Study on origin and behavior of radionuclides and trace elements in atmospheric environment

采用ICP-AES、中子活化分析和γ射线能谱法对2002年10月至2005年1月在川崎每周采集的颗粒物（PM）样品和1964年和2000年至2004年在福冈、长崎、筑波和川崎每月采集的大量沉积样品中的主微量元素和放射性核素进行了测定。因此，我们在本研究中获得了以下一些有价值的信息：从测定元素浓度的相关系数来看，Br-Sb和Sc-Fe-La分别表现出较好的相关性。从PM10的粒径分布来看，PM10的贡献分别大于Br-Sb和Se-Fe-La中的较大贡献。在各风向^<210>Pb和^7Be的平均放射性浓度中，南风吹时的放射性浓度高于北风吹时的放射性浓度。可以看出，^<222>Rn, ^…More <210>Pb的祖先，在大陆的扩散是海洋的1000倍甚至更多，^7Be受到宇宙射线纬度效应的影响。此外，还发现这些样品中两种核素的浓度将受降雨的支配。可以看出，长崎沉积物3 ~ 5月的稀土元素丰度模式与长崎黄壤粉尘（koosa）非常相似。这一事实表明，这几个月在长崎的证词将受到科沙的强烈影响。此外，从这些样品的Th/Sc比值可以清楚地看出，近年来（2000年至2004年）沉积中Kosa的贡献高于1964.4。除2000年夏季福冈采集的样品外，土壤中Si、Al、镧系元素、Th等元素的时间变化与样品总量基本一致。结果表明，沙尘在沙尘总量中占主导地位。1964年3 ~ 5月沉积物样品中的铀浓度、放射性铯的^<137>和U/Th比值明显高于其他月份。1964年的沉积样品似乎反映了春季平流层-对流层空气交换活跃，并受到1962-1963年核试验的影响。少

In this study, major/trace elements and radionuclides in various atmospheric samples, i.e. particulate matter (PM) samples collected weekly at Kawasaki from October 2002 to January 2005 and the bulk deposition samples collected monthly at Fukuoka, Nagasaki, Tsukuba and Kawasaki in 1964 and 2000 to 2004, were determined by using ICP-AES, neutron activation analysis and γ-ray spectrometry. Consequently, we obtained some valuable information in this study as follows ;1.From the correlation coefficient between the concentrations of determined elements, Br-Sb and Sc-Fe-La showed a good correlation, respectively. Considering the size distributions in PM10, it was seen that the contribution of PM10 was higher than that of larger one in Br-Sb and Se-Fe-La, respectively.2.In the average concentrations of radioactivities of ^<210>Pb and ^7Be each direction of the wind, those when the south wind blew were higher than those when the north wind did. It could be seen that ^<222>Rn, the ancestor of ^ … More <210>Pb, was diffusing 1000 times much or more as in the continent compared with in the ocean and ^7Be was influenced by the latitude effect of cosmic rays. Furthermore, it was found that the concentrations of both nuclides in those samples would be dominated by the rainfall.3.It can be seen that the lanthanoid abundance patterns in the Nagasaki depositions from March to May are very similar to that of the yellow soil dust (Kosa) in Nagasaki. This fact shows that the Nagasaki depositions during those months would be strongly influenced by Kosa. In addition, it became clear from the Th/Sc ratios in those samples that the contribution of Kosa was higher in the depositions in recent years (2000 to 2004) than in those in 1964.4.The temporal variation of the elements (Si,Al, lanthanides, Th etc) originated in soil was almost coincided with total amounts of the samples excluding those collected at Fukuoka in summer in 2000. It was suggested that the soil dusts dominated the total amounts of the depositions.5.The concentrations of uranium, radioactivities of ^<137>Cs and the U/Th ratios in the deposition samples in 1964 were apparently higher between March and May than those in other months. It seems that the deposition samples in 1964 reflected the active stratosphere-troposphere air exchange in the springtime and were affected by the nuclear test during 1962-1963. Less