This chapter aims at facilitating a comprehensive understanding of the alpine water issue. The nature and problems of alpine waters comprise a wide spectrum of natural features and processes, uses, pressures, and management options. Many of these aspects are presented in the following Chapters, but obtaining a comprehensive synthesis is certainly not an easy task. The content of the volume Chapters is synthesized and complemented with some basic considerations regarding water assessment, rising water conflicts and management issues. On the basis of this background, the necessity of integrated water management and inter- and transdisciplinary cooperation is emphasized. A vision of sustainable water management is presented towards supporting future orientations for water policy and management.

Riverine nutrient inputs of Lake Kivu were estimated by measuring the nutrient concentrations and water discharges of 21 rivers (13 on the Congolese side and 8 on the Rwandan side of the lake) in five sub-basins representing 1550 km² (30% of the river active<br /> area). The Congolese river basin was sampled by me and the Rwandan side by my colleague Jean-Népomuscène Namugize of the National University of Rwanda under the same project. Data on Water quality in the sampled rivers in relation to physico-chemical and nutrient concentrations are presented.<br /> Mean values ranging from 6.4 to 7.4 for pH and 144 to 638 μS.cm^-1 for Electrical conductivity were measured in the sampled rivers. Mean temperatures varied from 18.0 to 23.1°C. Discharge and total suspended solids from 0.21 to 7.30 m.s^-1 and 2 to 561 mg.L^-1 respectively. The catchment sizes of Congolese river basins of the lake were comprised between 11 and 296 km². Cropland-dryland was the first most dominant land use in the catchment (57%) and the second was Evergreen broadleaf forest (25%). Shrubland occupied 16% and Cropland-Woodland mosaic 1.4%. [...]

Rivers represent an important link between terrestrial and aquatic ecosystems. They can thereby act, as a pipe, transporting material downstream or as a reactor where intense biogeochemical processes take place and material is chemically reworked or removed. Valuable ecosystem services go along with the mineralization of organic matter (OM), like the removal of nitrate (NO₃^-) through denitrification. The ecological functioning of river systems is strongly shaped by the environmental heterogeneity and hydrological connectivity. Human modification of river corridors has dramatically altered hydrological variation and suppressed natural environmental heterogeneity. Efforts to restore streams and rivers aim at reconstituting these traits, thereby potentially accelerating biogeochemical transformation processes. [...]<br /><br />Flüsse stellen wichtige Verbindungen von terrestrischen und aquatischen Ökosystemen dar. Durch sie wird Material entweder stromabwärts transportiert oder in intensiven Umbauprozessen in der chemischen Struktur verändert oder aus dem System entfernt. An die Mineralisierung von organischem Material (OM) sind wertvolle Ökosystemleistungen gekoppelt, wie etwa der Abbau von Nitrat (NO₃^-) anhand von Denitrifizierung. Die ökologische Funktionsweise eines Flusssystems wird stark durch die Heterogenität des Systems und durch die hydrologische Konnektivität geprägt. Flusssysteme sind vielerorts durch den Menschen stark verändert worden, wobei die hydrologische Konnektivität stark reduziert und die Heterogenität unterdrückt wurde. Die heutigen Bemühungen Flüsse wieder zu renaturieren zielen darauf ab diese Eigenschaften wieder herzustellen, wodurch möglicherweise auch biogeochemische Umbauprozesse intensiviert werden. [...]

In Zeiten des Klimawandels und wachsendem Energiehunger der Menschheit hat die Photovoltaik-Technologie als nachhaltige und saubere Form der Energieerzeugung das Potential, einen Beitrag zur Energieversorgung ohne negative Nebeneffekte wie Klimagase oder radioaktive Endprodukte zu leisten. Dementsprechend erfuhr die Photovoltaik-Industrie in den letzen Jahren einen enormen Aufschwung, welcher sich besonders in Deutschland durch massiv ausgebaute Produktionskapazitäten für PV-Produkte und einen deutlich erhöhten Anteil von PV-Strom im Energiemix niederschlägt. Wie alle aufstrebenden und innovativen Industrien hat die PV-Industrie in Deutschland allerdings mit einer Reihe von Entwicklungshindernissen zu kämpfen. Beispielhaft kann hier internationaler Preisdruck oder Etablierungsschwierigkeiten gegenüber den vorherrschenden Technologien angeführt werden. Die vorliegende Arbeit untersucht unter Heranziehung des Konzepts der technologischen Innovationssysteme, welchen Einfluss Verbände und intermediäre Organisationen bei der Überwindung von Entwicklungshindernissen aufstrebender Technologie- und Industriebereiche spielen. Dazu wurden nach einer Evaluierung der im PV-Bereich aktiven Verbände und Intermediäre die Aktivitäten derselben zusammengetragen und auf Systemelemente komprimiert. Dabei handelt es sich um Strukturen innerhalb des PVInnovationssystems, welche aus der Arbeit der Verbände/Intermediäre hervorgehen und das Innovationssystem beeinflussen. Zur Untersuchung der Auswirkungen der Systembeiträge auf das Innovationssystem wurden die Elemente anhand von Systemfunktionen, also Schlüsselprozessen, mithilfe welcher die Funktionalität eines technologischen Innovationssystems bewertet werden kann, analysiert.<br /> Als Resultat der Analyse wird festgehalten, dass die Arbeit der Verbände und Intermediäre einen entscheidenden Einfluss auf die Funktionalität des technologischen Innovationssystems der deutschen PV-Industrie hat. Aktuelle Probleme in der Entwicklungsfähigkeit der Industrie werden von den Verbandsverantwortlichen erkannt und gezielt angegangen. Interessant ist an dieser Stelle, dass viele Aktivitäten, welche eigentlich auf eine Unterstützung der Verbandsoder Intermediärsmitglieder abzielen, ebenfalls Systembeiträge hervorbringen, welche die Funktionalität des Innovationssystems positiv beeinflussen.

In the Ethiopian Rift Valley, there are two main concerns about drinking water: fluoride and fecal contamination. OSHO (an Ethiopian NGO) works on a defluoridation project with household and community filters to remove fluoride from drinking water. The project area includes seven villages, with more than 300 household filters in use and one community filter.<br /> This is the first study on the impact of household defluoridation filters in rural Ethiopian microbial water quality. The visited villages use different water sources, such as surface water, boreholes, windmills or dug wells. Microbial contamination is present at the sources, and in much higher extent in the households.<br /> Compact Dry plates (Nissui Ltd, Japan) were uses to detect E.coli, total coliforms and Enterococci as fecal indicator organisms. The method is valid for detection and enumeration of microbial water contamination even under the challenging conditions of rural Ethiopia. The bacterial growth in dependence of incubation temperature showed similar counts above 30°C, which leads to representative results even if the power supply is interrupted. It was compared to standard methods (Colilert, IDEXX, and Petrifilm, 3M) and did not show significant differences.<br /> The household filters have an overall positive impact on fecal indicator organisms in all studied villages; nevertheless the contamination level is very high. The main contamination was taking place between the source and the inlet, respectively the jerrycan. There were no differences in drinking water quality found in a glass from household filter or community filter. The microbial inactivation of copper was tested in the lab and in the field, but no general improvement of the water quality found.<br /> Microbial contamination levels are alarmingly high in all studied households, and measures have to be taken enhance water quality. Hygiene and sanitation are very poor or absent in the area, and diarrheal diseases widespread. Technical possibilities to improve the situation are chlorination of the filters and source water, replacement of sand filter with candle filter,<br /> installation of sanitation facilities. They will not be sustainable without awareness creation and education of the interrelation between water, sanitation, hygiene and health.

The World Health Organization identified arsenic-contaminated drinking water as a dominant source of arsenic intake. Long- and short-term exposure to arsenic (As) causes cancer, vascular disease, skin lesions and neurological disorders. Therefore, a maximum concentration level of 10 µg/L was implemented in European and US drinking-water directives. Four chemical and physical water treatment processes are generally used to remove arsenic from water: adsorption, ion exchange, coagulation-coprecipitation, and membrane filtration. The performance of all treatment methods highly depends on pH, raw water chemistry, arsenic concentration and speciation, and the material used. In the last decade, nanoparticles have been tested in water treatment applications due to properties that could enhance treament efficiency, e.g. high reactivity and high surface area to volume ratio. Aluminum nanoclusters with 1-2 nm in size have been evaluated in a few studies to be good removal agents for humic acids and extremely effective coagulants due to strong flocculation. [...]<br /><br />Arsen-kontaminiertes Trinkwasser wurde von der Weltgesundheitsorganisation als eine der Hauptquellen für die Aufnahme von Arsen identifiziert. Der Kontakt mit Arsen führt zu lang- und kurzfristigen Beschwerden, zu denen Krebs, Gefässerkrankungen, Hautläsionen, und neurologische Störungen gehören. Aufgrund dessen wurde in Europäischen und US Trinkwasserverordnungen der maximale Arsengehalt auf 10 µg/L festgelegt. Generell werden vier chemische und physikalische Verfahren zur Entfernung von Arsen angewandt: Adsorption, Ionenaustausch, Koagulation-Kopräzipitation, und Membranfiltration. Die Leistung von allen Behandlungsmethoden ist stark abhängig vom pH, von der Wasserchemie, der Arsenkonzentration und –speziierung, sowie vom Behandlungsmaterial. Innerhalb des letzten Jahrzehnts wurden Nanopartikel zunehmend in der Wasseraufbereitung getestet, da sie sich durch besondere Eigenschaften auszeichnen, z.Bsp. hohe Reaktivität und ein grosses Oberflächen Volumen Verhältnis. Aluminium-Nanocluster haben eine Grösse von 1-2 nm und wurden in mehreren Studien als gutes Entfernungsmittel für Huminsäuren und als effektive Koagulanten wegen ihrer starken Ausflockung beschrieben. [...]

