Preliminary Public Dose Evaluation in Support of the Development of the
November 2012
Rare Element Resources Bear Lodge Project
29
Table 4.5 Radiation Dose Coefficients for Inhalation
Pathway
Radiation Dose Coefficients
(mrem pCi
-1
)
a
Decay Series
Radionuclide
Inhalation
Uranium
Uranium-238
2.1x10
-2
Uranium-234
2.5 x10
-2
Thorium-230
2.7 x10
-2
Radium-226
8.1 x10
-3
Lead-210
4.1 x10
-3
Polonium-210
8.1 x10
-3
Sum of all uraniun-238 decay
series radionuclides except radon-
222 (DC
U
)
9.3 x10
-2
Thorium
Thorium-232
4.4 x10
-2
Radium-228
6.3 x10
-3
Actinium-228
4.4 x10
-5
Thorium-228
1.2 x10
-1
Radium-224
8.9 x10
-3
Lead-212
1.2 x10
-4
Bismuth-212
1.4 x10
-4
Sum of all thorium-232 decay
series radionuclides except radon-
220 (DC
Th
)
1.8 x10
-1
Notes
a
Radiation DCs from ICRP 68 (ICRP, 1994a) except for revised radium-226 inhalation coefficients
from ICRP 72 (ICRP, 1996). All DCs are for the least soluble form. Inhalation dose coefficients are for 5 micron particle size.
mrem pCi
-1
= millirem per picocurie
DCF = Dose Coefficient
Table 4.1and the DCFs in Table 4.5 were used to calculate source specific dose factors to convert
AERMOD dust concentration output in μg m
-3
(micrograms per cubic meter) to an annual dose
estimated from inhalation. The following equations were used to calculate this factor:
=
365
Where:
CDF
i
= Concentration dose factor for radionuclide i (mrem pCi
-1
L)
BR
= average human breathing rate (22,200 L d
-1
)
DCFi =Dose conversation factor for radionuclide i [mrem pCi
-1
(from Table 4.5)]
The calculated CDF
Th
and CDF
U
are 1.45 x 10
6
and 7.54 x 10
5
mrem pCi
-1
L, respectively. These
CDFs then were used to calculate source specific, mass based particulate Dose Factors (DF)
