NERC-LV-539-32 THE BEHAVIOR OF 131I IN AN ARTIFICIAL RUMEN AND IN THE SIMULATED FLUIDS OF THE ABOMASUM AND INTESTINE Earl L. Whittaker Delbtirt S, Bart* National Environmental Research Center-Las Vegas U. S. ENVIRONMENTAL PROTECTION AGENCY Lis. ¥gs9 NV 89114 Published May 1974 This research performed under a Memorandum of Understanding No. AT(26-l}-539 for the U. S. ATOMIC ENERGY COMMISSION ------- This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Atomic Energy Commission, nor any of their contractors, subcontractors, or their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately-owned rights. Reference to a commercial product is not intended to constitute endorse- ment or recommendation by the Atomic Energy Commission or the Environmental Protection Agency over similar ones not mentioned. Available from the National Technical Information Service, U. S. Department of Commerce, Springfield, VA 22151 Price: paper copy $4.00, microfiche $1.45 ------- NERC-LV-539-32 THE BEHAVIOR OF 131I IN AN ARTIFICIAL RUMEN AND IN THE SIMULATED FLUIDS OF THE ABOMASUM AND INTESTINE by Julius Barth Earl L. Whittaker Delbert S. Barth National Environmental Research Center-Las Vegas U. S. ENVIRONMENTAL PROTECTION AGENCY Las Vegas, NV 89114 Published May 1974 This research performed under a Memorandum of Understanding No. AT(26-l)-539 for the U. S. ATOMIC ENERGY COMMISSION ------- ABSTRACT 131 The in vitro conversion of I-labeled sodium iodide to volatile iodine was investigated in the artificial rumen and in simulated abomasal and 101 intestinal fluids. In addition, the association of I-labeled iodide with rumen juice sediment, which includes microflora and feed debris, was also studied. The results show that under the conditions reported here, 101 1 01 I is not volatile. As much as three percent of the I was shown to be associated with rumen juice sediment in the artificial rumen. This value was reduced to 0.52 percent and 0.038 percent in the simulated abomasal and intestinal fluids, respectively. 11 ------- ACKNOWLEDGMENTS The authors thank J. A. Reagan for statistical analyses of the data and G. D. Potter and W. W. Sutton for their helpful suggestions in the preparation of this manuscript. ------- INTRODUCTION Gases of the rumen may be expelled by eructation and subsequently absorbed by the lungs. At this laboratory it was observed that I appears in the blood and milk of cattle very soon after an oral administration of I iodide. It was therefore postulated that I could have been converted to volatile iodine in the rumen and transported into the respiratory system by eructation where it could be absorbed. Experiments using the artificial rumen were designed to test this hypothesis. Dougherty et aj_. (1965), discussing work of others concerning eructated rumen gas, stated the following: A repetition by Dougherty ejt al_. (1962) of an experiment performed many years ago by Dougherty (1940) very effectively demonstrated that components of rumen gas which reach the lungs are absorbed. Dougherty ejb al_. (1962) and Shipe et^ a\_. (1962) demonstrated that certain odors carried in eructated gases from the rumen to the lungs were absorbed, thereby contaminating the mammary blood supply and trans- mitting off-flavors to the milk. The same substances tested in these experiments were also absorbed by the portal blood; however, contamination of milk was much slower by this route than it was when eructated gases were allowed to enter the lungs. 