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Ecological Effects of Nuclear Radiation Particular kinds of environmental perturbation are essentially replicated in many places. Because no two sites are identical, detailed prediction of effects requires knowledge of the ecosystem in question. Much can be learned, however, by carrying out generic studies designed to discover results of general applicability to many conditions. Studies supported by the U.S. Atomic Energy Commission to determine the effects of radiation on living organisms and how radionuclides move through natural envi- ronments have been the most extensive attempts to use a generic approach to obtain information required for making major policy decisions. This case study summarizes and analyzes these studies and their contributions both to the solution of problems at which they were directed and to ecological theory generally. 331

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Case Study CARL F. JORDAN, Institute of Ecology, University of Georgia, Athens, Georgia INTRODUCTION Ionizing radiation resulting from production of radionuclides by bombs and reactors was the first pollutant given major national and international attention. It became an environmental concern soon after the first test of a nuclear weapon, which occurred on July 16, 1945, at Trinity, New Mexico. Starting almost immediately after the test and continuing for years thereafter, field surveys were conducted at Trinity to discover the extent and degree of environmental contamination by radionuclides, per- sistence of radionuclides, and effects of radiation on organisms and eco- systems (Larson, 19631. The studies showed that it would be extremely important to understand the effect of this pollutant on organisms and how it moves through the environment. It was thought that dispersion of radioisotopes in the environment as a result of fallout, reactor develop- ment, waste disposal, nuclear war, and technological projects could pose serious environmental problems (Wolfe, 19631. As nuclear energy was developed, for both peaceful and military uses, programs were established to evaluate the environmental effects of human- produced radiation. Many of the programs were at laboratories that became parts of the complex supported by the U.S. Atomic Energy Commission (AEC), such as those at Argonne, Illinois; Brookhaven, New York; Han- ford, Washington; Idaho Engineering Laboratory; Los Alamos, New Mex- ico; Livermore, California; the Nevada test site; Oak Ridge, Tennessee; and Savannah River, South Carolina (Whicker and Schultz, 19821. Other programs were established at universities or in conjunction with state agencies. The effects of ionizing radiation and radionuclide movement in the environment were also studied in other countries. A series of symposia sponsored by the International Atomic Energy Agency dealt with the uses of radionuclides in various disciplines, such as hydrology and plant nu- trition, as well as with environmental contamination by radioactive ma- terials. The series of studies sponsored by the Environmental Sciences Branch of the Division of Biology and Medicine of AEC (later the Energy Research and Development Administration and now the Department of Energy) probably constituted the greatest concentrated effort ever ex- pended to understand the environmental impact of a pollutant. (Lists of 332

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ECOLOGICAL EFFECTS OF NUCLEAR RADIATION 333 proceedings, books, and bibliographies of primary references were com- piled by Klement and Schultz in 1980 and Whicker and Schultz in 1982.) The studies of environmental effects of nuclear radiation covered most aspects of ecology. Some dealt with life histories to determine at which stage in its life cycle an organism was most sensitive to ionizing radiation. Studies of population dynamics and population interactions were crucial in understanding the dynamics of radionuclides in food chains. Studies sponsored by AEC were carried out in various habitats to determine the effects of radiation on community structure and community pattern. De- termining changes in nutrient cycling and productivity of ecosystems also was a major goal of many studies. This case study illustrates a generic approach to evaluating environ- mental pollutants. Ecological theory often cannot be used to make accurate predictions about individual cases. Valuable predictions for specific cases often are based on local field experience, not on formal theory. Further- more, predictions are usually difficult to apply beyond the bounds of a specific case. In a generic approach, the effects of a pollutant on a large number of different organisms in different environments are studied, thereby providing a framework for predicting effects on new organisms or envi- ronments. THE ENVIRONMENTAL PROBLEMS Ionizing radiation is radiation with sufficient energy for its interactions with matter to produce an ejected electron and a positively charged ion (Whicker and Schultz, 19821. In large numbers, such interactions in the cells of living organisms can cause genetic and physiological damage and death. Low levels of ionizing radiation from cosmic rays and radionuclides in the earth's crust have always been present. Life has evolved in an environment of low background radiation. Some of the first environmental studies concerned the radioactivity discharged in the mid-1940s from reactors at Hanford, Washington, into the Columbia River (Whicker and Schultz, 19821. Others concerned the magnitude and duration of radioactivity at weapon test sites (Hines, 1962; Koranda, 1965, 1969; Larson, 19631. Studies at nuclear test sites were important, not only because of the environmental dangers at the sites themselves, but also because results could be used to predict conditions at sites affected by nuclear war. An important early stimulus for studies of radionuclides in the envi- ronment was observation of the fate of radioactive fallout from atmospheric tests of nuclear weapons. One particularly disturbing case involved the

