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(T/MF171) A new GREAT-ER study on the aquatic fate of detergents: The Ruhr catchment. Matthies, Michael1, Schulze, Carsten1, 1 ABSTRACT- GREAT-ER is a simulation model to calculate georeferenced frequency distributions of aquatic concentrations of 'down-the'drain' chemicals at different locations. It simulates the environmental fate of chemicals in riverine water, which is polluted by point source emissions via the sewerage system and a waste water treatment plant. It has been developed for the refined stage within the EU environmental risk assessment scheme. The GREAT-ER model combines a Geographical Information System (GIS) for data storage and visualisation with emission, waste water and aquatic fate models. The first phase has been finished in March 1999. As a further study area, the Rur catchment in western North-Rhine Westfalia has been incorporated. The area of the Ruhr catchment is approx. 2 500 km2 and discharges the waste water of about 1 million people. The largest city in the area is Aachen (Aix-La-Chapelle) with a population of about 250 000. As part of the integration phase, a hydrological model based on a nonlinear regression and a local refinement procedure has been developed. Two data sets have been developed to account for discharge situations in the years 1993 and 2000. Comparisons of measurements and simulation results of detergents are conducted for both years. For boron, linear alkylbenzenesulfonate (LAS), alcohol sulfate (AS), and alkohol ethoxylathe (AE) there is a good agreement between observed and predicted concentrations. However, for nitrilotriacetate (NTA) and ethylenediaminetetraacetate (EDTA) deviations between monitoring and simulation results are observed at some monitoring sites. This suggests that mainly inputs from industrial discharges have influenced the riverine concentrations of these substances. Key words: Aquatic fate modelling , detergents, GREAT-ER, GIS |
