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Herbizide, die durch Spray-Drift, Volatilisation oder Winderosion aus landwirtschaftlichen Flächen ausgetragen werden können wiederum auf Nichtzielpflanzen gelangen. Es wird angenommen, dass Wälder eine Senke für luftgetragene Pestizide darstellen. Wirkungen von luftgetragenen Herbiziden auf Nichtzielpflanzen können nicht ausgeschlossen werden. An Blättern von Nichtzielpflanzen haftende Herbizide können wiederum durch Regenereignisse aus der Laubschicht ausgewaschen werden und in den Boden gelangen. Welche Stoffe nach deren Deposition ausgewaschen werden oder aber in der Laubschicht verbleiben hängt vom Verteilungsverhalten an der Blattoberfläche ab. In der vorliegenden Dissertation wurde das Verteilungsverhalten von current-use Herbiziden und einiger ihrer Abbauprodukte an der Oberfläche von Nichtzielpflanzen bestimmt. Als Modellorganismus diente die Waldkiefer Pinus Sylvestris L. mit deren Nadeln Versuche zur Charakterisierung des Adsorptions- und Desorptionsverhaltens von 55 Herbiziden aus wässrigen Lösungen durchgeführt wurden. Es wurden Verteilungsversuche sowohl mit rekonstituiertem epikutikulärem Wachs als auch mit intakten Kiefernnadeln durchgeführt. Für den Stoff Terbuthylazin konnte bei Versuchen mit rekonstituierten epikutikulären Wachsen eine Aufnahme aus der wässrigen Lösung in das Wachs festgestellt werden. Der Verteilungskoeffizient zwischen Wachs und Wasser betrug für die Adsorption log KWachsW = 3, 0. Für die Desorption wurde ein höherer Verteilungskoeffizient von log KWachsW = 3, 3 ermittelt und auf Grund der Differenz eine teilweise irreversible Bindung des Terbuthylazins an das epikutikuläre Wachs angenommen. Sorptionsversuche mit wässrigen Lösungen und intakten Kiefernnadeln zeigten für 19 weitere Herbizide mit einem log KOW > 3,8 eine schnelle Adsorption aus der wässrigen Phase an die Nadeloberfläche mit einer mittleren Lebensdauer für die Adsorption von 12 Minuten (Aclonifen, Bifenox, Bromoxynil-octanoat, Diflufenican, Fenoxaprop-p-ethyl, Fluazifop-p-butyl, Fluroxypyrmeptyl, Haloxyfop-ethoxyethyl, Haloxyfop-methyl, Mefenpyr-diethyl, PCP, Pendimethalin, Picolinafen, Propaquizafop, Prosulfocarb, Pyridate, Quizalofop-ethyl, Triallate und Trifluralin). Die für diese Stoffe ermittelten Kutikula/Wasser-Verteilungskoeffizienten liegen im Bereich log KCW = 3,3 bis 4,8. Für 7 Stoffe war nach einer schnellen Verringerung der Konzentration in der wässrigen Phase eine weitere stetige Abnahme der Herbizidkonzentration mit einer Lebensdauer unter 2000 Minuten zu beobachten (Fluroxypyr-meptyl, Fenoxaprop-p-ethyl, Propaquizafop, Quizalofop-ethyl, Trifluralin, Fluazifop-p-butyl und Haloxyfop-methyl), was durch eine Aufnahme der Stoffe über die epikutikuläre Wachsschicht in das innere Gewebe der Kiefernnadeln erklärt werden kann. Die Stoffe Bromoxynil-octanoat, Fluroxypyr-meptyl, Propaquizafop, Quizalofop-ethyl und Trifluralin zeigten eine irreversible Aufnahme aus wässrigen Lösungen in Kiefernnadeln. In einem Laborversuch wurde die Deposition von Herbiziden auf intakten Kiefernnadeln simuliert. Die Verteilung zwischen der epikutikulären Wachsschicht, Niederschlagswasser und den nach Extraktion mit Dichlormethan verbleibenden Nadeln wurde für das Herbizid Isoproturon und seine Abbauprodukte ermittelt. Das hierfür entwickelte Versuchsdesign erlaubte die Messung der Verteilungsvorgänge an intakten, noch am Zweig befindlichen Kiefernnadeln. Die Translokation, Volatilisation und die Bildung von Abbauprodukten konnten quantifiziert werden. Die Laborversuche ergaben, dass Isoproturon bei Kontakt mit wässrigen Lösungen sofort (Lebensdauer unter 1 Minute) von der Oberfläche der Kiefernnadeln desorbiert und nicht in das innere Gewebe der Kiefernnadel aufgenommen wird. Darüber hinaus treten bei Driftrückständen kleiner Stoffmenge und Schichtdicke (1 ng/mm²) für Isoproturon hohe Verluste (zwischen 47 und 88 % der ursprünglich applizierten Menge) durch Volatilisation und abiotischen Abbau auf. Aus den Ergebnissen der Laborversuche können Rückschlüsse zum Verbleib des Herbizids Isoproturon im Waldökosystem getroffen werden. Sie zeigen, dass Driftrückstände von polaren Herbiziden durch Regenereignisse aus der Vegetationsoberfläche von Nichtzielpflanzen ausgetragen werden und in andere Umweltkompartimente gelangen können.

