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

大气环境中放射性核素和微量元素的来源和行为研究

基本信息

批准号：
15510012
负责人：
HONDA Teruyuki
金额：
$ 2.11万
依托单位：
Musashi Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

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

本研究采用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大气颗粒物（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气沉积物样品中的常量/微量元素和放射性核素进行了测定。结果表明：（1）从被测元素浓度间的相关系数来看，Br-Sb和Sc-Fe-La的相关性较好。从PM10的粒径分布来看，Br-Sb和Se-Fe-La中PM10的贡献大于较大粒径的贡献。2.在各风向的^ Pb和^7Be放射性平均浓度<210>中，南风时高于北风时。可以看出，^<222>Rn，^的祖先， ...更多信息 <210>Pb在大陆中的扩散量是海洋中的1000倍或更多，而^7Be则受到宇宙射线纬度效应的影响。3.长崎3 ~ 5月沉积物中镧系元素的丰度模式与长崎黄土尘（Kosa）中镧系元素的丰度模式非常相似。这一事实表明，在这几个月里，长崎的证词将受到高砂的强烈影响。此外，从Th/Sc比值可以看出，近几年（2000 ~ 2004年）的沉积物中，Kosa的贡献比1964年有所增加。4.土壤中来源的元素（Si、Al、镧系元素、Th等）的时间变化与除2000年夏季在福冈采集的样品外的样品总量基本一致。1964<137>年3 ~ 5月沉积物中铀浓度、~（13）Cs放射性活度和U/Th比值明显高于其他月份。1964年的大气沉降样品反映了春季平流层-对流层空气交换的活跃，并受到1962-1963年核试验的影响。少