Mich. Admin. Code R. 325.5270
Rule 270.
*Soluble (S): Insoluble (I).
**"Sub" means that values given are for submersion in a semi-spherical infinite cloud of airborne material.
***For purposes of these rules, it may be assumed that the daughter activity concentrations in the following table are equivalent to an air concentration of 10-7 microcuries of radon-222 per milliliter of air in equilibrium with the daughters polonium-218, lead-214, bismuth-214, and polonium-214:
Maximum Time Between Collection and Measurement (hours)* | Alpha-Emitting Daughter Activity Collected per Milliliter of Air | |
Microcuries per milliliter | Total Alpha Disintegrations per minute per milliliter | |
0.5 | 7.2 x 10-8 | 0.16 |
1.0 | 4.5 x 10-8 | 0.10 |
2.0 | 1.3 x 10-8 | 0.028 |
3.0 | 0.3 x 10-8 | 0.0072 |
* The duration of sample collection and the duration of measurement should be sufficiently short compared to the time between collection and measurement, as not to have a statistically significant effect upon the results.
****For soluble mixtures of U-238, U-234, and U-235 in air, chemical toxicity may be the limiting factor. If the percent by weight (enrichment) of U-235 is less than 5, the concentration value for a 40-hour workweek, table I, is 0.2 milligrams uranium per cubic meter of air average. For any enrichment, the product of the average concentration and time of exposure during a 40hour workweek shall not exceed 8 x 10-3 SA µCi-hr/ml, where SA is the specific activity of the uranium inhaled. The concentration value for table II is 0.007 milligrams uranium per cubic meter of air. The specific activity for natural uranium is 6.77 x 10-7 curies per gram U. The specific activity for other mixtures of U-238, U-235, and U-234, if not known, shall be:
SA = 3.6 x 10-7 curies/gram U U-depleted
SA = (0.4 + 0.38 E + 0.0034 E2) 10-6 E[GREATER THAN EQUAL TO] 0.72 where E is the percentage by weight of U-235, expressed as percent.
NOTE: In any case where there is a mixture in air or water of more than 1 radionuclide, the limiting values for purposes of this appendix should be determined as follows:
Example: If radionuclides a, b, and c are present in concentrations Ca, Cb, and Cc, and if the applicable Maximum Permissible Concentrations (MPC's) are MPCa, MPCb, and MPCc respectively, then the concentrations shall be limited so that the following relationship exists:
TABLE I | TABLE II | |||
c. Element (atomic number) and radionuclide | Column 1 Air (µCi/ml) | Column 2 Water (µCi/ml) | Column 1 Air (µCi/ml) | Column 2 Water (µCi/ml) |
If it is known that Sr-90, I-125, I-126, I-129, I-131, (I-133, Table II only), Pb-210, Po-210, At-211, Ra-223, Ra-224, Ra-226, Ac-227, Ra-228, Th-230, Pa-231, Th-232, Th-nat, Cm-248, Cf-254, and Fm-256 are not present | ------------ | 9 x 10-5 | ------------ | 3 x 10-6 |
If it is known that Sr-90, I-125, I-126, I-129, I-131, (I-133, Table II only), Pb-210, Po-210, Ra-223, Ra-226, Ra-228, Pa-231, Th-nat, Cm-248, Cf-254, and Fm-256 are not present | ------------ | 6 x 10-5 | ------------ | 2 x 10-6 |
If it is known that Sr-90, I-129, (I-125, I-126, I-131, Table II only), Pb-210, Ra-226, Ra-228, Cm-248, and Cf-254 are not present | ------------ | 2 x 10-5 | ------------ | 6 x 10-7 |
If it is known that (I-129, Table II only), Ra-226, and Ra-228 are not present | ------------ | 3 x 10-6 | ------------ | 1 x 10-7 |
If it is known that alpha-emitters and Sr-90, I-129, Pb-210, Ac-227, Ra-228, Pa-230, Pu-241, and Bk-249 are not present | 3 x 10-9 | ------------ | 1 x 10-10 | ------------ |
If it is known that alpha-emitters and Pb-210, Ac-227, Ra-228, and Pu-241 are not present | 3 x 10-10 | ------------ | 1 x 10-11 | ------------ |
If it is known that alpha-emitters and Ac-227 are not present | 3 x 10-11 | ------------ | 1 x 10-12 | ------------ |
If it is known that Ac-227, Th-230, Pa-231, Pu-238, Pu-239, Pu-240, Pu-242, Pu-244, Cm-248, Cf-249 and Cf-251 are not present | 3 x 10-12 | ------------ | 1 x 10-13 | ------------ |
and (b) the sum of such ratios for all radionuclides considered as not present in the mixture does not exceed 1/4, i.e.,
Mich. Admin. Code R. 325.5270