The challenge for molecular epidemiology and environmental studies is to further improve the process for assessing risk to human health from exposure to genotoxic agents. It is well recognized that exposure to ionizing radiation is unavoidable. The issue of exposures from nuclear power and nuclear waste receives the greatest public attention, yet these types of exposures are only a minor source of total environmental chemical and radiation exposures. However, for the populations at risk or close to these sources, the issue is a real one. The concern here is the risk of unforeseen accidents as well as the public’s lack of understanding the acute and chronic exposures differences and their associated risks.

Characterization of the dose response process is often done by the use of biomarkers detected in assays predictive of potential toxic outcomes and pathological changes. This often provides the opportunity for more effective preventive measures against exposures that deemed hazardous to human health. Biological markers, associated with environmentally induced genotoxic change, may also be useful for improving the prediction of risk to human health posed by accidental or environmental exposure. The desirable features of biological markers of genotoxic action are that biomarker measure should indicate a quantitative reaction to the action and should be associated with a genotoxic outcome. In order to define major contamination, its genotoxic effectiveness and to realize genetic or carcinogenic hazards in vitro studies are necessary which yield more information on genotoxicity of major pollutants. It is also important to search for correlation between evidence of the induced genotoxic damage in exposed living organisms or occupationally exposed human with accurate measures of exposures. This creates necessity to extrapolate from high doses (experimental, occupational or accidental) to low dose region. There may be many confounding factors affecting the simple extrapolation. In this paper are discussed influence of the shape of dose effects relationship, and physical or life style related factors on health risk.