The Importance of Environmental Monitoring Data in Environmental Risk Assessment: An Ecosystem Approach

Abstract

There is a growing interest in assessing risk to non-human biota following exposure to radionuclides. However, before dose to aquatic biota can be determined, it is critical to have a solid understanding of radionuclide concentrations in surface waters due to their importance in determining external and internal dose. Further understanding of a system can be reached by monitoring temporal changes in radionuclide levels in the water, especially if assessing the success of remediation activities. The current study has focused on estimating concentrations of 3H, 90Sr, 137Cs and 60Co in a small, Canadian Shield lake located downstream of two Waste Management Areas at AECL' s, Chalk River Laboratories site over a 40-year period. Overall, it was found that radionuclide activities have declined in the lake over the last 40 years, particularly for 137Cs and 60Co, which are much lower than they had been in the past. Tritium and 90Sr are measurable in the lake water and water represents a key route of exposure for these radionuclides.