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.