Arsenic (As), antimony (Sb) and mercury (Hg) have been heavily used throughout the last century and a half as pesticide, chemical weapons, flame retardants, in plastics and in ammunition, as amalgam for gold mining or as chemical catalysts. It was only recently that their negative impacts on the environment and humans have been evaluated. Such investigations almost always originated from reported environmental and human catastrophes. In the case of Hg, it was the Minamata Bay catastrophe in Japan. For As, it was the discovery of very high levels of naturally present As in the groundwater in SE Asia, impacting up to 100 million people. Sb has been much less studied than As or Hg and there is only very little legislation on this element although initial findings show that its behavior and toxicity are similar to As. However, these issues also exist locally. In Switzerland, 15-20t of Sb enters the soil each year through shooting activities while an important Hg pollution exists in Valais between Visp and Raron. Finally, hot-spots of naturally occurring As exist in the Jura, the Valais and in Tessin.
Our main goal is to study the behavior of As, Sb and Hg in soils in Switzerland in order to contribute to the remediation efforts in locally polluted areas. Our research also takes place in polluted areas of Bangladesh and of China so that we can understand the global behavior of these pollutants. Our focus is on assessing the microbial transformation of As, Sb and Hg in soils (e.g. biomethylation and biovolatilisation) by developing new analytical techniques (speciation analysis using chromatography and mass spectrometry). With these techniques we are able to precisely measure the different chemical species of these pollutants. Furthermore, our goal is to evaluate the influence of agricultural practices and climate change on these chemical species.
