Behaviour and Fluxes of Dissolved Antibiotics, Analgesics and Hormones During Flood Events in a Small Heterogeneous Catchment in the Grand Duchy of Luxembourg

The objective of this investigation is to analyse the variations of xenobiotic concentrations and the fluxes of dissolved xenobiotics during runoff events in the small rural Mess catchment (35 km²) in the Southwestern part of Luxembourg. Sulfonamides, tetracyclines, analgesics and hormones, dissolved nutrients, sulphate and chloride were measured to gather information about runoff generation. Typically, the highest values can be found during the first flush mainly in the rising limb of the flood hydrographs. The highest concentrations in eleven flood events are measured for ibuprofen (2,383 ng l^-1), estrone (27 ng l^-1) and diclofenac (20 ng l^-1). From the tetracycline group tetracycline (9 ng l^-1) itself is of relevance, while the sulfonamides are mainly represented by sulfamethoxazole (5 ng l^-1). The variable patterns of chemographs are attributed to the heterogeneous runoff generation characterised by different reactions of storm overflows from the combined sewer systems. During single flood events, the fluxes of ibuprofen (maximum 24,000 mg), 17α-ethinylestradiol (122 mg), 17β-estradiol (32 mg) or estrone (274 mg) are rather low.