Inhalation radioactive materials

Care must be taken in handling radon, as with other radioactive materials. The main hazard is from inhalation of the element and its solid daughters which are collected on dust in the air. Good ventilation should be provided where radium, thorium, or actinium is stored to prevent build-up of the element. Radon build-up is a health consideration in uranium mines. Recently radon build-up in homes has been a concern. Many deaths from lung cancer are caused by radon exposure. In the U.S. it is recommended that remedial action be taken if the air in homes exceeds 4 pCi/1. 

Poison A gas explosives-A/B, organic peroxide, flammable solid, materials dangerous when wet, chlorine, flourine, anhydrous ammonia, radioactive materials, NFPA 3 4 for any categories including SF>ecial hazards. PCB s fire, DOT inhalation hazzird, EPA extremely hazardous substances, and cryogenics. 

Masse, R., Cells at Risk, in Lung Modelling for Inhalation of Radioactive Materials (H. Smith and G. Gerber, eds) pp. 227-246,... 

Radioactivity results when some part of an atom is unstable. The instability exists because the orbital electrons or the nucleus contain too much energy. Radioactive atoms are called radionuclides. They release excess energy by emitting radiation. The type of radiation released (alpha, beta, or gamma particles) may be more or less hazardous to humans, depending on the location of the radioactive materials. Exposure to radioactive materials outside the body poses external hazards. Radioactive materials may also be hazardous when ingested, inhaled, or injected and thus pose internal hazards. The sections below describe the characteristics of radiation particles as external or internal hazards and as they may be encountered after a terrorist attack. Chapter 3 provides additional details and addresses health effects associated with exposure to radiation. 

The first method is quicker, but the filtration entailed in this reaction presents a hazard because of the danger of inhalation. If it is desired to employ volatile radioactive materials, e.g. to introduce 32P into the molecule, the second method is recommended. Further, the first method involves some danger because of the pressure developed in an enclosed reaction vessel containing ethyl chloride. It is considered essential that operations with the more volatile radioactive compounds (up to b.p. 150°/760 mm.) should be carried out in a completely enclosed system. This is possible with the second method, and the extra time of operation involves a decrease in the radioactivity of only 15 per cent compared with the first method.4... 

Two epidemiology studies have examined mortality among thorium workers neither found significant excess mortality. The standard mortality ratio (SMR) for all causes of death in a cohort of 3039 male workers in a thorium processing plant was 1.05 in comparison to United States white males (Polednak et al. 1983). The estimated radiation levels to the workers for inhalation intake ranged from 0.003-0.192 nCi/m (0.001-0.007 Bq/m ) for a period of 1-33 years. No evidence of overt industrial disease was found in a cohort of 84 workers at a thorium refinery exposed to <0.045-450 nCi/m (<0.002-0.02 Bq/m ) for <1-20 years (Albert et al. 1955). In both studies, the workers were exposed to other toxic compounds (uranium dust) as well as other radioactive materials (thoron, uranium daughters, thorium daughters, cerium). 

There is some evidence from animal studies that exposure to 90% enriched uranium may affect the immune system. Increased macrophage activity, associated with localized alpha tracks in all 5 lobes of the lungs, was seen in Fischer 344 rats exposed to 6,825.5 nCi/m (252 kBq/m ) through inhalation exposure to enriched uranium dioxide for 100 minutes. The increased activity was evident from days 1-7, 180, 360, 540, and 720 with increases in percent activity of 0.44, 2.15, 19.70, 6.54, and 37.84, respectively. The number and size of macrophage clusters in the lung increased with time postexposure. The radioactive material concentration of the mixture was estimated as 1.91 kBq/mg (51.6 nCi/mg) (Morris et al. 1992). The degree of enrichment was calculated based on this specific activity. 

The SITP is a quantity derived from the Annual Limit on Intake (ALI), an internationally accepted concept that has been acknowledged by the Government s Radioactive Waste Management Committee (RWMAC) as a valid method of establishing equivalent hazards of different waste types. The ALI is a derived limit for the permissible amount of radioactive material taken into the body of an adult radiation worker by inhalation or ingestion in a year. The ALI is the smaller value of intake of a given radionuclide in a year by the reference man that would result in either a committed effective dose equivalent of 0.05 Sv or 0.5 Sv to any individual organ or tissue. 

Krypton-85 is also used to study the flow of blood in the human body. It is inhaled as a gas, and then absorbed by the blood. It travels through the bloodstream and the heart along with the blood. Its pathway can be followed by a technician who holds a detection device over the patient s body. The device shows where the radioactive material is going and how fast it is moving. A doctor can determine whether this behavior is normal or not. 

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