Position of Sediments in Transfer of Radionuclides Released into Coastal Sea to Human Beings

Abstract

A great portion of radionuclides released into coastal sea is adsorbed into marine sediments and the adsorbed radionuclides causes the radioactive contamination of marine organisms and then transferred to human beings who consume them. In order to make a quantitative evaluation of this route, the transfer of 9 kinds of radionuclides from sediments to benthic organisms such as algae, bivalve and worm was observed. Then it was compared with the radioactivity in these organisms from radioactively contaminated sea water (Concentration factor). It was observed that the influence of sea water was larger than that of sediments as it was 10⁴ times larger for ⁵⁴Mn, 10³ times larger for ⁵⁹Fe, ⁶⁰Co, ⁹⁵Zr-⁹⁵Nb, ¹⁰⁶Ru-¹⁰⁶Rh and ¹⁴⁴Ce-¹⁴⁴Pr, 10² times larger for ⁶⁵Zn and 10-10² times larger for ^115mCd and ¹³⁷Cs.
Consequently, sea water can be considered as the main route and sediments as the secondary in the case of quantitative comparison of the effect on the accumulation of radionuclides by marine organisms and in the transfer of radionuclides to human beings.