Characterization of organic matter in aquatic systems under strong urban pressure: Sources, physico-chemical properties and interactions with organic pollutants

Abstract : Many organic pollutants are toxic for the aquatic biota but their fate in urban systems is still little studied, especially regarding Dissolved Organic Matter (DOM) effect on their distribution. Strong interactions with DOM play a key role in the speciation, bioavailability and toxicity of micropollutants. Understanding of the interaction processes, their dependence on local conditions and their temporal and spatial variations are needed for a sound risk assessment of micropollutants in Seine river basin. We make the characterization of the DOM present in surface water in the Seine river basin and its evolution to the crossing of the Paris agglomeration and the characterization of the interactions between the urbain DOM and organic micropollutants and the characterization of the interactions between the DOM and the suspended solids (mineral and organo-mineral complexes). Interactions between organic pollutants and mineral and organo-mineral complexes are being investigated. Several DOM samples from Seine Basin are being studied and their evolution in the crossing of the Paris Metropolitan Area, agricultural and forest zones are investigated. The Seine river basin, along an urban/industrial gradient, provide an interesting study site for DOM characterization and can show the predominant role of DOM in mitigating the contaminants fate and bioavailability in aquatic ecosystems.