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334 SELECTED CASE STUDIES movement of cesium-137 in the lichen-reindeer-human food chain in tun- dra ecosystems (Liden and Gustafsson, 1967; Nevstrueva et al., 1967~. Cesium-137, a relatively strong emitter of gamma radiation, has a rela- tively long half-life (30 years) and metabolic effects similar to those of potassium. It is adsorbed on the surface of lichens, which are abundant in the tundra. Lichens are an important food of reindeer, and the nuclide became concentrated in tissue of reindeer and of the Finnish Lapps and Alaskan eskimos, who depend heavily on reindeer for meat (Hanson et al., 1967; Lindell and Magi, 1967; Miettinen and Hasanen, 19671. Another potentially hazardous combination of nuclide and food chain that was identified early involved iodine-131, which, if deposited on pasture grass, quickly moves through dairy cattle to milk (Barth and Seal, 1967; Bergs- trom, 1967) and becomes concentrated in the thyroid (Turner and Jennrich, 19671. Although there was never any conclusive evidence of damage to humans, the potential for danger was recognized. Observation of potential hazards of fallout gave rise to systematic studies of radionuclide concentrations in several species, such as deer (Schultz and Longhurst, 1963), and to studies of the environmental factors im- portant in radionuclide accumulation (Davis et al., 19631. An important result of these analyses (see Auerbach, 1965, for review) was a series of international symposia (Whicker and Schultz, 19823 in which the problem of radioactive contamination and accumulation in food chains was high- lighted and brought to international attention. In 1957, AEC established the Plowshare Program to investigate and develop peaceful uses for nuclear explosions (Auerbach, 1971a; Kelly, 19661. Studies were carried out to obtain food-chain and transport data needed for calculating radiation doses to human populations and to assess the impact on the local environment. One of the first was designed to predict the environmental impact of the use of nuclear explosives to ex- cavate a harbor in the Cape Thompson region of Alaska (Wolfe, 19661. Another focused on the feasibility of using thermonuclear devices to create a new transisthmian canal in Panama (Atlantic-Pacific Interoceanic Canal Study Commission, 1970; Martin, 19691. Although the studies did not conclusively predict damage to human health as a result of using nuclear explosives in these regions, neither of the proposed excavations ever took place (for reasons never made public). As nuclear technology advanced to the point where nuclear energy could be used to generate electricity, studies began to address the ecological problems in siting nuclear power plants, particularly the problem of ra- dioactive discharge into the environment, both accidental and as a result of normal operations (Auerbach, 1971b; Schultz and Whicker, 19801.

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ECOLOGICAL EFFECTS OF NUCLEAR RADIATION 335 Underground detonations were also used experimentally to stimulate gas flow in geological formations of low permeability (Alldredge et al., 1976~. APPROACHES TO THE PROBLEM OF RADIOACTIVITY IN THE ENVIRONMENT After the early observations of environmental radioactivity caused by nuclear testing, experimental studies were begun to evaluate the problem. These studies had two basic aspects. One was the movement of radio- nuclides in the environment after accidental or deliberate release from a nuclear device or power plant (Comer, 1965~; radioactive tracers were often used to determine the pathway of each potentially dangerous nuclide and the rate of movement alone that nathw~v The Arena oc^~t ~,^~ Alas effect of ionizing radiation --D ~ red ~ ~1~ it ~r~.~ who; run ~_t _ _ ,, ~ ~.~ . on organisms in the environment v~ri^~l~ animal populations (French, 1965; Turner, 1975), plant communities (Whicker and Fraley, 1974), aquatic organisms (Blaylock and Trabalka, 1978), and other ecosystem components (Platt, 1965) were irradiated experimentally . Movement of Radionuclides in the Environment Before the advent of radioecology, studies of food chains and of whole ecosystems had scarcely been initiated. An important contribution of the studies of radionuclide dynamics was to show that species in ecosystems were connected with each other and how particular species depended on the flows and cycles of nutrients and energy among all the other species in the Rat U~r;A~ or I_ ~ ~^- ~-v~,~lil. ~VlUcil~c of Iee(lnH~K in f&.f~l~t-~O ~1~ ~ ~ those studies; e.g., they showed that the rate of