Polychlorinated biphenyls (PCB's) Data Sheet

Source of Exposure

Polychlorinated biphenyls (PCB's) compose a group of 209 possible isomers of unsubstituted biphenyls. They are a class of chemicals with one or more chlorine atoms attached to various parts of a biphenyl nucleus. PCBs were developed as a coolant for electrical transformers. Commercial materials are liquid in form. They have been sold under a variety of trade names called arochlor. Although PCBs have been banned for commercial use in the United States, environmental contamination with concomitant human exposure continues. Discarded transformers and lubricating oils remain common sources of recurring PCB pollution. Contamination of the environment continues through improper disposal, and in certain instances by contamination of food products during processing. Prior to restrictions in 1972, they were found in heat transfer fluids, hydraulic fluids, lubricants, plasticizers, coatings, inks, carbonless copy paper, adhesives, pesticides, electric wire insulation, immersion oil for microscopy, water permeability barriers and other products.

Symptoms

Generally, PCBs have a low order of acute toxicity but because of their high fat solubility and poor metabolism, they present a substantial threat to man. Because of their indefinite half life the problems with bioaccumulation are great. A major target organ of PCB contamination is the liver. Evidence of human toxicity grew out of an epidemic in Japan once called "the oil disease" or "Yusho". Symptoms and signs included acniform eruptions, dark brownish nails, cheese-like discharges from the meibomian glands as well as numbness and neuralgic limbs.

Other complaints were numbness, pain, hypoesthesia, and areflexia.(Marai and Kuroiwa, 1971) There was reduced nerve conduction velocity in peripheral nerves. Motor nerve conduction velocity, sensory neuropathy, and sensory and nerve conduction changes were seen. Occupational effects included burning of the skin, eyes, face, and edematous rashes(Ouw et al, 1976), nail pigmentation and deformity, ocular edema, pigmentation of the conjunctiva(Fishbein at al, 1982), malignant melanoma(Jensen, 1982), liver damage and cancer disturbances in menses(Umeda, 1978), premature delivery of small infants, decreased IgA and IgM levels, decreased T-helper cells, increased blood pressure, gastrointestinal symptoms, and respiratory symptoms (pneumonia, cough, wheezing).

Experimental animal studies have shown development of permanent neurobehavioral deficits in offspring of PCB exposed female mice.(Tilson, et all 1979) Less affected mice showed deficits in traversing a rod and in avoidance recognition. There were deficits in forelimb strength, visual placement, and development of a spinning syndrome (circling, bobbing, hyperactivity). Spinal and cranial nerve roots had histologic malformations (abnormal nerves fibers and glia).(Chow, et al, 1979) Female monkeys fed a diet with Arochlor 1248 (2.5 ppm)yielded offspring with locomotor hyperactivity and learning errors.(Bowman, et al, 1978) Arochlor 1242 also decreased norepinephrine and dxopamine levels in jellifish.(Fingerman and Rusell,, 1980)

Blood Concentrations

General population data indicates that PCBs are at measurable levels in almost all humans. The population data for the United States indicates an average PCB concentration < 0.03 - 2.0 ppb. (EHS data) However, PCB levels may differ greatly between countries and geographic regions due to variables such as dietary customs and agricultural practices.

Metabolism

PCBs are potent enzyme inducers.(Wasserman et al, 1979). The effect is long-term, existing after discontinuation of the PCBs. They affect the cytochrome P-45O and P-448 systems.(Letz, 1983). They decrease thiamine levels in the blood and liver of animals.(Deichman, 1981) They appear to elevate serum triglycerides.(Chase et al, 1982)

Summary

Classification:Polychlorinated biphenyls
Synonyms Chlorinated biphenyls
Chlorinated diphenyls
Polychlorinated polyphenols
Population Average < 0.03 - 2.0 ppb (serum)
Onset of symptoms < 20 ppb
Death Data not available
Half-Life Indefinite
LD 50 (oral-rat) 1,295 - 16,000 mg/kg
(Arochlor 1221) 3,980 mg/kg
(Arochlor 1232) 4,470 mg/kg
(Arochlor 1242) 4,250 mg/kg
(Arochlor 1248) 11,000 mg/kg
(Arochlor 1254) 11,295 mg/kg
(Arochlor 1260) 1,315 mg/kg
(Arochlor 1262) 11,300 mg/kg
(Arochlor 1268) 10,900 mg/kg
(Arochlor 2565) 6,310 mg kg
(Arochlor 4465) 16,000 mg/kg

References

Bahn,l A.K., Rosenwaike, I., Nerrmann, N., Grover, P., Stellman, J., O'Leary, K. "Melanoma after exposure to PCBS," New Eng J Med, 295: 450, 1976.

Beral, V., Evans, S., Shaw, N., Milton, G. "Malignant melanoma and exposure to fluorescent lighting at work," Lancet, 8293: 290-293, 1982.

Bowman, R.E., Heironimus, M.P. and Barsottil D.A. "Locomotor hyperactivity in PCB-exposed Rhesus monkeys", Neurotoxical, 2:251, 1981.