Die vielseitige Verwendung von Chrom in der metallurgischen und chemischen Industrie führt zu großen Abfallmengen mit erhöhter Chromkonzentration (z.B. Schlacke, Flugasche), die entweder mit Zement verfestigt und in der Umwelt als Deponie deklariert werden oder sie finden Wiederverwendung als Sekundär- oder Ersatzbrennstoffe in der Zementproduktion. Zusätzlich führt der Chromgehalt geogenen Ursprungs aus den Rohmaterialien Kalk und Ton zu erhöhten Chromkonzentration in zementartigen Materialien.<br />In der Umwelt kommt Chrom in zwei stabilen Oxidationszuständen als Cr(III) und Cr(VI) vor. Cr(III) wird entweder durch Adsorptionsprozesse gebunden oder fällt als schwerlösliches Cr(OH)₃ aus und ist deshalb nur in geringen Konzentrationen in Lösung enthalten. Cr(VI) hingegen, ist toxisch, karzinogen und in oxidativem Milieu als Oxyanion (CrO₄^2-) sehr gut löslich und kann in die Umwelt ausgewaschen werden. [...]<br /><br />The multifaceted use of chromium in chemical and metallurgical industries leads to large quantities of wastes (e.g. fly ash, slags) that are either stabilized with cement prior to disposal or used in cement production as secondary material or fossil fuel replacement. Additionally, the geogenic chromium source in the raw materials (limestone and clay) leads to enhanced Cr concentrations in cementitous materials.<br />In the environment chromium is stable as trivalent Cr(III) and hexavalent Cr(VI). In solution Cr(III) concentrations are low due to adsorption and incorporation processes in/on minerals and due to precipitation as Cr(OH)₃. Chromium(VI) is toxic, carcinogenic and highly soluble under oxidizing conditions since it is present as oxyanion (CrO₄^2-) - thus holding a high potential to be released to the environment. [...]

The goal of decision theory is to support decision makers in finding alternatives that lead to the best possible fulfillment of their objectives. This requires (1) the quantitative valuation of possible outcomes as a function of measurable system attributes, (2) the prediction of probability distributions of these attributes for each alternative, and (3) the ranking of all alternatives by combining (1) and (2). To obtain such quantitative predictions it is often necessary to elicit knowledge about influence factors, model parameters or attribute values from subject matter experts. Unfortunately, the characterization of subjective degrees of belief, in the Bayesian context, can be ambiguous. We suggest the use of imprecise probabilities to describe ambiguity of uncertainty. In this robust Bayesian concept we evaluated diverse classes of probability distributions. We found the <em>Density Ratio Class </em>the most adequate: (a) being able to adequately represent intersubjective knowledge, describing the state-of-the-art knowledge of science and technology, which is typically needed in environmental modeling and (b) having unique conceptual properties that are discussed below. Apart from the advantageous class properties, the <em>Density Ratio Class</em> is known to be difficult to elicit. [...]<br /><br />Das Ziel der Entscheidungstheorie ist es, Entscheidende dabei zu unterstützen, eine Entscheidungsalternative zu finden, die zur bestmöglichen Erfüllung ihrer Ziele führt. Das braucht (1) die quantitative Bewertung möglicher Konsequenzen in Funktion messbarer Systemattribute, (2) die Vorhersage von Wahrscheinlichkeitsverteilungen dieser Attribute für alle Entscheidungsalternativen und (3) das Erstellen einer Rangliste aller Entscheidungsalternativen durch die Kombination von (1) und (2). Um quantitative Vorhersagen zu erhalten, ist es oft unumgänglich, Wissen über Einflussfaktoren, Modellparameter oder Attributwerte von Fachexperten zu erheben. Leider kann die Charakterisierung subjektiver Überzeugungsgrade, in einem Bayesianischen Kontext verstanden, oft mit Ambiguität behaftet sein. Wir schlagen den Gebrauch von unpräzisen Wahrscheinlichkeiten vor, um Ambiguität in Bezug auf Unsicherheit zu beschreiben. In diesem robusten Bayesianischen Konzept evaluierten wir diverse Wahrscheinlichkeitsverteilungsklassen. Wir befanden die <em>Dichte-Verhältnis-Klasse</em> als die geeignetste: (a) Sie kann intersubjektives Wissen, welches den aktuellen Stand der Wissenschaft und der Technik beschreibt, adäquat beschreiben, was typischerweise in naturwissenschaftlichen Modellierungen gebraucht wird, und (b) sie weist einzigartige konzeptionelle Vorteile auf, welche unten benannt werden. Die <em>Dichte-Verhältnis-Klasse</em> ist, nebst ihren vorteilhaften Eigenschaften, für ihre nicht einfache Erhebung bekannt. [...]

Water is an everyday’s part of our life. It is substantial to our nutrition, cleaning or recreation. Yet, water goes generally unrecognised – we only realise its importance if there is something wrong with it. This implicit ubiquity is remarkable, not only because of the omnipresence of water for each person, but also because water is a product, which is sold on a market and purchased by the customer like every other product.<br />While constant research has explored technological, physical, biological or societal aspects of water (besides others), the scientific focus on the consumer’s side is about to emerge (Braden et al., 2009). In settings with unsafe drinking water for example, social scientists drive campaigns aiming at the user’s application of treatment methods and devices to fight potential health threats. Such unsafe drinking-water settings can typically be found in developing parts of the world. But even in these parts, the population is not entirely composed of poor. However, information about the wealthy residents can rarely be found, but it can help to understand the present state of affairs as a basis for intervention actions more thoroughly. Yet, the consumer’s choice is also a crucial part of the water cycle in settings where no such potential health threats exist. If the end-user is already provided with high-quality tap water, treating the water or consuming bottled water as an alternative appears redundant and peculiar. [...]<br /><br />Wasser ist ein alltäglicher Teil unseres Lebens. Es ist zentral für unsere Ernährung, Reinigung oder Erholung. Trotzdem wird Wasser kaum wahrgenommen – wir bemerken es erst dann, wenn etwas damit nicht stimmt. Diese selbstverständliche Allgegenwart ist bemerkenswert, nicht nur aufgrund der Omnipräsenz von Wasser für jede Person, sondern auch weil Wasser ein Produkt ist, das auf einem Markt verkauft und von Kunden gekauft wird wie jedes andere Produkt auch.<br />Während sich die Forschung kontinuierlich mit technologischen, physikalischen, biologischen oder gesellschaftlichen (neben weiteren) Aspekten des Wasser beschäftigt, hat sich eine wissenschaftliche Fokussierung der Konsumentenseite erst in jüngerer Zeit entwickelt (Braden et al., 2009). Sozialwissenschaftler führen beispielsweise Interventionskampagnen in Gebieten mit unsicherem Trinkwasser durch, die auf die Anwendung von Behandlungsmethoden und -geräten durch den Benutzer abzielen, um Gesundheitsbedrohungen zu vermeiden. Solche Gegebenheiten mit unsicherem Trinkwasser finden sich typischer Weise in den sich entwickelnden Teilen der Welt. Allerdings setzt sich auch in solchen Gebieten die Bevölkerung nicht ausschliesslich aus Armen zusammen. Erkenntnisse über die wohlhabenden Bewohner lassen sich hingegen nur selten finden, auch wenn diese Informationen hilfreich sind, wenn man den derzeitigen Stand der Dinge als Basis für zukünftige Interventionen tiefgreifender verstehen möchte. Doch auch in Gebieten, in denen keine Gesundheitsbedrohung aus unsauberem Trinkwasser existiert, ist die Wahlentscheidung des Konsumenten ein wesentlicher Teil des Wasserkreislaufes. Da wo der Endverbraucher bereits mit hochwertigem Leitungswasser beliefert wird, erscheint die Wasserbehandlung oder die Wahl von Flaschenwasser merkwürdig und überflüssig. [...]

