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1. The equations of Joseph and Sender (1958), which were em- ployed in computing the dispersion of radioactive wastes due to turbu- lent diffusion, are based on a statistical concept which provides a smoothed space and time distribution. A time record of the concentra- tion at any given point, or the spatial record of the concentration at any given time resulting from a single actual point source, would differ in a random manner from the smoothed distribution predicted by the equations of Joseph and Sender. There would thus occur, from any single discharge, periods of time during which the concentration over small areas would be higher than that predicted. Since there would also occur corresponding times and locations with concentrations less than predicted, and since our concern is, at least in part, with the in- tegrated effect of a number of such releases over time and space, this departure of the actual distribution from the predicted distribution does not introduce serious error in the final computations. 2. In the evaluation of the open sea environment, a 100 meter thick stirred layer was assumed. In some ocean areas this may be too large. In the case of a 10 meter stirred layer, the estimates of the time, tppc , required for the concentration to be reduced to environ- mental ppc levels would be increased by a factor equal toVTO, or approx- imately 3.2; the corresponding value of N, the allowable number of dis- charges per month, would be decreased by i/TO?, or approximately by a factor of 32. Such a small value of the layer depth for the open sea would be very unusual; any real overestimation of this factor is most probably compensated for by the neglect of transport of any activity to the deeper water. 3. In the computations for coastal waters, the possible concen- tration of activity on the bottom, due to uptake by suspended silts and subsequent settling, was not included. While this would be a conserva- tive factor for those organisms which spend most of their time swim- ming or drifting in the water, it may well be quite detrimental to bot- tom living forms, particularly detritus and filter feeders. Data are not available to evaluate adequately the significance of this phenomenon. It is primarily for this reason that our final recommendations relative to inshore waters are more conservative than might otherwise be war- ranted from a strict application of our numerical results. MONITORING AND RECORD KEEPING It is essential that a systematic monitoring program be initiated as soon as possible to determine the consequences of the release of radioactive wastes from nuclear-powered vessels, both civilian and military*. This program is required in order to protect public health and property, to modify regulations in the light of new knowledge, and to prepare for intelligent action if and when nuclear disasters occur in inshore environments. *A monitoring program has also been recommended by the Committee on Oceanography of the National Academy of Sciences ' National Research Council (in its report entitled â¢Oceanography 1960'1970"). 48
This program should be carried out by a single agency of the Federal government apart from that having regulatory authority. Since the work requires development of techniques for detecting low level ra- dioactivity and for sampling a wide variety of habitats and organisms, and since the nature of the problem will be continually changing with changing technologies of atomic power, the program must have a core of excellent scientists capable of backing a dynamic directorate. In order to attract such people (which is in itself a difficult problem), pro- vision should be made to allow them wide latitude for independent re- search related to the subject. The monitoring should cover all harbors in the United States and its territories entered by nuclear vessels to the extent required by such use. It should be flexible enough to encompass, when circum- stances require, all marine environments where organisms are ex- ploited by man. It should be directed towards the detection of the radio- active isotopes produced in both corrosion and fission processes, dis- tinguishing the quantities originating from fallout, from land based reactors and from nuclear vessels. Although those engaged in the program must be given wide lati- tude in its execution, the panel suggests that the following are sensible subjects for observation: commercially useful organisms; certain other organisms that have high concentration factors for any of the radioactive elements; the water and its suspended solids; and the sediments. In this regard it is recognized that the permissible concentrations recommended for the coastal waters are quite small from the stand- point of detection, and would require special counting techniques to de- termine. It is, however, not the concentration in the water phase of the environment, but rather the activity in the marine organisms, which is the controlling factor. The determination of environmental ppc values has been primarily an intermediate step to provide the necessary means of getting from the ppc value for the edible portions of marine organ- isms to the permissible rate of introduction of radionuclides to the en- vironment. An inspection of Table 2 shows that the ppc values in the marine organisms are generally several orders of magnitude above the corresponding ppc value for coastal water. It is thus obvious that the most profitable method of monitoring the effects of the introduction of nuclear wastes into the marine environment is through measure- ments on the biota. All nuclear-powered vessels should be required to maintain a record of all discharges of liquid waste effluent, of ion exchange resins, or of any other materials which, by the definitions used in this report, are classed as radioactive wastes. Such records should give informa- tion as to the location and time of each discharge; the concentration, total volume and total activity of each discharge (within the accuracies of available practical techniques for estimating these quantities); as well as an estimate of the isotopic composition of the discharge, with estimates of the amount of activity associated with each of the major constituents. Copies of such records should be transmitted at regular 49
intervals to the appropriate national agency, which will, in turn, supply condensations of these records to any international organization which may, by mutual agreement between governments, assume responsibility on an international basis for the monitoring and registry of nuclear waste disposal into the ocean. Provision should be included for the prompt reporting and dis- semination of information relative to the emergency or accidental re- lease of radioactive materials in amounts exceeding those recommend- ed in this report. 50