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2K - Sediment Assays (TUP/151) Response of algal cultures as indicator of wetland sediment toxicity. Trentin, Marina1, Cella, Arianna1, Manente, Sabrina1, Perin, Guido1, 1 Ca’ Foscari University, Venice, VE, Italy ABSTRACT- Lagoon ecosystems are particularly fragile and complex. This complexity is due to the extreme variability of the chemical and physical parameters, for example salinity, pH, sedimentation rate, granulometry. So it becames necessary to use a whole and complete methodology to investigate the effects of a pollution as a sum of single contributes, without the duty of looking for every single one. Bioassays are the principal weapon in this kind of studies. We evaluated the level of toxicity at sediments in a heavy metals polluted lagoon (Lagoon of Grado-Marano, Northern Adriatic Sea), using a native unicellular alga, Skeletonema costatum, tested with three different diluitions of elutriates, obtained from sediments collected in channels of the lagoon. At the same time, analysis were carried on to define the level of total metal and the speciation of the bioavailability geochemical phases. The comparison with chemical and bioavailability analysis of heavy metals in sediments gives information about the influence, in particular of the resuspension on the environment above. Key words: bioassay, sediment, Skeletonema costatum, toxicity |