In most European countries drinking water is treated before distribution. During drinking water treatment the water is disinfected, and particles, micropollutants and organic carbon compounds are removed. Microorganisms degrade organic compounds during different biofiltration steps, what leads to microbial growth in these filters and also to an increase of microorganisms in the water. After treatment, the concentration of microorganisms in drinking water is in the range of 10³-10⁵ cells/ml in case of no final disinfection step. In some European countries, namely Switzerland, Austria, The Netherlands and Germany, drinking water is distributed without the addition of a residual disinfectant. In such systems, microbial growth shall be limited by the low nutrient concentrations (predominantly organic carbon compounds) in the water. The objectives of this thesis were to (1) determine the factors influencing the microbial community composition of the biofilters in the drinking water treatment plant and of the final drinking water; (2) study whether the microbial community composition changes during drinking water distribution in the network or during stagnation in house installations until the water reaches the consumer. To study these questions, samples were taken and analyzed before and after each treatment step of the drinking water treatment plant of the city of Zürich, the adherent distribution network as well as separate household taps. In addition, the microbial community composition of the biofilters was studied. In this drinking water treatment plant lake water from 40 m depths is pre-ozonated (also for disinfection) before being treated by rapid sand filtration, intermediated ozonation, granular active carbon filtration and slow sand filtration. Afterwards the water is distributed with 10⁵ cells/ml without the addition of a residual disinfectant. [...]<br /><br />Oberflächengewässer wird in den meisten europäischen Ländern aufbereitet, bevor es als Trinkwasser verteilt wird. Während der Trinkwasseraufbereitung wird das Wasser desinfiziert, und Partikel, Mikroverunreinigungen und organische Kohlenstoffe werden entfernt. Der Abbau von organischen Kohlenstoffverbindungen erfolgt durch Mikroorganismen in verschiedenen Biofiltrationsstufen. Dies führt zu mikrobiellen Wachstum in diesen Filtern und dadurch auch zu einem Anstieg der Mikroorganismen im Wasser. Nach der Aubereitung beträgt die Konzentration der Mikroorganismen im Trinkwasser 10³-10⁵ Zellen/ml falls keine Enddesinfektion erfolgt. In einigen europäischen Ländern (z. B. Schweiz, Österreich, Niederlande, Deutschland) wird Trinkwasser ohne die Zugabe von Desinfektionsmitteln verteilt, wobei mikrobielles Wachstum durch die geringe Nährstoffkonzentration (meist Kohlenstoffverbindungen) im Wasser verhindert werden soll. Ziel dieser Arbeit war es herauszufinden (1) welche Faktoren die Biomasse und deren Zusammensetzung in den Biofiltern der Trinkwasseraufbereitung und letztendlich auch in unserem Trinkwasser beeinflussen (2) ob sich die mikrobielle Zusammensetzung und Zellkonzentration während der Trinkwasserverteilung im Netzwerk und in Hausinstallationen verändert, bis das Wasser den Endverbraucher erreicht. Um diese Fragestellungen genauer zu untersuchen wurden Proben vor und nach jedem Aufbereitungsschritt der Trinkwasseraufbereitungsanlage der Stadt Zürich, dem zugehörigen Trinkwassernetzwerk sowie von verschiedenen Haushalten genommen und analysiert. Ausserdem wurde die mikrobielle Zusammensetzung der Biofilter in der Aufbereitungsanlage untersucht. In dieser Trinkwasseraufbereitungsanlage wird Seewasser aus 40 m Tiefe ozoniert (dient u.a. der Desinfektion), bevor es über Schnellsandfiltration, Zwischenozonierung und darauffolgende Aktivkohlefiltration und Langsamsandfiltration aufgereinigt wird. Danach wird das Wasser mit einer mikrobiellen Zellkonzentration von 10⁵ Zellen/ml ohne die Zugabe eines Desinfektionsmittels verteilt. [...]

Understanding the fate of a xenobiotic inside an aquatic organism is crucial to predict its hazardous effects under environmental conditions. The severity of a toxic effect caused by an environmental pollutant is determined by toxicokinetic (TK) and toxicodynamic (TD) processes. TK processes determine the time course of a toxicant’s uptake, elimination, metabolism and distribution within an organism, TD processes describe the interaction of the active form of the chemical with the molecular target site in an organism and its link to the observed effect. TKTD models combine both TK and TD processes and relate concentrations of chemicals detected in the environment with the final effect. [...]<br /><br />Um schädliche Effekte einer Chemikalie in einem aquatischen Organismus unter Umweltbedingungen abschätzen zu können, ist es essentiel, die zugrunde liegenden Mechanismen und Prozesse zu verstehen. Toxikokinetische (TK) und toxikodynamische (TD) Prozesse bestimmen das Ausmass eines toxischen Effekts, der durch einen Schadstoff in  einem Organismus verursacht wird. TK Prozesse beschreiben den zeitlichen Verlauf der Aufnahme einer Chemikalie in den Organismus, der Elimination, der Metabolisierung und Verteilung innerhalb eines Organismus. TD Prozesse beschreiben die Wechselwirkung der aktiven Form einer Chemikalie mit dem molekularem Zielort und dessen Link mit dem beobachteten Effekt. Modelle, die TK und TD Prozesse kombinieren und in der Umwelt gemessene Chemikalienkonzentrationen mit dem beobachtbaren Effekt in Beziehung setzen können, sind TKTD Modelle. [...]

The incorporation of β-amino acids into peptides induces the formation of unique secondary structures and confers resistance to degradation by most proteolytic enzymes. These properties give rise to interesting new biomedical applications for β-peptides as bioactive α-peptide mimics. The β-aminopeptidases 3-2W4 BapA from <em>Sphingosinicella xenopeptidilytica </em>3-2W4, Y2 BapA from <em>Sphingosinicella microcystinivorans </em>Y2 and DmpA from Ochrobactrum anthropi LMG7991 possess the unusual catalytic ability to cleave backbone-elongated β³-amino acid residues from the N-termini of synthetic β- and mixed β,α-peptides that are otherwise resistant to proteolytic breakdown. [...]<br /><br />Der Einbau von β-Aminosäurebausteinen ruft in Peptiden einzigartige Sekundärstrukturen hervor und verleiht diesen Peptiden hohe Stabilität gegen enzymatischen Abbau. Diese aussergewöhnlichen Eigenschaften bilden die Grundlage für interessante biomedizinische Anwendungsmöglichkeiten von β-Peptiden als neuartige, biologisch aktive Peptidmimetika. Die β-Aminopeptidasen 3-2W4 BapA aus <em>Sphingosinicella xenopeptidilytica </em>3-2W4, Y2 BapA aus <em>Sphingosinicella microcystinivorans</em> Y2 und DmpA aus Ochrobactrum anthropi LMG7991 besitzen die ungewöhnliche Fähigkeit, N-terminale β³-Aminosäuren von synthetischen β- und β,α-Peptiden hydrolytisch abzuspalten, die ansonsten resistent gegen proteolytischen Abbau sind. [...]

Cryptic species are morphologically very similar, but reproductively isolated and sometimes evolutionarily old. They might differ in any trait other than morphology, including ecological, behavioural and physiological characteristics. If we do not recognize cryptic species and their biological differences, biodiversity assessments, functional ecosystem studies, and conservation measures might be inadequate. Studies that identify cryptic species and the differences between them are therefore urgently needed especially for endangered taxa and ecological keystone taxa.<br />In my doctoral thesis, I studied cryptic species of the ecologically important freshwater amphipod<em> Gammarus fossarum</em>. This morphospecies is an important fish prey, shredder of organic material, and host for parasites, therefore playing a key role in stream ecosystems. Previous studies have shown that G. fossarum contains at least three morphologically cryptic species, types A, B, and C. I focused on differences between these species with regard to geographical distribution, population genetic structure (which reflects biological characteristics and historical processes), and interactions with parasites. [...]<br /><br />Kryptische Arten sind reproduktiv isoliert, jedoch morphologisch sehr ähnlich. In allen nicht‐morphologischen Merkmalen, z.B. ihrer Ökologie, ihrer Physiologie und ihrem Verhalten, können sie sich dennoch deutlich unterscheiden. Werden kryptische Arten in Studien zur Biodiversität oder zu funktionalen Zusammenhängen in Ökosystemen nicht berücksichtigt, kann dies zu grossen Ungenauigkeiten führen, die einen wirkungsvollen Naturschutz erschweren. Forschungsprojekte zur Identifizierung kryptischer Arten und der Unterschiede zwischen ihnen sind somit unerlässlich, vor allem wenn es um bedrohte Arten oder Schlüsselarten in Ökosystemen geht.<br />In meiner Doktorarbeit habe ich kryptische Arten des <em>Gammarus fossarum</em>‐Artkomplexes untersucht, der wichtige ökologische Funktionen im Bachökosystem erfüllt. <em>G. fossarum</em> dient als Hauptnahrungsquelle für viele Fischarten, ist Zerkleinerer von totem organischem Material und dient als Zwischenwirt für unterschiedliche Parasiten. Frühere Arbeiten haben gezeigt, dass <em>G. fossarum</em> aus mindestens drei kryptischen Arten besteht, die als Typ A, B und C bezeichnet werden. Ich habe mich hier auf die Unterschiede zwischen diesen Arten in Bezug auf ihre geographische Verteilung, ihre populationsgenetische Struktur (die biologische Eigenschaften und historische Prozesse widerspiegelt) und ihre Interaktionen mit Parasiten konzentriert. [...]

Carbon nanotubes (CNTs) are engineered nanoparticles with unique physical and chemical properties making them promising for a broad range of industrial applications. Large scale synthesis and wide spread use of CNTs has increased the likelihood of the unintended release of CNTs into the environment. Environmental exposure of CNTs can occur during their whole life-cycle - production, use and disposal of CNTs, and CNTcontaining products. CNTs may reach the aquatic environment through waste water, runoff from contaminated areas, and aerosol-deposition. Knowledge about the partitioning of CNTs between the water column and the sediment is required to assess the potential impact of CNTs on the ecosystem. Depending on where (sediment or solution) and in which form (single CNTs or CNT agglomerates) CNTs are present in the aquatic environment, different organisms (benthic or pelagic) can be exposed and varying degrees of bioavailability would be expected, respectively. [...]<br /><br />Kohlenstoffnanoröhrchen (CNTs) sind synthetisch hergestellte Nanopartikel mit einzigartigen physikalischen und chemischen Eigenschaften, was sie für vielfältigste Anwendungen attraktiv macht. CNT Synthese und Anwendung in grossem Stil birgt das Risiko, dass CNTs ungewollt in die Umwelt gelangen. Eine Freisetzung in die Umwelt ist dabei während des gesamten Lebenszyklus der CNTs möglich, d.h. während der Produktion, der Nutzung und der Entsorgung von CNTs und Produkten, die diese enthalten. Die aquatische Umwelt kann über Abwasser, über Abschwemmung von kontaminierten Stellen und über Aerosol-Deposition betroffen sein. Um potenzielle Risiken der CNTs auf das Ökosystem abschätzen zu können, ist es relevant zu wissen, ob der Verbleib der CNTs mehrheitlich im Sediment oder in der Wassersäule zu erwarten ist. Je nach dem wo (Sediment oder Wassersäule) und in welcher Form die CNTs (einzeln oder als Agglomerate) vorliegen, werden andere Organismen exponiert sein (benthische oder pelagische) und wird die Bioverfügbarkeit der Partikel variieren. [...]

