Assessment of PCDD/Fs and PCBs in Sediments from the Spanish Northern Atlantic Coast

Surface coastal sediments (0–10 cm) collected from three natural environments on the Spanish Northern Atlantic Coast were analyzed so as to determine concentrations of 6 marker polychlorinated biphenyls (PCBs), 12 dioxin-like PCBs (dl-PCBs) and 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). An analytical procedure based on Soxhlet extraction followed by an automated cleanup and final high-resolution gas chromatography coupled to high-resolution mass spectrometry was applied for the determination of the persistent organic pollutants. Marker PCB levels ranged from 385.5 to 4,060.9 pg/g dry weight (d.w.) showing a similar congener pattern in all sediments dominated by the less volatile congeners PCB 153 and PCB 138. Linear correlations were found between marker and dl-PCBs. Toxicity equivalent values were calculated for PCDD/Fs and dl-PCBs reaching its maximum at 0.52 pg WHO1998-TEQ/g d.w., with an average dl-PCBs contribution on the toxicity of the samples of 75%, and showing to be in good agreement with background levels in the North-East Atlantic Ocean Coasts of nearly 1 pg/g WHO1998-TEQ d.w. Dimensionless environmental quality criteria were much lower than 1 indicating the low probability to induce ecotoxicological impacts.