海洋環境放射能と生物影響

摘要

The occurrence of 2011 Tohoku district off the Pacific Ocean Earthquake had a tremendous impact not only on Japan but also all over the world. In this paper summarizes an origin of radioactivity in marine environment and long-term fluctuation of ~(137)Cs concentration in seawater, bottom sediment and marine organism samples. The ~(137)Cs concentration in seawater, bottom sediment and marine organisms decreased year by year from 1983 to 2009 after prompt rise caused by the Chernobyl nuclear accident in 1986. The most recent results suggested that the ~(137)Cs concentration would not be more than 3mBq/L, 8 Bq/kg-dry and 0.24 Bq/kg-wet, respectively for seawater, bottom sediment and marine organism samples. Concentration factors for biological materials summarized in terms of the quantities of an element or radionuclide in marine organisms. The present report also summarizes knowledge so far attained on the assessment of doses and radiation impact on marine organisms, especially for sand lance (Ammodytes personatus) inhabiting in the coastal sea area off Fukushima nuclear power stations after the accident in 2011.