Subaquatic ammunition dumpsites of both, conventional as well as chemical ammunition do practically exist in every single ocean and even in a significant number of inland waters. Most of these dumpsites are based on related post world war dumping actions, when victorious and defeated states had to get rid of their enormous surplus stocks of ammunition and especially the not easy to be handled chemical warfare agents like mustard, phosgene and even nerve agents. After first attempts of conventional destruction like burning, explosion or even simple emptying of chemical agents into pits or holes in the ground, those attempts soon emerged to be very time-consuming and dangerous. Adequate destruction technologies of today’s standards like detonation chambers or plasma kiln did just not exist at that time. The persons in charge soon focused on a much more promising solution attempt: the dumping of this ammunition into surrounding water bodies. In the case of the post World War II dumping actions, the focusing on the former deep water sites soon turned out to be not practicable, based on related enormous costs and logistical problems. The Baltic Sea – with maximum water depths of about 150 m – seemed then to represent the easiest way to get rid of the problematic ammunition. By these activities 65,000 to up to 300.000 tons of chemical ammunition ended up in the Baltic Sea. Concerning conventional ammunition like water mines, torpedo warheads, high explosive devices etc., there is practically no information available but experts assume at least another 100.000 tons of conventional material in the Baltic Sea. Environmental aspects and the issue of protection of the sea were – like in other cases of subaquatic dumping actions worldwide – completely ignored at that time. Nevertheless, subaquatic dumping actions took place until the late 1980ies. Today these dumping sites – whether based on conventional or on chemical ammunition – do represent a very problematic and highly dangerous heritage to present and future generations: Corrosion of the containers and shells results in a not to be forecasted diffuse emission or rather leaking of the ammunition contents into the water body. Substances that are in most cases highly or even extremely toxic for humans, flora as well as fauna contaminate the marine environment with mostly unknown toxicological and ecotoxicological effects. The majority of these substances are known to have carcinogenic, teratogenic and/or mutagenic effects and practically nothing is known about the potential of these substances to end up in the food chains. Especially in recent years there are more and more findings of significantly increased arsenic values in fish that cannot be explained but there are strong signs that these values are based on ammunition dumpsites. Besides the mentioned toxicological and ecotoxicological effects, there are further significant risks as e.g. the possible access to the ammunition also in the context of terrorist and right-wing extremist activities, the continuous catching of and resulting injuring of fishermen by ammunition, the constant endangering of the civil and commercial shipping by direct contact or rather too close convergence to dumped ammunition especially in the context of self detonation or a sudden release of significant amounts of these substances e.g. in the context of an accident and last but not least the uncontrollable landing of containers and ammunition as well as already flushed out contents on coasts and beaches. Basically can be stated that there is still a significant need of action and scientific investigation in the general topic of subaquatic ammunition dumpsites and that related measures have to be taken immediately – especially concerning our sense of responsibility for future generations.

