For Health

BUILDING EVIDENCE

FOR HEALTH

Research Summary: PCBs

Download this research summary as a PDF
Contributors:

Robert Herrick, Harvard T.H. Chan School of Public Health

What are PCBs?

Polychlorinated biphenyls (PCBs) are a set of 209 synthetic organic chemicals. They all have a biphenyl ring structure with between one and ten chlorine atoms attached to the ring. PCBs were manufactured in the United States from about 1930 to 1977; the World Health Organization (WHO) estimated in 2003 that approximately 2 × 109 kg (4.4 trillion pounds) of PCBs were produced over those years. PCBs were widely used electrical, heat transfer, and hydraulic equipment; as plasticizers in various products; in paints and finishes; in pigments, dyes, and carbonless copy paper; and in other industrial and commercial applications.7 There are no known natural sources of PCBs.

How are we exposed to PCBs?

PCBs are found in soil, sediment, air, food, and water. They move readily between these environmental media, and they have been detected in polar ice thousands of miles from any place they were manufactured or used. They are remarkably resistant to degradation by natural biological and chemical processes, so they persist in the environment. The ubiquity of PCBs is largely the result of 4 factors: vast amounts of PCBs were produced; PCBs move freely between environmental media (air, water, soil) and the food chain; PCBs naturally degrade very slowly; and PCBs accumulate in living organisms. PCBs are a particular concern in buildings, where they volatilize from building materials and leak from fluorescent light fixtures. PCBs may enter the bodies of people inside buildings through inhalation, ingestion, and dermal absorption (Herrick et al. 2004). Elevated PCB levels in the blood of people in these buildings (including schools) have been reported by many investigators.2,8,11,17,20,30

Sources of PCBs in buildings

A number of products found in buildings contained PCBs.7 These include: dielectric fluid in transformers, capacitors, and other electrical equipment such as switches and circuit breakers; oil in motors and hydraulic systems; microscope oil; capacitors including fluorescent light ballasts; cable insulation; thermal insulation such as fiberglass, felt, foam, and cork; adhesives and tapes; oil-based paints; caulk, window glazing, and other sealants; plastics; ceiling tile coatings; and floor finishes. Some of these materials can still be found in buildings, particularly those constructed or renovated between about 1950 and 1978.

Why are PCBs a health concern?

The Environmental Protection Agency, the WHO, and the United States Department of Health and Human Services have long characterized PCBs as known animal carcinogens and probable human carcinogens. In 2016, however, the International Agency for Research on Cancer (IARC) reassessed the scientific literature and concluded that there is sufficient evidence in humans for the carcinogenicity of PCB. IARC, therefore, upgraded the classification of PCBs to Group 1, known human carcinogens.

While cancer risk has been the primary concern associated with PCB exposure, recent studies have demonstrated a range of other toxic effects, including many that pose particular hazards in built environments such as schools.21

  • Asthma & Respiratory Effects. Adults and children have an increased risk of asthma and infectious respiratory diseases when exposed to PCBs.4,18 There is a relationship between PCB exposures and lowered levels of immunoglobulins M and A (IgM and IgA) and increases in respiratory infections.22
  • Attentional Deficits and Cognitive Function. Adults who work in buildings with PCB window caulk showed higher rates of attentional deficits.26 Low-level prenatal exposure to PCBs caused an increase in ADHD-like behaviors in children.28 Children who had prenatal exposure to PCBs had higher incidence of behavioral disorders and lower IQ scores when they were 9 years old.32 Adolescents with elevated serum PCBs did more poorly on several tests of cognitive function than adolescents with low PCBs.23
  • Endocrine Effects. Adolescent girls with high PCB levels reach puberty at a younger age than girls with lower PCBs.6 In adolescents, thyroid function is reduced if their serum PCB level is elevated.29 Higher PCB levels in men is associated with a reduction in the levels of the male sex hormone, testosterone.10
  • Immune System Effects. PCBs are associated with immune system disruptions including increases in B cells and decreases in CD8+ and natural killer cells.34 Babies with higher prenatal PCB exposures had reduced immune response after vaccination for measles, mumps and rubella.35 Reduced antibodies against diphtheria and tetanus later in childhood were associated with higher PCB exposure in toddlerhood.3 PCB exposure altered lymphocyte distributions, decreased wheeze, and increased otitis media.36
  • Prenatal & Infant Exposure. Low level prenatal exposure to PCBs may affect thyroid hormone homeostasis.5 Prenatal exposure to PCBs may affect growth, especially in girls.16 Growth deficits were also seen among infants born near a chemical manufacturing plant that produced PCBs,14 specifically lower thymic index, which is an estimate of the volume of the thymus, an organ that plays a role in the differentiation and maturation of t-lymphocytes (Tcells, a critical part of the immune system).25 Associations were reported between prenatal PCB and p,p-DDE exposures and poor attention in early infancy, including alertness, quality of alert responsiveness, and cost of attention.27
  • Diabetes & Heart Disease. Hospitalization rates for diabetes in communities near a toxic waste site containing PCBs were amplified.15 Residents living in communities adjacent to the Hudson River, which contains high levels of PCBs, had an increased rate of hospitalization for coronary heart disease by over 35% and for acute myocardial infarction by nearly 40%.31 High levels of PCBs cause the liver to make more cholesterol and lipids, which then increase the risk of cardiovascular disease.9

