Levels and Distribution Patterns of Polychlorinated Biphenyl Congeners in Surface Sediments from Galicia Coast (North-Western, Spain) According to Granulometric Characteristics

Abstract

In order to know distribution patterns of polychlorinated biphenyl congeners in the marine environment from Galicia, PCBs n° 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180 were isolated by Soxhlet extraction from three fractions of different particle size (<0.063 mm, 0.063–0.2 mm and >0.2 mm) in surface marine sediments; the quantification was performed using GC-MS and GC-ECD. Distribution of PCB congeners was shifted in favour of higher chlorinated compounds (CBs 138, 153 and 180) and highly correlated to TOC content. In general, the finest fractions (<0.063 mm) of sediment presented the highest loadings of PCBs, only the sediment from As Pías zone exhibited the highest concentration of chlorinated congeners in the coarsest fraction. CB 52 concentration, slightly volatile compound, was related to water temperature. By means of multivariate techniques of data exploration as hierarchical cluster analysis and principal components analysis, sediment samples from un-contaminated and slightly contaminated areas were clearly separated; groupings between samples from nearby zones appeared.

Keywords:

• Polychlorinated biphenyls (PCBs)
• surface marine sediments
• Principal components analysis (PCA)
• Hierarchical Cluster Analysis (HCA)