The input of veterinary antimicrobials into the environment is of concern because of their potential to invoke bacterial resistance or to exert adverse effects on microbial communities. Veterinary sulfonamide antimicrobials enter soils via excretions of grazing livestock or manure application. A few weeks after application a major part of sulfonamides cannot be recovered from soil by conventional extraction methods, indicating a strong tendency of these antimicrobials to form nonextractable residues (NER). The mechanisms driving NER formation are either physical entrapment in organic matter or covalent bond formation. The latter seems more likely due to (i) the very rapid initial NER formation in soils and (ii) the possibility of sulfonamide covalent bonding to quinone moieties of natural organic matter via their aromatic amino group. To judge the long-term behavior and a possible remobilization as well as effects of sulfonamides in soils, it is essential to identify the binding pathway relevant for sulfonamides. The overall objectives of this PhD thesis were (i) to identify the main reaction pathways of sulfonamides with model compounds and organic matter isolates as well as the stability of the formed bonds, and (ii) to assess the factors and pathways governing NER formation of sulfonamides in soils. [...]<br /><br />Der Eintrag antimikrobieller Wirkstoffe in die Umwelt ist aufgrund negativer Auswirkungen auf mikrobielle Gemeinschaften und der möglichen Verbreitung von Resistenzgenen bedenklich. Antimikrobielle Sulfonamide aus der Tierhaltung werden durch Ausscheidungen weidender Tiere oder durch Applikation von Gülle in Böden eingetragen. Sulfonamide zeigen in Böden eine starke Tendenz zur Bildung gebundener Rückstände und sind mittels konventioneller Methoden nach einigen Wochen nicht mehr extrahierbar. Als Mechanismen für die Bildung gebundener Rückstände kommen physikalischer Einschluss in organische Substanz oder Bodenpartikel sowie die Bildung kovalenter Bindungen in Frage. Für eine kovalente Bindung sprechen die Befunde, dass die initiale Bildung gebundener Rückstände sehr schnell verläuft und eine Reaktion der aromatischen Aminogruppe der Sulfonamide mit Chinonen der organischen Substanz möglich ist. Um das Langzeitverhalten und eine mögliche Remobilisierung und damit verbundene Effekte in Böden zu verstehen, ist es notwendig, die Reaktionswege der Sulfonamide in Böden zu verstehen. Die Ziele dieser Arbeit waren es daher (i) die wichtigsten Reaktionswege von Sulfonamiden mit Modellverbindungen und Huminsäuren aufzuklären und die Stabilität dieser Bindungen zu bestimmen, sowie (ii) die Einflussfaktoren und Mechanismen der Bildung gebundener Rückstände in Böden aufzuklären. [...]

Information and communication technologies (ICT) are increasingly shaping the daily lives of people in Western societies. Current technological progress can be characterized by an increased power of technological components, combined with a continuous decrease in their size. These advances allow for the embedding of ICT components in commodities, and for their interconnection with each other and with technologies transmitting information, such as the Internet of mobile phones. This new generation of so-called 'smart' technologies is meant to support people in their accomplishment of everyday tasks, invisibly, automatically, and ubiquitously. [...]<br /><br />Informations- und Kommunikationstechnologien (IKT) prägen zunehmend das Alltagsleben vieler Menschen, insbesondere in der industrialisierten Welt. Rasante technologische Fortschritte ermöglichen kommenden IKT Generationen zusätzliche Möglichkeiten: Durch die ansteigende Leistungsfähigkeit der technologischen Komponenten, einhergehend mit einer ständigen Verringerung deren Grösse, können IKT Anwendungen vermehrt in Alltagsgegenstände eingebettet, sowie gegenseitig vernetzt werden. Sogenannt 'intelligente' Gegenstände sollen in Zukunft die Anwender und Anwenderinnen möglichst unsichtbar, automatisiert und allgegenwärtig bei der Bewältigung ihres Alltags unterstützen. [...]

In dieser Arbeit wurden die Inaktivierung von natürlichen Bakterienpopulationen und die Bildung von assimilierbarem organischem Kohlenstoff (engl. assimilable organic carbon (AOC)) während der oxidativen Behandlung von Trinkwasser mit Ozon, Chlor, Chlordioxid, Permanganat und Ferrat untersucht.<br />Die Desinfektion ist einer der wichtigsten Schritte in der Trinkwasseraufbereitung. Dazu können Oxidationsmittel wie Ozon, Chlor und Chlordioxid eingesetzt werden. Die Methoden und Richtlinien, mit denen die hygienische Qualität des Trinkwassers heute bewertet wird, prüfen nur das Vorhandensein von Indikatororganismen (E. coli und Enterokokken) und von aeroben mesophilen Keimen, was für eine umfassende Beurteilung der Desinfektionsleistung der Aufbereitung ungeeignet ist. Die vorliegende Arbeit hatte deshalb zum Ziel, die Desinfektionskinetik von natürlich im Trinkwasser vorkommenden Bakterien durch verschiedene Oxidationsmittel mittels Durchflusszytometrie (engl. Flow-Cytometry (FCM)), einer neuen und praktisch anwendbaren, mikrobiologischen Methode, zu untersuchen. [...]<br /><br />This thesis investigates inactivation of native drinking water bacteria and assimilable organic carbon (AOC) formation during oxidative water treatment with ozone, chlorine, chlorine dioxide, permanganate, and ferrate.<br />Disinfection is one of the most important steps in drinking water treatment. Oxidants such as ozone, chlorine, and chlorine dioxide are often applied for this purpose. Currently, methods to assess the drinking water quality rely on indicator organisms and aerobic mesophilic bacteria that are measured by cultivation techniques. However, these methods are not suitable for a broad assessment of the disinfection efficiency during water treatment. Therefore, one objective of this thesis was to measure the inactivation kinetics of natural bacteria by the selected six oxidants with flow-cytometry (FCM), an innovative and applicable microbiological method. [...]

Population growth and economic development are increasing demand for water resources. Although there is no global water scarcity as such, an increasing number of regions in arid and semi-arid countries are chronically short of water. Given this state of scarcity, agriculture as the biggest water user is becoming under severe scrutiny to account for the water it uses. As the demand for food is ever increasing, and there is no significant room to expand areas of cultivation, the increasing demand for food will have to be met through improved management of the available and limited resources, and/or through imports from outside. [...]<br /><br />Bevölkerungswachstum und wirtschaftliche Entwicklung führen in den meisten Entwicklungsländern zu einem steigenden Bedarf an Wasserressourcen, die vor allem in semiariden und ariden Gebieten ohnehin bereits sehr knapp sind. Zusätzliche landwirtschaftliche Nutzflächen sind gewöhnlich kaum vorhanden, so dass der steigende Nahrungsmittelbedarf primär mit Hilfe verbesserten Managements der knappen verfügbaren Wasserressourcen gedeckt werden muss. [...]

Over the last decades, dry season (boro) rice production in Bangladesh has been largely intensified to meet the rising food demand of the growing population and to ensure food self-sufficiency. To date, boro rice cultivation accounts for more than 50% of the country’s rice production, as it provides higher yields and yield security than the traditional rice varieties. Dry season rice requires large amounts of water for irrigation, which is mainly provided by groundwater abstraction from shallow tube wells, often containing high arsenic (As) concentrations. In the long-term, this may lead to As accumulation in paddy soils and further to elevated As contents in rice plants, threatening food quality, rice yields and human health.<br />In order to accurately assess all risks for human and environmental health associated with boro rice cultivation using As-rich groundwater for irrigation, detailed investigations of paddy soils and rice plants are necessary to provide insight into the complex cycling of As in lowland paddy field systems. Consequently, the aim of the present work was to shed light on the As cycling at a specific field site in Munshiganj district/Bangladesh. On the study site, boro rice has been grown from December until May since the early 1990s. During the growth season, the fields are irrigated intermittently through single water inlets into individual fields with As-rich groundwater extracted from a shallow aquifer by diesel powered pumps. Before harvest fields dry out and subsequently get inundated during monsoon flooding between mid June and late October. [...]<br /><br />In Bangladesch wurde der Anbau von Boro Reis über die letzten Jahrzehnte stark intensiviert, um den steigenden Nahrungsmittelbedarf der wachsenden Bevölkerung unabhängig vom Ausland decken zu können. Boro Reis bietet im Vergleich mit traditionellen Reisvarietäten höhere Erträge und Ertragsicherheit und macht heutzutage mehr als 50% der Reisproduktion des Landes aus. Der in der Trockenzeit angebaute Boro Reis erfordert jedoch eine intensive Bewässerung der Felder, für die häufig oberflächennahes Grundwasser verwendet wird, das mit geogenem Arsen (As) belastet ist. Langfristig kann dies zu erhöhten Arsengehalten in Reisfeldböden führen und in der Folge zu steigenden Arsenkonzentrationen in Reispflanzen, die dann Nahrungsmittelqualität, Erträge wie auch die menschliche Gesundheit bedrohen.<br />Um die Risiken für Mensch und Umwelt beurteilen zu können, die mit der Verwendung von arsenreichem Grundwasser für die Boro Reisproduktion verbunden sind, ist ein Verständnis des komplexen Arsenkreislaufs im Tieflandreisanbau notwendig. Die vorliegende Arbeit verfolgte das Ziel, den Arsenkreislauf an einem Feldstandort in Munshiganj/Bangladesch zu untersuchen, an dem seit Anfang der 1990iger Jahren von Dezember bis Mai Boro-Reis angebaut wird. Während der Reiswachstumsperiode werden die einzelnen Felder periodisch durch je einen Wassereinlass mit arsenreichem Grundwasser aus einem oberflächennahen Aquifer bewässert. Vor der Ernte trocknen die Felder aus und sind anschliessend von Mitte Juni bis Ende Oktober vom Monsun erneut überflutet. [...]

