Let us now analyze the role of radioecology in elucidating processes which occur in contaminated water bodies. As yet, even the most tech nically advanced countries continue to bury the diluted radioactive wastes from nuclear power plants in water bodies with sluggish flow and in larger rivers. This practice is most common in the USA. In the USSR /16-18/ several authors /43, 44/ have persevered in their attempts at solving the problem of decontamination of such water bodies by means of a series of interconnected reservoirs with water rich in silts, aquatic plants, and plankton. The principle is, essentially, to utilize the initial stages of the radioecological process in the contaminated waters. The authors assumed that most radioisotopes will build up in the biomass of the numerous organisms, and in the dead organic matter in the silts so that a significant degree of deactivation will already be achieved in the first reservoir; from the last reservoir in the chain, the outflowing waters will be almost com pletely decontaminated and might be safely used along their further course, if issuing in a river or lake. Decontamination will prove to be progressi vely more effective as the entire radioactivity passes into the silts and benthic sediments following the death of the aquatic organisms.
This method is certainly noteworthy and should be implemented despite its drawbacks. In the first place certain important radioisotopes etc.) can only be extracted from water at a very slow rate. Secondly, radioecological processes, far from ending at the bottom of the reservoirs, become more intense there /2, 3/. The benthos comprises hundreds of millions of amphibian organisms, such as insect larvae, tad poles, tritons, and others which subsist on radioactive food and leave the water body upon reaching a suitable developmental stage. Each new generation of these organisms carries over to the dry land significant amounts of radioisotopes. We have estimated and experimentally demon strated /45/ that the dead bodies of insects originating in radioactive waters are sufficient to contaminate the surrounding dry land to the same degree as that recorded in global contamination following nuclear tests.* Prominent, in this respect, is the contribution of insectivorous birds and water fowl which find their food in the radioactive silts. The buried iso topes are further disturbed by fish feeding at the bottom of the reservoirs. In addition, fresh-water fishes become especially dangerous for human consumption /18, 46/, while mollusks endanger the domestic animals.
We suggest that research of nuclear power plants on the decontamination of drainage should be carried out in collaboration with radioecologists, and investiations aimed at selecting the safest types of water bodies for the burial of radioactive wastes should be encouraged. It is probable that the
most suitable water bodies for the purpose would be those least abundant in amphibian fauna. Water bodies of this type may also be specially designed.
From the practical aspect, knowledge of radioecological processes makes it possible to select those representatives of fresh-water and marine fauna that may serve as indicators of the radioactivity at any given time, as well as of long-standing pollution of the waters with radioactive sub stances.
Japanese /47/ and American /20/ investigations provide abundant radio ecological data concerning the future of radioisotopes produced by nuclear explosions in the Pacific. There is no longer any doubt that in many cases fish and other oceanic food products become radioactive and unfit for con sumption as a result of ecological interrelationships. The ecology of marine organisms also makes it possible to forecast the survival of the commercially most valuable animals, such as cetaceans and fishes /4/, as well as on the radioecological control of food products; substantiation of this seems unnecessary in the present article.
Radioecological substantiation is required at present, in our opinion, in order to discourage the burying of concentrated radioactive wastes at the bottom of deep depressions in the oceans and in the Black Sea. The container walls become corroded and develop leaks within a fairly short time, after which the radioactive solutions may be picked up and spread by deepwater currents. Where the presence of such currents is question able, there is the possibility of radioactive ecological food chains (similar to those in running waters) with the progressively increasing transfer of the radioelements to the surface waters inhabited by commer cially valuable fauna. In principle, biological migration of radioisotopes is possible in all areas and from all depths of the present day oceans and seas.** The current task is to compile the actual proofs of the radioecological investigations in order to discourage and control any attempts at using marine depths for burying radioactive wastes.
Radioecological processes may be successfully applied for purposes other than controlling their biological danger, such as the elaboration of biogeochemical methods of prospecting radioactive raw materials, and the detection of radioactively contaminated areas /2/.
The persistent work of Cannon et al. in the USA resulted in a series of communications followed by a special monograph /48/ devoted to prospect ing for uranium deposits in the upper horizons, with the aid of radiological analyses of plants, and indicator plants. (The monograph is supplemented with an album of one hundred such plants.) Successful research in this field is also being conducted in the USSR /49, 50/ and the method is being put into practice.