Environmental application of frozen mitochondria assay: acute toxicity of sediment elutriates.

In an international cooperation contest and subsequent knowledge transfer, we tried to suggest frozen (-24 °C) heart beef mitochondria (FHBM24) assay as one of potential battery of tests, because of its features (really cheap, fast, easily reproducible, highly sensitive). Elutriates from Guanabara Bay (Rio de Janeiro, Brazil) sediments has been tested, in order to define its general acute toxicity for organisms living into its or in the overlying water body. FHBM24 assay can quantify: i) inhibition rate of mitochondrial respiration (measured as oxygen consumption) and ii) the eventual presence of uncoupling compounds. Obtained results clearly showed similar responses from sediments coming from same sampling sub-area. Moreover, alternative use of EDTA or albumine in the assay medium with the elutriates tested, permitted to distinguish respectively heavy metal’s or organic’s action and toxicity load. These information very well match together to chemical analysis of sediments and the corresponding Sediment Quality Guidelines application. Then, we proposed this bioassay like a part of a battery of ecotoxicological tests.