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2K - Sediment Assays (TUP/154) a comparison of sediment toxicity using different trophic organisms. Del Valls, Angel1, Guerra, Roberta2, Iacondini, Antonella3, 1 University of Cadiz, Puerto Real, Cadiz, Spain2 University of Bologna, Ravenna, Ravenna, Italy3 Montecatini Environmental Research Centre, Marina di Ravenna, Ravenna, Italy ABSTRACT- The main aim of this work was to study the feasibility of using different trophic organisms to evaluate the toxicity of sediments from a coastal lagoon. A total of six sediment samples collected from selected sites - representing a gradient of contamination - were analysed for total concentrations of Cd, Cr, Cu, Hg, Ni, Pb, and Zn, total organic carbon, acid volatile sulfides and simultaneously extracted metals, and organic micropollutants. Sediment elutriates were also analysed for the various metal concentrations, as well as nutrient content. Elutriate sediment toxicity tests were conducted with the rotifer Brachionus plicatilis, using its population decline (LT50) as a test endpoint. A commercially available test using bacteria (Microtox test) was also employed to test both the solid and liquid phase of the sediments. The results of Microtox test on solid phase, bioassay test with rotifers on elutriate phase of sediments, and a 10-day survival assay with the amphipod Corophium volutator were compared with a set of physico-chemical properties of sediments and elutriates. The outcomes of this study show that a combination of a liquid-phase bioassay using rotifers and a solid-phase bioassay using amphipods should be used for an in-depth investigation of sediment toxicity; however Microtox test could serve as a screening test to discriminate between highly and low toxic sediment samples. Key words: AVS/SEM, sediment toxicity, micropollutants, heavy metals |
