EPA-600/3-77-076 June 1977 Ecological Research Series TRITIUM RETENTION BY COWS AND STEERS AND TRANSFER TO MILK Environmental Monitoring and Support Laboratory Office of Research and Development U.S. Environmental Protection Agency Las Vegas. Nevada 89114 ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into five series. These five broad categories were established to facilitate further development and application of environmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The five series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3. Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies This report has been assigned to the ECOLOGICAL RESEARCH series. This series describes research on the effects of pollution on humans, plant and animal species, and materials. Problems are assessed for their long- and short-term influences. Investigations include formation, transport, and pathway studies to determine the fate of pollutants and their effects. This work provides the technical basis for setting standards to minimize undesirable changes in living organisms in the aquatic, terrestrial, and atmospheric environments. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161. ------- EPA-600/3-77-076 June 1977 TRITIUM RETENTION BY COWS AND STEERS AND TRANSFER TO MILK by A. L. Mullen, A. A. MoghissiJ J. C. Wawerna? B. A. Mitchell, E. W. Bretthauer, and R. E. Stanley Environmental Monitoring and Support Laboratory Las Vegas, Nevada 89114 ^Present Address Office of Interdisciplinary Programs Georgia Institute of Technology Atlanta, Georgia 30332 2Present Address Criminalistics Laboratory Las Vegas Metropolitan Police Department Las Vegas, Nevada 89106 ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S. ENVIRONMENTAL PROTECTION AGENCY LAS VEGAS, NEVADA 89114 ------- DISCLAIMER This report has been reviewed by the Environmental Monitoring and Support Laboratory-Las Vegas, U.S. Environmental Protection Agency, and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ------- FOREWORD Protection of the environment requires effective regulatory actions which are based on sound technical and scientific information. This information must include the quantitative description and linking of pollutant sources, trans- port mechanisms, interactions, and resulting effects on man and his environ- ment. Because of the complexities involved, assessment of specified pollutants in the environment requires a total systems approach which transcends the media of air, water, and land. The Environmental Monitoring and Support Laboratory- Las Vegas contributes to the formation and enhancement of a sound integrated monitoring'data base through multidisciplinary, multimedia programs designed to: • develop and optimize sustems and strategies for moni- toring pollutants and their impact on the environment demonstrate new monitoring systems and technologies by applying them to fulfill special monitoring needs of the Agency's operating programs This report presents the results of an investigation designed to evaluate the short- and long-term behavior of tritium in beef animals and dairy cows with emphasis on the resultant hazard to humans consuming meat and dairy products. It is hoped that this information will be of use to those individ- uals who must assess hazards from accidental release of tritium, designers of nuclear waste processing facilities and those responsible for nuclear reactor site selection. Additional information regarding this study may be obtained by contacting the Exposure Dose Assessment Branch of the Monitoring Systems Research and Development Division. Georg'e &. Morgan^ Director Environmental Monitoring and Support Laboratory Las Vegas iii ------- ABSTRACT Eight lactating dairy cows and three steers received a single oral ad- ministration of tritiated water. Milk and blood from the lactating cows and blood from the steers were periodically collected and analyzed for tritium content. The tritium content of whole milk decreased with time giving a curve expressed as a three component exponential which yielded half-times