The GEMCO PROJECT -2- The foodweb model The GEMCO project (Generic Estuarine Modelling system to evaluate transport, fate and impact of COntaminants) aims to build an user-friendly software application for the evaluation of concentrations of given chemical substances in water, suspended particulate matter (SPM), sediment and biota in any european estuary predefined by its main physical, physico-chemical and biological characteristics. ABARNOU, A. (1), LOIZEAU, V. (1), ROMAÑA, L.A. (2), BAART, A. (3), van HATTUM, B. (4), THOMAS, P. (5 ) (1) IFREMER, Direction de l’Environnement et de l’aménagement Littoral, Ecologie Côtière, B.P. 70, F PLouzané (2) IFREMER, Direction de l’Environnement et de l’aménagement Littoral, Polluants Chimiques, B.P. 330, F La Seyne/Mer (3) WL/DELFT Hydraulics, Marine and Coastal Management, P.O.Box 177, 2600 MH Delft, The Netherlands (4) VRIJE UNIVERSITEIT AMSTERDAM, Institute for Environmental Studies, De Boeleaan,1115, 1081 HV Amsterdam, The Netherlands (5) ATOFINA, Direction Sécurité Environnement, Cours Michelet, La Défense10, F Paris La Défense Key-words : virtual estuary, risk assessment, predicted environmental concentrations, modelling, trophic chain The GEMCO model includes two interacting sub-models 1. An abiotic model which predicts - the substance concentrations in abiotic compartments (water, SPM, sediment) - the SPM distribution and the Primary Production, 2. A foodweb model which calculates concentrations of these substances in species using data generated by the first sub-model. The FW model relies upon the biological processes. This generic model will be validated by data from previously studied estuary (e.g.Scheldt, Seine) 4. Processes. How the key-processes should be represented by simple and generic equations ? Should metabolization be considered as a function depending on compounds and species ? Expected results 1. Processes/parameters the foodweb model will highlight the mains processes acting on the distribution of chemicals in organisms and the relative importance of these processes on the fate of contaminants in biota. 2. Concentrations and chemical risk assessment the foodweb will predict concentrations of chemicals in biota and their variations. These PEC in biota (PEC : predicted environmental concentrations) are to be compared with PNEC (predicted non effects concentrations). The further step : the virtual estuary model. This FW model should be able to predict concentration of chemicals in the species, whether bioaccumulated or not, which live in main european estuaries. Initial research will be directed at answering the following questions. The GEMCO estuarine modelling project sets out to predict concentrations of contaminants in estuaries and subsequent bioaccumulation with a view to its use in marine risk assessment. The project is in its early stages and no results have been obtained so far. This poster is presented with a particular attention to the foodweb aspects of the model. The project aims to generalize existing bioaccumulation models to other chemical compounds that could reach estuarine organisms. Data base : measurements, processes G E M C O Abiotic model Delft Hydraulics Validation Ifremer Toulon Foodweb model IfremerBrest Validation IVM Amsterdam Primary Prod SPM VIRTUAL ESTUARY MODEL Characteristics estuary organisms chemicals PEC in water sediment and biota Structure of the project and role of partners General objective Acknowlegements 1. Estuarine context. The physical (bathymetry, sediment,...) and physico-chemical features (salinity, SPM,...) of the estuaries determine the species distribution and the structure of the foodwebs. How many types of foodwebs are to be considered ? which one, benthic and/or pelagic, freshwater, estuarine and/or marine foodweb. ? 2. Species. Which are the target-species ? Are they selected according to their biomass, their commercial value, their role in the trophic chain or their sensitivity to chemicals ? How many species need to be included ? 3. Contaminants. How the substances will be choosen according to their hydrophobicity (Kow) and their persistence (half-lifes) ? How metabolization will be described, depending on the species and on the chemical compounds ? Modelequation : For each organism, the concentration of a contaminant results from a mass balanced budget between uptake via respiration and feeding and their decrease by dilution growth, excretion, metabolization. The rates of biological processes depend on the weight of the animal (age dependent) and of environmental conditions (T°C, O 2, …). Metabolization of persistent compounds such as PCBs can be considered to be negligible CB28CB52 CB101CB118CB153 CB138 CB180 Calculated concentrations Measured concentrations Validation of the PCB bioaccumulation models PCB distribution in dab Dynamicmodel of PCB contamination inseabass The dab foodweb : a coastal benthic foodweb Theseabass foodweb : anestuarine pelagic foodweb PCB bioaccumulation model in marine and coastal foodwebs The starting point : bioaccumulation models Sediment Phytoplankton x 5 x 2 x 4 x 1 x3x3 Limanda limanda Bathyporeia pelagica Acrocnida brachiata Tellinafabula - concentrations in water (dissolved), SPM and phytoplankton are forced variables - environmental conditions (temperature, dissolved oxygen, chlorophyll,...) vary seasonally - biological functions (reproduction, growth,...) depend on environmental conditions Calculated concentrations Measured concentrations ng.g -1 d.w. dC i /dt = R i. A iw. C w + F i. P ij.a ij. C j - (E i + G i + Rep i + M i ). C i C D, C P, C Sed Pectinaria koreni C Biota ng.g -1 d.w.