【摘要】 利用137Cs示踪技术的前提条件是了解137Cs的大气沉降历史,从而准确求算区域环境中137Cs的背景值.本文利用日本秋田、东京及新泻地区137Cs年沉降数据,并结合相应的降水数据进行修正,对辽东湾地区137Cs的大气沉降进行了定量研究.结果表明,辽东湾地区137Cs的大气沉降趋势与北半球基本一致;1957—2008年辽东湾地区137Cs大气总沉降通量的模拟结果为1536 Bq·m-2(衰变校正至2009年),与该地区土壤中137Cs背景值较为接近;20世纪50年代末60年代初频繁的大气核试验和1986年的切尔诺贝利核事故是1963年和1986年两个137Cs沉降峰值产生的原因;1990年以后,沉降在地表的137Cs在风力侵蚀作用下,发生再悬浮,使得大气中137Cs沉降通量再次出现量级变化明显.福岛核事故产生的核素沉降对研究区的137Cs沉降通量的影响并不明显.更多还原

【Abstract】 Understanding the atmospheric deposition history of 137 Cs is important in applying 137 Cs tracer technique and obtaining accurate reference inventory of 137 Cs. Based on the records of 137 Cs deposition in Akita,Tokyo and Niigata in Japan,137 Cs atmospheric deposition in the Liaodong Bay region was investigated and quantified using the precipitation correction method. The results indicated that 137 Cs atmospheric deposition history in the Liaodong Bay was similar to that of the northern hemisphere. The cumulative atmospheric deposition inventory of 137 Cs from 1957 to 2008 was estimated to be 1536 Bq·m- 2( decay corrected to 2009). Two significant high values of 137 Cs atmospheric deposition in 1963 and 1986 were attributed to the frequent nuclear weapon tests in 1950 s ~ 1960 s and the Chernobyl nuclear accident in 1986,respectively. After 1990,137 Cs deposited on the surface was resuspended by the wind erosion,leading to another magnitude change of the137 Cs atmospheric deposition. The influence of the Fukushima nuclear accident to the 137 Cs atmospheric deposition of the study area was insignificant.更多还原