Fianco Ana C B, Roisenberg Ari, Bonotto Daniel M
Instituto de Geociencias, Universidade Federal do Rio Grande do Sul, Rio Grande do Sul, Brazil.
Isotopes Environ Health Stud. 2013;49(1):122-31. doi: 10.1080/10256016.2012.709243. Epub 2012 Aug 2.
The equivalent uranium (eU) activity concentration was analysed in selected granite samples at several sites in Porto Alegre, Southern Brazil, to obtain information on the radon ((222)Rn) generation by the aquifer rock matrices. Radon analyses of ground water and soil samples were also performed. Several samples exhibited a dissolved (222)Rn activity concentration exceeding the World Health Organization maximum limit of 100 Bq l(-1). The dissolved radon content in ground waters from the Fractured Precambrian Aquifer System exhibited a direct significant correlation with the eU in the rock matrices, which is a typical result of water-rock interactions. Variation in the soil's porosity was confirmed as an important factor for (222)Rn release, as expected, due to its gaseous nature. Thus, although the calcic-alkaline to alkaline Precambrian granitoid rocks of the study area are important reservoirs for underground resources, they can release high amounts of radon gas into the liquid phase.
对巴西南部阿雷格里港几个地点的选定花岗岩样本中的等效铀（eU）活度浓度进行了分析，以获取有关含水层岩石基质产生氡（(222)Rn）的信息。还对地下水和土壤样本进行了氡分析。几个样本的溶解(222)Rn活度浓度超过了世界卫生组织规定的100 Bq l(-1)的最大限值。前寒武纪裂隙含水层系统地下水中的溶解氡含量与岩石基质中的eU呈直接显著相关，这是水 - 岩相互作用的典型结果。正如预期的那样，由于氡的气态性质，土壤孔隙率的变化被确认为(222)Rn释放的一个重要因素。因此，尽管研究区域的钙碱性至碱性前寒武纪花岗岩类岩石是地下资源的重要储存库，但它们会向液相中释放大量的氡气。
