Inventory of radioactive material entering the marine environment: Sea disposal of radioactive waste

Variable amounts of packaged low level radioactive waste have been disposed at more than 50 sites in the northern parts of the Atlantic and Pacific Oceans. The last known disposal operation was in 1982, at a site about 550 km off the European continental shelf in the Atlantic Ocean. Since 1957, the IAEA has provided specific guidance and recommendations for ensuring that disposal of radioactive wastes into the sea will not result in unacceptable hazards to human health and marine organisms, damage to amenities or interference with other legitimate uses of the sea. In 1972, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter designated the IAEA as the competent international authority in matters related to sea disposal of radioactive waste. The Contracting Parties requested the IAEA to develop an inventory of radioactive wastes entering the marine environment from all sources as an information base with which the impact of radioactive materials from disposal operations can be more adequately assessed. The continuous compilation of these data could ensure that the IAEA recommendations on the disposal rate in a single basin are not overstepped. The inventory shows that between 1946 to 1982 an estimated 46 PBq1 (1.24 MCi) of radioactive waste coming from research, medicine, the nuclear industry and military activities were packaged, usually in metal drums lined with a concrete or bitumen matrix, and disposed of at sea. This inventory includes some unpackaged wastes and liquid wastes which were disposed of from 1950 to 1960. Beta-gamma emitters represent more than 98% of the total radioactivity of the waste and tritium alone represents one third of the total radioactivity disposed at the North East Atlantic sites. The other beta-gamma emitters radionuclides include 90Sr, 137Cs, 55Fe, 58Co, 60Co, 125I and 14C. The wastes also contain low quantities of alpha-emitting nuclides with plutonium and americium isotopes representing 96% of the alpha emitters present. 19 refs, figs and tabs