Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, O24 Wake, Nomi, Ishikawa 923-1224, Japan.
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
Radiat Prot Dosimetry. 2022 Sep 9;198(13-15):1058-1065. doi: 10.1093/rpd/ncac053.
This study revealed sedimentation processes based on 137Cs and 210Pb distribution, grain size and magnetic susceptibility of bottom sediments in West Nanao Bay, Japan. Surface sediment concentrations and inventories of these radionuclides were relatively low in the middle and eastern areas of the bay and high in the western area, which has several major river mouths, suggesting that the contribution of riverine input affected only the western area. In the middle and eastern areas, the level of 137Cs inventory was much lower than that of the soils, and the excess 210Pb inventory was at the same level or lower. These results indicate that removal effects are stronger than accumulation effects (riverine input) in these areas. The patterns of radionuclides were consistent with the results, that grain size was relatively large in the middle and eastern areas, implying strong current conditions, and that fine sediment accumulated less in these areas.
本研究揭示了日本南海湾西部基于 137Cs 和 210Pb 分布、底质粒径和磁化率的沉降过程。在海湾中部和东部，这些放射性核素的表层沉积物浓度和储量相对较低，而在西部有几个主要河口的地区则较高，这表明河流输入的贡献仅影响了西部地区。在中部和东部地区，137Cs 储量水平远低于土壤水平，过剩的 210Pb 储量处于相同水平或更低水平。这些结果表明，在这些地区，去除效应比积累效应（河流输入）更强。放射性核素的模式与结果一致，即中部和东部地区的粒径相对较大，暗示着强水流条件，这些地区的细沉积物积累较少。