return of a nuclide to an individual or species can depend on other sneci~.s ~n`1 On Pn`~ir^ factors. ^ ~7~O TV 1111 11-()m - r ~-~ ~ 1~ wilill~ll ta Perhaps the most important idea used in the efforts to understand radionuclide movement in food chains was the specific-activity concept discussed by Kaye and Nelson (19681. Specific activity is defined as the ratio of radioactive atoms to totr>.l ~tnmc Off the ~ 1~ ~ ~~ 4 ~111O V1 L11~ ~lll~ ~1~111~nt. my USlIlg the stable-element distribution in environmental samples as a chemical analog for the radionuclide, we can predict the dispersal of radionuclides through environmental pathways, if we know the stable-element chemistry of organisms constituting the links in the biological pathways of food chains and the ratio of the radionuclide to its stable element at the source of entry of the radionuclide into the food chain (Reichle et al., 19701. A modification of the specific-activity approach uses the ratio of the

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336 SELECTED CASE STUDIES potentially dangerous radionuclides to analogous nutrient elements. Sev- eral radionuclides produced in important quantities during nuclear reac- tions are chemically similar to nutrient elements important in animal diets. For example, strontium-90 is similar to calcium and is accumulated in bones, and cesium-137 and potassium are metabolized similarly. Known pathways and concentrations of calcium and potassium in food chains can be used to predict concentrations of the analogous radionuclides, after corrections are made for discrimination or concentration factors (Comer and Lengemann, 19671. Discrimination and concentration are affected by the atomic weight of the isotope, as well as feeding habits and other food- chain characteristics (Whicker and Schultz, 19821. The need to make predictions about the fates and concentrations of radionuclides in ecosystems where experimental tests were not feasible gave rise to the development of systems analysis techniques in ecology (Kaye and Ball, 1969; Shugart and O'Neill, 19791. These techniques used models of the flux and turnover of radionuclides in ecosystems. When data were not available, assumptions were based on studies in other eco- systems, on known metabolism of stable-element analogs in the species of interest, or on other appropriate physical, chemical, and biological models. Once all important ecosystem turnovers and transfers were for- mulated, equations were solved simultaneously to predict radionuclide dynamics through an entire ecosystem. One of the efforts to predict radionuclide movement in an ecosystem was an analysis of the fate of radioactivity, if thermonuclear devices were used to excavate a new canal across Central America (Kaye and Ball, 19691. The predictive model was based on stable-element data collected at the proposed site and at similar sites and on results of laboratory analy- ses. Because the canal was never excavated, the model was never tested. But Jordan et al. (1973) used a similar approach to predict the environ- mental residence half-time of strontium-90 after its release into a tropical rain forest. They then used atmospheric fallout measured before the at- mospheric-test ban in 1963 as model input and predicted concentrations of the nuclide in the forest through the end of the century. Measurements in 1974 (Jordan and Kline, 1976) showed that actual concentrations in the forest were higher than those predicted, because of atmospheric tests after 1963. The strontium-90 study showed that the environmental half-time of the isotope in this system was about 20 years and that loss was predom- inantly by physical decay. Predictions of movement of radionuclides in food chains also were based on laboratory data on the biological turnover of radionuclides in organisms and on the factors such as intake, assimilation, metabolism, and excre- tion that affect turnover (Reichle et al., 1970~. Other tracer studies

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ECOLOGICAL EFFECTS OF NUCLEAR RADIATION 337 showed the rate of movement of radionuclides between living and non- living portions of ecosystems (Auerbach, 19651. An important early study that showed how changes in ecosystem struc- ture affected radionuclide dynamics used a series of microcosms in com- bination with mathematical modeling (Patten and Witkamp, 1967~. Leaf litter tagged with cesium-134 was introduced into microecosystems com- posed of different combinations of soil, microflora, millipedes, and aqueous leachate. Field studies were much more difficult, because of the health hazard of radioactivity. However, the section of Oak Ridge National Laboratory that is now the Environmental Sciences Division carried out a study in which a whole stand of trees was inoculated with cesium-137 in 1962 and the movement of the nuclide in the ecosystem was followed for a number of years thereafter (Francis and Tamura, 19711. An unex- pected finding of that study was that much of the cesium did not move up through the leaves, but rather moved down into the roots and then into the soil when roots died and decomposed. Radiation Effects In addition to predicting the rate of nuclide movement through food chains and the amounts of radioactivity reaching valued species, it was necessary to know what effect a given amount of radioactivity