Analysis, Occurrence and Fate of Antiviral Drugs in the Aquatic Environment
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Analysis, Occurrence and Fate of Antiviral Drugs in the Aquatic Environment Analyse, Vorkommen und Verhalten von Antivirenmitteln in der aquatischen Umwelt Dissertation Zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaft Fachbereich 3: Mathematik/Naturwissenschaften Universität Koblenz‐Landau Vorgelegt am 12. März 2012 von Dipl. Geoök. Carsten Prasse geboren am 18.08.1981 in Marktheidenfeld Referent: PD Dr. Thomas A. Ternes Koreferenten: Prof. Dr. Joachim Scholz Prof. Dr. David L. Sedlak (Univ. of California, Berkeley (CA), USA) I SUMMARY IV DANKSAGUNG Im Laufe meiner Dissertation haben mich eine Vielzahl von Personen auf unterschiedlichste Weise unterstützt. Ohne euch wäre diese Arbeit nicht das was sie ist und ich bin euch allen zutiefst dankbar. Namentlich möchte ich mich bei folgenden Personen bedanken: Zu allererst möchte ich Thomas Ternes für die Betreuung meiner Arbeit danken. Du hast es auf einzigartige Art und Weise geschafft mich zu motivieren und zu fördern und mir gleichzeitig Raum gegeben meine Ideen zu verwirklichen. Danke für die tolle Zusammenarbeit, die kritischen Diskussionen und deine stets offene (Büro‐) Tür. Prof. Scholz und Prof. Sedlak danke ich für ihr Interesse an meiner Arbeit und die Übernahme des Koreferats. Manfred Wagner bin ich für die NMR Messungen sowie für seine Offenheit und Begeisterung an neuen wissenschaftlichen Fragestellungen dankbar. Den Mitarbeitern der BfG, insbesondere des Referats G2, danke ich für die tolle Zusammenarbeit und die unvergessliche gemeinsame Zeit. Ich könnte mir keine besseren Kollegen und keine bessere Arbeitsgruppe vorstellen. Meinem Büro‐Mitbewohner Dirk Löffler danke ich für sein offenes Ohr, die hilfreichen Diskussionen und seine Toleranz bei etwaigen Gefühlsausbrüchen. Ganz besonders möchte ich auch Arne Wick danken. Danke für deine Unterstützung bei der Planung der Versuche, für die hilfreichen Diskussionen der Ergebnisse und deine Freundschaft. Ich glaube man hat im Leben nicht oft das Glück, einen so außergewöhnlichen Menschen wie dich kennen zu lernen. Liebe Jungs der ‚Gruppe 5’: I made it! Meiner Familie, vor allem meinen Eltern, und meinen Freunden danke ich für die Unterstützung in den letzten Jahren. Ohne euch wäre ich nicht dort wo ich jetzt bin. Zuletzt möchte ich mich bei Carolin bedanken. Ohne deine Unterstützung, deine Geduld und deine Liebe hätte ich das Projekt ‚Doktorarbeit’ nicht geschafft. Wenn Leute lachen, sind sie fähig zu denken. (Dalai Lama) Dank euch allen hab ich viel gelacht ... I SUMMARY II SUMMARY SUMMARY In the last two decades, pharmaceuticals have attracted broad scientific interest as they have been shown to be ubiquitously present in the aquatic environment. In particular, considerable concern has been raised regarding potential effects on human health due to the presence of pharmaceuticals in finished drinking water. Furthermore, research conducted so far indicates that transformations of pharmaceuticals in the environment as well as technical processes might result in the formation of potentially toxic transformation products. Antiviral drugs are primarily used for the treatment of herpes, human immunodeficiency virus (HIV), hepatitis and influenza with prescribed amounts up to several tons per year. However, with the exception of oseltamivir and its active metabolite oseltamivir carboxylate, so far no information on their environmental behavior is available. Therefore, the aim of this thesis was to investigate the occurrence and fate of antiviral drugs in the urban water cycle, including the aquatic environment. For the analysis of antiviral drugs in the aquatic environment a highly sensitive method was developed based on solid‐phase extraction (SPE) followed by liquid chromatography tandem mass spectrometry (LC‐tandem MS). Due to the wide range of physico‐chemical properties, in particular with regard to the polarity of the analytes, two different approaches were investigated for their chromatographic separation, reversed‐phase (RP) and hydrophilic interaction liquid chromatography (HILIC). Good chromatographic separation of individual antiviral drugs was achieved with both methods. However, due to the higher sensitivity, reproducibility and accuracy, the RP method was used for further analysis of antiviral drugs in environmental samples. The limits of quantification in raw and treated wastewater as well as surface water ranged between 1 (abacavir, oseltamivir, oseltamivir carboxylate) and 100 ng L‐1 (ribavirin), 0.5 and 50 ng L‐1 as well as 0.2 and 10 ng L‐1, respectively. Subsequently, the developed method was applied to investigate the occurrence and elimination of antiviral drugs in wastewater treatment plants (WWTPs). With the