Long-terms effects of ionizing radiation

The fact that X-rays can induce mutation was established first in 1927. In the years following the mutagenic effects of some rays were described. When DNA was identified as the universal genetic material, it soon became obvious, and was confirmed by genetic evidence that the genetic material of all living beings is susceptible to radiation induced damage. When DNA is damaged by radiation enzymes within the cell nucleus attemp to repair that damage. If repair does not suceed or not correctly, the cell may die or may suffer changes in genetic information. It is thought that killing of cells is the basis for deterministic effect and that subtlechanges in information are important in the development of radiation-induced cancer or of genetic effects if these changes are induced in germ cells. This document describes aspects such as biological effects of ionizing radiation (deterministic radiation effects); stochastic radiation effect and quantification of risk; somatic effects; genetic effects of the ionizing radiation

Volcanoes and carcinomaof the thyroid : A possible association

Environmental factors contributing to incidences of thyroid carcinoma are re-evaluated and emphasized in this study. Thyroid cancers appear to occur independent of endemic goiter, based on epidemiologic and histologic evidence. While environmental factors appear to be important, the specific etiologic agent has not yet been identified or suggested. The number of thyroid cancer incidences available from cancer registries are analyzed in an attempt to identify a specific environmental carcinogenic agent. The presence of active volcanoes that produce abundant lava is found to be the common denominator of Iceland and Hawaii, where the incidence of thyroid cancer is outstandingly high. Comparison with other areas with active volcanoes is made. The presence of a carcinogenic agent in the lava is postulated and its possible mode of action on humans through fish products is hypothesized(AU)