ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France; IRSN/PRP-ENV/SESURE/Laboratoire d'études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex, France.
IRSN/PRP-ENV/SESURE/Laboratoire d'études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex, France.
Sci Total Environ. 2016 Oct 1;566-567:238-249. doi: 10.1016/j.scitotenv.2016.04.213. Epub 2016 May 21.
The purpose of this study is to evaluate the contamination in As, Ba, Co, Cu, Mn, Ni, Sr, V, Zn and REE, in a high uranium activity (up to 21,000Bq∙kg(-1)) area, downstream of a former uranium mine. Different geochemical proxies like enrichment factor and fractions from a sequential extraction procedure are used to evaluate the level of contamination, the mobility and the availability of the potential contaminants. Pb isotope ratios are determined in the total samples and in the sequential leachates to identify the sources of the contaminants and to determine the mobility of radiogenic Pb in the context of uranium mining. In spite of the large uranium contamination measured in the soils and the sediments (EF≫40), trace element contamination is low to moderate (2<EF<5), except for Ba (5<EF<15), due to the precipitation of barium sulfate resulting from mining activities. Most of the trace elements are associated with the most mobile fractions of the sediments/soils, implying an enhanced potential availability. Even if no Pb enrichment is highlighted, the Pb isotopic signature of the contaminated soils is strongly radiogenic. Measurements performed on the sequential leachates reveal inputs of radiogenic Pb in the most mobile fractions of the contaminated soil. Inputs of low-mobile radiogenic Pb from mining activities may also contribute to the Pb signature recorded in the residual phase of the contaminated samples. We demonstrate that Pb isotopes are efficient tools to trace the origin and the mobility of the contaminants in environments affected by uranium mining.
本研究的目的是评估一个高铀活动（高达 21000Bq·kg(-1)）地区下游的砷、钡、钴、铜、锰、镍、锶、钒、锌和稀土元素的污染情况。采用富集因子和顺序提取程序的不同地球化学示踪剂来评估污染水平、潜在污染物的迁移性和可用性。在全样和顺序浸出物中测定 Pb 同位素比值，以识别污染物的来源，并确定铀矿开采背景下放射性 Pb 的迁移性。尽管土壤和沉积物中测量的铀污染很大（EF≫40），但微量元素污染较低至中等（2<EF<5），除了钡（5<EF<15），这是由于采矿活动导致硫酸钡的沉淀。大多数微量元素与沉积物/土壤中最易迁移的部分有关，这意味着潜在可用性增强。即使没有 Pb 富集的迹象，受污染土壤的 Pb 同位素特征也具有很强的放射性。对顺序浸出物的测量表明，放射性 Pb 被输入到受污染土壤中最易迁移的部分。采矿活动中低迁移性放射性 Pb 的输入也可能导致受污染样品残余相中记录的 Pb 特征。我们证明，Pb 同位素是追踪铀矿开采影响环境中污染物来源和迁移性的有效工具。