Das heutige Klima unterliegt starken und rasch fortschreitenden Veränderungen. Diese Effekte sind mit grösster Wahrscheinlichkeit anthropogen verursacht. Seen reagieren sensitiv auf veränderte Klimaverhältnisse. Die primäre Reaktion ist die Erhöhung der Oberflächentemperatur. Dies hat Auswirkungen auf die physikalischen Verhältnisse im See wie auch auf die aquatischen Ökosysteme. Die Abschätzung zukünftiger Entwicklungen von Seen ist von grosser Bedeutung. Besonders bei Verwendung von Seewasser zur Trinkwasserversorgung ist die Wasserqualität von grösster Wichtigkeit. Durch langfristiges Wassermanagement und geeignete Massnahmen können die Folgen des Klimawandels abgedämpft werden. [...]

European rivers and streams have become increasingly fragmented since the 17^th century. Restoration of longitudinal connectivity to increase opportunity for fish migration is a main goal of river ecosystems. One such measure is the construction of block ramps; however, few studies have experimentally evaluated their effectiveness, especially for small non-salmonid fish.<br /> In this study, different block ramps were analysed with respect to their effectiveness for fish passage using mark-recapture experiments as well as PIT-tags based on microhoming behaviour of translocated fishes. We could demonstrate that with some exeptions all block ramps were to some extent passable for all studied species. Additionally, it could be shown that ramps with vertical drops seem to effect fish migration more severely than, ramps without vertical drops independent of their slope. Additionally we conducted different experiments to charaterize microhoming of bullheads in order to get a correct understanding of the results of our block ramp experiments. Bullheads that were translocated downstream tended to move upstream in the first days adter translocation but not exactly back to their initial place.

When <em>E. coli</em> is grown in long-term glucose limited continuous cultures it could be shown that a stable acetate cross-feeding polymorphism evolves repeatedly. However, the processes prior to genetic differentiation are still unknown. In this study we analyzed the gene expression of different genes involved in metabolism. We used <em>E. coli</em> MG1655 clones containing a plasmid with different promoter-GFP fusions. They were grown in continuous cultures and GFP expression was measured after ~5 generations to minimize the probability of mutations. We were interested in whether an isogenic population divides into two different acetate cross-feeding phenotypes. Most analyzed genes (<em>aceB, ackA, mglB, mlc, pck, ptsG</em>) showed variation in gene expression but no clear evidence for different cross-feeding phenotypes. In some experiments, the expression profile of <em>acs</em> (acetyl-CoA synthetase) suggested the occurrence of different phenotypic subpopulations. But also other mechanism than acetate cross-feeding could cause the heterogeneity in gene expression.

Seesedimente liefern wichtige Hinweise über vergangene Umweltverhältnisse, wobei Parameter wie Stickstoff(N)‐Gehalt, Kohlenstoff(C)‐Gehalt, C_org/N_total ‐Verhältnis und Isotopenverhältnisse (δ¹⁵N und δ¹³C) für die Analyse herangezogen werden. Variationen der C‐ und N‐ Isotopenverhältnisse in Sedimentarchiven helfen, Fluktuationen in den hauptsächlich biologisch gesteuerten N‐ und C‐Kreisläufen zu rekonstruieren und möglicherweise in Zusammenhang mit Umwelt‐ und/oder Klimaveränderungen zu stellen. Das primäre Isotopensignal in den Sedimenten kann jedoch durch mikrobielle Degradations- und Diageneseprozesse sekundär verändert werden, der Grad der Veränderung unter variablen Umweltbedingungen ist allerdings unklar.<br /> In dieser Arbeit wurde die N‐Isotopenalteration während der frühen Diagenese (bis ca. 280 Jahre BP), durch den Vergleich der δ¹⁵N‐Signale des Bulk‐Sediments mit dem δ¹⁵N‐Signal einer Phaeophytin‐ähnlichen Komponente (Phae), bei welcher veränderungsresistente N-Verbindungen vermutet werden, nachgewiesen. Der δ¹⁵N Unterschied von durchschnittlich 3.2‰, welcher Folge von Fraktionierungsvorgängen während der Biosynthese, der mikrobiellen Degradation des organischen Materials, sowie während der Diagenese entsteht, scheint, bis auf die obersten Sedimentschichten, relativ konstant zu bleiben. Eine starke Veränderung des Bulk δ¹⁵N in den obersten Sedimentschichten hin zu höheren Werten mit zunehmender Tiefe, bei gleichzeitigem Fehlen eines solchen Gradienten in den δ¹⁵N‐Signalen von Phae lässt zudem vermuten, dass eine N‐Isotopenalteration im Bulk‐Sediment in der frühen Phase der Diagenese stattfindet und unterstützt die Annahme, dass es sich bei dem Phae‐N um geschützten, diagenese‐resistenten N handelt. Die Analyse der Bulk und komponenten‐spezifischen N‐Isotopendaten deuten darauf hin, dass trotz der signifikanten Veränderung der δ¹⁵N‐Signale während der frühesten Diagenese an der Sediment‐Wasser‐Grenzschicht, das δ¹⁵N des Bulk‐Sediments relative Variationen der primären N‐Isotopensignale aus der Wassersäule widerspiegeln und damit die Rekonstruktion von Paläoumweltverhältnissen trotz der frühdiagenetischen NIsotopenalteration ermöglicht.<br /> Weitere geochemische Untersuchungen im Rahmen dieser Arbeit ergaben, dass die Sedimente des Cadagnosees nur einen sehr geringen Anteil anorganischen Kohlenstoffs besitzen und die organische Materie hauptsächlich lakustrinen Ursprungs ist. Neben den starken, durch Degradationsprozesse im oberen Sedimentbereich verursachten diagenetischen Veränderungen (starke Abnahme von N, C_org Zunahme des δ¹⁵N) zeigen C_org- und N‐Gehalt, sowie δ¹³C‐Signale nur leichte Veränderungen in den letzten ca. 10 000 Jahren BP, welche möglicherweise auf Veränderungen der Degradationsbedingungen zurückgeführt werden können. Mehr oder weniger invariante δ¹⁵N‐Signale im Bulk‐Sediment, sowie im Phae deuten an, dass der Stickstoffhaushalt des Cadagnosees keine starken Perturbationen während des Holozäns erfahren hat. Dies wiederum lässt darauf schliessen, dass sich die Ablagerungsbedingungen im Cadagnosee (Produktivität, Eintrag externen organischen Materials in den See bzw. Redoxbedingungen) über längere Zeiträume nicht stark verändert haben.

Floodplains are important biogeochemical reactors where enhanced organic matter (OM) and nutrient cycling take place. River-floodplain exchange connects the aquatic with the terrestrial system and therefore co-determines the transfer of solutes between river and floodplain.<br /> This thesis focuses on the Kafue River and Kafue Flats, a dam-influenced and annually flooded subtropical floodplain system in Zambia. Initial investigations of the system identified substantial river-floodplain exchange along the main stem of the Kafue River, and estimated large net exports of organic carbon and organic nitrogen from the system. However, the characteristics of this organic matter have not been investigated. The goal of this thesis was to characterize the OM in the Kafue River and Kafue Flats as a step toward better understanding its lability and dynamics along the river and into the floodplain. For this purpose, water samples from the river and floodplain were collected shortly after peak flooding in May 2010 and analyzed by measuring dissolved organic matter (DOM) and particulate organic matter (POM) concentrations, carbon (C) and nitrogen (N) isotopes in DOM and POM, and DOM’s spectrofluorometric properties.<br /> POM and DOM were found to have distinctly different compositions (δ¹³C, C:N), suggesting that POM originated from microbially derived compounds and DOM from terrestrially derived material, and that POM was substantially fresher and presumably more labile. OM composition showed spatial variation along the river as indicated by C:N, δ¹³C, and δ¹⁵N. River-floodplain exchange had an influence on these changes in OM composition along the river. DOM compositions, indicated by spectrofluorometric measurements, were similar along the river and into the floodplain, showing a strong terrestrial signal, even upstream at the dam outflow. However, there were floodplain stations with a substantially different composition from the river, indicating heterogeneity of floodplain processes.<br /> The findings of this Master thesis provide a detailed insight into the functioning of subtropical floodplain systems and contribute to better understand the effects of river-floodplain exchange on OM dynamics.

