山东半岛东部近岸表层沉积物放射性核素的季节性变化及其环境指示意义

基于2019年4月、7月、10月、12月渤黄海共享航次取得山东半岛东部近岸H01和H02站位多个季节沉积物样品，通过低本底γ能谱仪分析得到其表层沉积物放射性核素7Be、210Pbex、228Thex和 137Cs活度数据。结果表明，短半衰期核素7Be、228Thex与长半衰期核素210Pbex、137Cs在同一站位的季节分布存在差异，同一核素在H01和H02站位的季节分布也存在差异；H01站位的7Be和228Thex，H02站位的210Pbex和137Cs，受表层沉积物粒度影响较不明显，7Be和228Thex的季节变化受悬浮物质的输运和沉降的影响显著，而210Pbex和137Cs更多指示的是环流作用下的沉积物再分配；与H02相比，H01站位表层沉积物核素变化受大气沉降影响较低。H01和H02站位分别位于“Ω”形泥质体顶部和东部边缘，其物源和沉积动力环境存在差异，放射性核素7Be、210Pbex、228Thex和137Cs在示踪物质输运和沉降过程中具有重要意义。

Seasonal variation of radionuclides in surface sediments off the east coast of Shandong Peninsula and its environmental implications

Surface sediment samples were collected off the east coast of Shandong Peninsula in April, July, October and December of 2019 respectively. Radionuclides 7Be, 210Pbex, 228Thex and 137Cs of the surface sediments are analysed and discussed for different seasons. The results suggest that the seasonal distributions of 7Be and 228Thex are different from 210Pbex and 137Cs at same station, and the seasonal distribution of the same radionuclide vary from station to station. The variations of radionuclides seem to have nothing to do with the grain size of surface sediments. The seasonal variations of 7Be and 228Thex are significantly affected by the transport and settlement of suspended matter, while 210Pbex and 137Cs are more closely related to sediment redistribution. Comparing to the station H02, the changes of radionuclides in surface sediments at the station H01 are less affected by atmospheric sedimentation. H01 and H02 are located in different parts of the omega-shaped (Ω) mud deposits, owing to different sediment sources and dynamic environments. The study results further confirm that 7Be、210Pbex、228Thex and 137Cs are good tracers for illustrating sediment transport and deposition.