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4. Estimate of the fraction of the production of Oak Ridge National Laboratories shipped to other than AEC operations, that became wastes for sea disposal. During the period January 1956 to September 1957, ORNL shipped approximately 50,000 curies, measured at the time of shipment, for use by non-AEC facilities. Of this total, approximately 28,759 curies were isotopes with short half lives, while isotopes of strontium, cobalt, ce- sium, iron, and zinc amounted to 21,141 curies, of which 21,020 were shipped as "sealed sources". Assuming that sealed sources (cobalt bars, for example, used as radiation sources) will not find their way into commercial disposal routes when their initial usefulness has passed, 121 curies of long-lived isotopes appear as the potential supply that might have arrived at dockside for disposal at sea. During the same period, an estimated 25 curies (composition doubtful) was actually dis- posed of at sea. If the assumption concerning the fate of "sealed sources" is cor- rect and if the estimate of 25 curies disposed of at sea is correct, then approximately 20% of the ORNL shipments of "hazardous isotopes" to non-AEC users will eventually appear as wastes for sea disposal. PREVIOUS STUDIES Several studies have been made since 1950 that are either directly or indirectly concerned with the disposal of radioactive substances into the sea. The first of these, published as U.S. Bureau of Standards Handbook 52 (3) lists the quantities of each of a number of radioisotopes that can be retained safely in the body, as well as the concentration of each isotope that can be tolerated in drinking water and in air. The maximum permissible body burden, drinking water and air concentra- tions are considered to be the levels below which no readily detectable biological damage will occur in man under conditions of continual ex- posure at those levels. Although the recommendations contained in Handbook 52 were based upon the best biological and radiological evidence available, the authors note that in several cases the evidence available to them was scant and that the maximum permissible concentration levels should be revised as new evidence becomes available. In this connection Looney (9) suggested that the accepted level for radium, which forms the basis (in part) for the calculation of the permissible levels of other isotopes, is too high and recommends that the radium level be lowered until more information becomes available on the effects of radium in man over a normal lifetime. In calculations made later in this report, the recommended maxi- mum permissible levels in Handbook 52 have been used. We realize that man does not drink seawater; however, the Handbook 52 values give a basis for estimating the maximum permissible rate of ingestion of radionuclides that may be contained in marine food products.
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In 1954 a study was made by the sub-committee on Waste Disposal and Decontamination of the National Committee on Radiation Protection, of the problems connected with the disposal of radioactive materials in the ocean. This study was published as Handbook 58 of the National Bureau of Standards (4). Although Handbook 58 does not make specific recommendations with regard to disposal site locations, rates of dis- posal, etc., it does recommend that all radioactive wastes that are to be disposed of into the sea be packaged and that disposal be into water at least 1000 fathoms deep. These two recommendations form the basis for present AEC sea disposal regulations. In addition, Handbook 58 enumerates the physical, chemical, and biological factors thought to be important in regulating the dispersal of a contaminant throughout the oceans. However, because of lack of quantitative information, no at- tempt was made to combine the various factors to obtain an estimate of the level of contamination of the ocean and marine food products asso- ciated with stated disposal practices. In 1956 the National Academy of Sciences - National Research Council organized six committees to study various aspects of the bio- logical effects of atomic radiation. The report of one of these Commit- tees, the Committee on the Effects of Atomic Radiation on Oceanography and Fisheries, was published in 1957 as Publication 551 of the National Academy of Sciences - National Research Council (5). Publication 551 gives a detailed account of the state of knowledge of the physical, chemical, biological and geological factors involved in the interaction of radioactive wastes, especially fission product elements, with the marine environment. While much of this study is concerned with the deep oceans, and the massive quantities of materials that will be produced as a result of nuclear power production, it is, nevertheless, a useful guide in the attempted solution of all problems concerned with radioactive wastes and the marine environment. Following the 1956 meetings of the Committee on the Effects of Atomic Radiation on Oceanography and Fisheries, but before Publication 551 was completed, a meeting of several scientists from the United States and the United Kingdom was held, at which there was a liberal exchange of information concerning the problems of the disposal of ra- dioactive wastes in the oceans. At that meeting it was learned that the British Atomic Energy Authority plant at Windscale, on the Irish Sea, was discharging low level liquid wastes through a three mile long pipe- line, directly into the Irish Sea, with authorization to discharge at the rate of 1000 curies per month. The basis for the authorization was the results of a series of studies giving: (1) the detailed circulation of the Irish Sea area immediately seaward from the Windscale plant; (2) the uptake of activity by migratory fish that pass through the area; (3) the contamination of an edible seaweed that is harvested in an adjoining area, estimated from the circulation study and uptake experiments; and (4) the level of contamination of local beaches, estimated from the cir- culation study.
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It is now believed that as a result of monitoring studies made during the build-up to the 1000 curie per month discharge level, and a reassessment of the "safety factors" that were included in the original studies and recommendations, authorization has been given to discharge at the rate of 10,000 curies per month. A summary of the discussions at the meeting has been distributed under the title "Report of a Meeting of United Kingdom and United States Scientists on Biological Effects of Radiation in Oceanography and Fish- eries," National Academy of Sciences - National Research Council, Oc- tober 31, 1956 (6). A portion of that report is quoted below, as it has direct bearing on the studies of the present committee. Disposal into Coastal Waters Maximum quantities and rates of disposal of radioac- tive substances into coastal waters are set, in all cases, by two considerations. The first is the transfer of these sub- stances back to man and his surroundings. The second is the effect upon the marine resources and environment. Bulk Liquids In coastal waters it will, in general, be possible, in proper circumstances, to dispose of wastes in dilute liquid form, but the permissible quantities of radioactivity in such wastes may be expected to vary considerably from one area to another because of the diverse nature of coastal situations. A careful study is required to determine the safe quantity of each isotope in each situation, including the de- tails of the physical, chemical, and biological factors, and the habits of the human population potentially affected. Continuing studies are required at each disposal lo- cality to insure safety, to determine ultimate steady state conditions, and to detect possible long term variations aris- ing from variability of the environment. Such investigations have been carried out over a num- ber of years in the Irish Sea and the results indicate that fission products can be safely released in that area at an average rate of several hundred curies a day; it appears likely, therefore, that similar quantities of waste could be safely liberated in some other areas. In selecting locations for nuclear installations the waste disposal problems should be taken into account. Be- cause of the additive effects of wastes independently dis- charged into the same water mass, the proximity of other facilities is an important consideration. 10