Plutonium Burdens in People Living Around the Rocky Flats Plant

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United Stales Environmental Monttorcng Systems Environmental Protection Laboratory /-Ur(c3F& lfiy Research and Development EPA-600/S4-62-069 Mar 1963 t 4 t + I GEPA Project Summary Plutonium Burdens in People Living Around the Rocky Flats John C. Cobb, B. Charles Eversole, Phllip G. Archer, Roxanna Taggart, and A study was conductod t o find out whether tho tirruo of pooplo who had livod n w r to or downwind from Rocky Flru Nuclorr Worponr Facili*/ in Cole than tho tirruo of pooplo living forthor wry. In addition t o tirruo rnrlyrar. invortigators obtrinod information on age; sex smoking. occupationrl, and roridonce history, rnd causes of doath. Tho tirruo rr mpl or woro colloctod from autopsy cases during tho period 1976ratio in tho tirruo of pooplo who had not boon occupationrlly oxporod and who diod in Colorodo ovor that th rwy oar Srmolor wore colloctod from human groator than in tha lung. There obrervationr rofioct tho longer retention time of plutonium in tho livor. Rosults indicrtod thrt sex, age. and smoking hi r toy war. rll more strongly rdatod t o plutonium burden in the liver than dirtrnco from Rocky Flats. Additionally, roruhs show thrt a male at the avorrgo age of 65.4 yoars, as in this study. would h 8 V O 1.5 times more Plutonium in his liver if ho had been an 80prckyoar rmokor than if he had been a 8t the average sge, the ratio would have boon 1.3 times mor0 plutonium. Tho data on concentration rnd total lung burdon r n d on tho Pu-2401239 ratio in lung and liver ruggost that rolorror of plutonium from Rocky Flats comributod onlv 8 small amount to nonrmokor. For 8 SO-p8Ckyeaf smoker aroas: Are8 A -- up t o 25 k m from Rocky Flrtr; Aror B -- botwoon 26 and 60 k m from Rocky Flats; m d Aror C -- rtl of Colorrdo outaido 8 M) km rrdiur of Rocky F l m and oan of tho Cominontd With plutonium conc.rrtr.tionr in lung rblo, r rtopwiro. muttiplo rogrorrion indopndont vrrirblor of ago. p8ckyorrs Tho Pu-240/239ratios in tho livor lung, and tho total amount of plutonium burdon in tho livor was about 10 timr plutonium burdens in humrnr oast r n d southorst of tho sit., ss the total amount *McClerran Cenrral laboratory. currently 81 Lor Alamor National Laboratory of plutonium in humin tirruor was small rnd not vory diltoront from th8t o b 8.N.d by othor rosaarcherr who have rtudiod poplo from othor locations in thit Pmject Summary was develtorins Systems Labomtory, l a s Vegas NV. to rnnouncr koy findings o f the rorrarth projoct that is fully docummto d in a separate report of the same title tion at back). At the request of Senator Haskell of Colorado, a study was conducted to find out whether the tissue of people who had lived near to or downwind from Rocky

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Flats contained more plutonium than the tissue of people living fanher away. For those deceased who were autopsied and who had lived in eastern Colorado a t least five years. information was collected on age: sex; smoking, residential. and occupational history: cause of death; and presence of pulmonary or liver disease. Samples of lung. liver, gonads. adrenals and rib were collected for plutonium analysis. The isotopes for which the 240 to Pu-239. Plutonium in tissue from Colorado residents can arise from both worldwide fallout and from local sources such as the Rocky Flats plant near The amount of global atmospheric plutonium varies from year to year, depending on the types of atomic bombs being tested; however, the bulk of Plutonium from American and Russian nuclear test programs fell from the atmosphere by 1968. Subsequent measurements show that the amount of plutonium has been declining ever since. A possible source of plutonium in Colorado was a September 1957 fire a t the Rocky Flats plant which released plutonium-seeded smoke that was swept southward by a prevailing wind (Hammond. 1971). Another release occurred between January and June of 1968 and during 1969, when drums containing oil contaminated with plutonium were being moved. Several were damaged, releasing into the soil plutonium particles that were then resuspended in the air during high winds (Seed. 1971). These are two known acute releases from Rocky Flats; others could have occurred. and a continual, very low level was probably released from normal operations. Several other possible sources of plute nium exist in Colorado. Until September 1980, there had been 565 tests a t the nuclear test site in Nevada, of which 140 tests produced measurable amounts of radiation outside site boundaries (Hicks, 1981). Also, since 1968. the Peoples' Republic of China has conducted about 20 nuclear weapons tests that added to the global plutonium inventory. Since the Chinese tests were relatively