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 components through a number of mainly chemical measurements. Trace elements (mainly heavy metals), nutrients, PCBs, a toxicity test, and other general constituents were the main features considered. Principal component analysis was applied as a multivariate statistical technique for dimensionality 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 summarizing the information available in all the observed variables, supplying a link between the different classes of chemical substances detected in the water matrix and the different polluting inputs (industrial, agricultural, urban) to which the Venice Lagoon is subject (water matrix) and between the chemical composition (speciation of trace elements) of the sediment matrix and its toxicity.