Pit ~7 J 707/ ..CLASSIFIED I UNCLASSIFIED K-1071 Subject Category: BIOLOGY UNITED STATES ATOMIC ENERGY COMMISSION THE INHALATION OF RADIOACTIVE MATERIALS AS RELATED TO HAND CONTAMINATION By J. C. Bailey R. C. Rohr September 15, 1953 K-25 Plant Carbide and Carbon Chemicals Company Oak Ridge, Tennessee Technical Information Service, Oak Ridge, Tennessei Work performed under Contract No. W-7lt05-Eng-26. The Atomic Energy Commission makes no representation or warranty as to the accuracy or usefulness of the Information or statements contatned in this report, or that the use of any information, apparatus, method or process disclosed In this report may not Infringe privately-owned rights. The Commission assumes no liability with respect to the use of, or for damages resulting from the use of, any Information, apparatus, method or process disclosed in this report. This report has been reproduced directly from the best available copy. Reproduction of this information is encouraged by the United States Atomic Energy Commission. Arrangements for your republication of this document in whole or in part should be made with the author and the organization he represents. Since nontechnical and nonessential prefatory material has been deleted, the first page of the report is page 5. Printed in USA, Price 20 cents. Available from the Office of Technical Services, Department of Commerce, Wash- ington 25, D. C. GPO 3^6786 THE INHALATION OF RADIOACTIVE MATERIALS AS RELATED TO HAND CONTAMINATION J. C. Bailey and R„ C. Rohr Safety and Protection Division W. L. Richardson, Superintendent Supervised bys H. F. Henry CARBIDE AND CARBON CHEMICALS COMPANY A DIVISION OF UNION CARBIDE AND CARBON CORPORATION K-25 Plant Oak Ridge, Tennessee ABSTRACT Tests performed to determine the hazard associated with the inhalation of radio- active materials as the result of smoking with contaminated hands indicate that for dry uranium compounds adhering to the palmar surfaces of the hands, approxi- mately 1.0$ of the material may be transferred to a cigarette, and that of this approximately 0.2$ may appear in the smoke which is inhaled. Most of the con- tamination originally placed in a cigarette was found in the ash, and only 11$ of the material was not recovered following burning j approximately half of this loss may be attributed to normal losses inherent in the analytical process, the recovery efficiency for which was found by supplementary experiments to be 95$. THE INHALATION OF RADIOACTIVE MATERIALS AS RELATED TO HAND CONTAMINATION INTRODUCTION Experiments have been performed in an attempt to determine the hazard associated with the inhalation of radioactive materials as the result of smoking with contami- nated hands , The principal factors calculated were the fraction of material which may be transferred from the hands to cigarettes and the fraction of material on the cigarette which may be inhaled when the cigarette is smoked. SUMMARY OF RESULTS The tests indicate that for dry uranium compounds adhering to the palmar surfaces of the hands 5 approximately 1.0$ of the material may be transferred to a cigarette, and that of this approximately 0°2$ may appear in the smoke which is inhaled. Most of the contamination original 1 y placed in a cigarette was found in the ash, and only 11$ of the material was not recovered following burning! approximately half of this loss may be attributed to normal losses inherent in the analytical process, the recovery efficiency for which was found by supplementary experiments to be 95$. TRANSFER OF CONTAMINATION FROM HANDS TO CIGARETTES Contamination Under Field Conditions In order to simulate those working conditions which, from the standpoint of cigarette contamination, are considered to be the most hazardous that might be anticipated, a work surface highly contaminated with normal uranium tetra- fluoride was used as the source of contamination. Transferable contamination on the surface was between 7,000 and 16,000 dis./min./lOO cm. 2 (1,400 and 3,250 counts/min. at 20$ geometry), the average being 