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Case Study 36: Polychlorinated Biphenyl (PCB) Toxicity
Pages 622-638

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From page 622...
... 1 1 This monograph is one in a series of self-instructional publications designed to increase the primary care provider's knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients. The Agency for Toxic Substances and Disease Registry (ATSDR)
From page 623...
... Pretest ,^ (a} What should be included in the patients problem list? (b} What is a differential diagnosis for the patients altered liver enzymes?
From page 624...
... Polychlorinated biphenyls {PCBs) are a family of 209 chemicals with varying numbers of chlorine atoms attached in varying positions to two connected benzene rings (Figure 1~.
From page 625...
... During normal lighting operation, the PCBs are entirely enclosed; however, when the capacitorwears out, it may burn or break and leak PCBs. PCBs can be released into the general environment from poorly maintained toxic waste sites; by illegal or improper dumping of PCB wastes, such as transformer fluids; through leaks or fugitive emissions from electrical transformers containing PCBs; and by disposal of PCB-containing consumer products in municipal landfills.
From page 626...
... Composite analysis of commercial whole fish collected from Lake Ontario in 1980 found PCB levels of 0.11 to 4.90 parts per million (ppm)
From page 627...
... Other populations potentially more sensitive to PCBs are persons with compromised hepatic functioning, including those with incompletely developed glucuronide conjugation mechanisms due to congenital disorders such as Gilbert's syndrome, and persons with hepatic infections. Persons taking medications potentially toxic to the liver may also be at increased risk.
From page 628...
... In a second phase, PCBs were redistributed to the adipose tissue, skin and other fat-containing organs. More highly chlorinated PCBs redistribute to adipose tissue to a greater extent than do PCBs with a lower percentage of chlorine; the presence of more highly chlorinated PCBs appears to delay excretion of the lesser chlorinated compounds for reasons not clearly understood.
From page 629...
... O EPA considers PCBs to be probable human carcinogens. O PC8-lnduced chloracne can reflect systemic toxicity.
From page 630...
... The enzyme levels often show inconsistent patterns, however, and increases generally have not been associated with hepatic dysfunction, although approximately 10% of the Yusho patients experienced jaundice. Asymptomatic hepatomegaly has been reported in workers, many of whom had concomitant elevated serum PCB levels.
From page 631...
... On the basis of these data, EPA considers PCBs to be probable human carcinogens. O PCBe have a potential to cause developmental and fetotoxic effects In humane.
From page 632...
... New cases of chloracne should be reported to the local or state health department. Elevated liver enzymes are the most sensitive effect of PCB exposure in animals and have been detected in several human epidemiologic studies.
From page 633...
... Indirect Biologic Indicators Liver function tests may be the most sensitive sign of PCB toxicity in the absence of chloracne; however, these measures are of questionable value because they are nonspecific. Also, normal liver enzyme values do not rule out significant exposure; body burden still may be elevated.
From page 634...
... Diagnostic workup should be limited to liverfunction tests and dermatologic examination, with skin biopsy of lesions. Initial treatment of chloracne is based on cessation of exposure, good skin hygiene, and use of dermatologic measures commonly employed for acne vulgaris.
From page 635...
... The National Institute for Occupational Safety and Health (NIOSH) recommends a ten-hour TWA of 1 ~g/m3 based on the minimum reliable detectable concentration and potential carcinogenicity of PCBs.
From page 636...
... Dermatological findings in capacitor manufacturing workers exposed to dielectric fluids containing polychlorinated biphenyls (PCBs)
From page 637...
... It may contribute to the laboratory findings of elevated bilirubin (especially after a fast) but would not explain the clinical picture or elevated liver enzymes.
From page 638...
... A correlation between consumption of PCB-contaminated fish and elevated serum PCB levels has been shown in a study of residents of New Bedford, Massachusetts. For the general population, however, a clinically significant human body burden of PCBs is unlikely to occur through fish consumption alone.


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