BackgroundXenobiotics have been detected in essentially all parts of the water cycle. The analytical techniques havebeen improved significantly so that even small quantities of these compounds can now be detected indrinking water reservoirs. The input paths of those substances vary, but in most cases xenobiotics reachthe water cycle via sewage discharge either treated or untreated. Once in the water cycle, theconcentration and transport depend on hydraulic conditions including rainfall pattern and sewageoverflow, on the properties of the substances themselves, including sorption, degradation, andmetabolism. However, the behaviour and ecological impact of most xenobiotics, including endocrinedisruptors is widely unknown.ObjectivesThe overall goal of the proposal is to help people prepare for substance flows of selected emergingsubstances under present and changing environmental conditions by providing important technicalinformation (innovative analytical techniques), a monitoring strategy (low flow and floods), analyticalresults for Luxembourg, and process information (runoff generation and fluxes). Especially, informationabout the substance behaviour (concentrations, fluxes) during flood events and droughts is needed forsmall or medium size catchments. A further objective is to evaluate if these compounds can be used as atracer for water originating from sewer systems, purification plants or sanitary systems. In addition, thereis a lack of knowledge dealing with the impact of xenobiotics on living organisms.StrategyWe are going to describe the dynamic of twelve dissolved pharmaceutical compounds belonging to threecompound categories: hormones (estrone, 17ƒÀ-estradiol, 17ƒ¿-ethinylestradiol), analgesics (ibuprofen,diclofenac), and antibiotics (sulfathiazole, sulfamethazine, sulfamethoxazole, sulfadimethoxine,tetracycline, oxytetracycline, chlortetracycline). In addition, four surfactants (detergents) from thealkylphenolic compounds group (4-nonylphenol, 4-tert-octylphenol, nonylphenol monoethoxylate,nonylphenol diethoxylate) will be investigated. Furthermore, selected river bottom and suspendedsediments will be analysed.All target compounds will be extracted using a single solid phasestate of the art extraction procedures andwill be analyzed by liquid chromatography with tandem-mass spectrometry.Three Two basins, typical of the Mid-European low mountain range and mainly located in areas that arerelevant for drinking water production (partly Luxembourgish sandstone), are proposed for investigation.Thus the required hydro-climatological and chemical measurements during flood events and during lowflow conditions will be conducted in the rural Mess catchment (35 km2) and the, the urban Petrusse (44km2) and the Upper Sure (316 km2) at Bigonville. The corresponding monitoring strategy for xenobioticswill be both event based (fluxes) and also with a focus on low flow conditions (concentrations).In the context of the estrogenic effects, in vitro tests will be realised in the project. Cellular bioassays areused as cost-efficient screening tools for the integrated assessment of the presence of hazardouscompounds with estrogenic potential, and they might be an alternative to mass-based analytics.The project is connected with the PhD of Berenike MEYER. She will workworks on the exchange ofriver water with groundwater and an infiltration of pollutants into local aquifers. In addition, the runningPhD of Sebastian WREDE delivers information about runoff generation in relevant catchment ofdifferent scales. Additional results are taken from the PhD of Nuria MARTINEZ-CARRERAS, who issampling small river systems. She works on fingerprinting pollutant sources with a focus on nutrients.