Arsenic transformations in the human environment

众所周知，砷是一种毒药和致癌剂。我们建议研究砷的化学形式如何在环境中变化，以及这些变化如何影响暴露于砷时对人类有害影响的可能性。我们的目标之一是研究砷的化学形态的变化，从土壤和植物中发现的有毒无机砷到蘑菇中发现的无毒砷甜菜碱。通过这样做，我们希望能够分离出负责将砷从有毒形式转变为无毒形式的确切生物体和机制。我们还将确定杂货店常见的蘑菇中的砷形式，以及其他食品，包括觅食食品，这是一种越来越受欢迎的食品趋势。我们还将研究使用湿地植物去除水和土壤中的砷，这些植物可以吸收高浓度的砷，特别是木贼。在这些研究中，我们将使用我们拥有专业知识的工具：基于同步辐射的X射线分析方法（称为X射线吸收光谱法），辅以常规测试方法，以表征砷的分布;以及称为生物可及性的测试方法。生物可及性测试使我们能够在实验室中模拟人类或动物的胃肠道环境，并为我们提供可溶于人类胃和肠道的砷含量。拟议的工作将深入了解水和土壤砷污染的可能解毒和补救战略，以及加拿大人在食品供应中可能面临的砷暴露和风险。

Arsenic is well known as a poison and a cancer-causing agent. We propose to study how the chemical form of arsenic changes in the environment, and how these changes influence the potential for harmful effects to humans when they are exposed to arsenic. One of our objectives is to study the change of arsenic’s chemical form, from toxic inorganic arsenic, found in soil and plants, to non-toxic arsenobetaine, found in mushrooms. In doing this we hope to isolate the exact organisms and mechanisms that are responsible for changing arsenic from a toxic to a non-toxic form. We will also determine the arsenic forms in mushrooms commonly found in grocery stores, as well as other food products, including foraged foods, an increasingly popular food trend. We will also study the removal of arsenic from water and soil using wetland plants that take up large concentrations of arsenic, specifically Equisetum sp. (horsetails). For these studies we will use tools in which we have expertise: a synchrotron-based X-ray analysis method (called X-ray absorption spectroscopy), complemented by conventional testing methods, to characterize the distribution of arsenic; and a testing method called bioaccessibility. Bioaccessibility testing allows us to mimic the gastro-intestinal environment of humans or animals in a laboratory, and gives us the amount of arsenic that is soluble in the human stomach and intestines. The proposed work will give insight into possible detoxification and remediation strategies for arsenic contamination of water and soil, as well as the possible arsenic exposures and risks that Canadians may face in their food supply.