Grant: Alliance Grants

Natural radiation is all around us yielding inevitable exposure for both humans and non-human biota. Exposure can occur from natural radiation, normal human practices (such as medical radioisotope use), and potential accidental or malicious release of radioactive material into the environment. Public concerns related to nuclear technology need to be addressed, and a fundamental question from the public answered: "Are we safe?". Radiation dosimeters are routinely used with occupationally exposed workers. However, the average members of the public and certainly non-human biota do not have any sort of physical dosimetry routinely. When dosimeters are not utilized before a planned or unplanned exposure, the only method to perform direct physical measurement of ionizing radiation dose is to use retrospective dosimetry. There are, however, only a few methods to perform experimental retrospective dosimetry on human and non-human biota. At moderate to low doses, the only suitable retrospective physical dosimetry techniques are electron paramagnetic resonance (EPR) spectroscopy and optically stimulated luminescent (OSL) dosimetry. Those dosimetry techniques can be performed on biological samples of teeth, bone, fingernails/toenails, hair, and shells, and inorganic materials such as salts, glass, semiconductor materials and the like. This research program will investigate applications of physical retrospective dosimetry in and around nuclear facilities and at other locations where ionizing radiation exposure may be a risk factor. This research will explore novel and serendipitous materials to be used for retrospective dosimetry and promote how these measurements may be used in environmental assessment, chronic exposure evaluation, and accident dosimetry. This research will help fill a gap in Canada for retrospective physical dosimetry, and supplement currently used indirect methods to estimate dose to human and non-human biota, namely, indirect environmental measurement, environmental modelling, and epidemiology. The results will assist utilities, regulators, stakeholders, and policymakers better communicate risk from ionizing radiation exposure to the public.