recent and the retention half-time of plutonium in lung tissue is 500 days, a related contribution of plutonium to the lungs of people recently living in Colorado could exist Atmospheric transport and diffusion Processes would have dispersed the nuclear test site and Chinese debris clouds before they reached Colorado. so that plutonium loads would have been randomly distributed in the soil of the nium released by the Rocky Flats plant would be concentrated near the facility. In addition, Rocky Flats plutonium has an isotope ratio (240/239) of 0.06 compared to a worldwide fallout isotope ratio of 0.1 8. so that measurement of the Pu240/239 ratio in a sample permits an estimate of the Rocky Flats contribution to the sample. The highest known concentration of plutonium in the air in Colorado occurred during the 1957 fire. The relatively high level a t that time was probably of short duration as compared to the lower, more sustained levels associated with the oil drum spills during 1968 and 1969. Many measurements of soil plutonium concentration levels have been made around the perimeter of Rocky Flats. They show a much higher concentration of plutonium east and southeast of the site than at distant locations. This is probably due to prevailing winds that blow from west to east Relatively little soil contamination was found south. west. nonhwest, or northeast of the site. If the fire and spills a t Rocky Flats between 1957 and 1968-1969 caused plutonium exposure to local residents that was excessive in comparison to plutonium exposure from worldwide fallout. then an increased concentration of plutonium in tissue could be expected now among those who lived downwind from Rocky Flats during that period. This could be detected by a low ratio of Pu240 to Pu-239 in lung tissue, where the The usefulness of the study was not limited to the questions about Rocky Flats but included inquiry into the relationship between smoking history, age, sex. cause of death, and plutonium concentrations in liver and lung. Methods and Procedures The study was coordinated by the U.S. Environmental Protection Agency (EPA), Environmental Monitoring Systems Lab oratory. b s Vegas. Nevada, and conducted by the University of Colorado Medical Center and the Colorado State Health Department Fifteen hospitals in Denver, Pueblo. and Colorado Springs collected tissue samples for the study. Samples were collected from human autopsies in each of three collection areas: Area A -- up to 25 km from Rocky Flats; Area 6 -- between 25 and 50 km from Rocky Flats; and Area C -all of Colorado outside a 50 krn radius of Rocky Flats and east of the Continental Divide A total of 51 9 samples were collected. 147 from Area A 182 from Area 8.and 190 came mostly from heavily poDulated areas around Denver, Colorado Springs, and Pueblo, with scattered cases from a l l of eastern Colorado. Only three samples came from places within l o km of Rocky Flats, because the area was very sparsely Each set of samples generally included one whole lung. 750 grams of liver. both gonads, if available, both adrenals. if available, and a sample of rib. Interviews with next of kin yielded places of residence of the deceased. any possible occupational plutonium exposure, smoking history in packyears. age, sex. and cause of death. In lung tissue. the plutonium IS less evenly distributed than in the liver. and much of it i s deposited in the lymph nodes. Hence, only samples that included more than90 percent of eitherthe right or left lung were used. Laboratory of Sacramento, California. analyzed the lung and liver samples by both alpha pulse height analysis (APHA) and mass spectrometry. In addition. standards were checked by the Lawrence Livermore Laboratory, Knolls Atomic Power Laboratory. and Los Alamos Scientific Laboratory. The EPA, in consultation with the Health Depanments of Colorado and Jefferson County and with the University of Colorado, decided which tissue and how many would be collected, based on what was then known about plutonium distribution in the body from inhaled plutonium oxide particles. Because pulmonary lymph nodes tend to concentrate plutonium panicles from the lungs, lymph nodes were included in a l l During preparation of samples at autopsy, organs are removed from the body and sliced in such a way that blood or other fluids seep out and are washed away. Measurements indicated that if the liver lost about 1 0 percent of its weight in fluid seepage, only about 1.5 percent of resident plutonium was lost By far the largest pan of the plutonium burden is evidently rather firmly fixed to the tissue and does not drain off with the fluid. Consequently, due to changes in tissue fluids at time of death, total organ burden of plutonium is more meaningful than the organ tissue concentration alone and therefore was measured in the study.

