Experimental results on bioaccumulation of metals and organic contaminants from marine sediments

A test-system for the assessment of bioavailability and bioaccumulation of metals and organic contaminants in marine benthic organisms is described and results from studies where this system has been applied are assessed. Sediments tested were polluted harbour sediment (from Norway), and clean sediments spikes with metal containing weight materials for drilling muds. Contaminants that may bioaccumulate under relevant conditions are indicated. The test-system uses two species of ecological relevance (Nereis diversicolor and Hinia reticulata). Interspecies differences in bioaccumulation were found for several compounds, which show the importance of using species with different modes of living in such tests. Compared to other PAHs, pyrene was found to bioaccumulate to a high degree (BioAccumulation Ratio, BAR=213.5>sediment concentration ratio, SCR=97.4; bioaccumulation factor, organism dw. conc. to sediment dw. conc., BAF=1.02), which shows that extrapolating bioaccumulation results between different substances is difficult. When assessing bioavailability of specific compounds, it is most adequate to perform direct measurements on exposed organisms, such as the experiments described here. The high bioaccumulation of compounds such as pyrene and nickel may in some cases be attributed to manipulation of the sediments and (for pyrene) lack of subsequent aging, thereby overestimating bioavailability.