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625840 
Technical Report 
EPA Report 
Health effects assessment for polycyclic aromatic hydrocarbons (PAHs) 
U.S. Environmental Protection Agency :: U.S. EPA 
1984 
U.S. Environmental Protection Agency 
Cincinnati, OH 
EPA/540/1-86/013 
EPA 
1984 
540-541 
61 
English 
The major issue of the PAH risk assessment is the potential carcinogenicity of these compounds. There are limited data available which can be used for quantitative risk assessment, however, this does not imply that there are not adequate qualitative data to consider many of the members of this class as animal carcinogens. In addition, PAH containing mixtures are documented to contribute to increased incidence of cancer in the human population. The contribution of individual chemical species to the carcinogenic potency of these mixtures and the interactions of various components cannot be adequately addressed at present. The one PAH, benzo(a)pyrene for which adequate dose-response data following exposure by appropriate routes (inhalation, oral) are available has been used to develop a cancer-based risk assessment for PAHs. Since data indicate that benzo(a)pyrene is one of the most potent carcinogens of the PAHs tested, it is suggested that cumulative exposures to mixtures containing PAH concentrations should result in a risk that is less than that predicted for benzo(a)pyrene alone. However, it should be kept in mind that many of the PAHs are still inadequately characterized in terms of their carcinogenic potential; that interactions of constituents of mixtures are poorly defined; and that potency ranking has been done using mouse skin exposure data (data for other routes from which potency comparisons could be made are not available). Using data for stomach tumors in mice following oral exposure to benzo(a)pyrene, a q1* of 11.53 (mg/kg/day)-2 was computed for oral exposure. Similarly, using data on incidence of respiratory tumors in hamsters exposed to benzo(a)pyrene by inhalation exposure, as q1* of 6.11 (mg/kg/day)- 2 was derived.