Carcinogenicity chemical analysis

Since the detection efficiencies can be of the order of 15% or better and since there are approximately 4 X 1022 atoms per gram, the above sensitivity for a radioactivity with a half-life of one month means a few nuclei of the radioactive species in 1017 other nuclei. As Meyer points out (15), this is an incomparably greater sensitivity to any potentially carcinogenic additives than other means such as chemical analysis which yields impurities in parts per 106 or spectroscopic means with a maximum sensitivity of approximately one part in 109 (IS). 

Screening analysis was conducted for different exposure pathways and chemicals of concern. Using a screening level cutoff of a one-in-a-million excess risk for a 70-year lifetime exposure for the maximally exposed individual (MEI), a set of carcinogenic chemicals was identified for further analysis. For noncarcinogens, MEI exposure levels were compared to health thresholds. If the MEI exposure exceeded the established health threshold, further analysis was done. 

I I. A farming couple in Northern Michigan consult their physician about severe skin rashes and ulcers noted over the past year. They also have lost many cattle over the past year, and claim that their cattle feed changed in consistency and smell about 1 year ago. Chemical analysis of the feed shows high concentrations of polychlorinated biphenyls, a fertilizer related to known carcinogens. The physician sends the chemical to a laboratory for carcinogen testing, which is performed initially and rapidly by... 

Many mycotoxin diseases are associated with various species of fungal genera and their secondary metabolites.The adverse effect of fungal products have caused mass poisoning in both man and farm animals as shown in Table 1. As far as public health problems are concerned, Aflatoxin is well known as one of the most important environmental toxicants, since its potent hepato-carcinogenicity has been demonstrated in various experimental animals and its natural production in cereal and grains has been shown by chemical analysis. 

As discussed above, SAR analysis is more effective if we can predict/project the possible mechanism of action of the chemical. For genotoxic carcinogens, SAR analysis should include consideration of (i) the nature of the electrophile present or to be formed, (ii) possibility of stabilization of the intermediate, and (iii) the molecule to which the electrophile is attached. 

Hoffmann, D. and E.L. Wynder Chemical analysis and carcinogenic bioassays of organic particulate pollutants in Air pollution, Vol. 2, 2nd Edition, edited by A.C. Stem, Academic Press, New York, NY (1968) 187-247. Hoffmann, D. and E.L. Wynder A study of tobacco carcinogenesis. XL Tumor initiators, tumor accelerators, and tumor promoting activity of condensate fractions Cancer 27 (1971) 848-864. 

There are numerous methods available to identify the potential for chemicals to cause both healtli conditions and adverse effects on tlie eiiviroiiment. These can include, but are not limited to, toxicology, epidemiology, molecular and atomic structural analysis, MSDS sheets, engineering approaches to problem solving, fate of chemicals, and carcinogenic versus non-carcinogenic healtli hazards... 

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