Radiation protection at sea dumping of radioactive waste - 25 years of radio-ecology of the deep sea

Investigations of biological structures of dumping regions show that the total biomass is very small. The major part of biomass is contained in an upper layer between 0 and 2000 m depth. Between this layer and the sea bottom only few living creatures are found. At about 100 m above ground, however, the fraction of biomass per m3 water is rising again, and doubles at 10 m above ground. In the years of 1949 - 1982, about 5 PBq β/γ- and 0,68 PBq α-activities have been dumped. The values measured for Cs-137 measured in the dumping region do not differ significantly from values in other marine areas. Nuclear weapon fallout remains to be the dominant source of radioactive contamination. Plutonium values measured in the last years, however, seem to reveal an influence of wastes dumped until 1982. We have retrieved nine barrels, some of which were well preserved despite a storage time of more than eight years. Others, however, showed severe damage caused by compression. No settling has taken place by sessile organisms. Concentration factors, biological transport and the radiobiological effects on deap-sea organisms have also been investigated. Knowledge about these items proved to be very fragmentary. Radiation exposure of the shore population is caused mainly by consumption of sea products. A conservative estimate gave an ingestion dose of 30 μSv/year after 100 years and 1,5 mSv/year after 500 years. (orig./HP)