would have on the valued species. The behavior of individuals of a species is obviously important in the effect of radiation release. For example, burrowing animals are shielded from radiation (Buchsbaum, 19581. Other factors that influence radiation sensitivity in complex ways are body size, temperature, rate of reproduc- tion, and life span. It was initially predicted that the most important biological factor affecting sensitivity to radiation would be the volume of chromosomes, but the first tests suggested that interphase chromosomal volume was a better predictor of both species sensitivity (Sparrow et al., 1968) and pattern of community response (Woodwell and Whittaker, 19681. Another important hypothesis regarding radiation sensitivity (Henshaw, 1963) was that there is a threshold of radiation tolerance, which may be different for each species. For radiation exposure below this threshold, damage does not exceed that caused by natural background radiation. Studies of the effects of ionizing radiation on ecosystems were carried out in an oak-pine forest at Brookhaven, New York (Woodwell and Re- buck, 1967), a tropical rain forest (Odum et al., 1970), a northern hard- wood forest (Murphy et al., 1977), southern pine-hardwood forests in Georgia (Cotter and McGinnis, 1965) and in Tennessee (Witherspoon, 1965), a pine forest (McCormick, 1969), and a shortgrass prairie (Fraley

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338 SELECTED CASE STUDIES and Whicker, 19711. There were many other studies on the effects on populations and species (Appendix). In these studies, a shielded source of radiation was used, so that scientists could enter the irradiated areas. At the completion of an experiment, the source was removed. Because the source of radioactivity was thereby contained, there was no residual contamination, which was a problem in tracer studies. Results showed that radiation sensitivity of plants was correlated to some extent with interphase chromosomal volume, but there were frequent exceptions (Koo and deIrizarry, 1970; Woodwell and Whittaker, 19681. A much more useful generalization from the radiation studies is that sensitivity of plants depends on the ratio of photosynthetic tissue to total tissue (Woodwell, 1967, 1970~. The most sensitive plants are trees, which have a relatively low ratio of photosynthetic mass (leaves) to nonphoto- synthetic mass (stem and root). Shrubs are less sensitive than trees, and herbs and grasses are less sensitive than shrubs. Plants like algae, in which much of the tissue is photosynthetic, are highly resistant. Among trees, pine trees-which produce long-lived leaves-are more sensitive than deciduous hardwoods, in which replacement of leaves represents a smaller drain on energy reserves. Rhizomatous species, such as sedges, a large proportion of whose biomass is shielded by the soil, usually are relatively resistant. A generalization that applied to both plants and animals is that radiation sensitivity is correlated with size: the largest species are usually the most sensitive (Woodwell, 1967), as they are to stress in general (Woodwell, 19701. Two irradiation experiments contrasted the effects of long exposure (Woodwell, 1967) and short exposure (Odum, 19701. In the site exposed for a short time, sprouting of trees played an important part in ecosystem recovery (Jordan, 1969~. In a site chronically irradiated, root carbohydrate reserves were exhausted and sprouting was not important. Disturbed areas at that site were colonized by fortes and grasses with seeds that are widely dispersed and that germinate rapidly (Woodwell, 19671. CONCLUSION The AEC-sponsored studies of radiation in the environment resulted in two major conclusions. First, some but not all radionuclides released into the environment are concentrated as they are passed through food chains, and, if concentration factors are high, relatively low releases of radio- activity can pose a danger. Because every ecosystem and every food chain is different, potential danger depends in part on characteristics of the particular ecosystem and food chain and in part on the radionuclide. Concentration of radionuclides in food chains is a generic characteristic

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ECOLOGICAL EFFECTS OF NUCLEAR RADIATION 339 with the potential to occur in any ecosystem; for purposes of environmental safety, it must be predicted specifically for the ecosystem of interest. Second, although radiosensitivity is sometimes correlated with inter- phase chromosomal volume, a more practical index of radiation sensitivity is simply the size of an organism and its life span. Large organisms are almost always more sensitive to radiation than small organisms. Long- lived species usually suffer more from radiation exposure than short-lived species. In evaluating the effect of a particular radionuclide in ~ particular en- vironment, both the food-chain accumulation factors and the sensitivity of the organisms in the food chain to the predicted dose must be known. These factors are now known for some organisms in many types of eco- system, but must be evaluated in light of the specific conditions at par- ticular sites. REFERENCES ~, Alldredge, A. W., F. W. Whicker, and W. C. Hanson. 