Radium effects on aquatic organisms (radiation)

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Canada is one of the few countries actively involved in the full nuclear fuel cycle, including uranium mining and milling, fuel refining and fabrication, nuclear power and medical isotope generation and associated waste management. Currently, all operating uranium mines in Canada are located in Saskatchewan and two more mines/mills in this province could be developed. This intense Canadian involvement in the nuclear fuel cycle and stringent regulatory oversight has significant economic benefits to the country. The mining, milling and refining of uranium associated with this fuel cycle produces residues. Canadian regulations require safe management of these residues, including process wastewaters, tailings and waste rock stockpiles. Among the radionuclides of concern, radium (Ra-226) is of particular importance due to its long half-life (~1600 years), the hazards associated with its immediate daughter (radon), its high mobility under a number of common environmental conditions and its potential for bioaccumulation in tissues. While there are Canadian regulatory limits for radium in mining effluents, there is no Ra-226 guideline for the protection of aquatic life.The overall objective of this project is to provide the Canadian Nuclear industry and environmental regulators essential radium toxicity data for 13 key aquatic organisms. The specific research objectives are: 1) to identify sensitive endpoints to quantify low-level effects of Ra-226 on aquatic organisms; 2) to generate a coherent set of Ra-226 chronic toxicity data using aquatic organisms at environmentally relevant activity concentrations of radium; 3) to develop robust analytical procedures with inter-laboratory cross validations to quantify low activities of Ra-226 in environmental matrices (water and tissues); 4) to quantify Ra-226 bioaccumulation in selected organisms to feed dose modelling approaches by our project partners. The toxicity test results will allow the generation of a Species Sensitivity Distribution (SSD) necessary to derive a water quality guideline for the protection of aquatic life in Canada. The long-term goal is to establish a radiotoxicity research network to develop methods and technologies and train future scientists.