of 3.04 d 0.09, 11.1 ± 2.58, and >120 days. Tritium in the blood serum of steers de- creased with half-lives of 4.05 ± 0.21 and 40.4 ± 9.82 days. Additional study of the milk to assess tritium incorporation in the various fractions showed half-times of 2.93 ± 0.14 and 43.7 ± 4.28 days for milk serum; 2.08 ± 0.56 and >50 days for milk protein; and 3.28 ± 0.35 and 60.7 ± 43 days for butterfat. IV ------- CONTENTS Page FOREWORD iii ABSTRACT iv LIST OF FIGURES vi LIST OF TABLES vii ACKNOWLEDGMENTS vi i i INTRODUCTION 1 CONCLUSIONS 2 RECOMMENDATIONS 2 METHODS 2 RESULTS 4 DISCUSSION 14 REFERENCES 15 ------- LIST OF FIGURES Number 1. Average concentration of tritium in whole milk following a single oral administration of 100 mCi of tritiated water to four dairy cows. 2. Average concentration of tritium in milk components following a single oral administration of 200 mCi of tritiated water to four dairy cows. 3. Average concentration of tritium in blood serum following a single oral administration of triti- ated water to dairy cows and beef animals. 4. Average concentration of tritium in blood serum following a single oral administration of 65 mCi of tritiated water to three beef cattle. VI ------- LIST OF TABLES Number Page 1. Tritium Concentration in yCi/1 of Water Or Its 5 Equivalent in Whole Milk and Components Following A Single Oral Administration of 100 millicurie of Tritiated Water 2. Tritium Concentration in yCi/1 of Water Or Its Equiv- 7 alent in Milk Components Following A Single Oral Administration of 200 millicurie of Tritiated Water 3. Tritium Concentration in Blood Serum of Dairy Cows 10 Following A Single Oral Administration of 100 millicurie of Tritiated Water 4. Tritium Concentration in Blood Serum of Dairy Cows 10 Following A Single Oral Administration of 200 millicurie of Tritiated Water 5. Tritium Concentration in Blood Serum of Beef Cattle 12 Following A Single Oral Administration of 65 millicurie of Tritiated Water VII ------- ACKNOWLEDGMENTS The authors wish to express their appreciation to S. R. Lloyd, B. Johnson, L. Dana, J. Titus, R. Hope, and the other personnel of the U.S. Environmental Protection Agency Experimental Farm for their assistance during the experi- mental phase of this study, and to R. R. Kinnison and P. Fort for the sta- tistical analysis of the data. vnx ------- INTRODUCTION As an isotope of hydrogen, tritium is incorporated into essentially all components of biological systems. Tritium is produced as a result of nuclear fusion and, to a certain extent, nuclear fission explosives, including those used in the nuclear stimulation of natural gas formations (Moghissi and Carter, 1973). Tritium is also produced in all nuclear power reactors both as fission and activation products. Due to the presence of large quantities of tritium in the initial stages of operation, it is expected that tritium production in fusion reactors will be substantially higher than in fission reactors. Because of the problems associated with separation and disposal of tritium from nuclear waste, dilution is presently used as the disposal method for this radionuclide. However, it is expected that in the foreseeable future tritium will be sepa- rated and contained. Cow"s milk is recognized as one of the major routes of the intake of radioactive pollutants into the human body. Attempts to study tritium metab- olism in bovines have been numerous. Black et al.,(1964) studied the turnover rate of tritium in a total of 17 lactating and nonlactating cattle. They observed no difference in the turnover rate of tritium in body water (T ) in nonlactating as compared to lactating animals. Their T values ranged rrom 2.8 to 4.1 days with an average of 3.5 days. However, Aschbacher et al., (1965) studied a number of physiological parameters in dairy cows using four lactating and two nonlactating animals. They observed T values for tritium of 3.0 days for lactating and 5.2 days for nonlactating cows. The incorporation of tritium into the organic fraction of milk subsequent to the intake of tritiated food has also been