Micropollutants are emerging contaminants in surface waters. Pharmaceuticals are of special concern since they are designed to have eects on the human body. Some compounds like the hormones were found to have eects on the aquatic ecosystems at low concentrations. Pharmaceuticals are discharged into the wastewater after the excretion from the human body. In a project at Eawag, the importance of hospitals as point sources for pharmaceuticals is studied. Within this project a model for the prediction of the pharmaceutical concentrations and the pharmaceutical loads in the Swiss river network should be developed. The already existing national mass balance model accounts for the households as a source of pharmaceuticals but the hospitals as a second, important source for pharmaceuticals are not included in the modeling approach. The goal of this thesis is the implementation of the hospitals as source for pharmaceuticals in the national mass balance model and a comparison of the results of the national mass balance model and the so-called hospital model after the integration of the hospitals.<br /> The results are compared for eleven dierent groups of pharmaceuticals, with the main focus lying on iodinated contrast media, gadolinium containing contrast media and cytostatics. Different scenarios have been implemented regarding the fraction of the pharmaceuticals used in the hospitals and regarding the distribution of the pharmaceuticals between the hospitals. The consumption in the hospitals has been analyzed according to the number of beds in hospitals with specic departments (e.g. radiology department) or according to the number of treatments in the hospitals (e.g. the number of cancer treatments in each hospital).<br /> The analysis of the model results showed that the importance of hospitals as point sources for pharmaceuticals highly depends on the fraction of the pharmaceuticals used in hospitals. For very specic substances that are used in hospitals to a large extent (e.g. contrast media) the hospital model shows a dierent result, but for general pharmaceuticals (e.g. antibiotics or analgesics) the dierence in the result is very small. For pharmaceuticals, of which a high fraction is used in hospitals, a shift in the distribution of the pharmaceutical load to the bigger wastewater treatment plants was observed.<br />

Over the last centuries river systems have been heavily modified by human activities. Waterways were regulated and degraded, wetlands drained for land use, water resources used for drinking water or hydropower. Additionally, the intensive land use lead to water eutrophication. Consequences are changed runoff conditions and the loss of important ecological functions.<br /> Better knowledge of the ecological functions and needs of rivers have led to efforts to restore streams and their natural disturbance regimes. The aim is to re-establish the longitudinal connectivity, improve habitat and water quality, and protect as well as promote biodiversity. In Switzerland, 4'000 km of flowing waters should be revitalized within the next 80 years.<br /> But several studies show that restoration projects in many countries failed. Although increased habitat heterogeneity was achieved, biological diversity could hardly be improved. Accordingly, there must be more factors for a successful recolonization by biota. [...]<br /><br /> Fliessgewässer wurden in den letzten Jahrhunderten durch menschliche Aktivitäten stark verändert. Flüsse wurden begradigt, Feuchtgebiete zur Landgewinnung entwässert, Wasserressourcen zur Trinkwasserversorgung oder Wasserkraftnutzung genutzt. Zusätzlich führte die intensive Landnutzung zur Eutrophierung der Gewässer. Die Folgen: veränderte Abflussverhältnisse sowie der Verlust wichtiger ökologischer Funktionen.<br /> Erst gehäuft auftretende Hochwässer sowie ein besseres ökologisches Verständnis führten zum Umdenken und folglich zu Renaturierungsmassnahmen. Ziel dabei, die Längsvernetzung wiederherzustellen, den Lebensraum und die Wasserqualität zu verbessern sowie die Biodiversität zu fördern. In der Schweiz sollen bis in 80 Jahren 4'000 Gewässerkilometer renaturiert werden.<br /> Erste Studien zeigen jedoch, dass viele der umgesetzten Projekte weltweit zwar eine erhöhte Lebensraumheterogenität aufweisen, die biologische Diversität jedoch kaum verbessert werden konnte. Es stellt sich deshalb die Frage, welche Faktoren die Wiederbesiedlungen nach Renaturierungen beeinflussen und wie diese längerfristig verbessert werden können. [...]

The microbial community of any natural aquatic environment, when stained with nucleic acid stains and analyzed by flow cytometry, tend to cluster into two distinct fractions when sideward scatter (SSC) and green fluorescence is taken into account. One cluster shows low SSC as well as low green fluorescence and the other one shows high SSC and fluorescence. Based on these observations these two clusters have been given names LNA and HNA bacteria respectively. The majority of studies carried out in this field have focused on the abundance of these HNA and LNA cells in different environments and their relative activity. The main reason for this is a lack of suitable culture methods. There are many conflicting results about the activity and phylogeny of these LNA and HNA bacteria. HNA bacteria are generally regarded as active part of microbial community where as the LNA are regarded as the inactive part. However few authors regard LNA as active bacteria. The aim of this work was to better understand the underlying factors of this flow cytometry phenomenon.<br /> Two major factors namely stain accessibility due to cell membrane permeability and DNA compaction, were investigated for their influence on intensity of fluorescence. It was found that cell membrane permeability does not play a significant role, but DNA compaction may play a major role for low fluorescence intensity of LNA. Study of growth characteristics of an LNA isolate revealed that fluorescence intensity and SSC is influenced by the growth phase of bacteria. The present study pinpoints the limitation of classifying a natural community into low nucleic acid and high nucleic acid content bacteria based on fluorescence intensity observed by flow cytomery. The fluorescence of a bacterium may be influenced by many factors like cell membrane permeability, DNA topology, copy number of chromosomal DNA, physiological state of bacteria etc., which was also reflected in the study of growth characteristic of LNA isolate. So there exists a strong need to investigate the multiple factors which are responsible for the clustering of natural community.

Urine is the source of the major part of plant nutrients in municipal wastewater. Therefore, full nutrient recovery from source-separated urine is an attractive option for both treating wastewater and gaining a valuable fertilizer product. Full nutrient recovery can be achieved by first stabilizing collected urine by nitrification and then concentrating the urine by distillation. Since concentrations of all salts in urine increase with increasing removal of water also the sodium chloride (NaCl) content is high in the end. There are two problems related to NaCl, the first being the synergistic decomposition of ammonium nitrate by chloride and the second being soil salinity and sodicity related problems when applying the product as fertilizer. [...]

Speciation reversal occurs when either the divergent selection or the assortative mating that drove the genetic differentiation between sister species ceases to operate, gene flow increases and leads to collapse of those previously differentiated species. This process is usually associated with environmental change. Eutrophication was proposed to contribute to diversity loss through speciation reversal in stickleback, cichlids and whitefish. Here we study the phenotypic and genetic differentiation of whitefish species before and after eutrophication in a weakly polluted and a moderately polluted lake, using linear morphology, geometric morphometrics, and neutral genetic markers on contemporary and historical samples. In the moderately polluted lake, we found a decrease in genetic differentiation, overall decrease of variation in head shape and a decrease of within species variance from pre- to post-eutrophication. Species differences in body shape and head shape responded differently to eutrophication. While species differences in the relationship between feeding related traits and size decreased in Lake Constance, this was not true for body shape traits. The phenotypic distances in head shape between species clearly decreased and were constrained but not predicted by genetic isolation. None of these trends was apparent in the weakly polluted lake. Our study adds more evidence for speciation reversal in whitefish, but also indicates that additional phenotypic changes may have occurred that are not explained by hybridization alone. Our results may indicate that speciation reversal might be much more common than previously thought and represents a real danger for global biodiversity.

Two previously isolated strains (DSM 9103^T and LPM-4^T) able to grow with EDTA (facultatively and obligately, respectively) as the source of carbon, nitrogen and energy were investigated in order to clarify their taxonomic positions. The strains were strictly aerobic, Gram-negative, asporogenous and non-motile rods that required biotin for growth. Reproduction occurred by binary fission. The strains were mesophilic and neutrophilic. Their major fatty acids were summed feature 7 (consisting of C_18:1<em>ω</em>7<em>c</em>, C_18:1<em>ω</em>9<em>t</em> and/or C_18:1<em>ω</em>12<em>t</em>) and C_19:0 cyclo <em>ω</em>8<em>c</em>. The polyamine pattern revealed homospermidine as a major polyamine. Predominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylmonomethylethanolamine and diphosphatidylglycerol. <em>Mesorhizobium</em>-specific ornithine lipid was absent. The predominant isoprenoid quinone was Q-10. The DNA G+C values were 60.8 and 63.1 mol% (<em>T</em>_m) for strains LPM-4^T and DSM 9103^T, respectively. The level of 16S rRNA gene sequence similarity between these EDTA-utilizers was 99.3% while the DNA DNA hybridization value was only 37%. Both strains were phylogenetically related to members of the genera <em>Aminobacter</em> and <em>Mesorhizobium</em> (95–97 % sequence similarity). However, DNA DNA hybridization values between the novel EDTA-degrading strains and <em>Aminobacter aminovorans</em> DSM 7048^T and <em>Mesorhizobium loti</em> DSM 2626^T were low (10–11%). Based on their genomic and phenotypic properties, the new alphaproteobacterial strains are assigned to a novel genus, <em>Chelativorans</em> gen. nov., with the names <em>Chelativorans multitrophicus</em> sp. nov. (type strain DSM 9103^T=VKM B-2394^T) and <em>Chelativorans oligotrophicus</em> sp. nov. (type strain LPM-4^T=VKM B-2395^T=DSM 19276^T).

