Chronic exposure , radiation

Miettinen JK, Mussalo H, Hakanen M, et al. 1980. Distribution of plutonium and americium in human and animal tissues after chronic exposures. In International Radiation Protection Society, ed. Radiation protection A systemic approach to safety Proceedings of the 5th congress of the International Radiation Protection Society, Jerusalem, March 1980. New York Pergamon Press, 1049-1052. 

Individual dose assessment requires radiological data on all external and internal sources contributing to occupational and non-occupational radiation exposure (Steinhausler and Pohl, 1983). This is of particular importance in the case of low level Rn-d exposure, as man is always exposed to Rn-d at varying levels through all stages of life, e.g. at school, home or work. The resulting lifetime risk from this chronic exposure is influenced by the latent... 

Radiation causes dominant lethal mutations in the medaka (Oryzias latipes) (Shima and Shimada 1991). Mosquitofish (Gambusia spp.) from radionuclide-contaminated ponds in South Carolina differed from conspecifics in reference ponds, as judged by the frequency of DNA markers, and this is consistent with the hypothesis that these DNA markers may originate from genetic elements that provide a selective advantage in contaminated habitats (Theodorakis et al. 1998). Ionizing radiation at low-level chronic exposure reportedly has no deleterious genetic effects on aquatic populations because exposure is compensated by density-dependent responses in fecundity (IAEA 1976). However, this needs verification. 

Suffident data are available on the carcinogenic effects of radiation at different doses and dose rates (acute as well as chronic exposures) and in males and females of all ages, to enable tentative analysis of the influence of radiological variables and host factors on the dose-inddence relationship. With chemicals, on the other hand, most of the... 

Three-dimensional dose-rate/time/response surfaces for chronic exposure to carcinogens and ionizing radiation clarify the interactive roles of competing risks (Raabe, 1987). The three dimensions are average dose rate, exposure time, and risk. The unproved conceptualization afforded by them contributes to the planning and evaluation of epidemiological analyses and experimental studies involving chronic exposure to radiation toxicants (Raabe, 1987). 

Fliedner, T.M., Graessle, D.H. (2008). Hematopoietic cell renewal systems mechanisms of coping and failing after chronic exposure to ionizing radiation. Radiat. Environ. Biophys. 47 63-9. 

Exposure of people to radiation or radioactive substances, which can either be external exposure from sources outside the body or internal exposure from sources inside the body. The exposure can be classified as either normal or potential exposure either occupational, medical or public exposure and, in intervention situations, either emergency or chronic exposure. 

Unlike stochastic effects, non-stochastic effects are characterized by a threshold dose below which they do not occur. In addition, the magnitude of the effect is directly proportional to the size of the dose. Furthermore, for non-stochastic effects, there is a clear causal relationship between radiation exposure and the effect. Examples of non-stochastic effects include sterility, erythema (skin reddening), ulceration, and cataract formation. Each of these effects differs from the other in both its threshold dose and in the time over which this dose must be received to cause the effect (i.e. acute vs. chronic exposure). 

Deterministic effects are those that increase in severity as the radiation dose increases and for which a threshold is presumed to exist. Besides acute somatic effects, deterministic effects also include radiation effects (other than cancer and genetic effects) that continue to occur after an extended period (e.g., years) of chronic exposure. Such chronic exposures can arise from long-lived radionuclides (e.g., isotopes of plutonium and cesium) ingested via contaminated food or inhaled via contaminated air... 

Radioactive Strontium. No studies were located regarding death in humans following inhalation exposure to radioactive strontium. Information on the lethality of inhaled radioactive strontium is limited to acute exposure studies. Because of the bone-seeking behavior of strontium, an acute exposure to airborne 90Sr results in chronic exposure to radiation from 90Sr incorporated into bone. If insoluble radiostrontium compounds are inhaled, there could be long-term lung exposure (see discussion of the study by Willard and Snyder (1966) in Section 3.4.1.1). 

Acute exposure of large doses may cause radiation poisoning or radiation burns. Chronic exposure may result in cancer or mutations in one s children due damage to DNA. Organs with rapidly dividing cells such as bone marrow, intestines, and gonads are most vulnerable. Some effects do not appear until several years have passed. 

The sievert (Sv) is the SI unit of equivalent dose, which is defined as the absorbed dose multiplied by a weighting factor that expresses the long-term biological risk from low-level chronic exposure to a specified type of radiation. The Sv is another special name for J/kg. 

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