Spatial and temporal trends of PCBs (polychlorinated biphenyls) in mussel from Galician coast (1998-2008)

PCBs were determined in wild mussel samples collected in several points from Galician Rías (Rías de Ferrol, A Coruña, Muros, Vigo and Arousa), Spain, during the period 1998-2008. The concentration levels of ΣPCBs ranged from 0.62 to 107.5 ng g(-1), w.w. The isomer concentrations in the Mytilus galloprovincialis were in the order hexachlorobiphenyls>pentachlorobiphenyls>tetrachlorbiphenyls>trichlorobiphenyls. CBs 153, 138 and 101 congeners were the most abundant in these samples. Two biological parameters, fat content and condition index (CI), have also been investigated for these mussel samples. Univariate techniques confirm that levels of some compounds, CBs 28, 52, 138, 153, and 180, presented significant relation (p<0.05) with biological parameters. Multivariate techniques of data exploration such as Principal Component Analysis (PCA) showed that spatial trends of PCB levels appeared in the studied samples. Rias de Ferrol and A Coruña presented the highest levels of PCBs and Ría de Arousa the lowest levels of these compounds. In general, temporal trends (linear regressions) showed a decrease of PCB levels along the period 1998-2008.