Bonotto Daniel Marcos, Oliveira Ana Maria Marinello Assis de
Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista (UNESP), Câmpus de Rio Claro, Av. 24-A No.1515, C.P. 178, CEP 13506-900, Rio Claro, São Paulo, Brazil.
Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista (UNESP), Câmpus de Rio Claro, Av. 24-A No.1515, C.P. 178, CEP 13506-900, Rio Claro, São Paulo, Brazil.
J Environ Radioact. 2017 Jun;172:15-23. doi: 10.1016/j.jenvrad.2017.03.006. Epub 2017 Mar 14.
Po and Pb activity concentrations in spas groundwaters occurring at São Paulo (SP) and Minas Gerais (MG) states, Brazil, have been reported in this paper with a dual purpose: to compare different indices for evaluating the radionuclides mobility into waters and to evaluate the drinking water quality from dose calculations. The waters (75 sampling points) are extensively used for drinking in public places, bottling and bathing purposes, among other. The samples were taken from springs and wells drilled at different aquifer systems inserted in Paraná and Southeastern Shield hydrogeological provinces. The WHO guideline reference value for Pb and Po of 0.1 Bq/L in drinking water was not reached for Pb but the Po levels were equal or above it in four spas groundwaters from MG State. The maximum WHO guidance dose level of 0.1 mSv/yr was also reached or surpassed in them. The Pb "mobility index" taking into account the ratio of the weight of the dissolved Pb per unit volume of solution to its weight per unit weight of the rock matrix yielded values in the range of 0.01-5.2 kg/m. Another "mobility index" (Preference Ratio) expressing the ratio of Pb and U in the waters divided by the ratio of Pb and U in the rock matrices provided values between 0.004 and 7994. The Pb/U activity ratios of some spas groundwaters suggested preferential U transport relative to Pb into the liquid phase, whereas the ratio of the Pb to U mobility indices indicated the opposite. Such finding showed a better usefulness of the mobility indices for evaluating processes affecting the radionuclides release into the liquid phase during the water/rock interactions.
本文报道了巴西圣保罗州（SP）和米纳斯吉拉斯州（MG）温泉地下水中钋（Po）和铅（Pb）的活度浓度，目的有二：比较评估放射性核素在水中迁移的不同指标，并通过剂量计算评估饮用水质量。这些水（75个采样点）广泛用于公共场所饮用、瓶装和洗浴等用途。样本取自巴拉那和东南地盾水文地质省内不同含水层系统中的泉水和钻孔井水。饮用水中铅和钋的世界卫生组织指导参考值为0.1 Bq/L，铅未达到该值，但米纳斯吉拉斯州的四个温泉地下水中钋的含量等于或高于该值。它们还达到或超过了世界卫生组织的最大指导剂量水平0.1 mSv/年。考虑单位体积溶液中溶解铅的重量与其在岩石基质中单位重量之比的铅“迁移指数”值在0.01 - 5.2 kg/m范围内。另一个“迁移指数”（偏好比）表示水中铅和铀的比值除以岩石基质中铅和铀的比值，其值在0.004至7994之间。一些温泉地下水的铅/铀活度比表明相对于铅，铀更优先向液相迁移，而铅与铀迁移指数的比值则表明情况相反。这一发现表明迁移指数在评估水/岩相互作用过程中影响放射性核素释放到液相的过程方面更有用。
