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	厦门湾海水中不同粒级铀同位素的深度分布; Depth distributions of size-fractionated U isotopes in Xiamen Bay waters
	彭安国 ; 黄奕普 ; 陈敏 ; 杨伟锋 ; 邱雨生
	2012
关键词	海洋化学 238U 234U 粒级分布 深度分布 海水 厦门湾 marine chemistry 238U 234U size fractionation distribution profile seawater Xiamen Bay
英文摘要	于2003年3月在厦门湾一个时间系列研究站(24°25.88'n,118°04.72'E)采集了高潮时不同深度的海水,用聚碳酸酯膜分离不同粒级悬浮颗粒物(SPM),用α能谱法测定各粒级悬浮颗粒物的铀同位素,研究了海水中238u和234u的体积比活度(AV)、质量比活度(AM)、活度比值[Ar(234u/238u)]及238u、234u条件分配系数的粒级与深度分布特征.研究结果揭示了以下海洋学信息:(1)各粒级悬浮颗粒物中238u、234u的体积比活度和质量比活度的深度分布均表明,这两核素的深度分布趋势一致,反映出它们地球化学行为的一致性.(2)在所研究的不同水深处,在0.2~0.4、0.4~2.0、2.0~10.0、>10.0μM等4个粒级的SPM中,238u体积比活度AV(238u)的变化范围分别为0.04±0.00~0.15±0.01、0.04±0.00~0.13±0.01、0.29±0.02~0.43±0.02、1.06±0.06~4.11±0.24 bQ/M3;AV(234u)的相应值分别为0.08±0.00~0.08±0.00、0.05±0.00~0.13±0.01、0.27±0.01~0.37±0.02、0.84±0.05~3.95±0.24 bQ/M3.(3)在所研究的4个水深处的0.2~0.4、0.4~2.0、2.0~10.0、>10.0μM等4个粒级的SPM中,238u质量比活度AM(238u)的变化范围分别为0.100±0.000~0.319±0.021、0.022±0.000~0.167±0.013、0.049±0.003~0.113±0.005、0.024±0.002~0.081±0.005 bQ/g,而AM(234u)的相应值分别为0.114±0.014~0.364±0.045、0.027±0.005~0.168±0.013、0.052±0.003~0.098±0.008、0.029±0.002~0.064±0.005 bQ/g.(4)与238u、234u体积比活度的粒级变化顺序[也就是AV(>10.0μM)AV(2.0~10.0μM)>AV(0.4~2.0μM)=AV(0.2~0.4μM)]相反,这两核素质量比活度的粒级变化顺序为AM(0.2~0.4μM)≥AM(0.4~2.0μM)>AM(2.0~10.0μM)>AM(>10.0μM)≈AM(>0.2μM).(5)溶解态铀控制着总铀的地球化学行为,而颗粒态铀的地球化学行为则受控于大粒级颗粒物.(6)表层各粒级颗粒态Ar(234u/238u)值均<1.0,而溶解态铀和总铀的Ar(234u/238u)值均介于1.10~1.17之间.(7)不同粒级238u的条件分配系数(kd)介于802~11 406 dM3/kg之间,kd值随粒径减小而增大,意味着铀更有效地与小颗粒物相结合.; With high tide seawater samples collected at different depth of a time-series station(24°25.88′ N,118°04.72′ E)in Xiamen Bay in March 2003,the size-fractionated suspended particulate matter(SPM) were separated with polycarbonate filter membrane and U isotopes were determined with α-spectrametry in the size-fractionated SPM.The depth profiles of the volume-specific activities Av,mass-specific activities Am,AR(234U/238U),and condition distribution coefficient(Kd) of the size-fractionated 238U and 234U were studied.The following oceanographic information were revealed:(1) The volume-and mass-specific activities of the size-fractionated 238U and 234U showed a similar depth distribution feature,which reflected the consistent geochemical behavior of 238U and 234U.(2) At the different depth studied,Av(238U) in the size-fractionated SPM of 0.2--0.4 μm,0.4--2.0 μm,2.0--10.0 μm and>10.0 μm ranged from 0.04±0.00 to 0.15±0.01,from 0.04±0.00 to 0.13±0.01,from 0.29±0.02 to 0.43±0.02 and from 1.06±0.06 to 4.11±0.24 Bq/m3,respectively,and the corresponding Av(234U) were from 0.08±0.00 to 0.08±0.00,from 0.05±0.00 to 0.13±0.01,from 0.27±0.01 to 0.37±0.02 and from 0.84±0.05 to 3.95±0.24 Bq/m3,respectively.(3) At the different depth,Am(238U) in the size-fractionated SPM of 0.2--0.4 μm,0.4--2.0 μm,2.0--10.0 μm and>10.0 μm ranged from 0.100±0.000 to 0.319±0.021,from 0.022±0.000 to 0.167±0.013,from 0.049±0.003 to 0.113±0.005 and from 0.024±0.002 to 0.081±0.005 Bq/g,respectively,and the corresponding Am(234U) were 0.114±0.014--0.364±0.045,0.027±0.005--0.168±0.013,0.052±0.003--0.098±0.008 and 0.029±0.002--0.064±0.005 Bq/g,respectively.(4) In contrast to the variation trends of Av(238U)and Av(234U) the trends of size-fractionation of Av(238U) and Am(234U) was(0.2--0.4 μm) ≥(0.4--2.0 μm)>(2.0--10.0 μm)>(>10.0 μm) ≈(>0.2 μm).(5) While dissolved U controls the total U geochemical behavior,the particulate U geochemical behavior was controlled by large SPM.(6) All size-fractionated AR(234U/238U) in the surface seawater were lower than 1.0,but AR(234U/238U) of the dissolved and total U were all in values of 1.10--1.17.(7) The condition distribution coefficient(Kd) of the size-fractionated 238U varied from 802 to 11 406 dm3 /kg and it increased with the decrease of size-fractionation,which suggest more effective combination of U with small SPM than with large.; 国家自然科学基金资助项目(40806031);南华大学科研资助项目(WT-KF-2010-01;2007×QD36)
语种	zh_CN
内容类型	期刊论文
源URL	[http://dspace.xmu.edu.cn/handle/2288/108180]
专题	环境生态－已发表论文
推荐引用方式 GB/T 7714	彭安国,黄奕普,陈敏,等. 厦门湾海水中不同粒级铀同位素的深度分布, Depth distributions of size-fractionated U isotopes in Xiamen Bay waters[J],2012.
APA	彭安国,黄奕普,陈敏,杨伟锋,&邱雨生.(2012).厦门湾海水中不同粒级铀同位素的深度分布..
MLA	彭安国,et al."厦门湾海水中不同粒级铀同位素的深度分布".(2012).

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