131 This study was designed to assess the possibility that I iodide might be converted to volatile iodine or methyl iodide in rumen juice which could then be eructated into the respiratory tract. If iodide were indeed 1 ------- converted to iodine in the gastrointestinal tract, it would then be necessary to account for I losses by eructation as well as recycling of I via the respiratory system. Volatilization of I iodide from simulated abomasal and intestinal juice was included in this study. In 131 addition, the binding of I to rumen microflora and other sediment was also studied. Barth and Bruckner (1969 a,b) effectively employed an artificial rumen followed by simulated abomasal and intestinal fluids to study the uptake by binding agents of Cs, strontium, and other essential cations in order to reduce radionuclide transport to milk. This procedure also provides a means for investigating the solubility or availability for absorption of fallout radionuclides in a natural medium, taken directly from a rumen-fistulated steer, in the presence of viable rumen microflora. METHODS AND MATERIALS The artificial rumen and simulated abomasal and intestinal fluid procedure used is similar to that employed by Barth and Bruckner (1969 a,b) and is briefly described here with necessary modifications. Each digestion flask was prepared by addition of 250 ml of rumen juice to 250 ml of basal medium in a one-liter Ehrlenmeyer flask containing 3.75 g of powdered cellulose. The C02 outlet from each Ehrlenmeyer flask was connected to an I scrubber consisting of a 1.5- by 20-cm column of activated charcoal. The content of each flask was adjusted to pH 6.5 with saturated sodium carbonate solution and dosed with 0.7 to 1.2 yCi of carrier-free 131 Na I. Digestion flasks were incubated for about 21 hours in a water bath at 39°C, with a continuous stream of COp passing through the contents of each flask. ------- The artificial rumen fluid in each flask was then converted to simulated abomasal fluid by addition of 125 ml of simulated abomasal juice contain- ing 0.25 g pepsin and by adjusting the pH to three with 5.0 N HC1. The resulting mixture was incubated for three hours. The C02 flow was allowed 131 to continue slowly in order to sweep gaseous I that might be produced to the charcoal scrubber. Following the abomasal digestion phase, the simulated abomasal fluid was converted to a simulated intestinal fluid. One-hundred milliliters of 0.1N NaHC03 was added followed by 40 ml of bile. Fifty milliliters of an enzyme preparation containing 6.0 g pancreatin, 0.3 g trypsin, and 0.3 g erepsin was added and the pH was adjusted to six with 5.0 N NaOH. In- cubation continued for an additional three hours with a slow rate of (XL flow. At the beginning and end of each digestive phase, a 5-ml sample of rumen juice was removed and pipetted directly into 50 ml of 0.1N NaOH for 131 radioanalysis of I. Upon completion of each digestive phase, an ad- ditional 10-ml sample from each flask was removed and centrifuged for 20 minutes at the maximum speed of a Sen/all Table Model Centrifuge, Type M (over 5000 rpm). The supernatant was decanted into 0.1N NaOH for radio- analysis while the sediment was washed twice by resuspension in 5 ml of water and recentrifuged. All supernatants were combined. The washed sediment was analyzed for radioiodine. Fresh charcoal scrubbers were 131 used during each digestive phase for collection of gaseous I. Gamma spectrometry was carried out using opposed 5- by 9-inch sodium iodide crystals associated with a TMC 400-Channel Analyzer. Digestion flasks were run in duplicate for three separate trials. ------- A preliminary experiment was designed so that gas chromatography could be used to determine the chemical form of any volatile iodine. This operation was similar to the procedure described above except that the C02 outlet was connected to a small filter flask which served as a trap. This was followed by passing the gas through a 1.5- by 20-cm column of a mixture of calcium chloride pellets and anhydrous calcium sulfate which served as a drying agent. Plastic tubing was used to connect this column to the first scrubber which consisted of a "U" tube containing 4 ml of toluene. The toluene scrubber was placed in a Dewar flask contain- ing a slurry of ground dry ice and isopropyl alcohol. This was