Inhalation of radionuclides

Direct irradiation from a plume and inhalation of radionuclides in a plume are direct pathways of exposure. The others may involve many transfer processes between sections of the environment. An example of such a pathway is the deposition of l on grazing land, its direct retention on grass or its uptake into the grass from the soil, its ingestion by cows and the subsequent ingestion of cow s milk by people, especially children. 

Radiological emergencies are classified according to exposure pathways. Exposure of the public and workers to radiation following an accident may be either external or internal, or both and may be incurred by various pathways. The pathways of external exposure are derived from the source or the facility, the plume, the radionuclide contamination on surfaces, and radionuclide contamination of skin and clothing. Those of internal exposure are the inhalation of radionuclides in a plume, the inhalation of re-suspended radionuclides, the ingestion of... 

In emergencies, for calculations of doses from internal exposure consideration should generally be directed first to inhalation, because this pathway is of paramount importance for the implementation of urgent protective actions (sheltering, evacuation and prophylaxis with stable iodine). As discussed for external exposure due to the radionuclides present in the plume, internal exposure due to the inhalation of radionuclides present in the... 

The potential for inhalation of radionuclides should be assessed when necessary by measuring activity levels in air samples. The derived air concentration pAC, expressed in Bq/m ) is defined as that concentration of airborne activity which would result in the intake of Ij by a worker exposed continuously for one year (taken to be 2000 working hours). For a standard breathing rate of 1.2 m /h, the DAC would thus be given by ... 

Knatko VA, Mayall A, Drugachenok MA, et al. 1993. Radiation doses in southern Byelorussia from the inhalation of specific radionuclides following the Chernobyl accident. Radiat Prot Dosim 48(2) 179-183. 

The absorbed dose is usually defined as the mean absorbed dose within an organ or tissue. This represents a simplification of the actual problem. Normally when an individual ingests or inhales a radionuclide or is... 

Hofmann, W., Dose Calculations for the Respiratory Tract from Inhaled Natural Radionuclides as a Function of Age - II. Basal Cell Dose Distributions and Associated Lung Cancer Risk, Health Phys. 43 31-44 (1982). 

To avoid all these problems we developed a method, described below, for internal irradiation of blood with short-lived Rn-222 decay products. These radionuclides are always present in the entire human body, according to the inhalation of the normal atmosphere. Therefore no substances are brought into the blood which could have additional toxic effects. Furthermore the concentration of these nuclides in the blood is always extremely small, because of their short half-life, so that any chemotoxic effect can be excluded. 

Benjamin, S. A., Boecker, B. B., Cuddihy, R. G Snipes, M. B. and McClellan, R. O. (1976a). Nasal carcinomas in beagle dogs after inhalation of relatively soluble forms of beta-emitting radionuclides, Radiat. Res. 67, 572. 

Radioactive substances (radionuclides) are known health hazards that emit energetic waves and/or particles that can cause both carcinogenic and noncarcinogenic health effects. Radionuclides pose unique threats to source water supplies and chemical processing, storage, or distribution systems because radiation emitted from radionuclides in chemical or industrial waste systems can affect individuals through several pathways by direct contact with, ingestion or inhalation of, or external exposure to, the contaminated waste stream. While radiation can occur naturally in some cases due to the decay of some minerals, intentional and nonintentional releases of... 

B.5.3 Effective Dose Equivalent and Effective Dose Equivalent Rate. The absorbed dose is usually defined as the mean absorbed dose within an organ or tissue. This represents a simplification of the actual problem. Normally when an individual ingests or inhales a radionuclide or is exposed to external radiation that enters the body (gamma), the dose is not uniform throughout the whole body. The simplifying assumption is that the detriment will be the same whether the body is uniformly or nonuniformly irradiated. In an attempt to compare detriment from absorbed dose of a limited portion of the body with the detriment from total body dose, the ICRP (1977) has derived a concept of effective dose equivalent. 

EPA. 1988. Limiting values of radionuclide intake and air concentration and dose conversion factors for inhalation, submersion, and ingestion. Federal Guidance Report No. 11. Washington, DC U.S. Environmental Protection Agency, Office of Radiation Programs. EPA-520/1-88-020. 

Radiation-induced cancer incidence also could be estimated using calculations of the probability of cancer incidence per unit activity intake of specific radionuclides by particular ingestion and inhalation pathways or the probability per unit activity concentration of specific radionuclides in the environment by particular pathways of external exposure (Eckerman etal., 1999) probabilities of fatal cancers for the different exposure pathways also have been calculated. These probability coefficients differ from those developed by ICRP (see Section 3.2.2.3.2) in that they are calculated with respect to activity of specific radionuclides rather than dose, and they thus bypass the need to estimate the effective dose. For external exposure, the methods used by Eckerman etal. (1999) and ICRP (1991) to estimate responses essentially are equivalent. However, there are significant differences in the methods used to estimate responses from intakes of radionuclides, and the results obtained by Eckerman et al. (1999) differ substantially in a few cases (e.g., intakes of 232Th)... 

ICRP (1996). International Commission on Radiological Protection. Age-Dependent Doses to Members of the Public from Intakes of Radionuclides. Part 5 Compilation of Ingestion and Inhalation Dose Coefficients, ICRP Publication 72, Annals of the ICRP 25 (3/4) (Elsevier Science, New York). 

An analysis of the calculation results shows that, if using the conservative approach (time of NS waterborne storage prior to dismantlement 5 years, that of storage after dismantlement 0 years), imder the taken assmnptions effective exposure doses would be approximately the same for all professional groups equaling 20 pSv/year. The main contribution to the exposure dose would be due to inhalation intake of radionuclides with marine aerosols. 

Inhalation and ingestion of minor quantities of radionuclides. INTERNAL CONTAMINATION No immediate effects. Consult with specialist if possible. 

Inhalation and ingestion of large quantities of radionuclides. No immediate effects. Nasopharyngeal lavage. Early transfer to specialized center to increase excretion. 

Pickrell, J.A., Schnizlein, C.T., Hahn, F.F., Snipes, M.B., Jones, R.K. (1978). Radiation-induced pulmonary fibrosis study of changes in collagen constituents in different lung regions of Beagle dogs after inhalation of beta-emitting radionuclides. Radial Res. 74 363-77. 

ICRP. 1996. International Commission for Radiation Protection. Age-dependent doses to members of the public from intake of radionuclides Part 4, Inhalation dose coefficients. ICRP Publication 71. Oxford Pergamon Press. 

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