Foucher Delphine, Ogrinc Nives, Hintelmann Holger
Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada.
Environ Sci Technol. 2009 Jan 1;43(1):33-9. doi: 10.1021/es801772b.
To demonstrate the power of precise isotope ratio measurements of Hg in environmental samples and, more particularly, to test the use of stable isotopes as distinct tracers of the contamination source, we investigated a well-documented system, the Hg mining region near Idrija, Slovenia. Sediments alongside the Idrijca River, the Soca/Isonzo River, and in the Gulf of Trieste were analyzed to determine the variation in Hg isotopic composition versus distance from the source. Similar Hg isotopic signatures were observed among samples collected from the rivers Idrijca, Soca/Isonzo, and around the river mouth in the Gulf of Trieste, suggesting that sediments throughout the watershed of the Soca/Isonzo River to the Gulf of Trieste are dominated by Hg exported from the headwaters of the Idrijca River. Only locations on the southern part of the gulf, outside the river plume, showed lower values of the isotopic composition comparable to the Hg isotopic signature of Adriatic Sea sediments. Using a simple binary mixing-model, we could demonstrate that all samples investigated in this study were a result of variable proportions of Hg originating from the Idrija region (progressively decreasing from >90% in the northern partto <50% in the southern gulf) and from the Adriatic Sea. These results are, so far, the first evidence that tracking of mercury sources in natural systems using mercury stable isotope ratios is feasible.
为了证明环境样品中汞精确同位素比值测量的强大功能，更具体地说，为了测试稳定同位素作为污染源独特示踪剂的用途，我们研究了一个记录详尽的系统，即斯洛文尼亚伊德里亚附近的汞矿区。对伊德里亚河、索卡河/伊松佐河沿岸以及的里雅斯特湾的沉积物进行了分析，以确定汞同位素组成随距源距离的变化。在从伊德里亚河、索卡河/伊松佐河以及的里雅斯特湾河口周围采集的样本中观察到了相似的汞同位素特征，这表明从伊德里亚河源头输出的汞主导了索卡河/伊松佐河流域直至的里雅斯特湾的沉积物。只有海湾南部位于河羽流之外的地点，其同位素组成值较低，与亚得里亚海沉积物的汞同位素特征相当。使用一个简单的二元混合模型，我们能够证明本研究中调查的所有样本都是源自伊德里亚地区（从北部的>90%逐渐降至南部海湾的<50%）和亚得里亚海的不同比例汞的混合结果。到目前为止，这些结果是使用汞稳定同位素比值追踪自然系统中汞源可行的首个证据。
