Arsenic transformations in the terrestrial environment

众所周知，砷是一种有毒和致癌的物质。这项拟议的研究旨在研究环境中砷的化学形态如何从有毒转变为无毒。一个目标是研究土壤中有毒的砷(无机砷)在蘑菇中转化为无毒的砷甜菜碱。在这样做的过程中，我们希望分离出负责解毒砷的机制，特别是如果这些变化可以在没有生物有机体的情况下发生的话。第二个目标是确定这些解毒机制是否也发生在加拿大的泥炭沼泽中，因为最近的一项研究表明，泥炭沼泽可能是除蘑菇外唯一含有大量毒草甜菜碱的陆地隔间。第三个目标是开发一种方法，在以前的实验中和在环境样本中使用具有成本效益和快速的现场便携式仪器来寻找无毒的毒物甜菜碱。对于这些研究，除了将开发的现场便携式方法外，还将使用基于同步加速器的X射线分析方法(称为X射线吸收光谱)来测量样品中的砷形态，并辅之以我们实验室可以完成的常规测试方法。拟议的工作将使人们深入了解如何通过解毒来改善或管理砷的有害影响，并更基本地了解砷在环境中的行为。

Arsenic is well known as a poison and cancer-causing agent. The proposed research aims to study how the chemical form of arsenic changes from a toxic to a non-toxic form in the environment. One objective is to study the change of toxic arsenic in soil (inorganic arsenic) to non-toxic arsenobetaine in mushrooms. In doing this we hope to isolate the mechanisms that are responsible for detoxifying arsenic and specifically if these changes can take place in the absence of biological organisms. The second objective is to determine if these detoxifying mechanisms also take place in peat bogs in Canada, as a recent study suggests that peat bogs may represent the only other terrestrial compartment besides mushrooms with significant amounts of arsenobetaine. The third objective is to develop a method of looking for non-toxic arsenobetaine in the previous experiments and in environmental samples using a field portable instrument that is cost-effective and quick. For these studies, in addition to the field portable method that will be developed, synchrotron-based X-ray analysis methods (called X-ray absorption spectroscopy) will be used for the measurement of arsenic species in samples, complemented by conventional testing methods that can be done in our laboratory. The proposed work will give insight into how the hazardous effects of arsenic can be ameliorated or managed through detoxification, and a greater fundamental understanding of how arsenic behaves in the environment.