ABSTRACT
All living organisms and plants, including humans, have been exposed to ionizing and nonionizing radiation during the entire period of evolutionary processes. Ionizing radiation is known to induce mutations, some of which may have been harmful, and eliminated them, while others may have been beneœcial to the organisms that were participating in the struggle for survival during the period of evolution when the Earth’s atmosphere was rapidly changing from the anaerobic to aerobic condition. It is likely that radiation-induced mutations may be one of the factors that could have accelerated the rate of evolution of the species. At present, humans are exposed daily to background radiation. Individuals living at higher altitudes receive higher doses of background radiation than those residing at sea level. It is generally assumed that the background radiation is totally safe; however, this assumption may be incorrect. It is more likely that the background radiation may be causing mutations that do not appear during your lifetime, or that it may be causing mutations in inactive parts of the genome without having signiœcant impact on health, or it may be contributing to chronic diseases such as cancer. In addition to ionizing radiation, the atmosphere has varying levels of toxic chemicals, depending upon the region, which can also induce mutations similar to those produced by ionizing radiation. The combination of the two can markedly increase the risk of diseases. At this time, we do not know to what extent the prevalence of human diseases are associated with mutations induced by background radiation alone. Most human diseases should be considered as a result of the interactions among background radiation, environmental chemicals, and dietary and lifestyle-related factors.
