锶-89在模拟水稻田中的动力学行为

采用模拟污染物的同位素示踪技术探索了89Sr在水稻－田水－土壤系统中的消长与分配,并建立了其行为规律的数学模型,结果表明,田表水中89Sr-Sr含量迅速地降低,1d后由原始量的8．5ug/g降为4．0ug/g,以后逐渐降低,至试验结束（28d)时为0．7ug/g,表土中89Sr-Sr含量声速地增大,1d后即由0达12．4ug/g,试验结束时为20．9ug/g,水稻地上部,1d后由0[达8．8ug/g,以后也呈增加趋势,结束时达21．7ug/g,水稻根由1d的9．5ug/g达试试验结束时的39．6ug/g,田表水,表土及不稻植株中89Sr-Sr含量随时间变化的规律相应为：CW＝0.965e^-0.028t 7.635e^-0.470t,C=35.142(e^-0.028t-e^-0.470t),Cz=35.182-23.481e^-0.028t-11.701e^-0.470t。其次,在收获期,糙米中89Sr-Sr含量为1．6ug/g,稻壳为9．4ug/g,稻草为39．7ug/g,稻根为41．8ug/g,还测定了89Sr-Sr在收获期土壤中的铅垂 分布,表明,58．2％的89Sr-Sr滞留于表层2cm,并且其滞留量随土壤深度按指数规律衰减：C＝20.356e^-0.467x(r=-0.9433)。     

青菜-土壤生态系统中氚水的迁移与分布动态

采用模拟污染物的同位素示踪技术研究了两种引入方式（模拟灌溉和降雨）下氘水在青菜-土壤模拟生态系统中的迁移与分布动态,测定了植物和土壤样品中两种形态氚（自由水氚和结合态氚）的比活度,以探明氚水在青菜-土壤系统中的行为特性,不同引入方式对青菜吸收和积累氚水的影响,结果显示：引入土壤中的氚水,不仅在系统各分室间转移和分配,而且迅速向系统外散逸,以自由水氚和结合态氚形式存在于青菜组织中,以吸湿性水氚和结晶水氚存在于土壤,其中自由水氚（或吸湿性水氚）远大于结合态氚（或结晶水氚）;青菜茎中的总氚比活度高于叶和根中的比活度,运用示踪动力学分室模型原理对实验数据进行拟合得;土壤中的比活度C5（模拟灌溉）=91.59e^-0.1002t 99.91e^-9.1105t和Cs(模拟降雨）=78.09e^-0.5115t 48.27e^-0.0475t;青菜植株中的比活度Cv(模拟灌溉）=543.52(e^-0.1002t-e^-9.1105t)和Cv(模拟降雨）=647.07e^-0.5115t 241.28e^-0.0475t;方差分析结果表明各回归方程较好地反应了氚水在青菜-土壤系统中的变化动态。     

Meteorological data and risk assessment in France after the Chernobyl accident (26 April 1986). Historical update

The authors indicate the origin of the data used by the French Public Health Authority in 1986 to estimate the risk of the radioactive fall out following the Chernobyl accident. The technical means developed in order to establish this data, and the precedent experience gained, are described. The principal results are given. The terms of the 28 May 1986 note to the Academy of Sciences by R. Latarjet, which concluded that the low level of this fallout did not justify any countermeasure, except the control of the imported food, are confirmed. Rational dispositions are required in order to improve the information of the population, referring to the Swedish model, which involves the intervention of the medical staff specialized in radiotoxicology, radiopathology, nuclear medicine, and especially trained.     

Assessment of Elevated Radionuclide Levels in Soils Associated with an Avian Colony in a High Arctic Environment

This article presents the results of an investigation into the occurrence of elevated levels of radionuclides in soils associated with a seabird colony in the Arctic. Soils and other materials were collected from a seabird colony (primarily composed of kittiwakes) in Kongsfjorden, located in the High Arctic archipelago of Svalbard. The samples were analyzed for a suite of gamma emitting natural and anthropogenic radionuclides, including ¹³⁷Cs and nuclides of the ²³⁸U and ²³²Th series, to establish the level of enrichment and the behavior of the radionuclides in the immediate area. The results indicate that soils near the colony exhibit enrichment factors of 8 for ¹³⁷Cs, 5 for ²³⁸U and 2 for ²²⁶Ra compared to the nuclide content of soils from the general area. The spatial patterns of the nuclides in the soil are consistent with enrichment of the soil via run-off draining from a large accumulation of fecal and nesting material that has developed at the base of the colony. ¹³⁷Cs ingress to the soil appears to have peaked at some point in the past as patterns of enrichment at the colony are different to those exhibited by ²³⁸U, which must be assumed to be a steady state contribution. The means of introduction of radionuclides to the colony remains unclear but the transfer of ¹³⁷Cs from the marine environment to the terrestrial environment via the food chain and deposition of feces is discussed.     

95Zr在鱼-海水-底泥模拟生态系统中的迁移与分布

采用同位素示踪技术研究了^95Zr在鱼-海水-底泥模拟系统中的迁移与分布。旨在探明海洋鱼类对^95Zr的吸收以及^95Zr在海水生态系统中的行为特性。结果显示：（1）海水中的^95Zr比活度随时间呈快速下降,降至一半所需的时间仅为0.2d;底泥吸附的^95Zr主要集中在表层（0-2.5cm）,至试验后期（13-20d）其量占总量的99.5％以上,表明来自于海水中的^95Zr被表层底泥吸附,不易随渗流水向下迁移,海泥对^95Zr有强烈的吸附作用。（2）中华乌塘鳢从水体中摄入和吸收^95Zr的主要器官是肠胃道（内脏）,与水体直接接触而吸附、吸收的^95Zr主要集中在鱼鳃和鱼鳍中。肉、骨、肝脏和鱼卵中的比活度均比较低（略高于本底水平）,表明通过肠胃道吸收和鳃、鳍等组织吸附、吸收的^95Zr不易向肉、骨、肝脏和鱼卵等内部组织输运。（3）运用封闭3分室模型原理对实验数据进行拟合得：鱼体中的比活度Cf=0.05-6.36e^-3.4274t 6.61e^-0.2682t,海水中的比活度Cw=215.42e^-3.4274t 2.00e^-0.2682t,底泥中的比活度Cs=143.86 14.83e^-3.4274t-158.69e^-0.2682t;方差分析结果表明各回归方程较好地反应了^95Zr在鱼-海水-底泥生态系统中的消长动态。