Multivariate data analysis of sea waters and mussels in relation to pollution sources of trace elements

The total concentration of Cu, Zn and Pb in surface sea waters from the Bay of Muggia (Gulf of Trieste, Northern Adriatic Sea) was determined by anodic stripping voltammetry. The association of these trace elements in relation to the known sources of pollution was discussed. The content of eight trace elements (Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb) in the soft part of mussels (Mytilus galloprovincialis Lamarck) is also considered. The wild molluscs were sampled in the harbour of Trieste, in the proximity of an important city sewer. Principal component analysis was used to analyse the correlation matrix obtained from an 8 x 43 data matrix after a logarithmic transformation of the concentration variables. Eight variables were reduced to four principal components, which explained 80% of the total variance. The orthogonally rotated factor matrix shows that Co, Ni, Cd, and Pb are associated with the first principal component, Cu and Zn to the second, Hg to the third and Mn to the fourth principal component. The results of this multivariate data analysis are compared with those already obtained from two sampling sites in the Bay of Muggia and the origin of some trace metals in the soft part of mussels from the Gulf of Trieste is discussed.