal Gallbladder v. Abnormal Gallbladder

Another study by Brown in the same year illustrateded significantly higher than normal mortality rates from liver, gall bladder and biliary tract cancer in capacitor manufacturing workers who had been exposed to Aroclor 1254, 1242, and 1016. Contradiciting these findings, the ATSDR performed a study in 1993 that showed no increases in cancer mortalities from PCB exposure. Because of the uncertainty on the matter, it is hard to present conclusions from these studies.

PCBs and the Biological Systems

When PCBs do get into the body they can cause a number of problems due to their affect on hormones in the thyroid and other endocrine glands.

PCBs and Endocrine Disruption

Since hormones influence the normal functioning of many organs, some of the effects of PCBs may result from endocrine changes. Studies on female mice, minks, and monkeys have shown an inability to conceive and decreased fetal survival following repeated exposure to commercial PCBs. Male subjects exposed to commercial PCBs have reduced testes weight and reduced fertility. The pathway is unknown, but thought to be a result of an elevation in testosterone-metabolizing enzymes and continued depression of thyroid hormonal levels.

Immunological Effects and Tissue Damage

PCBs impair the immune system and weaken the body's defenses against pathogens. In some studies, the presence of PCBs has enhanced inflammatory responses leading to tissue injury.

Sources:

http://www.epa.gov/opptintr/pcb/effects.html

http://www.atsdr.cdc.gov/toxprofiles/tp17-c3.pdf