Halogenated flame retardants (HFRs) have been applied since the 1960s in various industrial and consumer products to protect humans as well as private and public possessions. In the past decade polybrominated diphenyl ethers (PBDEs), formerly the major applied HFRs were widely restricted and adopted as Persistent Organic Pollutants (POPs) in the Stockholm Convention due to their adverse effects on humans and the environment as well as their ubiquitous occurrence in the global environment. Besides PBDEs, various alternative HFRs have been applied for decades as well, or were recently developed to replace PBDEs. However, their potential adverse properties, environmental distribution and fate are largely unknown. Therefore, this thesis addresses the global occurrence, distribution and transport of alternative HFRs versus PBDEs in the marine atmosphere and seawater toward the Polar Regions in order to examine their longrange atmospheric transport (LRAT) potential. This thesis presents the first data on alternative HFRs in the atmosphere of the marine environment and the Polar Regions. Alternative brominated flame retardants (BFRs), Dechlorane compounds and PBDEs were investigated in high-volume air and seawater samples taken along several sampling transects in the Atlantic Ocean, Pacific Ocean and Indian Ocean toward the Polar Regions of the Arctic and Antarctic. In addition, three sampling cruises were conducted in the German Bight, North Sea. Several alternative HFRs were detected in the global marine atmosphere and seawater with hexabromobenzene (HBB), pentabromotoluene (PBT), pentabromobenzene (PBBz), 2,3- dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and Dechlorane Plus (DP) being the predominant compounds which were observed in concentrations similar or even higher than PBDEs. Total atmospheric concentrations ranged from <1 pg m-3 over the open oceans up to 42 pg m-3 over the East Indian Archipelago. Seawater concentrations ranged from <1 pg L-1 in open ocean seawater up to 21 pg L-1 in coastal regions, while estuarine concentrations reached up to 6800 pg L-1. Overall, the comparison revealed that alternative HFRs dominate versus PBDEs in air and seawater, both in coastal regions as well as the Polar Regions, showing a shift from PBDEs toward alternative HFR in the marine atmosphere and seawater. The distribution in the global atmosphere was strongly influenced by the proximity to potential source regions and the pathway of the sampled air masses. Highest concentrations were observed in continentally influenced air masses, while low background concentrations occurred during sampling of oceanic remote air masses. In general, Western Europe, East and Southeast Asia but also Africa were identified as source regions for the marine environment, especially for alternative HFRs as well as BDE-209. In contrast, relatively low peak concentrations of the PBDE congeners of the Penta- and OctaBDE mixtures under continental influence were observed, indicating limited emissions of legacy PBDEs. The dry air-seawater gas exchange estimation showed that the atmosphere is a source for seawater resulting in net deposition into the global oceans after atmospheric emissions and transport, both in coastal regions as well as in the open oceans. Besides atmospheric depositions, riverine discharge was shown to act as source for coastal environments. The investigation of sampling transects toward the Polar Regions revealed that several alternative HFRs – in particular HBB, PBT, DPTE, PBBz and DP – undergo LRAT toward the Polar Regions in an extent similar to PBDEs and, therefore, meet the LRAT criterion of POPs under the Stockholm Convention. DP was found to undergo LRAT attached to airborne particles whereby stereoselective LRAT differences were shown for the two DP stereoisomers. With respect to LRAT, the results of this thesis therefore imply that alternative HFRs – in particular HBB, PBT, DPTE and DP – aren’t suitable replacements for PBDEs, but chemicals of emerging global environmental concern and possible future POPs.

Recent studies have confirmed that the aquatic ecosystem is being polluted with an unknown cocktail of pharmaceuticals, their metabolites and/or their transformation products (TPs). Although individual pharmaceuticals are typically present at low concentrations, their continuous input into the aquatic ecosystem and their toxic and persistent presence are the major environmental concerns. Therefore, it is necessary to assess the environmental risk caused by these aquatic pollutants. Data on exposure are required for quantitative risk assessment of parent compounds and their transformation products (TPs) and/or metabolites. Such data are mostly missing, especially for TPs, because of the non-availability of TPs and very often metabolites for experimental testing. Therefore, the application of different in silico tools for qualitative risk assessment can be used. Also, the presence of these micro-pollutants (active pharmaceutical ingredients, APIs) in the aquatic cycle are increasingly seen as a challenge to the sustainable management of water resources worldwide due to ineffective effluent treatment and other measures for their input prevention. Given the poor prognosis for effluent treatment (‘end of the pipe’ approach) for input prevention of APIs in the environment, it is necessary to focus on the ‘beginning of the pipe’ strategy. The very beginning of the pipe is the molecules themselves. Therefore, novel approaches are needed like designing greener pharmaceuticals, i.e. better biodegradable ones in the aquatic environment after their release. Therefore, the present research work focused on two important topics a) assessment of the environmental risk associated with the presence of highly prescribed drugs and their TPs; b) demonstrating the feasibility of the ‘benign by design’ concept for designing biodegradable drug