subsequently attached to a column of activated charcoal which served as a backup scrubber. Toluene was used only during the artificial rumen phase, while the charcoal scrubber was used during all digestion phases. During the preliminary trial only, one digestion flask was used. Rumen juice was sampled at the beginning of the phase and at one, six, and 16-1/2 hours after dosing. Samples were collected at the beginning and 131 end of the abomasal and intestinal phases. The collection of I by the toluene liquid scrubber permitted later separation of organic and 131 inorganic gaseous I by gas-liquid chromatography and possible identification of organic and other forms. RESULTS AND DISCUSSION Results of the preliminary trial (data not shown) indicate practically no loss of I from the digestive juices during the incubation periods. 1 "31 Virtually no I was recovered in the toluene and charcoal scrubbers or ------- in the plastic tubing used. Chromatographic analysis, originally scheduled on the toluene to determine the form of I present, was not necessary since the toluene contained no radioactivity. The averages of the results of the three in vitro trials are shown in Table I. An analysis of variance indicates that there was no significant difference (p »0.05) between the activity levels in any of the nine fluids sampled. This indicates little, if any, loss due to volatility of I or binding of I to sediment. Radioactivity associated with the sediment was not significantly above background. Therefore, although some activity is associated with the sediment, it is within the limits that might be expected from experimental error. There was a sharp drop in sediment-associated I following abomasal digestion and almost no I was associated with sediment during the intestinal phase. This may be due to enzymatic digestion of the rumen microflora and other sediment present. I 01 Absence of I deposited on the charcoal scrubbers also demonstrates little or no I volatility in these digestive fluids. Though not statistically significant (p »0.05), there appears to be a slight drop in I remaining in whole juice and supernatant between the beginning and the end of the abomasal phase. This cannot be accounted for by I association with sediment or deposition on the charcoal scrubbers 131 and is possibly due to binding of I to the container during incuba- tion or centrifugation. ------- 131 TABLE I I DISTRIBUTION DURING IN VITRO DIGESTION Whole juice start Percent of I remaining Artificial Rumen % 100.00 102.36* Abomasal Phase % 100.00 96.52 Intestinal Phase % 100.00 98.59 at end of phase 101 Percent of I in supernatant at end of phase 131 Percent of I in sediment at end of phase Percent of I deposited on charcoal during phase 98.16 3.13 94.53 0.521 99.82 0.038 0.00062 0.001038 0.0000 *Value greater than 100$ is due to counting error. ------- 1 "31 These results suggest that I iodide present in rumen contents is not volatilized and it is not likely that it would be eructated as gaseous iodine into the bovine respiratory system where it might be absorbed through the tissues of the respiratory tract. ------- REFERENCES 1. Barth, J., Bruckner, B. H., Evaluation of Clays as Binding Agents for Reduction of Radionuclides in Milk. Binding Properties of Natural and Hydrogen Form Clays with Strontium and Essential Cations in Artificial Rumen and in Simulated Abomasal and Intestinal Fluids. J. Agr. Food Chem. 17:1340-1343, I969a. 2. Barth, J., Bruckner, B. H., Evaluation of Clays as Binding Agents for Reduction of Radionuclides in Milk. Binding Properties of Clays with 134cs in Artificial Rumen and in Simulated Abomasal and Intestinal Fluids, and Uptake of '34cs by Rumen Microflora. J. Aqr. Food Chem. 17:1344-1346, 1969b. 3. Dougherty, R. W., Physiological Studies of Induced and Natural Bloat in Dairy Cattle. J. Am. Vet. Med. Assoc. 96_:43-46, 1940. 