W10 PM Environmental Interactions of Marine Antifoulants
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 341-342

(JUN-1117-734916) Comparative assessment of the algal toxicity of three antifouling biocides considering modes of toxic action.

Koller, M¹, Junghans, M¹, Escher, B¹, ¹ Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Zurich, Switzerland

ABSTRACT- To prevent the settlement of benthic organisms, ship hulls and other submerged structures are treated with antifouling paints. Antifouling biocides are regularly emitted from these paints into the surrounding water phase. Despite their local application, antifouling biocides are thus frequently detected in marinas, where they can have adverse effects on the structure and functioning of aquatic ecosystems. In this study we performed a comparative assessment of the toxicity of three regularly detected antifouling biocides, Irgarol, SeaNine, and Tributyltin, for aquatic primary producers. This assessment is based on toxicity data, which were determined with synchronous cultures of the green alga Scenedesmus vacuolatus. With the selected toxicity endpoints, reproduction rate, the cell size, as well as chlorophyll fluorescence and other mode-of-action specific endpoints, not only toxicity values were determined but also the modes of toxic action of the three antifouling biocides were characterized. Accordingly, both, toxicity values as well as the modes of toxic action, are taken into account for the comparative toxicity assessment.

Key words: antifouling biocides, mode of toxic action, algal toxicity, comparative assessment