D2.1.1.4-Stima valori fondo

A robust assessment of the environmental quality of Venice lagoon should consider the concentration of trace elements naturally occurring in the sediment as a combination of waterborne (freshwater and seawater) and atmospheric inputs. Such concentrations, also called background values, are useful to support data evaluation and time trend analysis in order to understand the extent of anthropogenic influence on the chemical status. The assessment of sediment quality is indeed essential to confirm the achievement of the good ecological status for transitional water bodies as required by the EU Water Framework Directive (EC, 2000). In addition, sediment quality is crucial for the lagoon management and especially to allow the reuse of dredged sediments while preserving the quality and the overall biodiversity of the lagoon ecosystems. In this context, task T2.1.1.2 aims to i) collect and analyse the background values available in the literature for selected metals (i.e. As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in the Venice lagoon; ii) review approaches and methods used to derive such background values; iii) process data available in the literature (e.g. undisturbed radio dated cores from the Venice lagoon), and finally iv) propose ranges of background values for the entire lagoon as well as its sub-basins.