Degradation of selected pharmaceuticals and their metabolites in simulated waste water treatment conditions

Zdravilne učinkovine in mnogi njihovi presnovki so biološko aktivne spojine, ki po uporabi v humani ali veterinarski medicini po različnih poteh preidejo v okolje. Številne raziskave so potrdile njihovo prisotnost v odpadnih, površinskih in podtalnih vodah, zato smo lahko njihovemu vplivu posredno izpostavljeni z uživanjem pitne vode. Naraščajoča poraba zdravilnih učinkovin je v začetku devetdesetih let prejšnjega stoletja pripeljala do začetka obsežnejšega preučevanja njihovega vpliva na okolje. V diplomskem delu smo preučevali odstranjevanje izbranih zdravilnih učinkovin in njihovih presnovkov v pilotni čistilni napravi pod aerobnimi in anoksičnimi pogoji ter v sklopljenem sistemu anoksični-aerobni reaktor. Z merjenjem vrednosti različnih kemijskih parametrov (amonij, nitrat, nitrit, ortofosfat, kemijska in biokemijska potreba po kisiku) smo potrdili procesa nitrifikacije v aerobnih ter denitrifikacije v anoksičnih pogojih. Kot modelne spojine smo izbrali nesteroidne protivnetne učinkovine ibuprofen, naproksen, ketoprofen in diklofenak, antiepileptik karbamazepin, klofibrinsko kislino, humani presnovek lipidnega regulatorja klofibrata, presnovka karbamazepina akridin in akridon ter 1-(2,6-diklorofenil)indolin-2-on, presnovek diklofenaka. Visoka letna poraba učinkovin je potrdila smiselnost njihovega izbora. Spojine smo iz vodnih vzorcev izolirali z ekstrakcijo na trdnem nosilcu, pri tem smo raztopinam dodali interna standarda devteriran ibuprofen za zdravilne učinkovine ter 9-kloroakridin za presnovke. Sledila je derivatizacija z Nmetil- N-(tercbutildimetilsilil)-2,2,2-trifluoroacetamidom. Ločbo in analizo smo izvedli s plinskim kromatografom z masno spektrometričnim detektorjem. Izkoristki ekstrakcije so bili za vse spojine višji od 76 %. Odstranjevanje ibuprofena, naproksena, ketoprofena in akridina v aerobnih pogojih je bilo več kot 90-odstotno, medtem ko so se ostale spojine odstranjevale v manjši meri. V anoksičnih pogojih sta se najbolje odstranjevala naproksen (87 %) in akridin (64 %), ostale spojine so se odstranjevale manj kot 13-odstotno. V sklopljenih sistemih so se ibuprofen, naproksen in ketoprofen statistično značilno bolje odstranjevali kot v posameznih reaktorjih, medtem ko za druge spojine tega ne moremo trditi.Pharmaceuticals and many of their metabolites are biologically active substances that are used in human and veterinary medicine and subsequently reach the environment through different pathways. Numerous studies have confirmed their presence in wastewater, surface and subterranean water, thus we can be subject to their influence indirectly through consuming drinking water. In the beginning of the 1990s, the increase in consumption of pharmaceutical products led to the widespread study of their influence on the environment. In our work, we have studied the elimination of selected pharmaceuticals and their metabolites in a pilot wastewater treatment plant under aerobic and anoxic conditions and in the coupled anoxic-aerobic reactor system. By measuring various chemical parameters (ammonia, nitrate, nitrite, orthophosphate, chemical and biochemical oxygen demand) we have confirmed the processes of nitrification in aerobic conditions and denitrification in anoxic conditions. The model substances used were the non-steroidal anti-inflammatory drugs ibuprofen, naproxen, ketoprofen and diclofenac, the antiepileptic carbamazepine, clofibric acid, the human metabolite of the lipid regulator clofibrate, the metabolites of carbamazepine acridine and acridone, and 1-(2,6-dichlorophenyl)indolin-2-one, a metabolite of diclofenac. The substantial yearly consumption of the pharmaceuticals justified our selection. We have used solid phase extraction to isolate the compounds from the water samples, adding the internal standards deuterated ibuprofen and 9-chloroacridine (for pharmaceuticals and metabolites respectively) in the process. This was followed by derivatization with N-methyl-N-(tert-butyldimethylsilyl)-2,2,2-trifluoroacetamide. We have used gas chromatography coupled with a mass spectrometry detector to perform the separation and analysis. The extraction efficiency was above 76% for all studied compounds. The elimination of ibuprofen, naproxen, ketoprofen and acridine in aerobic conditions was over 90%, while other compounds were eliminated in a lesser degree. In anoxic conditions, only naproxen (87%) and acridine (64%) were eliminated substantially, the elimination of all other compounds was below 13%. The elimination of ibuprofen, naproxen and ketoprofen was greater in the coupled system than in individual reactors to a statistically significant degree, while we could not confirm the same for other compounds