repeatedly studied. Lubran and Corsini (1960) and Glascock and Wright (1962) studied tritium transfer into certain components of milk subsequent to the intake of tritiated triglycerides. These authors clearly showed the importance of considering the chemical form of tritium intake when determining the composition of tritiated compounds in milk. In a series of papers Kirchmann et al., studied tritium behavior in dairy cows (Kirchmann et al., 1969; Kirchmann et al., 1971; and Van den Hoek and Kirch- mann, 1971). These authors observed values of 3 to 5 days for the T of tritium in lactating cows. They also observed an increase of tritium concen- tration in milk solids if tritiated grass was fed to the cows when compared to intake as tritiated water. Values for the biological half-life of tritium in milk solids were compared to those in body water. Potter et al.,(1972) also studied tritium behavior using one dairy cow. They observed a two-component exponential excretion rate corresponding to half- lives of 3.1 and 40 days, respectively. They also showed a substantial incor- poration of tritium into the organic component of the milk. Due to concern over the continued release of large quantities of tritium ------- into the environment and because of the lack of consistent information on the behavior of tritium in components of man's food chain, this study was under- taken in dairy cows and beef animals to evaluate both the short- and long-term behavior in one of the more significant sources of exposure. CONCLUSIONS 1. Little significant difference was noted in the rate of tritium in body water turnover in lactating dairy cows versus steers. 2. Although whole milk is the major route of exposure of humans consum- ing tritiated dairy products, additional information on the turnover rate of tritium in milk solids is necessary before an accurate determination of radi- ation dose can be made. RECOMMENDATIONS In the event of contamination of agricultural areas with tritium, the potential hazard to humans ingesting tritiated dairy products must be carefully evaluated. As more knowledge is gained of the metabolism of specific tritiated compounds, it may be found that incorporation of tritium into nucleic acid, via deoxyribonucleic acid (DNA), may influence all aspects of biological activity and have greater effect than previously ascribed. Further studies with a biological receptor are necessary to accurately estimate exposure/dose result- ing from the consumption of tritium. METHODS These studies were carried out at the Nevada Test Site on the experimental farm operated by the U.S. Environmental Protection Agency for the U.S. Energy Research and Development Administration. The dairy animals selected for the study were either Holstein or Jersey cows 3 to 9 years of age, were in their 30th to 100th day of lactation, and were producing 20 to 31 kilograms (kg) of milk per day. The beef animals were 4- to 6-year-old Hereford steers. All the animals were allowed free access to water and alfalfa hay. In addition, the dairy cows received a pelleted commercial dairy feed containing 16% protein. The cows were milked with a milking machine, and blood samples from the cows and steers were taken by jugular venipuncture. Tritiated water was administered to each animal following collection of milk and/or blood for background activity determinations. The tritiated water was placed in gelatin capsules containing starch and administered orally using a balling gun. Milk samples were collected twice daily from the dairy animals, and blood samples ------- were collected from all animals hourly for the first 12 hours and then at longer intervals during the remainder of the project. Milk samples were stored in 4-liter polyethylene containers to which 10 milliliters (ml) of formaldehyde was added to retard spoilage. Blood samples were centrifuged and the serum portion was removed for tritium analysis. All samples were processed for analysis within 24 hours. This study was conducted as a series of three consecutive experiments. The milk transfer portion