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(W/EH035) Dose-response relationship of Benzo[a]pyrene exposure and DNA adduct formation in Baltic Sea blue mussels, Mytilus edulis. Skarphedinsdottir, Halldora1, Ericson, Gunilla2, Dalla Zuanna, Lisa2,3, Gilek, Michael1, 1 2 3 ABSTRACT- Monitoring of DNA adduct formation provides one of the best means to detect exposure to polycyclic aromatic hydrocarbons (PAHs). Studies on DNA adducts in aquatic organisms have mainly focused on fish, but comparably little is known about DNA adduct formation in mussels, despite their world-wide use in environmental monitoring. In this study we exposed Baltic Sea blue mussels (Mytilus edulis) to different doses of the genotoxic model substance benzo[a]pyrene (B[a]P), to established the dose-response relationship of DNA adduct formation. Bioaccumulation of B[a]P and DNA adduct formation in the mussels were determined after exposure to 5ml/l, 50ml/l and 100ml/l of radiolabelled B[a]P, under semi-static conditions for 4 days. DNA adducts were analysed in gill and digestive gland tissue, using the 32P postlabelling method, and B[a]P bioaccumulation was measured in gill, digestive gland and the rest of the mussel with liquid scintillation counting. The bioaccumulation results showed that B[a]P concentration in all tissue types increased with higher doses of B[a]P, with the highest concentration found in the digestive gland, and lowest in the rest of the mussel. Although the highest B[a]P concentration was found in the digestive gland, there was no significant formation of DNA adducts in this tissue. DNA adducts were on the other hand formed in the gills, with the highest DNA adduct levels in mussels exposed to 50ml B[a]P/l (5,9 ± 1,3 nmol adducts/mol nucleotides, mean ±SE) and in mussels exposed to 100ml B[a]P/l (5,2 ± 0,9 nmol adducts/mol nucleotides, mean ± SE). Key words: DNA adducts, Mytilus edulis, benzo[a]pyrene, dose-response |
