R 325.5270 Notes to Appendices A1 to A9.

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 40- hour 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> 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: 1. If the identity and concentration of each radionuclide in the mixture are known, the limiting values should be derived as follows: Determine, for each radionuclide in the mixture, the ratio between the quantity present in the mixture and the limit otherwise established in Appendix “A” for the specific radionuclide when not in a mixture. The sum of such ratios for all the radionuclides in the mixture may not exceed “1” (i.e., “unity”). 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: Ca + Cb + Cc < 1 MPCa MPCb MPCc 2. If either the identity or the concentration of any radionuclide in the mixture is not known, the limiting values for purposes of Appendix "A" shall be: a. For purposes of Table I, Column 1 b. For purposes of Table I, Column 2 c. For purposes of Table II, Column 1 d. For purposes of Table II, Column 2 6 x 10-13 4 x 10-7 2 x 10-14 3 x 10-8 3. If any of the conditions specified hereinafter are met, the corresponding values specified there may be used in lieu of those specified in Paragraph 2 above. a. If the identity of each radionuclide in the mixture is known but the concentration of one or more of the radionuclides in the mixture is not known, the concentration limit for the mixture is the limit specified in Appendix “A” for the radionuclide in the mixture having the lowest concentration limit; or, b. If the identity of each radionuclide in the mixture is not known, but it is known that certain radionuclides specified in Appendix “A” are not present in the mixture, the concentration limit for the mixture is the lowest concentration limit specified in Appendix “A” for any radionuclide that is not known to be absent from the mixture; or 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 ---------- 4. If the mixture of radionuclides consists of uranium and its daughter products in ore dust before chemical processing of the uranium ore, the values specified below may be used in lieu of those determined in accordance with Paragraph 1 above or those specified in Paragraphs 2 and 3. a. For purposes of Table I, Column 1, 1 x 10-10 µCi/ml gross alpha activity; or 5 x 10-11 µCi/ml natural uranium; or 75 micrograms per cubic meter of air natural uranium. b. For purposes of Table II, Column 1, 3 x 10-12 µCi/ml gross alpha activity; or 2 x 10-12 µCi/ml natural uranium; or 3 micrograms per cubic meter of air natural uranium. 5. For purposes of this note, a radionuclide may be considered as not present in a mixture if (a) the ratio of the concentration of that radionuclide in the mixture (Ca) to the concentration limit for that radionuclide specified in table II of Appendix “A” (MPCa) does not exceed 1/10, (i.e., Ca < 1 ) MPCa 10 and (b) the sum of such ratios for all radionuclides considered as not present in the mixture does not exceed ¼, i.e., (i.e., Ca + Cb + ......< 1 ) MPCa MPCb 4