of the study utilized two groups of four lactating dairy cows (three Hoisteins and one Jersey) in each group. Each of the cows was given a single 100-millicurie(mCi) dose of tritiated water. The milk from this group was analyzed for tritium activity in the whole milk. The total activity in the milk was determined directly by liquid scin- tillation counting utilizing an internal standard. The scintillation liquid consisted of p-xylene containing 7 grams (g) of 2,5-diphenyloxazole (PPO) and 1.5 g of bis-(o-methylstyrylbenzene) (bis-MSB) per liter mixed with Triton N101 (Rohm and-Haas, Philadelphia, Pennsylvania) in a volume ratio of 2:1. This mixture could incorporate up to 10 ml of water or milk in a 25-ml vial (Lieber- man and Moghissi, 1970). Counting efficiency was determined by using an inter- nal standard with identical system properties (Moghissi and Carter, 1968). The whole milk was mixed thoroughly and two aliquots of each sample were prepared with one of them having a known quantity of tritium added. The second group of dairy cows received 200 mCi of encapsulated tritiated water each. Milk from these cows was separated into milk, serum, butterfat, and protein fractions and the tritium activity of each fraction was determined. Milk serum was separated by the addition of trichloracetic acid (15 g/100 ml). The presence of about 100 milligrams(mg) of hydrogen ions per gram in the acid was regarded as acceptable and within expected errors. The mixture was allowed to stand for about 30 minutes and filtered, and the filtrate was distilled. The tritium activity in the distillate was determined by liquid scintillation counting. Cream was separated from the milk by cryogenic centrifugation. Fat was separated from cream using heat and 100 ml of Triton and 25 grams of hexameta- phosphate per liter of cream as described by Horowitz (1970). The purity of the fat was checked using the Babcock test (Hausler, 1972). The proteins were separated from the milk serum and dried for several days in an oven at a temperature of 40° C. The dried protein was weighed and the organically bound tritium separated by combustion (oxidation) in a Parr bomb. After the water of combustion was collected, its tritium content was determined by liquid scintillation counting (Moghissi et al./ 1975). After installation of a large scale azeotropic distillation system (Mo- ghissi et al. , 1973), the protein and serum separation was repeated using this procedure and the results indicated a reasonable agreement between the two methods. In order to determine the difference in blood tritium levels between ------- lactating and nonlactating animals, three Hereford steers were each adminis- tered 65 mCi of tritiated water in the same manner as the dairy cows. Blood was collected from all three groups of cows and the serum portion analyzed by direct liquid scintillation counting. The data were analyzed by performing a nonlinear least squares regression on a sequence of successively more complex mathematical models in the class of sums of exponential terms functions. The best of the regression functions was chosen using the general linear hypothesis test and half-lives were calculated from the exponential coefficients of the best-fit regression. RESULTS The individual values for whole milk are shown in Table 1 for the four cows receiving 100 mCi of tritiated water. The half-lives for tritium transfer to whole milk are presented graphically in Figure 1. This figure represents the mean of the whole milk concentration values listed in Table 1. Tritium in the whole milk of cows appears to decrease with a 3.04 ± 0.09-day half-life during the 20 days following oral administration of 100 mCi of tritiated water. The transfer of tritium to milk then changed to exhibit a slope with a half- time of 11.1 ± 2.58 days followed by a much longer half-time of >120 days. In order to determine the biological half-time of tritium in the different milk components, a second experiment was conducted in which each of the dairy cows received 200 mCi of tritiated water. The results