Grant: Discovery Grants Program - Individual

Lead and arsenic are toxic elements which are encountered in daily life. Serious health effects may result from chronic exposure to even moderate levels of these elements. The objectives of the proposed research relate to the development of novel x-ray fluorescence (XRF) techniques to detect lead and arsenic, and to uncover how these elements distribute in the body. Specifically, the objectives include the use of XRF in the following interrelated themes of research: (1) the development of a transformative new miniature x-ray tube XRF approach to assess exposure to trace elements at environmental levels; (2) the use of a new synchrotron radiation microprobe to discover the nature of arsenic in human skin; and (3) the use of the highest precision bone lead system in the world to better understand the critical issue of lead kinetics. A miniature x-ray tube approach, applied for the first time to arsenic measurement in skin models or ""phantoms"", has provided a significant step forward over any previous method. Method improvements are proposed, along with careful dosimetry, and experimentation into the novel detection of selenium, lead, and possibly other trace elements of interest. There is currently no detailed understanding of how arsenic distributes in human skin. This is of interest as both a fundamental research question and as a necessary component for the eventual application of the miniature x-ray tube techniques we are developing. A new microprobe technique at the Canadian Light Source will be used to reveal this distribution. The kinetics of lead in the human body is only partially understood. Since the vast majority of lead in the body resides in bone tissue, bone lead measurement is key to solving this puzzle. Major occupational and environmental lead exposure surveys will be undertaken using the world's most sensitive bone lead XRF system, and results used to develop better computer models of lead kinetics.