Radiation 2006. In association with the Polymer Division, Royal Australian Chemical Institute. Incorporating the 21st AINSE Radiation Chemistry Conference and the 18th Radiation Biology Conference, conference handbook

Full text: Selenium is an environmentally relevant trace metal, recognised not only for its role as an essential trace nutrient in living systems, but also for its devastating impacts at elevated concentrations, including fish deformities and death from selenium-laden waters and sediment. There are escalating concerns that the consumption of selenium-contaminated foods (e.g. fish and bivalves) will have an impact on human health. A comprehensive understanding of organic and inorganic selenium tissue concentrations is required if we are to assess the toxic effects of selenium in marine organisms and the flow-on effects to human consumers. Currently, whole sediment bioassays measuring total metal concentration effects are being used to assess the toxicity of metal contaminated sediments. However, for most sediment-dwelling organisms, sediments particles, pore waters and overlying waters, as well as food sources (e.g. algae) may all contribute to the accumulation of metal contaminants. Furthermore, the species of metal (and not the total metal concentration) in each of these compartments will also modify metal toxicity and uptake rates. For most species routinely used in toxicity tests, the relative importance of the different contaminant exposure pathways (overlying waters, sediment, food) has not been evaluated. If we know which compartment(s) induce toxic responses in the test organisms, we can use that knowledge to more effectively manage contaminated environments. The radiotracer 75Se produced in HIFAR was used to determine the uptake routes and accumulation sites in biological organisms. Comparatively, high sensitivity of gamma counter techniques and minimal sample preparation to ICP-MS and AAS provided for a faster and more efficient method to monitor the uptake of selenium. Biodistribution studies evaluating the bioavailability of Se from water, sediment and algae in the endemic Australian marine bivalve Anadara trapezia is presently under investigation and progress to date be reported