| Agent Name |
Cesium, radioactive |
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| Formula |
Cs |
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| Major Category |
Radiation Hazards |
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| Synonyms |
Caesium; The most important radionuclides are Cesium-134 (13967-70-9) and Cesium-137 (10045-97-3); For the stable isotope, see "Cesium" and "Cesium hydroxide." |
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| Category |
Radionuclides |
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| Description |
Silver metal with a melting point of 28.5 degrees C. Reacts explosively with water to form cesium hydroxide; [Merck Index] The mineral, pollucite, is 13% stable cesium oxide; |
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| Sources/Uses |
Naturally occurring is Cs-133 (7440-46-2). "Radioactive cesium-137 is produced when uranium and plutonium absorb neutrons and undergo fission." [ATSDR] Of the 11 major radionuclides, only three have long enough half-lives to persist in the environment: Cs-134, Cs-135, and Cs-137. The decay product of Cs-137 is Ba-137m with a T1/2 of 2.6 minutes. Ba-137m emits a gamma ray with an energy of 0.6 MeV, and this is what makes Cs-137 an external radiation hazard. Cs-137 is used in cancer radiation therapy. [Argonne] |
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| Comments |
Most Important Radionuclide: Cs-137
Source: Fission of uranium and plutonium;
Half-Life: 30 years
Effective Half-Life: 70 days
Specific Activity: 88 Ci/g
Decay Mode: Beta
GI Absorption: "essentially all"
Lung Clearance Half-Time: Days (all compounds)
Critical Organ: Total body;
Internal Toxicity: High
Annual Limit on Intake: 0.1 mCi
Tenth-Value Layer: 18.9 mm Pb
Gamma Ray Constant: 3.5 R/h @1 cm per mCi
Radiation Energy (MeV): Beta 0.514 (95%); Ba-137m Daughter
Radiation Accidents: Goiania, Brazil accident in 1987 with 50 people contaminated and 4 deaths from a Cs-137 source (1375 Ci) taken from an abandoned teletherapy machine; 6 other accidents and 25 reports of "Meltings of Radioactive Materials";
[See Glossary for references.] See "Radiation, ionizing."
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| Reference Link |
Cesium | Radiation Protection | US EPA |
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| Exposure Assessment |
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| Vapor Pressure |
4.24 x 10 -09 mm Hg |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: CESIUM, RADIOACTIVE IONIZING RADIATION
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