РЕЗУЛЬТАТЫ МОНИТОРИНГА РАДИОАКТИВНОГО ЗАГРЯЗНЕНИЯ ПРОМЫСЛОВЫХ МОРСКИХ ГИДРОБИОНТОВ В СЕВЕРО-ЗАПАДНОЙ ЧАСТИ ТИХОГО ОКЕАНА ПОСЛЕ АВАРИИ НА АЭС «ФУКУСИМА-1» В 2011 г.

Abstract

Results of several years monitoring on radioactive pollution of fisheries objects in the Russian EEZ and adjacent North-West Pacific (fish, crabs, shrimps, marine algae) after the accident at Fukushima Dai-ichi nuclear power plant in 2011 are generalized. Two catastrophic releases of radioactive isotopes to atmosphere and directly to the ocean happened at Fukushima in late March and early April, 2011. However, not a single case of dangerous pollution of fish or seafoods caught by Russian fishermen was detected. The highest activity of radioisotopes (137Cs up to 8.1 Bq/kg, 134Cs to 6.9 Bq/kg ww) was found for fish (pink salmon juveniles) caught off Kuril Islands in several days after the strongest release of radionuclides into the atmosphere. Soon, in summer 2011, the level of radioactive pollution in this area came close to the regional background level, the pre-accident level was restored in 2012, and the tendency to decreasing of radioactive pollution (that was observed after the nuclear tests termination) was restored in 2013. The observed radioactive contamination of fish, invertebrates and algae tissues is considerably (in 1–2 orders) below the sanitary permissible levels for isotopes of Cs and Sr. Lack of significant consequences of the Fukushima Dai-ichi accident for bioresources of Russian waters is explained by spatial patterns of the water drift from Fukushima coast driven by oceanic currents in spring-summer of 2011 that was directed generally eastward, far from the Russian coasts. There is noted that radioactive contamination of fish tissues is determined by current radiation situation (here and now), no signs of accumulation and transfer of pollution by migratory species are found.