A multivariate assessment of sediment contamination in dredged materials from Spanish ports

This paper summarises the performance of simple multivariate exploratory analyses to investigate on their potential application for dredged material characterization and management. The data from 25 sampling stations located at 7 different Spanish ports, produced a matrix consisting of 300 observations on 10 variables: the metals Cd, Cu, Cr, Hg, Ni, Pb and Zn, the metalloid As, the sum of PAHs and PCB congeners, and the proportion of fines and organic matter content. The cluster analysis was suitable to separate the sediments according to the extent of contamination while the PCA indicated that the data was defined by two principal factors: a first one that accounts for 56.4% of the total variance, describing the metallic contaminants except Ni and Cr, and a second one that accounts for 14.4% of the total variance describing the organic contaminants PAHs and PCBs. The use of these two simple and untutored multivariate techniques seems a cost-effective approach for future pre-dredging investigations in the studied areas providing useful information for dredged material characterization and management with little additional effort.