M5 PM Marine Environmental Chemistry of Organic Pollutants
Monday, 14 November 2005: 1:50 PM - 5:30 PM in 321-323

(LIE-1117-761150) Distribution and sources of PAHs in sediments and mussels from the western Baltic Sea.

Liehr, Gladys¹, Witt, Gesine¹, ¹ Baltic Sea Research Institute (IOW), Rostock, Germany

ABSTRACT- During 2002 and 2004, sediment and mussels were sampled at 2 stations (dumping site, reference site) from the Mecklenburg Bight, western Baltic Sea. At each station the concentration, distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediment and soft body tissue of Arctica islandica were investigated and analysed using Gas/Chromatography Mass spectrometry (GC/MS). Bioaccumulation factors (BAFs) of individual compounds from sediment were calculated and discussed according to the compound availability. The total PAH concentration (sum of 2- to 6-ring aromatic hydrocarbons) varied between 50 and 5500 ng/g dw. The highest concentration was measured in surface sediments from the dumping site. The contamination levels were higher by a factor of 80 to 200 as compared to the reference site. A ratio between Phenanthrene/Anthracene to Flouranthene/Pyrene and LMW/HMW (low molecular weight/high molecular weight) indicated that the PAHs in sediments are of pyrogenic origin. Total PAH concentrations in the soft tissue of A. islandica sampled at the dumping site were much higher (>1000 ng/g dw) compared to mussels from the reference site. These extremely high concentrations were just found in mussels which are directly sampled in harbours. Bioaccumulation factors for the PAHs were also higher in mussels from the dumping site. A. islandica was situated on the surface sediment. They were in direct contact with the sediment and were able to absorb particles from the resuspended sediment as well as the dissolved fraction of PAHs. Therefore the lower molecular PAHs (mainly 3-ring aromatics, which are water soluble) were more accumulated than the higher molecular weight, stronger sediment-bounded, compounds (4-6-ring aromatics) at both sites. A lower, decreasing abundance (1 Ind./m²) and a missing of recruits and adult mussels at the dumping site are further indices for unsuitable environmental conditions.

Key words: PAHs, sediment, mussels, Bioaccumulation factor