What can I do?

The issue of PCBs in buildings requires attention. There is unequivocal evidence that PCBs are common in building materials, and fluorescent light ballasts. These sources can cause PCB contamination of the building environment. Airborne PCB levels far in excess of EPA health-based guidelines have been frequently measured in buildings. People occupying these buildings, including students, teachers and staff of schools, residents, or workers in contaminated buildings have been shown to have elevated serum PCB levels.

What is also clear is the lack of policies and guidelines for owners and occupants of buildings that may contain PCBs. A 2016 report by US Senator Markey24 concluded that in the case of schools, there is a lack of transparency and inconsistency in communication between schools, EPA, the states, and the people in the school buildings. In addition, the Senate report found that EPA enforcement and communications are inconsistent. For example there is no requirement for a building owner or property manager to conduct sampling to determine whether PCBs are present in a building. Under TSCA regulations, however, if PCBs are found at levels exceeding 50 ppm that is considered an unauthorized use. Some EPA regions have interpreted that to mean that the PCB-containing materials must be removed,33 while other regions have advised school districts not to test for PCBs.24 Given the uncertainties surrounding the associations between PCB exposures and health effects, particularly among children, precautionary approaches to managing PCBs in building materials are warranted. Effective mitigation approaches are available and have been demonstrated to effectively minimize exposure.1,19

