Actinium, Radioactive

Radiation Limits / Potential

Atomic number 89; valence: 3; no stable nuclides; known isotopes (mass numbers): 209-233; naturally occurring isotopes: 227, 228; homologous with lanthanum; more basic than lanthanum; strong electropositive element; forms insoluble salts, e.g., carbonate, oxalate, phosphate, etc., just as the lanthanides; rapidly oxidizes to AcO3 in moist air
/Actinium-225/ Atomic weight = 225.02322; half-life = 10.0 days; alpha emission, 5.935 MeV
/Actinium-227/ Atomic weight = 227.027747; half-life = 21.77 years; negative beta emission, 0.045 MeV; alpha emission, 5.043 MeV
/Actinium-228/ Atomic weight = 228.031014; half-life = 6.15 hours; negative beta emission, 2.127 MeV
DECAY PATHWAY: Actinium-225, half-life 10.0 days, decays via alpha emission, 5.935 MeV, to francium-221, half-life 4.9 minutes. Francium-221 decays via alpha emission, 6.458 MeV, to astatine-227, half-life 32.2 minutes; decays via beta emission, 0.312 MeV, to radium-221, half-life 28 seconds.
DECAY PATHWAY: Actinium-227, half-life 21.77 years, decays via beta emission (98.62%), 0.045 MeV, to thorium-227, half-life 7,340 years. Thorium-227 decays via alpha emission, 6.146 MeV, to radium-223, half-life 11.425 days. Actinium-227 decays via alpha emission (1.38%), 5.043 MeV, to francium-223, half-life 22.00 minutes. Francium-223 decays via beta emission, 1.149 MeV, to radium-223.
DECAY PATHWAY: Actinium-228, half-life 6.15 hours, decays via beta emission, 2.127 MeV, to thorium-228, half-life 1.9116 years.
ALI values have been established for individual radionuclides and are presented in Table 1 in Appendix B to PART 20.1001-20.2401. The ALI values for inhalation, presented in Column 2 in Table 1, correspond to a committed effective dose equivalent of 5 rems (0.05 Sv) or a committed dose equivalent of 50 rems (0.5 Sv) to any individual organ or tissue, whichever is more limiting. If the ALI value presented in Table 1 is limited by the 50-rem committed dose equivalent, the controlling organ is listed directly below the ALI value, and the stochastic ALI value based on the 5-rem committed effective dose equivalent is listed ... directly below the organ name. If a stochastic ALI is listed in parentheses, that value should be used to calculate the committed effective dose equivalent.
OCCUPATIONAL VALUES FOR ACTINIUM-224
CLASS ORAL Ingestion ALI (uCi) INHALATION ALI uCi) INHALATION DAC (uCi/mL)
D, all cds except for W & Y 2E+3 LLI wall 2E+3 3E+1 Bone surf 4E+1 1E-8
W, halides and nitrates - 5E+1 2E-8
Y, oxides and hydroxides - 5E+1 2E-8
OCCUPATIONAL VALUES FOR ACTINIUM-225
CLASS ORAL Ingestion ALI (uCi) INHALATION ALI uCi) INHALATION DAC (uCi/mL)
D, all cds except for W & Y 5E+1 LLI wall 5E+1 3E-1 Bone surf 5E-1 1E-10
W, halides and nitrates - 6E-1 3E-10
Y, oxides and hydroxides - 6E-1 3E-10
OCCUPATIONAL VALUES FOR ACTINIUM-226
CLASS ORAL Ingestion ALI (uCi) INHALATION ALI uCi) INHALATION DAC (uCi/mL)
D, all cds except for W & Y 1E+2 LLI wall 1E+2 3E+0 Bone surf 4E+0 1E-9
W, halides and nitrates - 5E+0 2E-9
Y, oxides and hydroxides - 5E+0 2E-9
OCCUPATIONAL VALUES FOR ACTINIUM-227
CLASS ORAL Ingestion ALI (uCi) INHALATION ALI uCi) INHALATION DAC (uCi/mL)
D, all cds except for W & Y 2E-1 (Bone surf) 4E-1 4E-4 (Bone surf) 8E-4 2E-13
W, halides and nitrates - 2E-3 (Bone surf) 3E-3 7E-13
Y, oxides and hydroxides - 4E-3 2E-12
OCCUPATIONAL VALUES FOR ACTINIUM-228
CLASS ORAL Ingestion ALI (uCi) INHALATION ALI uCi) INHALATION DAC (uCi/mL)
D, all cds except for W & Y 3E+3 9E+0 (Bone surf) 2E+1 4E-9
W, halides and nitrates - 4E+1(Bone surf) 6E+1 2E-8
Y, oxides and hydroxides - 4E+1 2E-8
EFFLUENT CONCENTRATIONS ESTABLISHED BY THE NRC FOR SOME ACTINIUM COMPOUNDS
RADIONUCLIDE CLASS AIR (uCi/mL) WATER (uCi/mL)
Actinium-224 D, all compounds except forthose given for W and Y 5E-11 3E-5
W, halides and nitrates 7E-113 -
Y, oxides and hydroxides 6E-11 -
Actinium-225 D 7E-13 7E-7
W 9E-13 -
Y 9E-13 -
Actinium-226 D 5E-12 2E-6
W 7E-12 -
Y 6E-12 -
Actinium-227 D 1E-15 5E-9
W 4E-15 -
Y 6E-15 -
Actinium-228 D 2E-11 3E-5
W 8E-11 -
Y 6E-11 -
QUANTITIES OF NRC LICENSED MATERIAL REQUIRING LABELING
RADIONUCLIDE QUANTITY (uCi)
Actinium-224 1
Actinium-225 0.01
Actinium-226 0.1
Actinium-227 0.001
Actinium-228 1
Find more information on this substance at: PubChem, PubMed