Carcinogens assessing risks from

Bogdanffy, M.S., Mathison, B.H., Kuykendall, J.R. Harman, A.E. (1997) Critical factors in assessing risk from exposure to nasal carcinogens. Mutat. Res., 380, 125-141... 

Management of Assessed Risks from Carcinogens (W.J. Nicholson, Editor, Annals of the New York Academy of Sciences, Vol. 363, April 30 1981) is a broad, multiauthor treatment. My own paper in this volume, Regulation of carcinogens in food provides some historical perspective on food safety and also deals with the problem of naturally-occurring carcinogens. 

The above represent the most widely available generic approach to hydrocarbon assessment. Risks from carcinogenic components (BTEX PAH) are assessed first as they usually drive die risks. The remaining petroleum hydrocarbons are assessed as a series of 13 fractions defined on the basis of Equivalent carbon (EC) numbers rather than carbon numbers . The EC number is related to the boiling point of individual compounds and retention time on a GC column. For example, the EC number of benzene is 6.5 because its boiling point and GC retention time are approximately halfway between those of 77-hexane (6-carbon chain) and 77-heptane (7-carbon chain). The TPHCWG chose the concept of EC numbers because these values are more logically related to compound mobility in the environment than carbon numbers. 

The reader should note that tlie introductory comments in tine similarly titled subsections of the previous section applies to carcinogens as well. The calculation proceeds as follows. First, smn tlie cancer risks for each exposure patliway contributing to exposure of the same individual or subpopulation. For Superfimd risk assessments, cancer risks from various exposure patliways are assumed to be additive, as long as tlie risks are for tlie same individuals and time period (i.e., less-tlian-lifetime e.xposures have all been converted to equivalent lifetime exposures). Tliis smnmation procedure is described below ... 

Neither an inhalation nor an oral slope factor is currently available for monomethylhydrazine. Slope factors for 1,1-dimethylhydrazine and 1,2-dimethylhydrazine were available but have been withdrawn from the U.S. EPA Integrated Risk Information System (IRIS) (U.S. EPA 1986). For a preliminary carcinogenicity assessment, the withdrawn inhalation slope factor for 1,1-dimethylhydrazine (cited in ATSDR 1994) will be used as a surrogate for monomethylhydrazine. The assessment follows previously described methodologies (NRC 1985 Henderson 1992). 

The treatment of rats, both male and female, for two years with tamoxifen revealed a dose-related increase in malignant liver tumors (Table 7.2). Thus, the table indicates that liver carcinomas caused by tamoxifen show a dose-related increase in both sexes, with a similar incidence, and metastases showed a slight but similar incidence. Research by various groups on the mechanisms underlying the carcinogenicity of tamoxifen has been extremely important in assessing the risk from this important drug and has allowed it to continue to be used. 

Retrospective identification of risk from waterborne infectious disease is a relatively simpler task compared with carcinogenic risks. Many acute effects can be identified with proper population surveillance, related to probable origin, and quantified. Assessments of microbial risks from theoretical projections would be extremely complex. They... 

USEPA (2005d) Supplemental guidance for assessing susceptibility from early-life exposure to carcinogens. Washington, DC, United States Environmental Protection Agency, Risk Assessment Forum (EPA/630/R-03/). 

Examples of product class carcinogenicity hazard identifications and assessments and ultimate risk communications for biopharmaceuticals approved in the United States for chronic use or based on potential cause for concern are provided in Table 19.4a (products without carcinogenicity assessment) and Table 19.4b (products with carcinogenicity assessment). The data are derived from publicly available regulatory assessments and product labels. Specific examples are discussed below. 

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