南海东北部表层沉积物天然放射性核素与^(137)Cs

Specific activity and distribution of natural radionuclides and ^(137)Cs in surface sediments of the northeastern South China Sea

用HPGeγ谱仪测定了南海东北部表层沉积物中的放射性核素 .结果给出 7种核素的平均比活度分别为40 K :538Bq/kg ,2 10 Pb :1 1 6Bq/kg ,2 2 6Ra:2 7 7Bq/kg ,2 2 8Ra:4 4 9Bq/kg ,2 2 8Th :4 2 0Bq/kg ,2 38U :35 4Bq/kg和137Cs:1 1 6Bq/kg ,2 10 Pb的比活度随离岸距离增大 ,2 2 6Ra比活度随离岸距离没有明显变化 ,其余核素比活度随离岸距离减小 .与对我国近海其他海域报道的沉积物放射性核素含量相比 ,40 K和137Cs稍低于其他海域 ,其余核素为中等水平 .

Natural radionuclides 40K, 210Pb, 226Ra, 228Ra, 228Th, 238U and 137Cs in surface sediments from the northeastern South China Sea are measured by HPGe γ spectrometer. The mean specific activities of above 7 nuclides are respectively 538, 116, 27.7, 44.9, 42.0, 35.4 and 1.16 Bq/kg. The results show that 210Pb in sediments increases and 226Ra is no variance and others nuclides decrease with distance from coast. By comparison with other China coastal sea areas, the specific activities of 40K and 137Cs are lower and other nuclides are mid-level.