exception of ribavirin all antiviral drugs were detected in WWTP influents with concentrations ranging between 5 and 2,000 ng L‐1. The comparison of concentrations in WWTP influents and effluents revealed a high elimination efficiency for acyclovir, penciclovir, stavudine, oseltamivir carboxylate, lamivudine and abacavir during wastewater treatment. For nevirapine, oseltamivir and zidovudine similar concentrations were found in WWTP influents and effluents. Nevertheless, most of the antiviral drugs were also detected in WWTP effluents indicating their emission into receiving waters. Consequently, the analysis of surface water samples revealed the widespread occurrence of antiviral drugs in concentrations up to 190 ng L‐1 and 170 ng I SUMMARY L‐1 for acyclovir and zidovudine, respectively. The widespread occurrence of antiviral drugs in surface waters was also demonstrated in a sampling campaign at the river Ruhr with 30 sampling points along the river. For most of the antiviral drugs analyzed higher concentrations were observed at sampling sites further downstream along the Ruhr. Furthermore, elevated concentrations downstream of WWTPs clearly showed the importance of WWTP effluents as point sources for the release of antiviral drugs into surface waters. In addition, for the river Rhine, exceptionally high concentrations of oseltamivir compared to its active metabolite oseltamivir carboxylate were observed. This was unexpected as oseltamivir is extensively metabolized to oseltamivir carboxylate in the human body (> 75%), resulting in oseltamivir/oseltamivir carboxylate (OP/OC) ratios of 0.2‐0.3. In surface waters OP/OC ratios between 0.3 and 3.0 were observed, attributable to the partial removal of oseltamivir carboxylate during wastewater treatment. In contrast to this, in the river Rhine significantly higher OP/OC ratios (OP/OC = 12‐13) were observed, indicating the contribution of other sources in addition to urinary excretions of treated individuals. The analysis of samples taken at the international sampling station in Weil am Rhein, at the border between Germany and Switzerland, revealed a strong inhomogeneity in concentrations of oseltamivir and oseltamivir carboxylate across the river transect. Highest concentrations of oseltamivir (up to 200 ng L‐1) were observed in samples taken near the eastern riverbank, whereas it was completely absent in samples taken near the western riverbank. For oseltamivir carboxylate a similar trend was observed even though concentrations were significantly lower (up to 13 ng L‐1). In contrast to this, acyclovir, penciclovir and zidovudine were homogeneously distributed in all samples. Furthermore, the analysis of samples taken approx. 5 km upstream of the sampling station (near Basel) revealed the absence of both oseltamivir and oseltamivir carboxylate. This strongly suggested the inflow of waters containing high concentrations of oseltamivir and oseltamivir carboxylate in close proximity to the sampling station. Based on these findings, emissions from the pharmaceutical industry close to the sampling station Weil am Rhein could be assigned to be responsible for the high oseltamivir loads of up to 2 kg d‐1, which was finally confirmed by analysis of treated wastewater samples taken from the industrial WWTP in Basel. A monitoring campaign during the swine flu pandemic in November/December 2009 in the Rhine near Koblenz revealed that the analysis of oseltamivir carboxylate in surface waters could be used to follow the course of flu epidemics. Based on the observed OP/OC ratios a differentiation between individual sources of oseltamivir and oseltamivir carboxylate in the river Rhine, namely urinary excretions of treated individuals and industrial discharges, was possible. During the monitoring campaign an intermittent contribution of both sources was observed with urinary excretions being primarily responsible for observed river loads during the time period with the highest II SUMMARY number of reported swine flu cases. Furthermore, acyclovir and zidovudine were detected in most of the samples in concentrations < 10 ng L‐1. Also for these compounds a high variation of river loads was observed with loads in general increasing with increasing river discharges, thus indicating the contribution of untreated wastewater discharges e.g. due to combined sewer overflows. Due to the high concentration up to 2,000 ng L‐1 in WWTP influents and the extensive elimination during wastewater treatment, the fate of acyclovir was investigated in greater detail. Laboratory batch experiments were conducted with sewage sludge taken from the aerobic nitrification compartment of the biological treatment unit from a conventional WWTP. To be able to characterize the influence of the chemical structure on the degradability of organic compounds and the formation