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Only individuals who lived in eastern Colorado for at least five years since 1968. who neither worked at Rocky Flats nor had been otherwise occupationally exposed to plutonium. were included in the study Distance from Rocky Flats was noted for three time periods the last five years of life: the period from 1968 to 1970; and the time of the fire in 1957 The distribution of the causes of death was compared to the distribution of causes of death for the entire state for the same period of years to determine the degree to which the samples were representative of the population who died in Colorado during those same years. Plutonium samples were analyzed by alpha spectroscopy for the presence of sample was counted on either a Frisch Grid detector for approximately 2000 minutes or on a silicon solid state detector for approximately 3000 minutes Plutonium samples were loaded by evaporation on rhenium filaments, placed in the source of the mass spectrometer and Ionized by heating to 1900’C From this. the Pu-240/239 atom ratio and dpm With plutonium concentrations. organ burdens, and isotope ratios in lung and liver tissue as the dependent variable. a stepwise, multiple regression analysis was used to test the data with independent variables of age, packyears of cigarette smoking, and distance from Rocky Flats. Samples were analyzed separately by sex and for selected areas. Of the 519 sample sets obtained for the study, those from 41 control area residents have not been analyzed for plutonium because of budget constraints. Ten were excluded from analysis because of various problems (See Figure 1 .). For the 468 with interviews. 1 9 were excluded from the study because the Individual mtght have been occupationallv exposed to plutonium or had lived In an area where other plutonium exposure could have occurred The remaining 449 sets of samdes included in the study represenfed an aged population with females slightlv older than males. The males were much heavier smokers. Almost two thirds of the females were nonsmokers People who resided within 50 km east and south of Rocky Flats during the 1957 fire had a minutely lower average ratio of Pu-24Ot 239 in their livers than did those living in the other study areas, but distance from Rocky Flats did not show any consistent relationship for this group Males had a slightly but significantly higher average liver burden of plutonium thanfemales. but they also smoked significantly more Liver burden appears to be low and weakly related to any of the variables in females: however in males. both age and packyears of smoking were FiRun 1. Brmmkdown of 5 I 9 outopsiod individuals. LANL3

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. usually positwety and significantly related to liver burden Nonsmokers and light smokers were more likely to have no plutonium in their lungs than were heavy smokers The data on Pu-240/239 ratio in lungs tended toward the ratio found in soil, as a function of distance from Rocky Flats. but w i t stgtistically weak The mean value for concentration of plutonium tn the lungs of people who had lived in erstcm Colorado was very similar to the median value estimated by Mclnroy (1979) for the Colorado population and is only slightly higher than the median value estimated by Feenne (1 979) for a much younger and heahhier population in New York City. For liver plutonium concentration. the mean for eastern Colorado was only rhghtly higher than the estimated median of both Mclnroy and Fisenne. which could be accounted for by differences in age. sex, and smoking Results indtcated that sex. age. and smoking history were all more strongly related to plutonium burden in the liver than distance from Rocky Flats Differences between mean liver burdens for male heavy versus light smokers, between males and females of each group, and between older and younger males were all signrficant Females did not show an age difference in liver burden and smoking did not seem to have an influence in women. There are several possible explanations for finding that older people have larger plutonium burdens thrn do younger people First the peak of plutonium pollution fromworldwide fallout occurred in 1963, afterwhich it dropped during the next four years by a factor of 15 (Efurd, 1977). Young people born since then would therefore have had considerably Second. young people have healthier lungs in general and are better able to eliminate inhaled particulates than older people. Third, from 1950 to 1970, older people were still smoking more than younger people. Only in recent years have teenagers begun to smoke so much (Last. 1980). Fourth, since plutonium was first used in 1945. an older person would generally have been exposed to more plutonium than a younger person. Finally. for growing children. the amount of air inhaled per unit time increases with Increasing lung size. which increases with age All of these factors would tend to give older people a larger plutonium Pu-240/239 ratios in the liver were significantlv higher than in the lung Additionally. the total amount of plutonium burden in the liver was about 10 times greater than in the lung Both of these observations are explained bv the fact that retention half-time of plutonium in the liver \s30 times longer than in the lung Thus, the liver would reflect the accumulation of plutonium over a person s whole lifetime and consequently have a much greater plutonium burden and a The results of …