An accurate estimate of global water uses with high spatial resolution is a key to assessing global water scarcity and to understanding human's interference with the ecosystems. In spite of the progress made previously, there is a lack of spatially explicit assessment of both green and blue water uses in agriculture. In this paper, we estimated consumptive water use (CWU) in cropland on a global scale with a spatial resolution of 30 arc-minutes. A GIS-based version of the EPIC model, GEPIC, is used for the estimation. The results show that in crop growing periods, global CWU was 5938 km³ a^–1 in cropland around the year 2000, of which green water contributed to 84%. On an annual basis, global CWU was 7323 km³ a^–1 in cropland, of which green water contributed to 87%. We compared the simulated consumptive blue water use (CBWU) with the statistical CBWU at the national level among individual countries, and at the federal state or province level in the USA and China. The comparison indicates a good agreement between the simulated and statistical CBWU, suggesting a satisfactory performance of the GEPIC model and reliability of the estimation in irrigated cropland. The importance of green water in both crop production and food trade calls for a better management of green water, in addition to blue water.

Crop production is the single largest cause of human alteration of the global nitrogen cycle. We present a comprehensive assessment of global nitrogen flows in cropland for the year 2000 with a spatial resolution of 5 arc-minutes. We calculated a total nitrogen input (IN) of 136.60 trillion grams (Tg) of N per year, of which almost half is contributed by mineral nitrogen fertilizers, and a total nitrogen output (OUT) of 148.14 Tg of N per year, of which 55% is uptake by harvested crops and crop residues. We present high-resolution maps quantifying the spatial distribution of nitrogen IN and OUT flows, soil nitrogen balance, and surface nitrogen balance. The high-resolution data are aggregated at the national level on a per capita basis to assess nitrogen stress levels. The results show that almost 80% of African countries are confronted with nitrogen scarcity or nitrogen stress problems, which, along with poverty, cause food insecurity and malnutrition. The assessment also shows a global average nitrogen recovery rate of 59%, indicating that nearly two-fifths of nitrogen inputs are lost in ecosystems. More effective management of nitrogen is essential to reduce the deleterious environmental consequences.

The evolutionary origin of the only north-west Saharan haplochromine cichlid, <i>Astatotilapia desfontainii</i>, was explored using mitochondrial DNA sequences. Phylogenetic analyses revealed that this species belonged to the main East African-Nilotic haplochromine clade, but was a distinct lineage that diverged from modern haplochromines in the Pliocene. The results suggest that <i>A. desfontainii</i> is a relict haplochromine lineage that has endured major climate fluctuations in North Africa.

High spatial resolution satellite data contribute to improving land cover/land use (LCLU) classification in agriculture. A classification procedure based on Quickbird satellite image data was developed to map LCLU of diversified agriculture at sub-communal and communal level (7 km²). Segmentation performance of the panchromatic band in combination with high pass filters (HPF) was tested first. Accuracy of field boundary delineation was evaluated by an object-based segmentation, a per-field and a manual classification, along with a quantitative accuracy assessment. Sub-communal classification revealed an overall accuracy of 84% with a <i>κ</i> coefficient of 0.77 for the per-field vector segmentation compared to an overall accuracy of 56–60% and a <i>κ</i> coefficient of 0.37–0.42 for object-based approaches. Per-field vector segmentation was thus superior and used for LCLU classification at communal level. Overall accuracy scored 83% and the <i>κ</i> coefficient 0.7. In diversified agriculture, per-field vector segmentation and classification achieved higher classification results.

This review summarizes the application of <i>Tetrahymena</i> spp. in ecotoxicology, in order to promote a more integrated, multi-level ecotoxicological assessment approach regarding the effects of chemical stressors on several biological levels (from molecule to ecosystem). Such a multi-level testing approach in one species facilitates the establishment of missing causal relationships between biochemical responses and ecological effects. The review illustrates that <i>Tetrahymena</i> spp. represent excellent ecotoxicological test species due to their important role in the microbial foodweb, wide distribution and abundance, sequenced genome in <i>T. thermophila</i>, large background knowledge and scientific publications in cellular biology, ecology and ecotoxicology. Several bioassays have already been developed on different biological organisation levels, such as enzyme assays (biochemical level), behavioral tests (individual level), population growth tests (population level) and microcosms (community level). Moreover, specific mode-of-action based assays are available (e.g. genotoxicity), or are in development (e.g. endocrine disruption and neurotoxicity). <i>Tetrahymena</i> spp. combine traits of (1) a single cell, thus might replace or complement specific cell-line testing approaches, with traits of (2) a whole organism and population, thus allowing to study complete metabolic pathways and its consequences on population growth and genetic adaptation. Assays involving <i>Tetrahymena</i> spp. might easily be adapted for a rapid multi-level <i>in situ</i> or <i>ex situ</i> toxicity biosensor test system for ecologically relevant risk assessment.

An understanding of the distribution and spatial structure of the natural vectors of zoonothic pathogens is of interest for effective disease control and prevention. Here, we investigate the range-wide population genetic structure of common pochard (<i>Aythya ferina</i>), a long-distance migratory duck and potential vector of highly pathogenic avian influenza. We collected several hundred samples from breeding and wintering grounds across Eurasia including some H5N1-positive individuals and generated partial sequences of the mitochondrial control region and multilocus microsatellite genotypes. Genetic differentiation among breeding populations was significant for both marker types but higher for maternally inherited mtDNA than for biparentally inherited nuclear markers. There was only weak genetic divergence between ducks sampled in Europe and East Asia, and genetic differentiation between populations was not generally associated with geographical distance. No evidence of genetic substructure was detected for ducks sampled on the European wintering grounds. Our results suggest limited breeding-site fidelity, especially in females, but extensive population admixture on the wintering grounds. The specific role of pochards as natural vectors of zoonotic pathogens and in particular H5N1 remains to be clarified but our results point to wintering grounds as potential hotspots for disease transmission.

Ecological sanitation (Ecosan) is a relatively new concept being promoted in many developing countries to improve sanitation coverage and recycle nutrients in excreta for agricultural production. We conducted a cross-sectional study in Kabale municipality, western Uganda to determine the coverage of Ecosan and factors affecting its uptake. A total of 806 respondents were interviewed, randomly selected from 32 of 77 (42%) villages in Kabale municipality. We held six focus group discussions and 10 key informant interviews. Ecosan coverage was found to be 20% (163/806). The factors that were significantly associated with Ecosan coverage included education, occupation, religion and age. Our study found a relatively high Ecosan coverage in Kabale municipality compared to the targeted national coverage of 15% by 2018. Policy-makers and organizations in Ecosan development ought to take into consideration the influence of education and socio-economic factors for successful uptake of ecological sanitation.

The development of biodegradable metallic materials designed for implants or medical stents is new and is one of the most interesting new fields in material science. Besides biocompatibility, a detailed understanding of corrosion mechanisms and dissolution processes is required to develop materials with tailored degradation behavior. The materials need to be sufficiently stable as long as they have to fulfill their medical task. However, subsequently they should dissolve completely in a controlled manner in terms of maximum body burden.<br/> This study focuses on the elemental and time resolved dissolution processes of a magnesium rare earth elements alloy which has been compared to pure magnesium with different impurity level. The here described investigations were performed using a novel analytical setup based on a micro-flow capillary online-coupled via a flow injection system to a plasma mass spectrometer. Differences in element-specific and time-dependent dissolution were monitored for various magnesium alloys in contact with sodium chloride or mixtures of sodium and calcium chloride as corrosive media. The dissolution behavior strongly depends on bulk matrix elements, secondary alloying elements and impurities, which are usually present even in pure magnesium.

Background: <i>Entamoeba histolytica</i> is an important protozoan intestinal infection in resource-poor settings, including Vietnam. The study objective was to assess risk factors of <i>E. histolytica</i> infection in a community in Vietnam, where wastewater and human excreta are used in agriculture. A case-control study was conducted among residents of Hanam province, Northern Vietnam. Cases (n = 46) infected with <i>E. histolytica</i> and non-infected controls (n = 138) were identified in a cross-sectional survey among 794 randomly selected individuals and matched for age, sex and place of residence. Potential risk factors including exposure to human and animal excreta and household wastewater were assessed with a questionnaire.<br/> Results: People from households with an average socio-economic status had a much higher risk of <i>E. histolytica</i> infection (odds ratio [OR]=4.3, 95% confidence interval [CI]: 1.3-14.0) compared with those from households with a good socioeconomic status. Those individuals who never or rarely used soap for hand washing had a 3.4 times higher risk for infection (OR=3.4, 95% CI: 1.1-10.0), compared to those who used always soap. In contrast, none of the factors related to use of human or animal excreta was statistically significant associated with <i>E. histolytica</i> infection. People having close contact with domestic animals presented a greater risk of <i>E. histolytica</i> infection (OR = 5.9, 95% CI: 1.8-19.0) than those without animal contact. <i>E. histolytica</i> infection was not associated with direct contact with Nhue river water, pond water and household's sanitary conditions, type of latrine or water source used.<br/> Conclusions: Our study suggests that in settings where human and animal excreta and Nhue River water are intensively used in agriculture, socio-economic and personal hygiene factors determine infection with <i>E. histolytica</i>, rather than exposure to human and animal excreta in agricultural activities.

In the context of rapid urbanization across Sub-Saharan Africa there is a critical need for more robust decision-making between different ways of providing sanitation services in existing and new peri-urban areas. In several countries, authorities tried to find solutions by developing strategies to address sanitation problems in the form of Strategic Sanitation Plans. In Burkina, Strategic Sanitation Plans have been elaborated and implemented since the 1990s. Fada N'Gourma, a secondary city in Burkina, also adopted a Strategic Plan for wastewater and excreta management in 2006. In this study we use material flow analysis as a decision making tool to verify technology options of the Plan. A model was developed and data was collected in order to assess material and nitrogen flows. The status quo situation was compared to scenario based on the proposals made in the Sanitation Plan.<br/> Results show that the technology options which were recommended improved human health in the short term. However, the options led to groundwater pollution in the medium term. Compared to the current situation, matter and nitrogen flows would increase by 7% and 7.4% respectively in groundwater. It is thus concluded that the proposed options will not achieve the Plan's stated objectives of environmental protection.