1976. Some environmental impacts associated with project Rio Blanco. Pp. 65-73 in C. E. Cushing, ed. Radioecology and Energy Resources. Proceedings of the Fourth National Symposium on Radioecology. Dowden, Hutchinson, and Ross, Stroudsburg, Pa. Atlantic-Pacific Interoceanic Canal Study Commission. 1970. Interoceanic Canal Studies; Annexes 1-5; Vols. 1-6. Atlantic-Pacific Interoceanic Canal Study Commission, Wash- ington, D.C. Auerbach, S. I. 1965. Radionuclide cycling: Current status and future needs. Health Phys. 11: 1355-1361. Auerbach, S. I. 1971a. Contributions of radioecology to AEC mission programs. Pp. 3-8 in D. J. Nelson, ed. Radionuclides in Ecosystems. Proceedings of the Third National Symposium on Radioecology. U.S. Atomic Energy Commission, Washington, D.C. Auerbach, S. I. 1971b. Ecological considerations in siting nuclear power plants: The long- term biotic effects problem. Nucl. Safety 12:25-34. Barth, D. S., and M. S. Seal. 1967. Radioiodine transport through the ecosystem, air- forage-cow-milk using a synthetic dry aerosol. Pp. 151-158 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Symposium. Pergamon Press, Oxford, Eng. Bergstrom, S. O. W. 1967. Transport of fallout t3~Iintomilk. Pp. 159-174inB. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Symposium. Pergamon Press, Oxford, Eng. Blaylock, B. G., and J. R. Trabalka. 1978. Evaluating the effects of ionizing radiation on aquatic organisms. Adv. Radiat. Biol. 7:103-152. Buchsbaum, R. 1958. Species response to radiation: Radioecology. Pp. 124-141 in W. D. Claus, ed. Radiation Biology and Medicine. Addison Wesley, Reading, Mass. Comar, C. L. 1965. Movement of fallout radionuclides through the biosphere and man. Annul Rev. Nucl. Sci. 15:175-206. Comar, C. L., and F. W. Lengemann. 1967. General principles of the distribution and movement of artificial fallout through biosphere to man. Pp. 1-18 in B. Aberg and F.

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340 SELECTED CASE STUDIES P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an Interna- tional Symposium. Pergamon Press, Oxford, Eng. Cotter, D. J., and J. T. McGinnis. 1965. Recovery of hardwood stands 3-5 years following acute irradiation. Health Phys. 11: 1663- 1673. Davis, J. J., W. C. Hanson, and D. G. Watson. 1963. Some effects of environmental factors upon accumulation of worldwide fallout in natural populations. Pp. 35-38 in V. Schultz and A. W. Klement, eds. Radioecology. Proceedings of the First National Symposium on Radioecology. Reinhold, New York. Fraley, L., and F. W. Whicker. 1971. Response of a native shortgrass plant stand to ionizing radiation. Pp. 999-1006 in D. J. Nelson, ed. Radionuclides in Ecosystems. Proceedings of the Third National Symposium on Radioecology. U.S. Atomic Energy Commission, Washington, D.C. Francis, C. W., and T. Tamura. 1971. Cesium-137 soil inventory of a tagged Liriodendron forest, 1962 and 1969. Pp. 140-149 in D. J. Nelson, ed. Radionuclides in Ecosystems. Proceedings of the Third National Symposium on Radioecology. U.S. Atomic Energy Commission, Washington, D.C. French, N. R. 1965. Radiation and animal populations: Problems, progress, and projections. Health Phys. 11: 1157- 1568. Hanson, W. C., D. G. Watson, and R. W. Perkins. 1967. Concentration and retention of radionuclides in Alaskan Arctic ecosystems. Pp. 233-245 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Sympos- ium. Pergamon Press, Oxford, Eng. Henshaw, P. S. 1963. Radiation effects and peaceful uses of atomic energy in the animal sciences: Radiation and biologic capability. Pp. 13-17 in V. Schultz and A. W. Klement, eds. Radioecology. Proceedings of the First National Symposium. Reinhold, New York. Hines, N. O. 1962. Proving Ground: An Account of the Radiobiological Studies in the Pacific, 1946- 1961. University of Washington Press, Seattle. Jordan, C. F. 1969. Recovery of a tropical rain forest after gamma irradiation. Pp. 88-98 in D. J. Nelson and F. C. Evans, eds. Symposium on Radioecology. Proceedings of the Second National Symposium. CONE 670-503. U.S. Department of Commerce, Spring- field, Va. Jordan, C. F., and J. R. Kline. 1976. Strontium-90 in a tropical rain forest: 12th-year validation of a 32-year prediction. Health Phys. 30:199-201. Jordan, C. F., J. R. Kline, and D. S. Sasser. 1973. A simple model of strontium and manganese dynamics in a tropical rain forest. Health Phys. 24:477-489. Kaye, S. V., and S. J. Ball. 1969. Systems analysis of a coupled compartment model for radionuclide transfer in a tropical environment. Pp. 731-739 in D. J. Nelson and F. C. Evans, eds. Symposium on Radioecology. Proceedings of the Second National Sym- posium. CONE 670-503. U.S. Department of Commerce, Springfield, Va. Kaye, S. V., and D. J. Nelson. 1968. Analysis of specific-activity concept as related to environmental concentration of radionuclides. Nucl. Safety 9:53-58. Kelly, J. S. 1966. Foreword. Pp. iii-iv in N. J. Wilimovsky and J. N. Wolfe, eds. Environment of the Cape Thompson Region, Alaska. U.S. Atomic Energy Commission, Washington, D.C. Klement, A. W., and V. Schultz. 1980. Terrestrial and Freshwater Radioecology. A Selected Bibliography. Dowden, Hutchinson and Ross, Stroudsburg, Pa. Koo, F. K. S., and E. R. deIrizarry. 1970. Nuclear volume and radiosensitivity of plant species at El Verde. Pp. G-15 G-20 in H. T. Odum and R. F. Pigeon, eds. A Tropical Rain Forest. U.S. Atomic Energy Commission, Washington, D.C.

