Audry Stéphane, Blanc Gérard, Schäfer Jörg
Université Bordeaux 1, UMR CNRS 5805 EPOC, Traceurs Géochimiques et Minéralogiques (T. G. M.), Avenue des facultés, 33405 Talence cedex France.
Sci Total Environ. 2006 Jun 15;363(1-3):216-36. doi: 10.1016/j.scitotenv.2005.05.035. Epub 2005 Jun 24.
The partitioning of particulate trace metals was investigated during one year of monthly sampling of suspended particulate matter (SPM) at eight sites along the Lot-Garonne fluvial system, known for its polymetallic pollution. The chemical partitioning in five operationally defined fractions (exchangeable/carbonate, Fe/Mn oxides, organic matter/sulfides, acid soluble, residual) was determined using a multiple single extraction approach. This approach showed that Cd, Zn, Pb and Cu were mainly associated with acid soluble phases (84-95%, 65-88%, 61-82% and 55-80% of the respective total metal content), and therefore showed a high mean potential of mobilization and bioavailability. In the Riou-Mort River, draining the smelting-wastes, Zn, Cd and Mn showed high mobility as they were little associated with the residual fraction (1-2%) and mainly bound to the 'exchangeable' fraction of SPM (60-80%), probably weakly adsorbed on amorphous freshly-precipitated sulfide and/or oxide phases. Upstream and downstream of the anthropogenic source of metallic pollution, Mn and Cd, and Zn to a lesser extent, remained highly reactive. The other trace metals were mainly associated with the residual fraction and thus less mobile. However, the multiple single extraction scheme revealed that the most reactive transport phases were non-selectively extracted by the conventional extractants used here. These selectivity problems could not have been observed if sequential extraction was used.
在洛特-加龙河流水系的八个地点，对悬浮颗粒物（SPM）进行了为期一年的月度采样，以研究颗粒态痕量金属的分配情况，该水系以多金属污染而闻名。采用多次单次萃取方法，测定了五个操作定义组分（可交换/碳酸盐、铁/锰氧化物、有机物/硫化物、酸溶物、残渣）中的化学分配。该方法表明，镉、锌、铅和铜主要与酸溶相相关（分别占各自总金属含量的84 - 95%、65 - 88%、61 - 82%和55 - 80%），因此显示出较高的平均迁移潜力和生物有效性。在排放冶炼废物的里奥莫尔特河中，锌、镉和锰显示出高迁移性，因为它们与残渣组分的关联较小（1 - 2%），主要与SPM的“可交换”组分结合（60 - 80%），可能弱吸附在新沉淀的无定形硫化物和/或氧化物相上。在金属污染人为源的上游和下游，锰和镉，以及程度稍轻的锌，仍然具有高反应活性。其他痕量金属主要与残渣组分相关，因此迁移性较小。然而，多次单次萃取方案表明，这里使用的传统萃取剂会非选择性地萃取最具反应活性的迁移相。如果使用顺序萃取，这些选择性问题就不会被观察到。
