Health risk analysis carcinogens

Dunkel, V.C. and Williams, G.M. Biological significance of endpoints in short-term tests for carcinogens and mutagens. In Proceedings of the Third Life Sciences Symposium on Health Risk Analysis, in press. 

If linear (dose) models without thresholds are to be used for carcinogen (or other) risk assessment, estimation of exposure at specified levels becomes irrelevant to risk assessment or, at least, its use is nonintuitive. For example, a carcinogen risk analysis may be based on a linear, nonthreshold health effects model. The total health risk would thus be proportional to the long-term exposure summed for all affected people for the identified period, and exposure of many people at low concentrations would be equivalent to exposure of a few to high concentrations. The atmospheric dispersion that reduces concentrations would also lead to exposure of more people therefore, increments... 

DK NFA. 1990. Quantitative Risk Analysis of Carcinogens. Sphorg, Denmark National Eood Agency of Denmark, Institute of Toxicology, Ministry of Health. 

Crettaz, P., Rhomberg, L., Brand, K., Pennington, D.W., Jolliet, O., 2002. Assessing human health response in life cycle assessment using EDlOs and DALYs carcinogenic effects. International Journal of Risk Analysis 22 (5), 929—994. 

Metal Emission Limits. Limits for metals, both carcinogenic and noncarcinogenic, are based on an adjusted stack height. Failure to meet these limits requires risk assessments using site specific factors and modeling to establish limits for each metal. The assessments are based on the probability of developing adverse health effects or cancer, based on an inhalation exposure pathway to maximum exposed individuals located near the incinerator (see Hazard ANALYSIS AND RISKASSESSL nt). 

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. 

At present (1981), more than 1400 papers are published annually on the analysis, formation, chemistry, biochemistry, metabolism and biological effects of N-nitroso compounds. There is no equivocal and convincing evidence of carcinogenicity in humans of At-nitroso compounds. Therefore, an answer is needed to the question whether exposure to traces of these compounds from the general environment... poses a risk to human health. In this situation animal data must be extrapolated to man, with all the inherent uncertainties. 

The U.S. Environmental Protection Agency (EPA) divides the health effects of toxic chemicals into two broad categories for risk-assessment purposes risk of noncancer (noncarcinogenic) health effects and risk of cancer (carcinogenic risk) (Chapter 7). The same analysis of exposure is used for both noncarcinogenic and carcinogenic risk however, the relationship of exposure to effect is analyzed differently for noncancer and carcinogenic risks. 

---