References

  1. Allen J, Minegishi T, McCarthy J, Fragala M, Coghlan K, Stewart J, MacIntosh D. 2011. Performance Evaluation of Mitigation Methods for PCBs in Construction Materials. In: Proceedings of Indoor Air 2011: The 12th International Conference on Indoor Air Quality and Climate. Austin, TX, USA. June 5-10, 2011.
  2. Ampleman, M.D., Martinez, A., DeWall, J., Rawn, D.F., Hornbuckle, K.C. and Thorne, P.S., 2015. Inhalation and Dietary Exposure to PCBs in Urban and Rural Cohorts via Congener-Specific Measurements. Environmental Science & Technology, 49(2), pp.1156-1164.
  3. Barrett, J.R., 2010. Diminished Protection?: Early Childhood PCB Exposure and Reduced Immune Response to Vaccinations. Environmental Health Perspectives, 118(10), p.A445.
  4. Carpenter, D.O., Ma, J. and Lessner, L., 2008. Asthma and Infectious Respiratory Disease in Relation to Residence Near Hazardous Waste Sites. Annals of the New York Academy of Sciences, 1140(1), pp.201-208.
  5. Chevrier, J., Eskenazi, B., Bradman, A., Fenster, L. and Barr, D.B., 2007. Associations Between Prenatal Exposure to Polychlorinated Biphenyls and Neonatal Thyroid-Stimulating Hormone Levels in a Mexican-American Population, Salinas Valley, California. Environmental Health Perspectives, 115(10), p.1490.
  6. Denham, M., Schell, L.M., Deane, G., Gallo, M.V., Ravenscroft, J. and DeCaprio, A.P., 2005. Relationship of Lead, Mercury, Mirex, Dichlorodiphenyldichloroethylene, Hexachlorobenzene, and Polychlorinated Biphenyls to Timing of Menarche Among Akwesasne Mohawk Girls. Pediatrics, 115(2), pp.e127-e134.
  7. Erickson, M.D. and Kaley, R.G., 2011. Applications of Polychlorinated Biphenyls. Environmental Science and Pollution Research, 18(2), pp.135-151.
  8. Gabrio, T., Piechotowski, I., Wallenhorst, T., Klett, M., Cott, L., Friebel, P., Link, B. and Schwenk, M., 2000. PCB-blood Levels in Teachers, Working in PCB-Contaminated Schools. Chemosphere, 40(9), pp.1055-1062.
  9. Goncharov, A., Haase, R.F., Santiago-Rivera, A., Morse, G., McCaffrey, R.J., Rej, R., Carpenter, D.O. and Akwesasne Task Force on the Environment, 2008. High Serum PCBs are Associated with Elevation of Serum Lipids and Cardiovascular Disease in a Native American population. Environmental Research, 106(2), pp.226-239.
  10. Goncharov, A., Rej, R., Negoita, S., Schymura, M., Santiago-Rivera, A., Morse, G., Carpenter, D.O. and Akwesasne Task Force on the Environment, 2009. Lower Serum Testosterone Associated with Elevated Polychlorinated Biphenyl Concentrations in Native American Men. Environmental Health Perspectives, 117(9), p.1454.
  11. Herrick, R.F., 2010. PCBs in School—Persistent Chemicals, Persistent Problems. New Solutions: A Journal of Environmental and Occupational Health Policy, 20(1), pp.115-126.
  12. Herrick, R.F., Meeker, J.D. and Altshul, L., 2011. Serum PCB Levels and Congener Profiles Among Teachers In PCB-Containing Schools: A Pilot Study. Environmental Health, 10(1), p.56.
  13. Herrick R, Stewart J, Allen J. 2015. Review of PCBs in US Schools: A Brief History, an Estimate of the Number of Impacted Schools, and an Approach for Evaluating Indoor Air Samples. Environ Pollut Res. Volume 23
  14. Hertz-Picciotto, I., Trnovec, T., Kočan, A., Charles, M.J., Čižnar, P., Langer, P., Sovčikova, E. and James, R., 2003. PCBs and Early Childhood Development in Slovakia: Study Design and Background. Fresenius Environmental Bulletin, 12(2), pp.208-214.
  15. Kouznetsova, M., Huang, X., Ma, J., Lessner, L. and Carpenter, D.O., 2007. Increased Rate of Hospitalization for Diabetes and Residential Proximity of Hazardous Waste Sites. Environmental Health Perspectives, 115(1), p.75.
  16. Lamb, M.R., Taylor, S., Liu, X., Wolff, M.S., Borrell, L., Matte, T.D., Susser, E.S. and Factor-Litvak, P., 2006. Prenatal Exposure to Polychlorinated Biphenyls and Postnatal Growth: A Structural Analysis. Environmental Health Perspectives, 114(5), p.779.
  17. Liebel, B., Schettgen, T., Kerscher, G., Broding, H.C., Otto, A., Angerer, J. and Drexler, H., 2004. Evidence for Increased Internal Exposure to Lower Chlorinated Polychlorinated Biphenyls (Pcb) in Pupils Attending a Contaminated School. International Journal of Hygiene and Environmental Health, 207(4), pp.315-324.
  18. Ma, J., Kouznetsova, M., Lessner, L. and Carpenter, D.O., 2007. Asthma and Infectious Respiratory Disease in Children–Correlation to Residence Near Hazardous Waste Sites. Paediatric Respiratory Reviews, 8(4), pp.292-298.
