Detalle de: Input Characterization of Sedimentary Organic Contaminants and Molecular Markers in the Northwestern Mediterranean Sea by Exploratory Data Analysis

Deposition zones of the NW Mediterranean were characterized according to the source of organic pollutants (i.e., UCM, PAHs, PCBs, DDTs) and lipidic compounds (i.e., alkanes and sterols) identified in surface sediments (31 samples) by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Score plots of the two main principal components showed a cluster comprising the off-shore Barcelona and Rhône prodelta samples corre sponding to the most polluted samples, while the remaining samples were clustered together. Loading plots revealed that most of the compounds were present in the first component except benzo[ ghi ]fluoranthene, the major DDT metabolites (i.e., DDE and DDD), and perylene, which was probably of diagenetic origin. In order to define further the cluster containing the most samples, a second data base that excluded the Rhône and offshore Barcelona samples was constructed. Score plot of the two principal components showed that three different depositional environ ments could be clearly defined, namely the Gulf of Lions, the Ebro prodelta, and the deep sea basin. Similar clustering was confirmed by HCA. The loading plots enabled riverine-transported compounds such as n -alkanes, PCBs, DDTs, sterols, and perylene (first component) to be distinguished from pyrolytic PAHs (second component). Furthermore, in order to obtain an apportionment of the inputs received to each station, a recently developed factor analysis multivariate curve resolution (MCR) method based on the alternating least squares (ALS) positive factorization of a data matrix was carried out for the first time on marine sediment samples. The ALS positive matrix factoriza tion method enabled the apportionment of the environmental source of the main components of the compounds in the area of study.