A. Arizzi Novelli

An integrated approach to sediment quality assessment: The Venetian lagoon as a case study

Abstract Recent research trends in sediment quality assessment have demonstrated the need for an integrated approach which combines chemical characterisation with biological effects evaluation, both in the laboratory (toxicity bioassays) and in situ (macrobenthic community structure investigations). The Sediment Quality Triad organises these three aspects of sediment quality assessment in a single approach, where each component is complementary to the others. Considering the lack of previous studies, this preliminary work aimed to verify the potential of an integrated approach in a complex ecosystem, the Venetian lagoon. Five sampling stations along a presumed quality gradient were chosen. The chemical analyses of heavy metals and organic pollutants have been compared with the results of the toxicity bioassays (Microtox ® solid phase, saline extracts and pore water, and sea urchin Paracentrotus lividus sperm cell bioassay performed with saline extracts) and with the characterisation of the infaunal community structure. The results of this first application pointed out the complementarity of the three approaches and the ability of the integrated approach in discriminating different levels of environmental stress. Nevertheless, deeper investigations both on the response of the macrobenthic community to natural variability and on the environmental toxicity of several sulphur compounds (i.e. elemental sulphur) will be necessary.

A Sperm Cell Toxicity Test Procedure for the Mediterranean Species Paracentrotus Lividus (Echinodermata: Echinoidea)

This work describes the procedure developed in our laboratories for performing sperm cell toxicity tests using the autochthonous North Adriatic sea urchin Paracentrotus lividus Lmk. The procedure, derived from Dinnel (1987), was developed following the auto-ecological characteristics of P. lividus and in harmony with US Environmental Protection Agency standard procedures. Experiments conducted over a four-year period using copper as reference toxicant allowed the evaluation of method precision and intralaboratory reproducibility by different operators using organisms from different batches, in changing spatial (sampling sites) and temporal conditions (EC50 0.055 mg l−1 ± 0.0081 SD; CV = 14.7%; n = 25). These experiments with copper provided EC50 and NOEC data (0.032 ± 0.008 mg l−1). Results demonstrated the reliability of the method, as compared to other oceanic sea urchin species.This work describes the procedure developed in our laboratories for performing sperm cell toxicity tests using the autochthonous North Adriatic sea urchin Paracentrotus lividus Lmk. The procedure, derived from Dinnel (1987), was developed following the auto-ecological characteristics of P. lividus and in harmony with US Environmental Protection Agency standard procedures. Experiments conducted over a four-year period using copper as reference toxicant allowed the evaluation of method precision and intralaboratory reproducibility by different operators using organisms from different batches, in changing spatial (sampling sites) and temporal conditions (EC50 0.055 mg l−1 ± 0.0081 SD; CV = 14.7%; n = 25). These experiments with copper provided EC50 and NOEC data (0.032 ± 0.008 mg l−1). Results demonstrated the reliability of the method, as compared to other oceanic sea urchin species.

Effect of Particulate Matter on Copper and Surfactants' Acute Toxicity to Echinogammarus Tibaldii (Crustacea, Amphipoda)

The adsorbent capacity of particulate matter was well demonstrated especially for toxic substances with positive charge. In fact the acute toxicity of copper and cationic surfactants didodecyldimethylammonium bromide and cetyltrimethylammonium bromide towards the Crustacean Amphipod Echinogammarus tibaldii, was considerably reduced by adding fluvial sediment, humic acid and bentonite. For copper the highest detoxification seems to be carried out by humic acids, whereas, for cationic surfactants, by bentonite. The lower or nil detoxification of non ionic (polyethylene glycol dodecyl ether), anionic (sodium dodecylbenzensulphonate) and zwitterionic (tetradecyldimethylammonium propanesulphonate and cetyldimethylammonium methanecarboxylate), and the high detoxification of cationic surfactants, seems to confirm the major role of the “head” groups comparatively to the hydrocarbon tails in the interaction of those substances with the adsorbent materials. Nevertheless bentonite seems to exert a significant detoxi...