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U.S. Department of Energy
Office of Scientific and Technical Information

Rationale for assessment of risk from exposure to 2,3,7,8-TCDD

Technical Report ·
OSTI ID:6936965

The human health risk assessment is supported by methodology for utilizing toxic effects in animals consisting of carcinogenic and noncarcinogenic responses as a result of chronic, subchronic and acute exposures. One of the initial steps in a risk assessment activity involves the estimation of exposure levels. These estimates are typically based on either direct environmental measurements or predictions obtained from fate and transport models. The decision to develop assessment of risk from chronic exposure based on a nonthreshold model is made if a chemical demonstrates carcinogenic activity in animal bioassays and/or in human epidemiological studies. In the absence of any positive human epidemiologic data, it is assumed that a substance which induces a statistically significant carcinogenic response in animals has the probability to cause cancer in humans. The carcinogenic potential of 2,3,7,8-TCDD has been established based on chronic exposure in rodents. In addition, 2,3,7,8-TCDD has also been shown to be a liver cancer promoter in rodents. In the risk assessment on dioxins based on chronic exposure in experimental animals, 2,3,7,8-TCDD is regarded as a carcinogenic substance.

Research Organization:
Environmental Protection Agency, Cincinnati, OH (USA). Office of Environmental Criteria and Assessment
OSTI ID:
6936965
Report Number(s):
PB-90-232133/XAB; EPA--600/J-86/524
Country of Publication:
United States
Language:
English