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(W/EH101) Polychlorinated naphthalene levels and congener patterns in benthic food chains in the Baltic sea. Lundgren, Kjell1, Ishaq, Rasha2, van Bavel, Bert1, Broman, Dag2, Tysklind, Mats1, 1 2 ABSTRACT- Polychlorinated naphthalenes (PCNs) have been commercially produced and used mainly in electrical devices. In addition this group of compounds has also been found as a by-product in technical PCB mixtures. PCN congeners are found as contaminants in samples from all compartments of the environment. In background sediments PCNs are generally present at low levels (pg/g dry weight). Reported PCN levels in biota are typically in the range of ng/g lipid weight to Key words: polychlorinated naphthalenes, baltic sea, benthic food chain, accumulation |
g/g lipid weight. Some of the PCN congeners have been identified as highly persistent and bioaccumulate in organisms. In toxicological tests 2,3,6,7-chlorine-substituted PCNs show similar toxicity as the mono-ortho-PCBs, i.e. three orders of magnitudes less toxic compared to TCDD. Polychlorinated naphthalene levels and congener patterns in a benthic food chain, surface bottom sediment - amphipods (Monoporeia affinis) - isopods (Saduria entomon) - fourhorned sculpin (Oncocottus quadricornis), in the Baltic sea were studied in one sampling site near Stockholm and another near Ume&adot; in the north of Sweden. The analyses of the samples show that the surface sediment average load of PCNs is nine times higher outside Stockholm (840 pg/g dry weight) compared to the location outside Ume&adot; (89 pg/g dry weight). The difference in PCN levels between the stations is less pronounced in biota. The average levels in Amphipods are 32 ng/g lw (Stockholm) and 12 ng/g lw (Ume&adot;). For the top consumers, isopods (7.5 ng/g lw and 8.5 ng/g lw) and fourhorned sculpins (1.2 ng/g lw and 1.3 ng/g lw), the PCN levels are very similar. Low chlorinated naphthalenes are found in the food chain base. Higher chlorinated homologues accumulate in the top of the chain.