Ingestion of radioactive materials

All skin cuts, accidental ingestion of radioactive materials, and major spills must be reported immediately to the instructor. 

Do not eat, drink, chew gum, apply cosmetics, smoke, ordo anything else that could lead to ingestion of radioactive materials while in the area in which radioactive materials are used. 

Ingestion is often a very important source of dose, oeeurring when eontaminated food is eaten or from contamination on the hands. Ingesting milk eontaminated hy the Chemohyl accident has caused many cases of thyroid cancer in Belarus and Ukraine. Very high, possibly fatal doses have resulted from ingestion of contamination from a ruptured souree. If eontam-ination is suspected, wash your hands, do not eat or smoke, keep your hands away from your mouth, and advise the pubhe to do the same. However, early (deterministie) injuries and deaths from ingestion of radioactive material are very rare. 

Several medical applications require the ingestion of radioactive materials that concentrate in a particular organ. The emitted radiation is detected on a photographic plate to obtain an image of the organ. What type of radiation-alpha, beta, or gamma-would be best suited for this technique Why ... 

Items 1, 3, and 10 below specifically deal primarily with external radiation hazards, while the remaining items deal with contamination and ingestion of radioactive materials. Safety requires that both aspects be considered in all operations. 

As we discussed in Section 19.2, the energy associated with radioactivity can ionize molecules. When radiation ionizes important molecules in living cells, problems can develop. The ingestion of radioactive materials—especially alpha and beta emitters—is particularly dangerous because the radioactivity once inside the body can do even more damage. The effects of radiation can be divided into three different types acute radiation damage, increased cancer risk, and genetic effects. 

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. 

Constraints of Plant Design. The potential hazards encountered in the uranium feed materials processing industry include many that are common to the heavy chemicals industry. However special problems present themselves owing to direct radiation, the possibility of inhalation and ingestion of radioactive dusts and gases, nuclear safety, and more unusual chemical hazards. 

The radioanalytical chemistry laboratory is subject to all of these hazards with the addition of radioactive solids, liquids and gases. The potential risks to laboratory workers from radioactive materials include exposure to ionizing radiation, both from external sources and from internal sources that were inhaled, ingested, or absorbed through the skin. Contamination of the immediate work area is a safety concern that becomes amplified if the contamination is not removed promptly and is subsequently spread over a much wider area. Each of these hazardous situations may result from an unintended release or from improper handling of radioactive materials. Often, the person who is affected is not the one who caused the problem in the first place. 

Contamination includes two types of radioactive material on surfaces or embedded in surfaces, namely fixed contamination and non-fixed contamination. There is no definitive distinction between fixed and non-fixed contamination, and various terms have been used to describe the distinction. For practical purposes a distinction is made between contamination which, during routine conditions of transport, remains in situ (i.e. fixed contamination) and, therefore, cannot give rise to hazards from ingestion, inhalation or spreading, and non-fixed contamination which may contribute to these hazards. The only hazard from fixed contamination is that due to external radiation exposure, whereas the hazards from non-fixed contamination include the potential for internal exposure from inhalation and ingestion as well as external exposure due to contamination of the skin should it be released from the surface. Under accident conditions, and under certain use conditions such as weathering, fixed contamination may, however, become non-fixed contamination. 

In other cases where the radioactive material is released, it can he deposited upon environmental surfaces or skin. It could also he inhaled or ingested. The radioactive material on skin and environmental surfaces can usually he washed away, but the close contact with skin may give high doses of radiation to the skin from those isotopes that emit alpha and beta radiation. When radioactive material is inhaled or ingested, it continues to emit radiation and gives the internal areas of the body exposure. If the radioactive material has a chemical affinity for a particular organ of the body, it may accumulate there and selectively irradiate that particular organ. Examples are radioactive iodine (accumulates in tlie thyroid), radioactive cesium (accumulates in the liver), or radioactive strontium (accumulates in bone). 

There is a difference between being exposed to radiation and being contaminated by radioactive material. Persons who have been exposed to radiation are not radioactive and are not dangerous to rescuers or medical personnel. Persons who have radioactive contamination of their skin or clothes will be radioactive until the clothes are removed and the material is washed from their skin. A person who has ingested a radioactive material may or may not be dangerous to others, depending on the penetrating power of the particle or wave involved. One way to think of the difference between exposure and contamination is the barnyard example. If you smell a cow pile, you have been exposed. If you step in a cow pile, you have been contaminated. 

The deposition or presence of radioactive material in a place where it is not desired and may be harmful. In regard to personnel there are two types of radioactive contamination external and internal. External radioactive contamination is the presence of radioactive material on the skin. Internal radioactive contamination is the presence of radioactive material within the body due to ingestion, inhalation, or absorption. Railings... 

The nature of the contamination of the environment, as well as the degree of hazard, is given by properties of the radiation source and by the character of the contamination (whether it occurs during the usual operation of nuclear equipment or treatment of radioactive materials, or whether it results from an accident). The human organism can be exposed either directly (by inhalation, ingestion of contaminated water and/or food, or contamination of the skin) or indirectly (when contaminated materials enter into... 

Committed doses are defined in cases of intakes of radioactive materials, mainly by ingestion, inhalation, or absorption through the skin, in terms of internal radiation impact. In most cases, the quantities of committed absorbed dose, committed equivalent dose, and committed effective... 

Exposure of a person may be external or internal and may be incurred by various exposure pathways (see Section 9.3). External exposure may be due to direct irradiation from the source, airborne radionuclides in the air (immersion or exposure to an overhead plume), or radionuclides deposited onto the ground and onto a person s clothing and skin. Internal exposure follows from the inhalation of radioactive material either directly from a plume or resuspended from contaminated surfaces, from the ingestion of contaminated food and water, or through contaminated wounds. Total effective dose can be calculated by taking into account all dominant exposure pathways by which persons were exposed. 

Inhalation of radioactive material in the plume Ingestion of food directly contaminated by plume and milk or meat from grazing animals waste tank explosion... 

Unlike external dosimetry, an individual s internal radiation dose cannot be directly measured or monitored. Internal dose must be inferred from measurements of radioactive material concentration in excreta, in the body, or in the air a person is breathing. Measurement of radioactive material in the body or in excreta is referred to as "bioassay measurement." The purpose of bioassay measurements or air sampling is to determine what quantity of material has been taken into the body. Direct bioassay measurement of an individual is preferable to using air concentrations. The most common routes are by inhalation or ingestion, although dermal absorption is possible with some materials such as tritium and material may also be taken in through wounds. 

The ionising radiations encountered in industry are principally a, p, y and X-rays, bremsstrahlung and neutrons. Persons can be irradiated by sources outside the body (external irradiation) or from radionuclides deposited within the body (internal irradiation). External irradiation is of interest when the radiation is sufficiently penetrating to reach the basal layer of the epidermis (i.e. the living cells of the skin). Internal irradiation arises following the intake of radioactive material by ingestion, by inhalation or by absorption through the skin or open wounds. 

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