of this experiment are shown in Table 2 and Figure 2. The initial half-times shown by the milk com- ponents indicate little difference between the milk serum and the butterfat with half-times of 2.93 ± 0.14 days and 3.28 ± 0.35 days, respectively. The protein fraction of the milk exhibited a considerably shorter half-time of 2.08 ± 0.56 days. The longer half-time portion of the curves showed the normal variance of results with time and lower activity. The shortest half- time was indicated by the tritium activity in the serum portion of the milk. This was found to be 43.7 ± 4.28 days. The results of the protein analysis showed that a relatively constant incorporation of tritium into protein oc- curred during the 2nd and 3rd months after administration, followed by a half- time of >50 days for the remainder of the study. The incorporation of tritium into butterfat decreased with a longer half-time of 60.7 ± 43.0 days and then increased during the latter part of the study. The blood levels of tritium were similar for both the lactating dairy cows and the beef animals during the first 12 hours after administration as shown in Tables 3 and 4 and Figure 3. The tritium levels in blood serum from beef cattle shown in Table 5 were averaged and the half-lives determined to be 4.05 ± 0.21 days and 40.36 ± 9.82 days as shown in Figure 4. ------- TABLE 1. TRITIUM CONCENTRATION IN yCi/1 OF WATER OR ITS EQUIVALENT IN WHOLE MILK AND COMPONENTS FOLLOWING A SINGLE ORAL ADMINISTRATION OF 100 mCi OF TRITIATED WATER MILK r-POSt 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 16 18 20 22 24 H-21 251 209 178 156 128 98.1 80.2 63.2 51.6 41.2 33.2 28.0 21.9 16.6 13.2 9.33 5.30 3.76 1.78 1.40 H-90 283 277 218 189 158 124 105 86.5 69.4 49.1 48.1 40.7 31.3 25.0 20.4 13.3 8.64 6.00 2.90 2.45 H-171 344 376 332 274 244 176 138 116 98.8 69.2 57.6 51.9 39.0 30.9 23.6 16.2 9.94 6.46 3.50 2.00 J-175 428 405 314 276 232 182 142 116 103 76.8 63.2 54.6 41.0 35.2 27.1 17.6 10.4 6.76 3.20 2.29 Day-Post 26 28 31 34 37 40 43 49 56 63 70 77 84 91 98 105 112 119 126 154 161 H-21 0.929 0.792 0.378 0.202 0.132 0.888 0.105 0.040 0.030 0.038 0.028 0.029 0.027 0.030 0.030 0.024 0.029 0.025 0.051 0.069 0.054 H-90 1.62 1.10 0.601 0.333 0.223 0.122 0.139 0.058 0.040 0.042 0.038 0.045 0.043 0.033 H-171 1.64 1.10 0.590 0.376 0.294 0.158 0.181 0.068 0.065 0.075 0.888 J-175 1.71 1.05 0.48 0.330 0.210 0.120 0.160 0.076 0.057 0.071 0.063 0.045 0.043 0.047 0.038 0.033 0.030 0.030 0.060 0.069 0.029 ------- 10 0) U a. 10 -5 10 20 40 60 DAYS 80 100 Figure 1. Average concentration of tritium in whole milk following a single oral administration of 100 mCi of tritiated water to four dairy cows. ------- TABLE 2. TRITIUM CONCENTRATION IN yCi/1 OF WATER OR ITS EQUIVALENT IN MILK COMPONENTS FOLLOWING A SINGLE ORAL ADMINISTRATION OF 200 mCi OF TRITIATED WATER d 0.3 1 1.4 2 2.4 3 4 5 6 7 9 11 14 16 22 24 29 31 37 45 52 59 65 72 79 86 93 100 107 114 120 Serum ' H*-16 181 354 261 206 188 142 160 139 91.8 72.7 39.0 22.0 6.98 2.97 0.385 0.225 0.217 0.098 0.027 0.020 0.034 0.067 0.013 0.011 0.010 0.010 0.006 0.003 0.004 0.009 H-132 144 403 284 290 242 267 244 169 153 95.0 54.0 27.0 17.2 4.45 3.04 1.27 0.720 0.091 0.019 0.016 0.039 0.023 0.022 0.006 0.004 0.003 0.057 0.063 H-135 J**-175 322 300 426 235 358 206 315 210 314 237 310 203 248 147 "180 124 145 75.0 43.4 26.2 22.5 20.7 16.0 8.00 2.19 1.44 1.85 0.770 0.750 0.450 0.300 0.053 0.042 0.039 0.030 0.023 0.019 0.090 0.025 0.026 0.013 0.016 0.015 0.013 0.009 0.010 0.008 0.014 0.007 0.019 0.003 0.005 0.005 0.009 0.010 Protein H-16 73 159 145 123 114 95.1 69.6 50.6 44.7 35.3 15.2 4.38 7.03 3.27 2.72 0.956s 1.04 1.29 0.407 0.426 0.584 0.678 0.243 0.499 0.154 0.119 0.103 0.043 0.072 0.060 0.048 H-132 112 94.4 151 152 119 43.0 16.1 12.1 4.42 2.56 0.717 0.664 1.14 1.10 0.684 0.626 1.09 0.866 1.60 0.480 0.252 0.444 H-135 245 138 — .. 