derivatives, which will have the better biodegradability in the environment after their release. The present thesis includes four research articles (1-4) which address these approaches. The first article is about the qualitative environmental risk assessment using the example of transformation products formed during photolysis (photo-TPs) of Diatrizoic acid (DIAT). Photolysis is the chemical reaction in which the compound is broken down by photons and often in combination with hydroxyl radicals. Photolysis is the most common abatement process of micro-pollutants in the environment. The qualitative risk assessment of DIAT and selected photo-TPs was performed by the PBT approach (i.e. Persistence, Bioaccumulation and Toxicity), using chemical analysis, experimental biodegradation test assays, QSAR models with several different toxicological endpoints and in silico read-across approaches. The second article addresses a tiered approach of implementing green and sustainable chemistry principles for theoretically designing better biodegradable and pharmacologically potent pharmaceuticals derivatives. Photodegradation process coupled with LC-MSn analysis, biodegradability testing and in silico tools such as quantitative structure-activity relationships (QSAR) analysis and molecular docking proved to be a very significant approach for the preliminary stages of designing chemical structures that would fit into the ´benign by design´ concept in the direction of green and sustainable pharmacy. Metoprolol (MTL) was used as an example. The third article was also the conceptual framework to get new drug derivatives that are biodegradable in order to tackle the global challenge of micro-pollutants in the aquatic cycle. This study increased the knowledge about the role of the attachment of certain functionalities to the parent drug molecule for its biodegradability whilst conserving drug-likeness. This approach was in the past a totally neglected issue within drug development. Atenolol (ATL), a selective &#946;1 blocker, was selected as an example to incorporate the additional attribute such as biodegradability into its molecular structure while conserving its substructures responsible for &#946; adrenergic receptor blocker activity. In fourth article, the concept of designing green biodegradable pharmaceuticals has been proven through expanded experimental analysis setting out from the experiences collected as described in article two and three. This study could be considered as a more extensive feasibility study of rational design of green drug derivatives. The non-selective &#946;-blocker Propranolol (PPL) was used as an example. The risk assessment study (Article #1) contributes in enhancing the existing knowledge about the life cycle and behavior (fate) of pharmaceuticals with a special focus on photo-TPs which are generally formed during advanced effluent treatment and enter as such into the environment. Based on the obtained results, the application of the in silico tools for qualitative risk assessment analysis increased knowledge space about the environmental fate of TPs in case of their non-availability for experimental testing. The benign by design studies (Article #2-4) were based on the knowledge and experience collected during the work on DIAT. It demonstrated the feasibility of a novel approach of designing comparatively better degradable and pharmacological potent derivatives through the implementation of ´green chemistry´ principles. However, the present approach is in the juvenile stage and further knowledge has to be collected beforehand for the full implementation of this approach into drug development.

Die selektive katalytische Reduktion (SCR) mit Ammoniak als Reduktionsmittel gehört zu den bedeutenden Stickoxidminderungsmaßnahmen bei Personenkraftwagen. Aufgrund des Gefahrenpotentials von Ammoniak wird eine wässrige Harnstofflösung mit einem Harnstoffgehalt von 32,5 % als Reduktionsmittelträger verwendet. Die technischen Herausforderungen im Umgang mit diesem Reduktionsmittelträger liegen in der Kältestabilität mit einem Gefrierpunkt von -11,5°C, der begrenzten Haltbarkeit und der Gefahr zur Bildung von Harnstoffablagerungen in der Abgasanlage. In der Arbeit wird das Ablagerungs- und Alterungsverhalten dieser wässrigen Harnstofflösung unter möglichst realen Bedingungen untersucht. Die Alterung des Reduktionsmittels wird durch verschiedene Fahrzeug- und Umwelteinflüsse während des Betriebes verursacht. Neben der thermischen Alterung als größte Einflussquelle werden ebenfalls tiefe Temperaturen mit Phasenwechseln, die Art der Behälterentgasung, die Fahrdynamik, der Luftdruck und die Hydrolyse hinsichtlich eines Alterungseinflusses untersucht. Auf Basis dieser Daten wird ein empirisches Alterungsmodell entwickelt, was die Bestimmung eines maximalen Alterungszustandes der wässrigen Harnstofflösung erlaubt. Die veränderten chemisch-physikalischen Eigenschaften des gealterten Reduktionsmittels sowie dessen Auswirkungen auf die Emissionen werden in dieser Arbeit bestimmt. Ablagerungen in der Abgasanlage entstehen ausgehend von einer Wandfilmbildung bei niedriger Verdampfungsrate und hoher Verweilzeit des Reduktionsmittels auf kühlen Flächen. Der auskristallisierte Harnstoff wandelt sich je nach Dauer und Ausmaß der thermischen Belastung in Folgeprodukte um. Die Ablagerungsbildung wird im Realbetrieb phänomenologisch beschrieben und charakterisiert. Auf dieser Basis wird das reale Ablagerungsverhalten auf einen Prüfzyklus übertragen und eine geeignete Bewertungsmethode entwickelt. In einer systematischen Untersuchung wird der Einfluss der Wandtemperatur, der Einspritzfrequenz, des Einspritzdrucks, des Einspritzwinkels, der Tropfengröße, der Oberflächenspannung und der Reduktionsmittelalterung experimentell ermittelt. Daraus werden allgemein Möglichkeiten zur Minderung von Harnstoffablagerungen in der Abgasanlage entwickelt und beschrieben.