The influence of salinity and organic matter on the distribution coefficient (<i>K</i>_{<small>d</small>}) for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in a brackish water-clay system was studied. The distribution coefficients (<i>K</i>_{<small>d</small>}) for PFAs onto inorganic clay surfaces increased with salinity, providing evidence for electrostatic interaction for the sorption of PFAs, whereas the relationship between <i>K</i>_{<small>d</small>} and organic carbon content (<i>f</i>_{<small>oc</small>}) suggested that hydrophobic interaction is the primary driving force for the sorption of PFAs onto organic matter. The organic carbon normalized adsorption coefficient (<i>K</i>_{<small>oc</small>}) of PFAs can be slightly overestimated due to the electrostatic interaction within uncoated inorganic surfaces. In addition, the dissolved organic matter released from coated clay particles seemed to solvate PFA molecules in solution, which contributed to a decrease in <i>K</i>_{<small>d</small>}. A positive relationship between <i>K</i>_{<small>d</small>} and salinity was apparent, but an empirical relationship for the 'salting-out' effect was not evident. The <i>K</i>_{<small>d</small>} values of PFAs are relatively small compared with those reported for persistent organic pollutants. Thus, sorption may not be a significant route of mass transfer of PFAs from water columns in estuarine environments. However, enhancement of sorption of PFAs to particulate matter at high salinity values could evoke potential risks to benthic organisms in estuarine areas.

Cyanobacteria have been recognized as key players in the precipitation of calcium carbonate in marine and freshwater systems. These bacteria increase pH, (as a result of photosynthetic activity) and also produce extracellular polysaccharides, which act as binding sites for Ca²⁺ and CO₃^2-. Both processes influence the morphology and the mineralogy of the carbonate minerals. In order to clarify the role of polysaccharides of picocyanobacteria upon calcium carbonate precipitation, both their buffering capacity and ability to induce precipitation need to be investigated. In this experimental study, we characterized the polysaccharides of three unicellular autotrophic picocyanobacterial <i>Synechococcus</i>-type strains by potentiometric titration and infrared spectroscopy. Potentiometric titrations were conducted to determine the total buffering capacity. The nature and concentration of active sites of the polysaccharides was clarified with the aid of potentiometric titration and spectral analysis of an aqueous cellular suspension. Precipitation experiments with polysaccharides of different strains allowed an estimation of their potential to precipitate calcium carbonate. The results presented here indicate that polysaccharides from cyanobacteria have a strong potential to exchange protons with their surrounding environment. Precipitation experiments demonstrated that extracellular polysaccharides of all the strains studied able to precipitate calcium carbonate.

Even though lake sediments constitute a significant long-term carbon sink, studies on the regulation of carbon burial in lakes sediments have, to date, been surprisingly few. We investigated to what degree the organic carbon (OC) being deposited onto the bottom of Lake Kinneret (Israel) is buried in the sediment at four different sites with varying degrees of oxygenation and varying supply of allochthonous particles from the River Jordan. For estimation of the OC burial efficiency (OC BE), i.e., the ratio between buried and deposited OC, we calculated OC burial from dated sediment cores, and calculated OC deposition using three different approaches. Calculation of OC deposition from sediment trap-derived mass deposition rates multiplied with the OC content of surface sediment yielded OC BE values that were at odds with published values for sediments dominated by autochthonous OC sources. Calculation via sediment trap data on organic matter flux collected within the Lake Kinneret monitoring program, as well as calculation of OC deposition as the sum of OC burial plus OC mineralization, returned fairly congruent estimates of OC BE (range 10–41%), but only if the sediment trap data were corrected for the proportion of resuspended particles in the traps. Differences in OC BE between sites were small, indicating that OC source (common to all sites) was a more important regulator of OC BE in Lake Kinneret than oxygen exposure or mineral particles characteristics.

The goal of the FOEN project “Strategy Micropoll“ was to develop a strategy regarding micropollutants originating from wastewater. Besides an analysis of water quality in Switzerland and other aspects, this included the evaluation of the efficiency of complementary wastewater treatments such as ozonation followed by sand filtration (ozonation-SF) and different processes including powdered activated carbon addition (PAC) in eliminating micropollutants from wastewater treatment effluent. Two large-scale pilot studies were conducted at the wastewater treatment plants (WWTP) Wüeri in Regensdorf (ozonation followed by sand-filtration) and Vidy in Lausanne (ozonation followed by sandfiltration and PAC followed by ultrafiltration). The studies were done in close collaboration with experts from research, practice and with personnel and financial support of cantonal water protection agencies (Gewässerschutzfachstellen) and the operators of the WWTPs. In both studies, samples before and after various treatment steps were analysed for micropollutants and ecotoxicological effects, in order to get insight into the efficiency of the different treatment steps. The focus laid on studying the effects of the advanced treatment technologies, ozonation and PAC, on the removal efficiency for polar, persistent and bioactive substances as well as possible side products and their biological effects. This report focuses on the study performed at the WWTP Vidy in Lausanne from April 2009 to July 2010 with four major measurement campaigns being conducted. Detailed information on the Regensdorf study can be found in Abegglen et al. (2009). The Lausanne study is described in Margot et al. (2011). Results at the WWTP Vidy showed that both ozonation-SF and PAC-UF treatments are useful measures to reduce the concentration and biological effects of micropollutants in treated wastewater and therefore in surface water bodies. Total elimination efficiency with regard to the measured specific effects was generally above 80 %. Similarly, advanced treatment led to lowered risk quotients, i.e. the relationship between measured concentrations and environmental quality standards, as well as reduced toxicity in bioassays, and thus lowered risk of adverse effects. There was no evidence of toxic effects due to the formation of stable by-products during ozonation (i.e. by-products still present after the final filtration step). A final filtration step with biological activity (such as a sand filter) after ozonation is recommended, in order to minimize the risk of reactive and potentially toxic ozonation by-products being released in waterbodies. Overall, the application of bioassays for comparing the performance of advanced wastewater treatment methods has proven to be relevant and useful. In general, in vitro bioassays were deemed most promising for the routine monitoring of the performance of advanced treatment in WWTPs, however only specific cellular effects are assessed in those tests. Certain in vivo bioassays also showed the beneficial effects of ozonation-SF and PACUF treatment such as the fish early life stage test with Oncorhynchus mykiss.

Micropollutants from municipal wastewater generally influence the water quality of rivers with a high amount of municipal wastewater. They might also affect water bodies that have an important function as drinking water resources. For micropollutants from municipal wastewater, we distinguish four different input pathways into surface waters: (1) Input with treated wastewater through wastewater treatment plants; (2) input with untreated wastewater through sewer overflows if the capacity of the sewer system or the wastewater treatment plant is exceeded; (3) input through leaks in the sewer network or wrongly connected sewers; and (4) input of polluted rainwater from roofs and sealed areas through rainwater channels. Because many micropollutants are not considerably degraded in conventional wastewater treatment plants, the major part of them enters the surface waters with the treated wastewater effluents of wastewater treatment plants. Using a prioritization procedure, 47 Swiss-specific micropollutants were identified out of 250 candidate substances. The selected Swiss-specific micropollutants are representative for the contamination caused through micropollutants from municipal wastewater. Beside the Swiss-specific micropollutants, locally appearing chemicals from commerce and industry might be of importance. This has to be considered depending on the particular situation. For the ascertainment of micropollutants in surface waters, we suggest a procedure in two steps: (1.) Identification of potentially contaminated waterbodies; and 2.) detailed assessment of the potentially contaminated waterbodies. In the first step, mainly estimations are used, such as the estimation of the wastewater fraction in the waterbodies. In the second step, for a more detailed assessment, different sampling strategies and a selection of the Swissspecific micropollutants for chemical analysis is suggested. The proposed sampling strategies focus mainly on the determination of the basic contamnation through continuously through municipal wastewater entering substances. For the evaluation of the water quality, the measured data are compared to ecotoxicologically based quality criteria. Therefore, based on the technical guidance document for environmental quality standards of the EU, quality criteria were derived. For the assessment of the water quality, predicted environmental concentrations (PEC) are compared to annual average environmental quality standards (AA-EQS). Based on the Modular Stepwise Procedure (MSP, MSK) of the Federal Office for Environment (FOEN), the water quality is divided into five classes: excellent / good / moderate / unsatisfying / poor. Based on the presented assessment concept, further investigations can be prioritized, and reduction strategies and measures for the reduction of micropollutants from municipal wastewater can be evaluated.

Der vorliegende Schlussbericht des Projektes: In- Line- Koagulation zur Aufbereitung von Trinkwasser mittels Membranfiltration fasst die Ergebnisse des gesamten Projektes von Mai 2009 bis Februar 2011 zusammen. Eine auf der Zusammensetzung der Rohwässer basierende, bedarfsabhängige Dosierung von metalloxid (Fe, Al)- haltigen Fällmitteln oder PAK kann die Behandlung von stark belasteten Quell- und Oberflächenwässern mit Membranverfahren vereinfachen und führt ausserdem durch die gezielte Abtrennung gelöster organischer Stoffe zu einer besseren Qualität des Filtrats.