154 106 54.5 47.0 10.37 9.78 8.29 3.52 4.95 1.43 1.32 0.970 0.588 0.653 0.481 0.452 0.884 0.583 0.118 0.057 0.086 0.132 J-175 98.8 135 283 177 118 102 94.5 25.0 3.26 2.52 2.55 1.49 1.05 0.910 1.82 2.06 0.822 1.05 1.08 0.596 0.099 0.056 0.082 0.076 0.114 Fat H-16 24.0 __— 78.9 72.0 87.6 75.5 37.7 26.5 14.7 6.86 4.32 2.42 1.66 0.429 0.336 0.151 0.085 0.061 0.065 0.033 0.032 0.030 0.026 0.047 0.040 0.090 0.023 H-132 110 100 70 9 93.5 65.2 53.1 39.0 28.7 16.6 12.0 6.79 2.58 1.60 0.687 0.178 0.060 0.086 0.153 0.059 0.052 0.227 0.258 0.396 0.421 H-135 17.9 83 8 -it. o 75.6 56.3 42.0 33.5 22.6 20.2 9.39 5.96 1.66 0.955 0.510 0.162 0.093 0.066 0.052 0.066 0.051 0.034 0.033 0.038 0.154 0.149 0.038 0.025 11 9 72 i 68.5 60.5 53.8 39.9 37.2 23.8 8.99 4.40 1.04 0.661 0.398 0.189 0.673 0.078 0.054 0.055 0.070 0.039 0.043 0.048 0.053 0.111 0.080 0.150 0.037 ------- TABLE 2. TRITIUM CONCENTRATION IN uCi/1 OF WATER OR ITS EQUIVALENT IN MILK COMPONENTS FOLLOWING A SINGLE ORAL ADMINISTRATION OF 200 mCi OF TRITIATED WATER (Continued) Time d 128 135 137 142 144 149 156 158 163 177 185 191 199 205 215 226 233 240 247 254 261 269 275 282 H*-16 0.002 0.006 0.004 0.017 0.011 0.010 0.010 0.002 0.005 0.003 0.002 0.003 0.005 0.004 0.002 0.001 Serum H-132 H-135 0.008 0.004 0.003 0.003 0.002 0.006 0.004 0.005 0.003 0.002 0.002 0.003 J**-175 Protein H-16 ' 0.041 0.057 0.054 0.047 0.041 0.033 0.017 0.013 0.016 0.039 0.029 0.024 0.030 0.039 0.0278 0.0207 H-132 H-135 0.101 0.101 0.088 0.066 0.035 0.026 0.035 0.051 0.054 0.041 0.023 0.0297 0.0315 0.026 0.015 Fat J-175 0.141 0.094 0.071 0.034 0.032 0.017 0.026 0.026 0.022 0.032 0.043 0.017 0.024 0.013 0.017 0.016 H-16 0.011 0.028 0.048 0.022 0.021 0.022 0.020 0.014 0.015 0.016 0.021 0.016 H-132 H-135 0.022 0.022 0.034 0.026 0.031 0.026 0.019 0.013 0.012 0.045 0.016 0.024 0.099 J-175 0.034 0.036 0.021 0.024 0.017 0.013 0.009 0.009 0.014 0.023 0.028 0.023 0.014 0.035 0.057 0.064 0.045 0.036 0.018 0.017 00 *H = Holstein **J » Jersey ------- 10 10 10 u 10 a. -2 10 -3 10 o MILK SERUM' T|.J =2.93±0.14 d e PROTEIN :Tb= 2.08±0.56d • BUTTERFAT: Tb=3.28±0.35d ©PROTEIN: • BUTTERFAT: T^60.69±43.04 d OMILK SERUM: T^=43.69±4.28d o o 20 40 60 80 100 120 DAYS 140 160 180 200 220 Figure 2. Average concentration of tritium in milk components following a single oral administration of 200 mCi of tritiated water to four dairy cows. ------- TABLE 3. TRITIUM CONCENTRATION IN BLOOD SERUM OF DAIRY COWS FOLLOWING A SINGLE ORAL ADMINISTRATION OF 100 mCi OF TRITIATED WATER Time h 1 2 3 4 5 6 7 8 9 10 H-21 yci/i 124 232 259 250 238 242 248 335 229 H-90 yCi/1 250 318 303 330 298 295 305 294 291 279 H-171 yCi/1 136 326 410 426 412 430 428 427 437 404 J-175 yCi/1 112 374 406 414 417 411 440 441 410 423 TABLE 4. TRITIUM CONCENTRATION IN BLOOD SERUM OF DAIRY COWS FOLLOWING A SINGLE ORAL ADMINISTRATION OF 200 mCi OF TRITIATED WATER Time d H-116 yci/i H-132 yCi/1 H-135 yci/i J-175 yci/i 1/24 2/24 3/24 4/24 5/24 6/24 7/24 8/24 9/24 10/24 11/24 12/24 2 16 24 173 313 308 354 378 329 369 356 372 247 331 343 38. 2.98 0.629 240 320 355 403 391 418 406 397 384 365 377 401 16.2 2.87 150 197 306 334 340 394 359 359 362 340 362 375 58.3 9.93 2.74 272 425 505 437 507 495 488 491 457 449 507 492 87.6 8.70 1.52 10 ------- 10 QC LU CO Q O 2 i «o 10 (lOOmCi) 1 234 5 67 89 10 11 (200mCi) U a. 10 1 23456 89 10 11 (65mCi) Figure 3. 123456789 10 11 HOURS Average concentration of tritium in blood serum following a single oral administration of tritiated water to dairy cows and beef animals. 11 ------- TABLE 5. TRITIUM CONCENTRATION IN BLOOD SERUM OF BEEF CATTLE FOLLOWING A SINGLE ORAL ADMINISTRATION OF 65 mCi OF TRITIATED WATER Time d 1/24 2/24 3/24 4/24 5/24 6/24 7/24 8/24 9/24 10/24 11/24 12/24 1 2 8 16 23 28 30 65 72 79 86 93 106 114 121 128 135 139 142 144 149 156 158 163 Cow #662 VCt /I ___ 127 165 174 181 215 218 203 184 206 202 210 208 135 110 28.3 11.4 5.45 1.92 0.071 0.064 0.056 0.044 0.028 0.065 0.029 0.038 0.028 0.023 0.015 0.018 0.020 0.009 0.015 0.010 Cow #669 UCi/1 ___ 118 126 191 219 223 256 239 239 255 240 265 221 122 144 37.3 12.1 5.51 2.09 0.096 0.063 0.076 0.039 0.078 0.067 0.023 0.030 0.021 0.018 0.018 0.018 0.017 0.022 0.011 0.021 0.009 Cow #675 yCi/1 72 194 165 184 194 202 216 206 207 212 214 215 216 173 105 11.2 4.84 2.21 0.065 0.075 0.047 0.031 0.030 0.030 0.020 0.018 0.025 0.017 0.022 0.045 0.084 0.012 0.010 0.009 12 ------- 10 O O g GO ^ 0 *! 