Carcinogenic effects of benzene

In addition to carcinogenic effects, animal studies have shown the effects of benzene exposure on the immune system. Reid et al. showed a significant decrease in splenic cell proliferation in mice exposed to benzene for 14 days. Experimental animal studies also reported reduced circulating white blood cells, as well as changes in spleen morphology and weight in various experimental animal studies. These experimental animal studies further support the observation from 1913 by Wintemits and Hirschfelder that rabbits exposed to 

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EPA (1998). Carcinogenic Effects of Benzene An Update. National Center for Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Washington, D.C., EPA/600/P-97/001F. Accessed at http //www.epa.gov/ncea/pdfs/benzenef.pdf. 

Aksoy, M. 1989. Leukemogenic and carcinogenic effects of benzene. Adv. Mod. Environ. Toxicol. 16 87-98 cited in Chem. Abstr. CA 113(2) 11293a. 

USEPA, Attachment to IRIS file for benzene, 10/14/98, Response to the Peer-Review Draft Carcinogenic Effects of Benzene An Update, EPA/600/P-97/001A, June 1997... 

The use of benzene as the desorption solvent in-aeases the hazards of analysis because of the potential carcinogenic effects of benzene. 

Table 8.4 provides a few examples of these various protective limits. Recall that RfD is for non-carcinogenic effects only benzene is regulated as a carcinogen (see later). 

Fishbein, L. (1988) Genetic effects of benzene, toluene and xylene. In Fishbein. L. O Neill, I.K., eds. Environmental Carcinogens Methods of Analysis and Exposure Measurement. Vol. 10, Benzene and Alkylated Benzenes (lARC Scientific Publications No. 85). Lyon. lARC, pp. 19-46... 

The most characteristic toxic effect of benzene in both human and animal models is the depression of the bone marrow, leading ultimately to aplastic anemia (Rozen and Snyder 1985 Snyder and Kocsis 1975 Snyder et al. 1993b). Rozen and Snyder (1985) have noted that abnormalities of humoral and cell-mediated immune responses following benzene exposure of C57BL mice by inhalation are presumably caused by a defect in the lymphoid stem cell precursors of both T- and B-lymphocytes. They also observed that bone marrow cellularity and the number of thymic T-cells increased, presumably as a compensatory response in these cell lines in response to benzene exposure. This compensatory proliferation may play a role in the carcinogenic response of C57BL mice to inhaled benzene. 

Specific cellular toxic effects from benzene have been described and those include, among others, the central nervous system (doses of over 100 ppm), liver, kidney, skin, immunological, and carcinogenic. The various toxicological effects of benzene will not be discussed in this chapter... 

Chronic Effects of Benzene Cytogenicity, Carcinogenicity, Leukaemia,... 

Although many of the aromatic compounds based on benzene have pleasant odors, they are usually toxic, and some are carcinogenic. Volatile aromatic hydrocarbons are highly flammable and burn with a luminous, sooty flame. The effects of molecular size (in simple arenes as well as in substituted aromatics) and of molecular symmetry (e.g., xylene isomers) are noticeable in physical properties [48, p. 212 49, p. 375 50, p. 41]. Since the hybrid bonds of benzene rings are as stable as the single bonds in alkanes, aromatic compounds can participate in chemical reactions without disrupting the ring structure. 

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