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ECOLOGICAL EFFECTS OF NUCLEAR RADIATION 341 Koranda, J. J. 1965. Preliminary studies of the persistence of tritium and i4C in the Pacific Proving Ground. Health Phys. 11: 1445- 1457. Koranda, J. J. 1969. Residual tritium at Sedan Crater. Pp. 696-708 in D. J. Nelson and F. C. Evans, eds. Symposium on Radioecology. Proceedings of the Second National Symposium. CONF 670-503. U.S. Department of Commerce, Springfield, Va. Larson, K. H. 1963. Continental close-in fallout: Its history, measurement, and charac- teristics. Pp. 19-25 in V. Schultz and A. W. Klement, eds. Radioecology. Proceedings of the First National Symposium. Reinhold, New York. Liden, K., and M. Gustafsson. 1967. Relationships and seasonal variation of 137CS in lichen, reindeer, and man in northern Sweden 1961-1965. Pp. 193-208 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an Inter- national Symposium. Pergamon Press, Oxford, Eng. Lindell, B., and A. Magi. 1967. Observed levels of '37Cs in Swedish reindeer meat. Pp. 217-219 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Symposium. Pergamon Press, Oxford, Eng. Martin, W. E. 1969. Radioecology and the feasibility of nuclear canal excavation. Pp. 9- 22 in D. J. Nelson and F. C. Evans, eds. Symposium on Radioecology. Proceedings of the Second National Symposium. CONF 670-503. U.S. Department of Commerce, Springfield, Va. McCormick, J. F. 1969. Effects of ionizing radiation on a pine forest. Pp. 78-87 in D. J. Nelson and F. C. Evans, eds. Symposium on Radioecology. Proceedings of the Second National Symposium. CONF 670-503. U.S. Department of Commerce, Springfield, Va. Miettinen, J. K., and E. Hasanen. 1967. 137CS in Finnish Lapps and other Finns in 1962- 6. Pp. 221-231 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Symposium. Pergamon Press, Oxford, Eng. Murphy, P. G., R. R. Sharitz, and A. J. Murphy. 1977. Response of a forest ecotone to ionizing radiation. Pp. 43-48 in J. Zavitkovski, ed. The Enterprise, Wisconsin, Radiation Forest. USERDA TID-26113-p2. U.S. Energy Research and Development Administra- tion, Washington, D.C. Nevstrueva, M. A., P. V. Ramzaev, A. A. Moiseer, M. S. Ibatullin, and L. A. Teplykh. 1967. The nature of '37Cs and 90Sr transport over the lichen-reindeer-man food chain. Pp. 209-215 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Pro- cesses. Proceedings of an International Symposium. Pergamon Press, Oxford, Eng. Odum, H. T. 1970. Summary. An emerging view of the ecological system at El Verde. Pp. I-191 I-281 in H. T. Odum and R. F. Pigeon, eds. A Tropical Rain Forest. U.S. Atomic Energy Commission, Washington, D.C. Odum, H. T., P. Murphy, G. Drewry, F. McCormick, C. Schinan, E. Morales, and J. A. McIntyre. 1970. Effects of gamma radiation on the forest at El Verde. Pp. D-3 D-75 in H. T. Odum and R. F. Pigeon, eds. A Tropical Rain Forest. U.S. Atomic Energy Commission, Washington, D.C. Parzyck, D. C., J. P. Witherspoon, and J. E. Till. 1976. Validation of environmental transport models in the CUEX methodology. Pp. 194-198 in C. E. Cushing, ed. Radioecology and Energy Resources. Proceedings of the Fourth National Symposium on Radioecology. Dowden, Hutchinson, and Ross, Stroudsburg, Pa. Patten, B. C., and M. Witkamp. 1967. Systems analysis of i34cesium kinetics in terrestrial microcosms. Ecology 48:813-824. Platt, R. B. 1965. Radiation effects on plant populations and communities: Research status and potential. Health Phys. 11: 1601 - 1606. Reichle, D. E., P. B. Dunaway, and D. J. Nelson. 1970. Turnover and concentration of radionuclides in food chains. Nucl. Safety 11:43-55.