10 'a. U) -1 10 =4.05 ± 0.21 d 246 HOURS 8 10 12 20 40 60 DAYS 80 100 120 Figure 4. Average concentration of tritium in blood serum following a single oral administration of 65 mCi of tritiated water to three beef cattle. ------- DISCUSSION Results of this study show that the turnover rate of tritium in the body- water pool of lactating dairy cows is not appreciably different from nonlac- tating beef animals at 3 days and 4 days, respectively. The tritium turnover rate 60 days after ingestion showed even less difference, 44 days for lactating dairy cows and 40 days for beef animals. This result is similar to that noted by Black et al.,(1964) who found the average half-life for body water in lactating cows to be 3.54 ± 0.10 days and that in nonlactating cattle to be 3.40 ± 0.18 days over the course of a 15-day study following intravenously administered tritiated water to dairy cows and steers. The greater differences in T noted by Aschbacher et al.,(1965) 3 days for nonlactating and 5 days for lactating cows may have been due to the use of fat, nonlactating, nonpregnant cows/ whereas the present study and Black's study utilized steers. There may be differences in the rate of tritium turnover between the two experimental groups due to the differences in formation and turnover of muscle by steers versus adipose tissue by nonlactating cows. The difference in the rate of incorporation of tritium into proteins as compared to its incorporation into non-exchangeable portions to form stable carbon-tritium lipid bonds is indicated by the shorter T of 2.08 and about 50 days for protein in milk as compared to T of 3.28 and 61 days for butterfat. The concentration of tritium in fat was noted by Schirch and Mason (1963) while investigating concentrations in humans chronically exposed to tritium. Moyer and DuVigneaud (1972) found the appearance of tritium in protein was maximal after 1 day following intravenous administration to rats, but fell to about 20 percent of the peak level by day 5. Tritium incorporated into serum fatty acids became maximal during day 1 and remained relatively constant until the 12th day, whereas, the appearance of tritium in serum cholesterol increased over a period of 12 days. It would appear that the complexity of the chemical transformations of tritium (Smith and Taylor, 1969) does not allow a simple conclusion to be drawn concerning the fate of ingested tritium. The relatively long half-time of >120 days for the transfer of tritium to whole milk indicates that milk may be the major contributor to the radiation dose of humans consuming tritium-contaminated dairy products. However, al- though milk solids constitute only 1/10 of the total volume of milk, the radiation dose resulting from consumption of butterfat and cottage cheese may exceed that from whole milk due to the longer biological half-lives and in- corporation of tritium in fat, protein, and carbohydrates. It will be neces- sary to establish the turnover of tritiated milk solids in humans before it will be possible to accurately estimate the radiation dose resulting from the consumption of tritium-contaminated dairy products. 14 ------- REFERENCES Aschbacher, P. W., T. H. Kamal and R. G. Cragle. 1965. "Total body water estimations in dairy cattle using tritiated water." J. Animal Sci. 24:430. Black, A. L., N. F. Baker, J. C. Hartley, T. E. Chapman and R. W. Philips. 1964. "Water turnover in cattle." Sci. 144:876. Glascock, R. F., and E. W. Wright. 1962. "Some Examples of the Use of Radio- isotopes in Biochemistry." Uses of Radioisotopes In Animal Biology and the Medical Sciences. Vol. 1. Academic Press, New York. p. 185. Hausler, W. J., Jr., ed. 1972. Standard Methods for the Examination of Dairy Products. Am. Pub. Health. Assoc. Washington, D.C. p. 225. Horowitz, W., ed. 1970. Official Methods of Analysis of the Association of Official Analytical Chemists. Assoc. of Official Anal. Chem. , Washington, D.C. 1015 pp. Kirchmann, R., A. Lafontaine, J. Van den Hoek and G. Koch. 1969. "Transfer and distribution of tritium among the main components of milk produced by cows having ingested contaminated water." Cpmp. Rend. Soc. Biol. 63;1459. Kirchmann, R., J. Van den Hoek and A. Lafontaine. 