Mutagenicity and Carcinogenicity

H. F. Mower, Carcinogens and Mutagens in the Environment, CRC Press, Boca Raton, Fla., 1983. 

Mutagenicity. The AJ-nitrosamines, in general, induce mutations in standard bacterial-tester strains (117). As with carcinogenicity, enzymatic activation, typically with Hver microsomal preparations, is required. Certain substituted A/-nitrosamine derivatives (12) induce mutations without microsomal activation (31,33,34). Because the a-acetoxy derivatives can hydroly2e to the corresponding a-hydroxy compounds, this is consistent with the hypothesis that enzymatic oxidation leads to the formation of such unstable a-hydroxy intermediates (13) (118). However, for simple /V-nitrosamines, no systematic relationship has been found between carcinogenicity and mutagenicity (117,119—123). 

Ames B.N., McCann J. Yamasaki E. (1975) Methods for detecting carcinogens and mutagens with the Salmonella/mammalian microsome mutagenicity test. MutatRes, 31, 347-364. 

One important point of controversy in risk extrapolation is the existence of the threshold level for carcinogenic and mutagenic response to a pollutant. Some argue that an organism is able to cope with low doses of a substance through metabolic processes or repair mechanisms, so that harmful effects do not appear until a certain minimum threshold, or "safe dose", is surpassed. Others contend that a carcinogenic substance must be considered potentially harmful at any dose, and that even a single molecule may initiate a tumor at the cellular level. This is the so-called "one-hit" hypothesis. 

Sunscreens and their degradation metabolites analyzed in this study are potential inducers of the oestrogen (ER) and aryl hydrocarbon receptors (AhR, also known as Dioxin Receptor). Ectopic activation of these pathways can cause severe damage to organisms and their ecosystem by altering reproduction, hormonal and/or circulatory systems [73-75] as well as they have been associated with carcinogenic and mutagenic effects [76-78]. 

Sulfonated azo dyes are widely used in different industries [16]. Some structure of sulfonated and unsulfonated azo dyes is shown in Fig. 1. These water-soluble azo dyes will enter the environment generally with wastewater discharge. Also, these sulfonated and unsulfonated azo dyes have a negative aesthetic effect on the wastewater, and some of these compounds and biodegraded products are also toxic, carcinogenic, and mutagenic [17]. There exists clear evidence that sulfonated azo dyes show decreased or no mutagenic effect compared to unsulfonated azo dyes... 

Ishinishi, N. Koizumi, A. McClellan, R. 0. Stober, W. Carcinogenic and Mutagenic Effects of Diesel Engine Exhaust Elsevier Science Publishers, 1986. 

Hayes, M.A. 1987. Carcinogenic and mutagenic effects of PCBs. Pages 77-95 in S. Safe (ed.). Polychlorinated Biphenyls (PCBs) Mammalian and Environmental Toxicology. Environ. Toxin Ser. 1. Springer-Verlag, New York. 

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