11,000 dis./min./lOO cm. . The degree of contamination was determined by the standard method used at K-25, which consists of rubbing approximately 100 cm. of the surface vigorously with a test paper backed by 3 fingers, and reading the activity with a Samson alpha survey meter. The hands were rubbed over the work surface and the contamination was then thoroughly rubbed into the hands so that no very loose material remained on the hands. After repeated contact with this surface, the contamination on the palm attained a value of 83,000 dis./min. (12,500 counts/min. at 15$ geometry), the change in contamination level with repeated contact being small toward the end of the test. The hands were monitored with a Samson alpha survey meter, and each cigarette was handled for a period of about 1 minute. Only 1 hand was used in handling a cigarette, and the hands were recontaminated after each cigarette was handled. The 12 cigarettes so contaminated were counted whole in a laboratory type proportional alpha counter. The hand and cigarette counts were corrected for counting geometries, and the fraction of the material transferred was determined. The results, shown in table 1, indicate that between 0.7$ and 1.6$ of the material on the palmar surface of the hand was transferred to the cigarette; the average value was 1.0/$ - 0.09$* and the fraction transferred appeared to be essentially independent of the degree of contamination. The results of the tests by which the various counting geometries were deter- mined are given in the appendix. TABLE 1 Transfer of Contamination to Cigarettes - Working Conditions Hand Counts (. Cigarettes ;/min . ) „ ( dis . /min. ) Transferred No. (c/mih.) (dis./min. ) $ (15$ Geometry) (3$ Geometry) 1 3,250 21,700 73 243 1.12 2 3,500 23,300 62 207 0.89 3 3,500 23,300 88 293 1.26 4 5,000 33,300 73 243 0.73 5 6,250 a, 700 128 427 1.02 6 5,000 33,300 120 400 1.20 7 7,250 48,300 109 363 0.75 8 7,500 50,000 158 526 1.05 9 10,250 67,400 219 730 1.08 10 10, 500 70,000 166 554 0.79 11 10,000 66,700 217 724 1.08 12 12, 500 83,400 390 1300 1.56 Average k 1.04 - 0.09 Maximum Contamination Transfer In order to determine the maximum amount of uranium which may be transferred to a cigarette, a laboratory test similar to that described above was used. In this case, uranium oxide was transferred from a jar and was spread evenly over the hands but was not rubbed into the hands; the cigarettes were handled as described above. Since there was a considerable amount of loose material on the hands, the fraction transferred to the cigarettes was somewhat greater than that found in the field test, the average being 1.8$. The counts for the cigarettes were determined by splitting them and counting the papers flat; "on the basis of the average of several comparisons, this configuration appeared to have essentially the same 30$ geometry as when the cigarettes were counted whole. The results of this test are shown in table 2, but since the experi- mental method did not appear to simulate actual working conditions at K-25, the results were not included in the averages summarized on page 7. * The limits of error indicated throughout this report are the standard errors of the means. TABLE 2 Trans fer of Contamination to Cigarettes Laboratory Test with Hands Dusted Hand Contamination Cigarette Contamination Transferred No. (c/min.) (15% Geometry) (dis„/min.) (c/min. on Paper) (30% Geometry) (dis„/min,) % 1 1,250 8,330 33 110 1.3 2 1,500 10,000 87 290 2.9 3 2,750 18,300 102 340 1.9 4 3,500 23,300 177 590 2.5 5* 3,250 21,700 121 403 1.9 6 5,250 35,000 155 516 1.5 7 5,750 38,300 177 590 1.5 8 11,000 73,300 284 946 1.3 9 > 12, 500 > 83 3 300 291 970 1.2 Averag* a 1.78 - 0.06 10 >12 9 500 >83,300 1,140** 3,800 4.6 * No material was added to the hands before handling this cigarette. ** This cigarette was used to wipe material off the hands in order to obtain an estimate of the maximum amount of material which is transferable under the most extreme conditions. INHALATION OF CONTAMINATION FROM CIGARETTES In order to determine the maximum fraction of contamination which might be inhaled from a contaminated cigarette during smoking, 0.1 cm. 3 of uranyl fluoride solution containing approximately 22,200 alpha dis./min., or 11,100 counts/min.