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5G - Species sensitivities distribution (TUP/215) Biology based effect modelling to optimise ballast water treatment with the disinfectant hydrogen peroxide. Jak, Robbert1, Smit, Mathijs1, 1 TNO-MEP, Dept. for Ecological Risk Studies, Den Helder, The Netherlands ABSTRACT- Chemical treatment of ballast water is a potential measure to reduce the introduction of non-indigenous species to the marine environment caused by shipping. The disinfectant hydrogen peroxide is a promising candidate, since it is known as a strong disinfecting oxidant. It can be generated electrochemically from sea water without the addition of additional chemicals, and it decomposes rapidly into water and oxygen. So, both effectiveness of the treatment and environmental effects after the release of ballast water can be controlled. A study was performed to apply a risk-based methodology to estimate effective treatment regimes, considering time-varying exposure levels, and species sensitivity distributions (SSD). In order to predict optimal treatment regimes, time-to-event modelling was implemented in a mechanistic effect model. The basis for this model is the relationship between exposure concentration, exposure time and (acute) effect, so-called 3-dimensional dose-response curves. These 3-dimensional relationships were established for a number of test-organisms from different taxonomic groups (Artemia salina, Corophium volutator, Brachionus plicatilis, Skeletonema costatum, Dunaliella tertiolecta, and Vibrio fisheri). Data from these 3D dose-effect curves were used to establish Species Sensitivity Distributions (SSDs) for different exposure regimes of hydrogen peroxide that are effective in killing a certain percentage of the individuals of the populations of the "generic species community". This approach is in fact an inverted version of the method to derive environmental quality criteria based on SSDs. The final result of this SSD application is a 3-dimensional plane showing the percentage of organisms killed as a function of the hydrogen peroxide concentration and time (exposure duration). Methodology and test data will be presented and evaluated in the perspective of the possibilities to apply on board generated hydrogen peroxide as a chemical treatment method of ballast water. Key words: time variable exposure, SSD, mechanistic effect modelling, ballast water |
