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(M/EH093) The global fate of antifouling biocides: Implications from a box-model approach. Ranke, Johannes1, 1 ABSTRACT- Antifouling biocides are toxicants deliberately released to the marine biosphere in thousands of tons per year. Benefits of biocidal antifouling technologies are high travelling speed and low fuel consumption of ships. One way of decreasing the environmental damage connected with those benefits is the use of biocides for which rapid and irreversible transformation to metabolites of known, low toxicity is scientifically well established. In an attempt to increase understanding of the interplay of transformation, sorption and transportation of antifouling agents in the global marine biosphere, residence times of four widely used biocides were calculated for a 9-box model system representing water and sediment of commercial harbors, adjacent estuaries, the continental shelf and the open sea. Uncertainty of the resulting residence times in the system is due to a) variance of biocide specific input parameters, b) uncertainty about the adequacy of determination methods for biocide specific input parameters, since mutual superimposition of sorption and transformation complicates the design and interpretation of laboratory studies considerably, c) uncertainty of model parameters and about adequacy of the model structure. Uncertainty a) was quantified by Monte Carlo Simulations, varying biocide specific input parameters. Residence times calculated for copper, 2-tert-butylamino-4-cyclopropylamino-6-methylthio-1,3,5-triazine (active ingredient in Irgarol® 1051), tributyltin and 4,5-dichloro-N-octyl-4-isothioazoline-3-one (active ingredient in Sea-Nine® 211) were 42 800 years, 10.2 years, 16.9 days and 0.9 days, respectively. Overall uncertainty scores for the evaluation of the spatiotemporal range of the biocides (Multidimensional risk analysis of antifouling biocides, Ranke, J. and B. Jastorff, Environ. Sci. Poll. Res. 7(2)105, 2000) on a scale from a (lowest uncertainty) to d (highest uncertainty) were a (copper), c (Irgarol), b (tributyltin) and d (Sea-Nine). Key words: antifouling agents, fate, persistence, uncertainty |