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342 SELECTED CASE STUDIES Schultz, V., and W. M. Longhurst. 1963. Accumulation of strontium-90 in yearling Co- lumbian black-tailed deer, 1950-1960. Pp. 73-76 in V. Schultz and A. W. Clement, eds. Radioecology. Proceedings of the First National Symposium. Reinhold, New York. Schultz, V., and F. W. Whicker. 1980. Nuclear fuel cycle, ionizing radiation, and effects on biota of the natural environment. CRC Crit. Rev. Environ. Control 10:225-268. Shugart, H. H., and R. V. O'Neill. 1979. Introduction. Pp. 1-6 in H. H. Shugart and R. V. O'Neill, eds. Systems Ecology. Benchmark Papers in Ecology. 9. Dowden, Hutch- inson, and Ross, Stroudsburg, Pa. Sparrow, A. H., A. F. Rogers, and S. S. Schwemmer. 1968. Radiosensitivity studies with woody plants. I. Radiat. Bot. 8:149-186. Turner, F. B. 1975. Effects of continuous irradiation on animal populations. Adv. Radiat. Biol. 5:83-144. Turner, F. B., and R. I. Jennrich. 1967. The concentration of i3tI in the thyroids of herbivores and a theoretical consideration of the expected frequency distribution of thyroidal '3iI in a large consumer population. Pp. 175-182 in B. Aberg and F. P. Hungate, eds. Radioecological Concentration Processes. Proceedings of an International Sympos- ium. Pergamon Press, Oxford, Eng. Whicker. F. W.. and L. Fraley. 1974. Effects of ionizing radiation on terrestrial plant , communities. Adv. Radiat. Biol. 4:317-366. Whicker, F. W., and V. Schultz. 1982. Radioecology: Nuclear Energy and the Environ- ment. Vols. I and II. CRC Press, Boca Raton, Fla. Witherspoon, J. P. 1965. Radiation damage to forest surrounding an unshielded fast reactor. Health Phys. 11: 1637- 1642. Wolfe, J. N. 1963. Impact of atomic energy on the environment and env~rvnme~ Amp. Pp. 1-2 in V. Schultz and A. W. Klement, eds. Radioecology. Proceedings of the First National Symposium. Reinhold, New York. . . ~ _ .~ 1 ~ ~an_ ~ , , Wolfe, J. N. 1966. Committee on environmental studies for Project Chariot, Plowshare Program. Pp. ix-x in Environment of the Cape Thompson Region, Alaska. U.S. Atomic Energy Commission, Washington, D.C. Woodwell, G. M. 1967. Radiation and the pattern of nature. Science 156:461-470. Woodwell, G. M. 1970. Effects of pollution on the structure and physiology of ecosystems. Science 168:429-433. Woodwell, G. M., and A. L. Rebuck. 1967. Effects of chronic gamma radiation on the structure and diversity of an oak-pine forest. Ecol. Monogr. 37:53-69. Woodwell, G. M., and R. H. Whittaker. 1968. Effects of chronic gamma irradiation on plant communities. Q. Rev. Biol. 43:42-55. APPENDIX: Some Sources of Information on Radioecology Aberg, B., and F. P. Hungate, eds. 1967. Radioecological Concentration Processes. Pro- ceedings of an International Symposium. Pergamon Press, Oxford, Eng. Cushing, C. E., ed. 1976. Radioecology and Energy Resources. Proceedings of the Fourth National Symposium on Radioecology. Dowden, Hutchinson, and Ross, Stroudsburg, Pa. Hanson, W. C., ed. 1980. Transuranic elements in the environment. U.S. DOE Rep. DOE/ TIC-22800. U.S. Department of Energy, Washington, D.C. icky HanfntA .Qvmnoci''m on Radiation and Terrestrial Ecosystems. Hungate, F. P., ed. 1~VJ. A4~llJ~VA~v^ Health Phys. 11: 1255-1675

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ECOLOGICAL EFFECIS OF NUCLEI AVIATION 343 Klement, A. W., and V. Schultz. 1980. Freshwater and Terrestrial Radioecology: A Se- lected Bibliography. Dowden, Hutchinson, and Ross, Stroudsburg, Pa. Nelson, D. J., ed. 1971. Radionuclides in Ecosystems. Proceedings of the Third National Symposium on Radioecology. U.S. Atomic Energy Commission, Washington, D.C. Nelson, D. J., and F. C. Evans, eds. 1969. Symposium on Radioecology. Proceedings of the Second National Symposium. CONE 670-503. U.S. Department of Commerce, Springfield, Va. Odum, H. T., and R. F. Pigeon, eds. 1970. A Tropical Rain Forest. A Study of Irradiation and Ecology at El Verde, Puerto Rico. U.S. Atomic Energy Commission, Washington, D.C. Schultz, V., and A. W. Klement, eds. 1963. Radioecology. Proceedings of the First National Symposium on Radioecology. Reinhold, New York. Thompson, R. C., and W. J. Blair, eds. 1972. Hanford Symposium on the Biological Implications of the Transuranium Elements. Health Phys. 22:533-957. Whicker, F. W., and V. Schultz. 