Brown, D.P. and Jones, M. "Mortality and industrial hygiene study of workers exposed to polychlorinated biphenyls", Arch Environ Health, 36: 120-129, 1981.

Chang, K.J. "Immunologic evaluation of patients with polychlorinated biphenyl poisoning: Determination of lymphocyte subpopulations", Toxicol and Appl Pharm, 61: 58-63, 1981.

Chase, K.N., Wong, O., Thomas, D., et al. "Clinical and metabolic abnormalities associated with occupational exposure to polychlorinated biphenyl (PCBs)", J Occup Med, 24: 109-114, 1982.

Chen,, R.C., Chang, Y.C., Chang, K.L., Lu, F.J. and Tung, T.C. "Peripheral neuropathy caused by chronic polychlorinated biphenyls poisoning", J Taiwan Med Assoc, 80: 47, 1981.

Chow, S.M., Miike, T., Payne, W.M., and Davis, G.J. "Neuropathology of 'spinning syndrome' induced by prenatal intoxication with a PCB in mice", Ann NY Acad Sci, 320: 373, 1979.

Deichmann, W.B. 'Halogenated cyclic hydrocarbons" in Clayton, G.D. and Clayton, F.E. (Eds.) Patty's Industrial Hygiene and Toxicology, 3rd Ed., New York: John Wiley and Sons, 1981, 3645-3669.

Fingerman, S.W. and Russell, L.C. "Effects of the polychlorinated biphenyl Arochlor 1242 on locomotor activity and on the neurotransmitters dopamine and norepinephrine in the brain of the gulf killifish, Fundulus grandis", Bull Environ Contam Toxicol, 25: 682, 1980.

Fischbein,, A., Wolfe, M.S., Bernstein, J., Sflikoff, D., Thornton, J. "Dermatological findings in capacitor manufacture workers exposed to dielectric fluids containing polychlorinated biphenyls (PCB)II, Arch of Environ Health, 37: 69-74, 1982.

Jensen, A.A. "Melanoma, fluorescent lights, and polychlorinated biphenyls", Lancet, 8304: 935, 1982.

Kimbrough, R.D. "The toxicity of polychlorinated polycylic compounds and related chemicals", Crit Rev Toxicol, 2: 445, 1974.

Fetz, G. "The toxicology of PCB's-an overview for clinicians", West J Med, 138: 534-540, 1983.

Kreiss, K., Roberts, C., Humphrey, H. "Serial PBB levels, PCB levels, and clinical chemistries in Michigan's PBB cohort", Arch Environ Health, 37: 141-147, 1982.

Kuratsune, M., Yoshimura, T., Matsuzaka, J. and Yamaguchi, A. "Epidemiologic study on Yasho, a poisoning caused by ingestion of rice oil contaminated with a commercial brand of polychlorinated biphenyls", Environ Health Perspect, 1: 119, 1972.

Maroni, M., Columbi, A., Arbosti, G., Cantoni, S., Foa, V. "Occupational exposure to polychlorinated biphenyls in electrical workers to health effects". Brit J Ind Med, 38: 55-60, 1981.

Norback, D.H. and Allen, J.R. "Chlorinated aromatic hydrocarbon induced modifications of the hepatic endoplasmic reticulum: concentric membrane arrays", Environ Health Perspect, 1: 137p 1972.

O'Donoghue, J.L. Neurotoxicity of Industrial and Commercial Chemicals, Vol II, Boca Raton,, Florida: CRC Press, Inc., 1985.

Ouw, H.K., Simpson, G.R., Siyali, D.S. "Use and health effects of Arochlor 1242, a polychlorinated biphenyl, in an electrical industry", Arch Environ Health, 31: 189-194, 1976.

Sax, N.I. Dangerous Properties of Industrial Materials, 6th Ed., New York: Van Nostrand Reinhold Co., 1984.

Shigematsu, N., Ishimaru, S., Satio, R., Iheda, J., Matsuba, K., Sugizama, K., Masuda, Y. "Respiratory involvement in polychlorinated biphenyls poisoning", Environ Research, 16: 92-100, 1978.

Tilson,l H. A., Davis, G.J., McLachlan, J.A. and Lucifer, G.W. "The effects of polychlorinated biphenyls given prenatally on the neurobehavioral development of mice", Environ Res, 18: 466, 1979.

Umeda, G. "Some problems on health effects of polychlorinated biphenyls", Ecotoxicology and Environ Safety, 1: 437-446, 1978.

Wasserman, M., Ron, M., Bercovici, B., Wasserman, D., Cucos, S., and Pines, A. "Premature delivery and organochlorine compounds: polychlorinated biphenyls and some organochlorine insecticides", Environ Res, 28: 106-112, 1982.

Wasserman,, M., Wasserman, D., Arcos, S. et al. "World PCB's map: storage and effects in man and his biologic environment in the 1970's", Ann NY Acad Sci, 320: 69-124, 1979.

Wong, C.K., Chen, C.J., Cheng, P.C., Chen, P.H. "Mucocutaneous manifestations of polychlorinated biphenyls (PCB) poisoning: a study of 122 cases in Taiwan", Brit J Derml, 107: 317-323, 1982.