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Radioactivity in the Canadian aquatic environment
J. Environ. Radioactivity 1 (1984) 79-81
Book Review
Radioactivity in the Canadian aquatic environment. Associate Committee on Scientific Criteria for Environmental Quality, National Research Council Canada, NRCC No 19250, 1983. Available for $8.00 from Publications, N R C C / C N R C Ottawa, Canada K1A 0R6. More than 97% of the water in the global hydrologic cycle is in the ocean. Ice sheets and glaciers contain a little less than 2%, groundwater 0.5%, and the remainder is in lakes, rivers, soil moisture and the atmosphere. The oceans receive 2 x l0 ta kg of sedimentary material every year, and particulate matter from rivers has residence times of the order of 10 years in the ocean. These and many other useful facts can be found in a Canadian report based upon a review of the literature relating to the effects of ionizing radiation in the aquatic environment. Emphasis has been placed on sources of radionuclides in the Canadian aquatic environment; on the transport, distribution, and behaviour of radionuclides in freshwater, marine, and estuarine systems; and on the dosimetry of ionizing radiation with respect to aquatic organisms, populations and ecosystems. Canada has some particular circumstances with regard to environmental radioactivity. The country is in the front rank of the production of power by heavy water reactors. Until now Canada is the only nation which has experienced the re-entering of a nuclear-powered satellite over its territory. As a considerable part of Canada is in the Arctic and subarctic regions, special radioecological conditions prevail there. Although the report has its basis in Canadian experiences it also provides a description of the present knowledge of radioactivity in the aquatic environment in general. Many years of studies of runoff from 79 J. Ent'iron. Radioactivity (l) ( 1 9 8 4 ) - - ~ England, 1984. Printed in Great Britain
Elsevier Applied Science Publishers Ltd,
80
Book review
Canadian rivers have shown that approximately one-fifth of the 9°Sr and 1-2% of the 137Cs in the drainage area have been flushed out by river flow. This observation seems applicable also to many other places in the world. The Canadian studies have mostly been in freshwater systems. In recent years the Canadians have, however, intensified their studies of estuarine systems; one of the reasons for this trend is that the Point Lepreau Nuclear Generating Station in New Brunswick is sited on the coast. Sedimentation has been particularly followed using Z~°Pb, ~37Cs and Pu tracer techniques. The report contains a number of useful tables. The concentrations of natural radionuclides in seawater and sediments are based upon the National Academy of Sciences report from 1971 (Radioactivity in the marine environment). Another table gives the immersion doses to biota in mrad year-t from 1 ~lCi ml-t. In this case old units are used, but, in general, the report has used SI units. The tables which show bioaccumulation factors need some revision. I would have preferred those in the NEA report, Review of the continued suitability of the dumping site Jbr radioactive waste in the North-east Atlantic (April 1980). Concentration factors which differ by a factor of i0 may be acceptable. However, in the case of 1"tC in the marine environment, the present report gives a factor of 1 for fish, while the NEA report states it as 5 x 103. The aquatic environment does not seem to be particularly sensitive to radiation. The report mentions studies which have shown that the lethal dose (LD 50/30) for fish varies between 11 and 560 Gy. Some species of primitive algae may have lethal doses exceeding 10kGy (I Mrad). Studies of the interaction of temperature and salinity with radiation show that environmental factors influence the radiosensitivity of aquatic organisms. In an experiment it was thus shown that low salinity favours the survival of irradiated fish at high temperatures, while fish at low temperatures are more resistant to radiation at high salinities. The Soviet investigations of radiation effects on fish in water with high 9°Sr and 137Cs concentrations are also mentioned. In this connection it is regrettable that the particulars under which these very important radioecological data have been obtained are not available from our Soviet colleagues. The Canadian Committee has made some recommendations, which, although directed to Canadian colleagues, may have more general applicability. The committee emphasises the importance of studies of naturally occurring radionuclides. It is stressed that the laboratories
Book review
81
involved in the programme should participate in intercomparison studies and should give sufficient information on, e.g. errors, in order to evaluate the data. Transport studies of radionuclides in the aquatic systems should be encouraged. Studies of uptake and release by biological systems should be used to provide better models of radionuclide movement through the food chain to replace simple organism/water concentration factors. Finally, more research on radiation-induced somatic and genetic changes in populations of aquatic organisms should be performed. The report is dedicated to Ivan Lindsay Ophel, Chairman of the NRCC Panel on Radioactivity in the Canadian Aquatic Environment, who died on 12 April 1983. The publication is a worthy memorial to Ivan who contributed significantly to our understanding of aquatic radioecology in general and to the information on the behaviour of 9°Sr in fresh water systems in particular.