*, was injected into each of several cigarettes by means of a hypodermic syringe. The cigarettes were "smoked" approximately 2/3 of their length by pulling air through them with air samplers, the part- thus "smoked" including the portion injected with material. The activity in the smoke was collected by using filter papers in the samplers or by using water bubblers in the smoke stream. Approximately 0.2% of the material was collected from the smoke, while an average of 89% was found in the unsmoked butt and the ash, most of this appearing in the ash. The yield of the analytical method was found by supplementary experiments to be 95%J thus, if the experimental recovery figure is corrected for loss due to the analytical method, the results show that about 94% of the material originally injected in the cigarette remained in the butt and ash. The results of these tests are summarized in table 3T F~/'g ure 2 Counting Geometries Geometry for Hand Counts In determining the hand counting geometry in these experiments, the hands were contaminated from a jar of finely powdered UOp, the material was thoroughly rubbed into the palms of the hands, and the palm of each hand was monitored with a Samson meter. The hands were then washed twice with the standard K-25 hand decontamination agent*, using a small quantity of water (approximately 400 cm.-') which was carefully retained and analyzed for uranium,, Following decontamination, the hands were monitored with a Poppy alpha meter, capable of detecting about 20 counts/min„| in no case did any detectable contamination remain on the hands. The ratio of the disintegration rate of the recovered material to the sum of the left and right palm counts was found to be 14.4 - 2.5$, and accordingly 15$ was taken to represent the counting geometry for the Samson.. The results are tabulated in table 10, TABLE 10 Hand Counting Geometry Test 1 2 3 4 5 6 Average Hand Counts (c> 'min.) Left Right Total 3,250 3,250 6,500 7,500 8,250 15,750 3,250 3,500 6,750 4,000 4,250 8,250 6,000 6,750 12,750 4,500 4,250 8,750 Recovered U. (dis./min. ) 4.47 7.96 3ol7 13.8 8.04 9.82 10 4 10^ icA lOf 10 4 Geometry 14.5 19.8 21.3 6.0 15.9 8.9 14.4 - 2.5 Geometry for Cigarette Counts In order to determine the counting geometry for the cigarettes, 12 cigarettes were contaminated by rubbing UO2 onto the cigarette papers each cigarette was counted whole in a laboratory type counter and was then chemically analyzed for uranium. The counting geometry as calculated from the counting rate and the known disinte- gration rate of the recovered material was 31.8 - 0.8$, or approximately 30$j the results are shown in table 11. * SBS-310, a hand cleanser manufactured by the Sugar Beet Products Company, Saginaw, Michigan. UNIVERSITY OF FLORIDA 3 1262 08905 5478 18 TABLE 11 Cigarette Counting Geometry Test 1 2 3 4 5 6 7 8 9 10 11 12 Average Count 59 200 108 166 227 118 599 887 889 1,204 1,035 822 Dis./Min„ 198 624 344 698 670 384 1,890 2,716 2,464 3,696 3,124 3,404 Geometry _i 29.8 32.1 31.4 33.3 33.9 30.7 31.7 32.6 36.1 32.5 33.1 24.1 31.8 i 0.8 Geometry for Transferable Contamination The geometry for counting transferable activity was determined by a comparison of the counting rates obtained by means of a Samson alpha survey meter with the results obtained by extracting, plating, and counting the uranium on the samples. The results, tabulated in table 12, indicate an efficiency of 18.5 * 1.5/6, or approximately 2C#„ TABLE 12 Counting Geometry for Transferable Activity Samson Reading Analysis Count ing Efficiency Sample (o/min.) 100 (dis./min. ) 1,286 % 1 7.8 2 250 1,504 16.6 3 300 1,781 16.8 4 300 1,741 17.2 5 350 2,315 15.1 6 400 1,460 27.5 7 650 3,938 16.5 8 900 5,561 16.2 9 1,500 9,716 15.4 10 1,600 7,619 21.0 11 1,900 8,034 22.8 12 2,100 7,520 28.0 13 3,000 15,534 19.3 Average 18.5 - 1.5 I