| Agent Name |
Radium |
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| CAS Number |
7440-14-4 |
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| Formula |
Ra |
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| Major Category |
Physical Agents |
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| Category |
Radionuclides |
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| Description |
Brilliant, white metal that blackens on exposure; Melting point = 700 degrees C. [Merck Index] |
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| Sources/Uses |
Used in cancer treatment and industrial radiography; [Merck Index] |
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| Comments |
In the first quarter of the 20th century, watch dial painters ingested small amounts of radium in the luminous paint. Mortality studies showed increased rates of bone-related cancers in these workers. [Sullivan, p. 757-8] There is sufficient evidence that ingestion of radium-228 causes bone sarcomas and that ingestion of radium-226 causes bone sarcomas and carcinomas of the paranasal sinuses and mastoid processes. [IARC]
Most Important Radionuclide: Ra-226
Source: Decay product of U-238 decay series;
Half-Life: 1600 years
Effective Half-Life: 44 years
Specific Activity: 1 Ci/gm
Decay Mode: Alpha
GI Absorption: 20%
Lung Clearance Half-Time: Weeks
Critical Organ: Bone
Internal Toxicity: Very High
Annual Limit on Intake: 0.0006 mCi
Radiation Energy (MeV): Alpha 4.78 (95%); Gamma 0.186 (4%) + daughters;
Radiation Accidents: Ingestion of 2 mCi of radium bromide resulted in death 4 years later; Two incidents of "Meltings of Radioactive Materials";
[See Glossary for references.] See "Radiation, ionizing."
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| Restricted |
No longer used in luminous paints for watch dials; |
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| Reference Link |
Radium | Radiation Protection Program | US EPA |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
Not evaluated |
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| Reference Link |
ATSDR ToxFAQs - Radium |
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| Adverse Effects |
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| IARC Carcinogen |
Known Carcinogen |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: RADIUM, RADIOACTIVE IONIZING RADIATION
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