  19. MacIntosh D, Minegishi T, Allen J, Levin-Schwartz Y, McCarthy J, Stewart J, Coghlan K. 2011. Risk Assessment for PCBs in Indoor Air of Schools. In: Proceedings of Indoor Air 2011: The 12th International Conference on Indoor Air Quality and Climate. Austin, TX, USA. June 5-10, 2011.
  20. Marek, R.F., Thorne, P.S., Wang, K., DeWall, J. and Hornbuckle, K.C., 2013. PCBs and OH-PCBs in Serum from Children and Mothers in Urban and Rural US Communities. Environmental Science & Technology, 47(7), pp.3353-3361.
  21. Massie, M. and Terenzi, K. (2011). PCB Lighting in NYC Schools: Dangerous, Inefficient, and Obsolete. [online] New York Lawyers for the Public Interest. Available at: http://www.nylpi.org/images/FE/chain234siteType8/site203/client/ NYLPI.orgPublicInterestObsolescenceReport.pdf.
  22. Nakanishi, Y., Shigematsu, N., Kurita, Y., Matsuba, K., Kanegae, H., Ishimaru, S. and Kawazoe, Y., 1985. Respiratory Involvement and Immune Status in Yusho Patients. Environmental Health Perspectives, 59, p.31.
  23. Newman, J., Gallo, M.V., Schell, L.M., DeCaprio, A.P., Denham, M., Deane, G.D. and Akwesasne Task Force on the Environment, 2009. Analysis of PCB Congeners Related to Cognitive Functioning in Adolescents. Neurotoxicology, 30(4), pp.686-696.
  24. Office of Senator Edward J. Markey (2016). ABCs of PCBs: A Toxic Threat to America’s Schools. [online] U.S. Senate. Available at: https://www.markey.senate.gov/imo/media/doc/2016-10-05-Markey-PCB-Report-ABCsofPCBs.pdf.
  25. Park, H.Y., Hertz-Picciotto, I., Petrik, J., Palkovicova, L., Kocan, A. and Trnovec, T., 2008. Prenatal PCB Exposure and Thymus Size at Birth in Neonates in Eastern Slovakia. Environmental Health Perspectives, 116(1), p.104.
  26. Peper, M., Klett, M. and Morgenstern, R., 2005. Neuropsychological Effects of Chronic Low-Dose Exposure to Polychlorinated Biphenyls (Pcbs): A Cross-Sectional Study. Environmental Health, 4(1), p.22.
  27. Sagiv, S.K., Nugent, J.K., Brazelton, T.B., Choi, A.L., Tolbert, P.E., Altshul, L.M. and Korrick, S.A., 2008. Prenatal Organochlorine Exposure and Measures of Behavior in Infancy Using the Neonatal Behavioral Assessment Scale (NBAS). Environmental Health Perspectives, 116(5), p.666.
  28. Sagiv, S.K., Thurston, S.W., Bellinger, D.C., Tolbert, P.E., Altshul, L.M. and Korrick, S.A., 2010. Prenatal Organochlorine Exposure and Behaviors Associated with Attention Deficit Hyperactivity Disorder in School-Aged Children. American Journal of Epidemiology, 171(5), pp.593-601.
  29. Schell, L.M., Gallo, M.V., Denham, M., Ravenscroft, J., DeCaprio, A.P. and Carpenter, D.O., 2008. Relationship of Thyroid Hormone Levels to Levels of Polychlorinated Biphenyls, Lead, P, p’DDE, And Other Toxicants in Akwesasne Mohawk Youth. Environmental Health Perspectives, 116(6), p.806.
  30. Schwenk, M., Gabrio, T., Päpke, O. and Wallenhorst, T., 2002. Human Biomonitoring of Polychlorinated Biphenyls and Polychlorinated Dibenzodioxins and Dibenzofuranes in Teachers Working in a PCB-Contaminated School. Chemosphere, 47(2), pp.229-233.
  31. Sergeev, A.V. and Carpenter, D.O., 2005. Hospitalization Rates for Coronary Heart Disease in Relation to Residence Near Areas Contaminated with Persistent Organic Pollutants and Other Pollutants. Environmental Health Perspectives, 113(6), p.756.
  32. Stewart, P.W., Lonky, E., Reihman, J., Pagano, J., Gump, B.B. and Darvill, T., 2008. The Relationship Between Prenatal PCB Exposure and Intelligence (IQ) in 9-Year-Old Children. Environmental Health Perspectives, 116(10), p.1416.
  33. Stoller, K. (2005). Letter to Kaplowitz. [ebook] United States Environmental Protection Agency. Available at: https://media.wix.com/ugd/561311_684ce3cdfb1748a1b104598c3b2f8b2d.pdf
  34. Svensson, B.G., Hallberg, T., Nilsson, A., Schütz, A. and Hagmar, L., 1994. Parameters of Immunological Competence in Subjects with High Consumption of Fish Contaminated with Persistent Organochlorine Compounds. International Archives of Occupational and Environmental Health, 65(6), pp.351-358.
  35. Weisglas-Kuperus, N., Patandin, S., Berbers, G.A., Sas, T.C., Mulder, P.G., Sauer, P.J. and Hooijkaas, H., 2000. Immunologic Effects of Background Exposure to Polychlorinated Biphenyls and Dioxins in Dutch Preschool Children. Environmental Health Perspectives, 108(12), p.1203.
  36. Weisglas-Kuperus, N., Vreugdenhil, H.J. and Mulder, P.G., 2004. Immunological Effects of Environmental Exposure to Polychlorinated Biphenyls and Dioxins in Dutch School Children. Toxicology Letters, 149(1), pp.281-285.