CHEMOMETRIC STUDIES IN THE LAGOON-OF-VENICE, ITALY - 1 - THE ENVIRONMENTAL-QUALITY OF WATER AND SEDIMENT MATRICES

Water, particulate, and sediments were collected at a few sites in the Venice Lagoon (Italy) in order to evaluate the quality of these compo nents through a number of mainly chemical measurements. Trace elements (mainly heavy metals), nutrients, PCBs, a toxicity test, and other ge neral constituents were the main features considered. Principal compon ent analysis was applied as a multivariate statistical technique for d imensionality reduction, for the formulation of a multivariate quality criterion, and for identification of the most significant variables. The first few (2-3) principal components have proven useful in summari zing the information available in all the observed variables, supplyin g a link between the different classes of chemical substances detected in the water matrix and the different polluting inputs (industrial, a gricultural, urban) to which the Venice Lagoon is subject (water matri x) and between the chemical composition (speciation of trace elements) of the sediment matrix and its toxicity.