Hazard Identification of Anti-fouling Paints and Contaminated Sediments by the Use of Biological Tests in Brackish Water

Abstract: Ecotoxicological test methods are important tools in environmental risk assessment to investigate possible adverse effects that chemical substances may cause to aquatic ecosystems. The main aim of this doctoral thesis was to identify potential toxicity (hazard) of anti-fouling compounds and paints as well as contaminated sediments. Mainly tests with the red macroalga Ceramium tenuicorne and the harpacticoid copepod Nitocra spinipes were used. Toxicity of anti-fouling paints with a physical (biocide-free) or a chemical mode of action for use on pleasure boats and ships was investigated (Paper I and III). Several of the biocide-free paints were found to be toxic and some were even more toxic than paints based on leaching of biocides (Paper I and III). In paper II, release rates of Cu and Zn from both pleasure boat and ship paints were assessed and showed that the biocide-free paints release large amounts of Zn. The influence of salinity and organic matter on Cu toxicity to C. tenuicorne was investigated under brackish water conditions. Organic matter had a clear reducing effect on Cu toxicity while the effect of salinity had a minor impact on the toxicity (Paper IV). The potential toxicity of sediments was investigated by developing an ecotoxicological approach for screening of contaminated sites (Paper V). The results showed that sediments with known historical pollution were most toxic while reference sediments were least toxic. Also, the observed toxicity of some of the sediments could not be explained by the analyzed substances. In conclusion, the studies of anti-fouling paints have shown that the biocide-free paints can be very toxic and that the great release of Zn from biocide-free paints could have implications for the coastal ecosystem. Organic matter had a greater impact on Cu toxicity than salinity. The study with sediments provided a promising screening tool for use in prioritizing processes of contaminated sites. Finally, the importance of combining biological testing and chemical analysis was highlighted.