Chen Jiubin, Gaillardet Jérôme, Louvat Pascale
Equipe Géochimie et Cosmochimie, Institut de Physique du Globe de Paris (IPGP), Université Paris-Diderot, UMR CNRS 7154, 4 place Jussieu, 75252 Paris, France.
Environ Sci Technol. 2008 Sep 1;42(17):6494-501. doi: 10.1021/es800725z.
The use of zinc (Zn) isotope ratios as a tracer of anthropogenic contamination has been assessed using an extensive collection of river water samples from the Seine River basin (France) collected between 2004 and 2007. The 66Zn/64Zn ratios (expressed as delta66Zn) of dissolved Zn have been measured by MC-ICP-MS after chemical separation of Zn using an improved technique adapted to large volumes of water. Significant isotopic variations (0.07-0.58 per thousand) occur along a transect from pristine areas of the Seine basin to the estuary and with time in Paris, and are coherent with the Zn enrichment factor. Dissolved Zn in the Seine River displays conservative behavior, making Zn isotopes a good tracer of the different sources of contamination. Dissolved Zn in the Seine River is essentially of anthropogenic origin (> 90%) compared to natural sources (< 7%). Roof leaching from Paris conurbation is a major source of Zn, characterized by low delta66Zn values that are distinct from other natural and anthropogenic sources of Zn. Our study highlights the absence of distinctive delta66Zn signatures of fertilizer, compost or rain in river waters of rural areas, and therefore suggests the strong retention of Zn in the soils of the Basin. Our study demonstrates that Zn isotope ratios will be a powerful new tool to trace pathways of anthropogenic Zn in the environment.
利用2004年至2007年期间从法国塞纳河流域采集的大量河水样本，评估了锌（Zn）同位素比值作为人为污染示踪剂的用途。在采用适用于大量水样的改进技术对锌进行化学分离后，通过MC-ICP-MS测量了溶解态锌的66Zn/64Zn比值（以δ66Zn表示）。从塞纳河流域的原始区域到河口，以及在巴黎随时间变化，均出现了显著的同位素变化（千分之0.07 - 0.58），且与锌富集因子一致。塞纳河中的溶解态锌表现出保守行为，这使得锌同位素成为不同污染来源的良好示踪剂。与自然来源（<7%）相比，塞纳河中的溶解态锌主要源自人为活动（>90%）。巴黎都市圈的屋顶淋溶是锌的主要来源，其特点是δ66Zn值较低，这与锌的其他自然和人为来源不同。我们的研究强调，农村地区河水中不存在化肥、堆肥或雨水的独特δ66Zn特征，因此表明流域土壤对锌有很强的截留作用。我们的研究表明，锌同位素比值将成为追踪环境中人为锌路径的有力新工具。