4. Dougherty, R. W., Mullenax, C. H, Allison, M. J., Physiological Phenomena Associated with Eructation in Ruminants, in Dougherty, R. W., Allen, R. S., Burroughs, W., Jacobson, N. L., McGilliard, A. D., Physiology of Digestion in the Ruminant, pp. 159-170, Butterworth, Washington, 1965T 5. Dougherty, R. W., Shipe, W. F., Gudnason, G. V., Ledford, R. A., Peterson, R. D. Scarpellino, R., Physiological Mechanisms Involved in Transmitting Flavors and Odor to Milk. I. Contribution of Eructated Gases to Milk Flavor. J. Dairy Sci. _45:472-476, 1962. 6. Dougherty, R. W., Stewart, W. E., Nold, M. M., Lindahl, I. L., Mullenax, C. H., Leek, B. F., Pulmonary Absorption of Eructated Gas in Ruminants. Am. J. Vet. Res. _23:205-212, 1962. 7. Shipe, W. F., Ledford, R. A., Peterson, R. D., Scanlan, R. A., Geerken, H. F., Dougherty, R. W., Morgan, M. E., Physiological Mechanisms Involved in Transmitting Flavors and Odors to Milk. II. Transmission of Some Flavor Components of Silage. J. Dairy Scj. 45:477-480, 1962. ------- DISTRIBUTION 1-20 National Environmental Research Center, Las Vegas, NV 21 Mahlon E. Gates, Manager, NVOO/AEC, Las Vegas, NV 22 Robert H. Thalgott, NVOO/AEC, Las Vegas, NV 23 Richard M. Pastore, NVOO/AEC, Las Vegas, NV 24 David G. Jackson, NVOO/AEC, Las Vegas, NV 25 Arthur J. Whitman, NVOO/AEC, Las Vegas, NV 26 Elwood M. Douthett, NVOO/AEC, Las Vegas, NV 27 Paul B. Dunaway, NVOO/AEC, Las Vegas, NV 28 Ernest D. Campbell, NVOO/AEC, Las Vegas, NV 29 - 30 Technical Library, NVOO/AEC, Las Vegas, NV 31 Chief, NOB/DNA, NVOO/AEC, Las Vegas, NV 32 Roger Ray, NVOO/AEC, Las Vegas, NV 33 Thomas 0. Fleming, NVOO/AEC, Las Vegas, NV 34 Paul J. Mudra, NVOO/AEC, Las Vegas, NV 35 Robert L. Loux, NVOO/AEC, Las Vegas, NV 36 Bennie G. DiBona, NVOO/AEC, Las Vegas, NV 37 Robert J. Catlin, Office of Environmental Affairs, USAEC, Washington, DC 38 Martin B. Biles, DOS, USAEC, Washington, DC 39 Tommy F. McCraw, DOS, USAEC, Washington, DC 40 Assistant General Manager, DMA, USAEC, Washington, DC 41 Gordon C. Facer, DMA, USAEC, Washington, DC 42 John R. Totter, DBER, USAEC, Washington, DC 43 John S. Kirby-Smith, DBER, USAEC, Washington, DC 44 L. 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Frances Allen, ORM, EPA, Arlington, VA 60 Regional Admin., Region IX, EPA, San Francisco, CA 61 Regional Radiation Representative, Region IX, EPA, San Francisco, CA 62 Eastern Environmental Radiation Facility, EPA, Montgomery, AL 63 Peter Halpin, Chief, APTIC, EPA, RTP, NC 64 K. M. Oswald, LLL, Mercury, NV 65 Bernard W. Shore, LLL, Livermore, CA 66 James E. Carothers, LLL, Livermore, CA 67 Howard A. Tewes, LLL, Livermore, CA 68 Lawrence S. Germain, LLL, Livermore, CA 69 Paul L. Phelps, LLL, Livermore, CA 70 Charles I. Browne, LASL, Los Alamos, NM 71 George E. Tucker, Sandia Laboratories, Albuquerque, NM 72 Harry S. Jordan, LASL, Los Alamos, NM 73 Arden E. Bicker, REECo, Mercury, NV 74 Savino W. Cavender, REECo, Mercury, NV 75 Carter D. Broyles, Sandia Laboratories, Albuquerque, NM 76 Melvin L. Merritt, Sandia Laboratories, Albuquerque, NM ------- 77 Richard S. Davidson, Battelle Memorial Institute, Columbus, OH 78 Verle Q. Hale, Battelle Memorial Institute, Las Vegas, NV 79 Steven V. Kaye, Oak Ridge National Lab., Oak Ridge, TN 80 Leo K. Bustad, Washington State University, College of Veterinary Medicine, Pullman, WA 81 Leonard A. Sagan, Palo Alto Medical Clinic, Palo Alto, CA 82 Vincent Schultz, Washington State University, Pullman, WA 83 Arthur Wallace, University of California, Los Angeles, CA 84 Wesley E. Niles, University of Nevada, Las Vegas, NV 85 Robert C. Pendleton, University of Utah, Salt Lake City, UT 86 William S. Twenhofel, U. S. Geological Survey, Denver, CO 87 Paul R. Fenske, Desert Research Institute, University of Nevada, Reno, NV 88 John M. Ward, President, Desert Research Institute, University of Nevada, Reno, NV 89 - 90 Technical Information Center, USAEC, Oak Ridge, TN (for public availability) ------- |