Radium

Agent Name
Radium
CAS Number
7440-14-4
Formula
Ra
Major Category
Physical/Radiation
Synonyms
Radium and compounds;
Category
Radionuclides
Description
Brilliant, white metal that blackens on exposure; Melting point = 700 degrees C. [Merck Index]
Sources/Uses
Used in cancer treatment and industrial radiography; [Merck Index]
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."
Restricted
No longer used in luminous paints for watch dials;
Biomedical References

Exposure Assessment

Reference Link #2

Adverse Effects

IARC Carcinogen
Established
NTP Carcinogen
Human carcinogen

Diseases, Processes, and Activities Linked to This Agent

Diseases

Occupational diseases associated with exposure to this agent: