Chronic toxicity of uranium to three benthic organisms in laboratory spiked sediment

International audienceDue to mining activities, concentration of uranium (U) in the environment nearby operating sites can significantly increase. The derivation of quality criteria for U in freshwater ecosystems, rivers and lakes includes the consideration of contaminated sediments and the associated risk to the benthic life. Therefore, the derivation of a quality criteria for sediment has been viewed as a logical and necessary extension of the work already done to establish water quality criteria. In order to contribute to the determination of a Quality Standard for sediment (QSsediment) according to the European recommendations, this study focuses on the acquisition of a new toxicity dataset. Three complementary benthic organisms (Chironomus riparius, Hyalella azteca, Myriophyllum aquaticum) were chronically exposed to U spiked to a standard laboratory-formulated sediments, according to their related bioassay guidelines (ISO/FDIS16303, OECD 218/9, ISO/DIS 16191). Results obtained regarding the toxicity of U made it possible to determine a QSsediment value of 4 mgU kg-1 dry mass. This value was shown conservative compared to the toxicity already reported in the literature for U in natural sediments