Dias Cíntia Melazo, Telles Everaldo C, Santos Roberto Ventura, Stenström Kristina, Nícoli Iêda Gomes, da Silveira Corrêa Rosangela, Skog Göran
National Commission of Nuclear Energy, Brasilia, Brazil.
J Environ Radioact. 2009 Apr;100(4):348-53. doi: 10.1016/j.jenvrad.2008.12.017. Epub 2009 Feb 11.
Nuclear power plants release (14)C during routine operation mainly as airborne gaseous effluents. Because of the long half-life (5730 years) and biological importance of this radionuclide (it is incorporated in plant tissue by photosynthesis), several countries have monitoring programs in order to quantify and control these emissions. This paper compares the activity of (14)C in soils taken within 1km from a Brazilian nuclear power plant with soils taken within a reference area located 50km away from the reactor site. Analyses of total carbon, delta(13)C and (137)Cs were also performed in order to understand the local soil dynamics. Except for one of the profiles, the isotopic composition of soil organic carbon reflected the actual forest vegetation present in both areas. The (137)Cs data show that the soils from the base of hills are probably allocthonous. The (14)C measurements showed that there is no accumulation due to the operation of the nuclear facility, although excess (14)C was found in the litter taken in the area close to power plant. This indicates that the anthropogenic signal observed in the litter fall has not been transferred yet to the soil. This study is part of an extensive research programme in which other samples including air, vegetation and gaseous effluents (taken in the vent stack of the Brazilian nuclear power reactors Angra I and II) were also analyzed. The present paper aimed to evaluate how (14)C emissions from the nuclear power plant are transferred and stored by soils present in the surroundings of the reactor site. This is the first study concerning anthropogenic (14)C in soils in Brazil.
核电站在日常运行过程中主要以气态空气污染物的形式释放碳 - 14。由于这种放射性核素的半衰期很长（5730年）且具有生物学重要性（它通过光合作用被植物组织吸收），几个国家都设有监测项目以量化和控制这些排放。本文比较了巴西一座核电站周边1公里范围内土壤中的碳 - 14活度与距离反应堆场址50公里处参考区域土壤中的碳 - 14活度。还对总碳、δ(13)C和铯 - 137进行了分析，以了解当地土壤动态。除了其中一个剖面外，土壤有机碳的同位素组成反映了两个区域实际存在的森林植被情况。铯 - 137数据表明，山脚下的土壤可能是外来的。碳 - 14测量结果显示，尽管在靠近核电站区域采集的凋落物中发现了过量的碳 - 14，但核设施运行并未导致土壤中碳 - 14积累。这表明在凋落物中观察到的人为信号尚未传递到土壤中。本研究是一项广泛研究计划的一部分，该计划还分析了包括空气、植被和气态污染物（取自巴西安格拉一号和二号核电站反应堆通风烟囱）在内的其他样本。本文旨在评估核电站排放的碳 - 14如何被反应堆场址周边土壤转移和储存。这是巴西关于土壤中人为碳 - 14的第一项研究。