1982. Radioecology: Nuclear Energy and the Environ- ment. Vols. I and II. CRC Press, Boca Raton, Fla. Committee Comment Environmental problem-solving is hindered by differences in insight derived from general and specific approaches. General ecological theory usually makes only crude predictions about specific conditions or impacts at a specific site. Useful predictions for a specific case often are based on local field experience, rather than on formal theory, and it is difficult to determine their applicability beyond the bounds of the specific case. The AEC studies used both generic and specific approaches. Studies were carried out on a wide variety of ecosystems in an effort to form generalizations about radioactivity in the environment. The relative sen- sitivity of plants as a function of the ratio of photosynthetic tissue to total tissue (photosynthesis:respiration ratio) is an example of a generalization that emerged from these comparative studies. Studies on conditions at a specific site or with a specific nuclide were useful in predicting effects of the same nuclide under similar conditions. For example, the Arctic studies suggested that scavenging might be important wherever lichens were dom- inant members of the community. This case study suggests the value of approaching many types of en- vironmental perturbations both generically and specifically. The generic approach predicts what, in general, to expect from a perturbation, re- gardless of where it occurs; the specific approach addresses the question of whether the specific case differs in any important way from the general case. The many studies in radioecology have resulted in one of the most successful evaluations of the impact of an environmental hazard. One

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344 SELECTED CASE STUDIES reason is that they were adequately funded. Most environmental evaluation must be carried out with less support than was available for the radio- ecological work. The results of these studies show that thorough under- standing can be achieved if enough time and money are allocated. Another notable characteristic of the AEC studies was the separation of studies of radionuclide movement in the environment from studies of the effects of ionizing radiation. Had these two aspects of the radiation problem not been separated, much less progress would have been made. Experiments in which exposure to radiation was great enough to reveal dose-response relationships would have been impossible with radionu- clides released into the environment. Conversely, laboratory studies cannot reveal how radionuclides behave in nature. Studies sponsored by AEC, particularly those of nuclide movement through the environment, made an important contribution to the emergence of "ecosystem ecology" (Odum, 1965; Odum and Golley, 1963), in which a major focus is the flow of energy and elements through a unit of land- scape. This work supplements and extends studies oriented toward the ecology of individuals, populations, species, and communities. This examination of the history of AEC-sponsored environmental ra- diation studies suggests that their contribution to ecological knowledge has been as important as, or perhaps even more important than, the con- tr~bution of ecological knowledge to the design and interpretation of the AEC studies. During the four decades of radioecological studies, the constant interplay between experimental results and general theory has proved fruitful to the basic science of ecology and the applied field of radioecology. References Odum, E. P. 1965. Feedback between radiation ecology and general ecology. Health Phys. 1 1: 1257-1262. Odum, E. P., and F. B. Golley. 1963. Radioactive tracers as an aid to the measurement of energy flow at the population level in nature. Pp. 403-410 in V. Schultz and A. W. Klement, eds. Radioecology. Proceedings of the First National Symposium. Reinhold, New York.