日本沿岸域における海底土の¹³⁷Cs放射能濃度と化学的及び物理的要素との相関分析

抄録

Chemical and physical factors were measured in bottom sediments taken in coastal waters around Japan. They include concentration of ¹³⁷Cs, stable elements, particle size distribution, organic carbon, nitrogen contents and density. Intercorrelations among the factors were calculated in order to study the relationship between the concentration of ¹³⁷Cs and the physical and chemical factors of bottom sediments. Significant correlations (r > 0.8) existed between the ¹³⁷Cs concentration and some factors such as total organic carbon, 75 μm passing rate and specific surface area in samples taken in areas without any impact of the Fukushima Dai-ichi Nuclear Power Station accident. However, the sediment samples taken in the waters off Miyagi, Fukushima and Ibaraki Prefectures, where accident-derived ¹³⁷Cs was found, did not show any good relationships between ¹³⁷Cs and any other factors, suggesting that newly added Fukushima-derived ¹³⁷Cs, which was unevenly distributed in seawater, deposited onto the sediment irrespective of the pre-accident relationships among the chemical and physical factors.