X-rays Illuminate Toxic Elements
Toxic elements in the environment may occur naturally or because of human activities, such as mining. Whatever their source, the presence of toxic elements is of considerable concern because of their potential effect on organisms and ultimately on human health.
In order to understand how an element moves through the ecosystem, we must determine its precise chemical nature and how that can changed. The chemical form directly affects, among other things, how easily the element can travel through groundwater or be taken up by organisms, and how toxic or benign it might be. The forms of arsenic, for example, which are found in high concentrations in seafood are not toxic, but the free ion arsenite, commonly found in the environment, is deadly.
In the technique of X-ray absorption spectroscopy (XAS), a very intense and highly tuned beam of X-rays illuminates an intact sample and provides detailed information about the local chemical environment of the element. In earlier work at the Stanford Synchrotron Radiation Laboratory in California, Dr. Ingrid Pickering used XAS to investigate various potentially toxic elements occurring in bacteria, plants and insects.
As Canada Research Chair in Molecular Environmental Science, Dr. Pickering will utilize the Canadian Light Source-Canada's first synchrotron- to explore the fate of elements in the environment. One study will investigate the levels and chemical forms of arsenic in various organisms in a natural high-arsenic ecosystem. In another, plants with the unique ability to transport into their leaves and tolerate high concentrations of a toxic element will be examined. Understanding the mechanisms involved will facilitate the possible use of plants to remove the element from contaminated soil or water.