title: Biodegradability of 14C-labeled antibiotics in a modified laboratory scale sewage treatment plant at environmentally relevant concentrations.
abstract: For all new pharmaceuticals, an environmental risk assessment (ERA) has to be performed according to guidelines developed by the European Medicines Evaluation Agency. An important factor of this procedure is the assessment of the predicted environmental concentration in the aquatic environment, which is significantly influenced by the biodegradability of pharmaceuticals in sewage treatment plants. Established standardized methods for determining biodegradation under laboratory conditions apply to substance concentrations, which are much higherthan those expected in reality. Against this background, the laboratory scale sewage treatment plant (LSSTP), as described by the Organisation for Economic Cooperation and Development (OECD) Guideline No. 303A, was modified to construct a lossless system, which allows laboratory testing at realistic concentrations. To verify the experimental setup, the antibiotics benzylpenicillin, ceftriaxone, and trimethoprim were tested at low concentrations (microg/L) using 14C-labeled compounds. The results show that approximately 25% of benzylpenicillin was mineralized, whereas ceftriaxone and trimethoprim were not mineralized at all. Due to the high total recoveries of added radioactivity (> or =95%) and the fact that the findings comply with available literature data, the lossless operation of the test system could be proved. Consequently, the modified LSSTP is a suitable tool to determine more realistic biodegradation data required for the exposure assessment within the scope of an ERA for pharmaceuticals.
authors.affiliation: ECT Oekotoxikologie GmbH, Boettgerstrasse 2-14, D-65439 Floersheim, Germany. th-junker@ect.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Junker
authors.forename: Radka
authors.initials: R
authors.lastname: Alexy
authors.forename: Thomas
authors.initials: T
authors.lastname: Knacker
authors.forename: Klaus
authors.initials: K
authors.lastname: Kümmerer
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000737:chemistry*; D002443:Ceftriaxone / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism*; D017408:Guidelines as Topic; D007220:Industrial Waste; D007880:Legislation, Drug; D010400:Penicillin G / Q000378:metabolism; D018570:Risk Assessment / Q000379:methods* / Q000592:standards; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014295:Trimethoprim / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002247:Carbon Isotopes; D004785:Environmental Pollutants; D007220:Industrial Waste; D012722:Sewage; D002443:Ceftriaxone; D014295:Trimethoprim; D010400:Penicillin G