1971. "Transfer et incor- poration du tritium dans les constituants de 1'herbe et du lait en condi- tions naturelles." Health Phys. 2^:61. July, 1971. Lieberman, R., and A. A. Moghissi. 1970. "Low-level counting by liquid scin- tillation. II. Applications of emulsions in tritium counting." Int. J. Appl. Radiat. Isotopes. 21:319. Lubran, M., and G. Corsini. 1960. Mineiva Nucl. 4_:130. Moghissi, A. A., and M. W. Carter. 1968. "International standard with identi- cal system properties for determination of liquid scintillation counting efficiency." Anal. Chem. 40;812. Moghissi, A. A., and M. W. Carter. 1973. Tritium. Messenger Graphics, Phoenix, Arizona, p. 3277. Moghissi, A. A., E. W. Bretthauer and E. H. Compton. 1973. "Separation of water from biological and environmental samples for tritium analysis." Anal. Chem. 45:1565. 15 ------- Moghissi, A. A., E. W. Bretthauer, E. L. Whittaker and D. N. McNeils. 1975. "Oxygen bomb combustion of environmental and biological samples for tritum analysis." Inter. J. Appl. Isotopes. Moyer, A. W., and V. DuVigneaud. 1972. J. Biol. Ghent. 143;373. Potter, G. D., G. M. Vattuone and D. R. Mclntyre. 1972. "Metabolism of triti- ated water in the dairy cow." Health Phys. 22;405. Schirch, L. v., and M. Mason. 1963. J. Biol. Chem. 238:1032. Smith, T. E., and R. T. Taylor. 1969. "Incorporation of tritium from triti- ated water into carbohydrates, lipids, and nucleic acids." UCRL-50781. 24 p. Van den Hoek, J., and R. Kirchmann. 1971. Radioecology Applied to the Pro- tection of Man and His Environment. Comm. of European Communities, p. 1. 16 *U.S. GOVERNMENT PRINTING OFFICE: 1977-784^60 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing) 1. REPORT NO. EPA-600/3-77-076 3. RECIPIENT'S ACCESSION NO. 4. TITLE AND SUBTITLE TRITIUM RETENTION BY COWS AND STEERS AND TRANSFER TO MILK 5. REPORT DATE June 1977 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) A. L. Mullen, A. A. Moghissi, J. C. Wawerna, B. A. Mitchell, E. W. Bretthauer and R. E. Stanley 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS Environmental Monitoring and Support Laboratory Office of Research and Development U.S. Environmental Protection Agency Las Vegas, NV 89114 10. PROGRAM ELEMENT NO. 1FA628 11. CONTRACT/GRANT NO. 12. SPONSORING AGENCY NAME AND ADDRESS U.S. Environmental Protection Agency-Las Vegas, NV Office of Research and Development Environmental Monitoring and Support Laboratory Las Vegas, NV 89114 13. TYPE OF REPORT AND PERIOD COVERED FINAL FY70-71 14. SPONSORING AGENCY CODE EPA/600/07 15. SUPPLEMENTARY NOTES 16. ABSTRACT Eight lactating dairy cows and three steers received a single oral ad- ministration of tritiated water. Milk and blood from the lactating cows and blood from the steers were periodically collected and analyzed for tritium content. / The tritium content of whole milk decreased with time giving a curve expressed as a three-component exponential which yielded half-times of 3.04 ± 0.09, 11.1 ± 2.58, and >120 days. Tritium in the blood serum of steers de- creased with half-lives of 4.05 ± 0.21 and 40.4 ± 9.82 days. Additional study of the milk to assess tritium incorporation in the various fractions showed half-times of 2.93 ± 0.14 and 43.7 ± 4.28 days for milk serum; 2.08 ± 0.56 and >50 days for milk protein; and 3.28 ± 0.35 and 60.7 ± 43 days for butterfat. O££CP.:PTO?!£ KEY WORDS AND DOCUMENT ANALYSIS Jb.lDENTIFiERE/OPEN ENDED TERMS !C. COSAT! I >dd/Group Beef Biochemistry Cattle Dairy Cows DISTRIBUTION STATEMENT RELEASE TO PUBLIC Dairy Products Isotopes Radiation chemistry Radiobiology Tritium j Tritium retention j Tritium transfer '•. Nevada Test Site 19. SECURITY CLASS (This Report) UNCLASSIFIED I 02E j 06A | 06H j 06R ' 07E 18B aiTNoTo F~PAG'ES~ 28 20. SECURITY CLASS (This page) UNCLASSIFIED 22. PRICE EPA Form 2220-1 (9-73) ------- |