Asker Aarkrog Riso National Laboratory, Denmark
Book Review
Radioactivity in the Canadian aquatic environment. Associate Committee on Scientific Criteria for Environmental Quality, National Research Council Canada, NRCC No 19250, 1983. Available for $8.00 from Publications, N R C C / C N R C Ottawa, Canada K1A 0R6. More than 97% of the water in the global hydrologic cycle is in the ocean. Ice sheets and glaciers contain a little less than 2%, groundwater 0.5%, and the remainder is in lakes, rivers, soil moisture and the atmosphere. The oceans receive 2 x l0 ta kg of sedimentary material every year, and particulate matter from rivers has residence times of the order of 10 years in the ocean. These and many other useful facts can be found in a Canadian report based upon a review of the literature relating to the effects of ionizing radiation in the aquatic environment. Emphasis has been placed on sources of radionuclides in the Canadian aquatic environment; on the transport, distribution, and behaviour of radionuclides in freshwater, marine, and estuarine systems; and on the dosimetry of ionizing radiation with respect to aquatic organisms, populations and ecosystems. Canada has some particular circumstances with regard to environmental radioactivity. The country is in the front rank of the production of power by heavy water reactors. Until now Canada is the only nation which has experienced the re-entering of a nuclear-powered satellite over its territory. As a considerable part of Canada is in the Arctic and subarctic regions, special radioecological conditions prevail there. Although the report has its basis in Canadian experiences it also provides a description of the present knowledge of radioactivity in the aquatic environment in general. Many years of studies of runoff from 79 J. Ent'iron. Radioactivity (l) ( 1 9 8 4 ) - - ~ England, 1984. Printed in Great Britain
Elsevier Applied Science Publishers Ltd,
80
Book review
Canadian rivers have shown that approximately one-fifth of the 9°Sr and 1-2% of the 137Cs in the drainage area have been flushed out by river flow. This observation seems applicable also to many other places in the world. The Canadian studies have mostly been in freshwater systems. In recent years the Canadians have, however, intensified their studies of estuarine systems; one of the reasons for this trend is that the Point Lepreau Nuclear Generating Station in New Brunswick is sited on the coast. Sedimentation has been particularly followed using Z~°Pb, ~37Cs and Pu tracer techniques. The report contains a number of useful tables. The concentrations of natural radionuclides in seawater and sediments are based upon the National Academy of Sciences report from 1971 (Radioactivity in the marine environment). Another table gives the immersion doses to biota in mrad year-t from 1 ~lCi ml-t. In this case old units are used, but, in general, the report has used SI units. The tables which show bioaccumulation factors need some revision. I would have preferred those in the NEA report, Review of the continued suitability of the dumping site Jbr radioactive waste in the North-east Atlantic (April 1980). Concentration factors which differ by a factor of i0 may be acceptable. However, in the case of 1"tC in the marine environment, the present report gives a factor of 1 for fish, while the NEA report states it as 5 x 103. The aquatic environment does not seem to be particularly sensitive to radiation. The report mentions studies which have shown that the lethal dose (LD 50/30) for fish varies between 11 and 560 Gy. Some species of primitive algae may have lethal doses exceeding 10kGy (I Mrad). Studies of the interaction of temperature and salinity with radiation show that environmental factors influence the radiosensitivity of aquatic organisms. In an experiment it was thus shown that low salinity favours the survival of irradiated fish at high temperatures, while fish at low temperatures are more resistant to radiation at high salinities. The Soviet investigations of radiation effects on fish in water with high 9°Sr and 137Cs concentrations are also mentioned. In this connection it is regrettable that the particulars under which these very important radioecological data have been obtained are not available from our Soviet colleagues. The Canadian Committee has made some recommendations, which, although directed to Canadian colleagues, may have more general applicability. The committee emphasises the importance of studies of naturally occurring radionuclides. It is stressed that the laboratories
Book review
81
involved in the programme should participate in intercomparison studies and should give sufficient information on, e.g. errors, in order to evaluate the data. Transport studies of radionuclides in the aquatic systems should be encouraged. Studies of uptake and release by biological systems should be used to provide better models of radionuclide movement through the food chain to replace simple organism/water concentration factors. Finally, more research on radiation-induced somatic and genetic changes in populations of aquatic organisms should be performed. The report is dedicated to Ivan Lindsay Ophel, Chairman of the NRCC Panel on Radioactivity in the Canadian Aquatic Environment, who died on 12 April 1983. The publication is a worthy memorial to Ivan who contributed significantly to our understanding of aquatic radioecology in general and to the information on the behaviour of 9°Sr in fresh water systems in particular.
Asker Aarkrog Riso National Laboratory, Denmark