Occurrence, distribution and behavior of hydrophilic ethers in the aquatic environment
Daria Katarzyna Demers-Stępień
- The objective of the present doctoral thesis was to investigate the occurrence, distribution, and behaviour of six hydrophilic ethers: ethyl tert-butyl ether (ETBE), 1,4-dioxane, ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme) in surface-, waste-, ground- and drinking water samples. Solid phase extraction and gas chromatography/mass spectrometry were used to analyze the six hydrophilic ethers. Altogether more than 150 surface water samples, almost 100 of each groundwater and wastewater samples, and 10 raw and drinking water samples were analyzed during the research project.
Initially, the method was validated in order to simultaneously determine the analytes of interest in various aquatic environments. A solid phase extraction method that uses coconut charcoal (Resprep® activated coconut charcoal, Restek) or carbon molecular sieve material (SupelcleanTM Envi-CarbTM Plus, Supelco) for analyte absorption were found suitable for determination of ETBE, 1,4-dioxane, and glymes in surface-, drinking-, ground- and wastewater samples. Precision and accuracy of both methods was demonstrated for all analytes of interest. The recovery of target compounds from the ultrapure water spiked at 1.0 µg L−1 was between 86.8 % and 98.2 %, with relative standard deviation below 6 %. The samples spiked at 10.0 µg L−1 gave slightly higher recovery of 90.6 % to 112.2 % with a relative standard deviation below 3.4 % for each analyte. Detection and quantification limits in ultrapure water and surface waters were furthermore established. The limit of quantitation (LOQ) in ultrapure water ranged between 0.024 µg L−1 to 0.057 µg L−1 using Restek cartridges, and 0.030 µg L−1 to 0.069 µg L−1 using Supelco cartridges. In the surface water samples the calculated LOQ was 0.032 µg L−1 to 0.067µg L−1 using coconut charcoal material and 0.032 µg L−1 to 0.052 µg L−1 using the carbon molecular sieve material. Moreover, stability of the unpreserved and preserved water samples as well as the extracts was determined. Preservation of samples with sodium bisulfate (at 1 gram per Liter) resulted in much better stability of the ethers in water samples. Subsequently, 27 samples obtained from seven surface water bodies in Germany (Rivers Rhine, Lippe, Main, Oder, Rur, Schwarzbach and Wesel-Datteln Canal) were analyzed for the six hydrophilic ethers. ETBE was present in only two surface waters (Rhine River and Wesel-Datteln Canal) with concentrations close to the LOQ (up to 0.065 µg L−1). 1,4-Dioxane was detected in all of the water samples at concentrations reaching 1.93 µg L–1. Monoglyme was identified only in the Main and Rhine Rivers at the maximum concentration of 0.114 µg L–1 and 0.427 µg L–1, respectively. Very high concentrations (up to 1.73 µg L−1) of diglyme, triglyme, and tetraglyme were detected in the samples from the Oder River. These glymes were also detected in the Rhine River; however the concentrations did not exceed 0.200 µg L–1. Furthermore, tetraglyme was detected in the Main River at an average concentration of 0.409 µg L–1 (n = 6) and in one sample from the Rur River at 0.192 µg L–1.
Four sampling campaigns were conducted at the Oderbruch polder between October 2009 and May 2012, in order to study the behavior of the hydrophilic ethers and organophosphates during riverbank filtration and in the anoxic aquifer. Moreover the suitability of these target compounds was assessed for their use as groundwater organic tracers. At the time of each sampling campaign, concentrations of triglyme and tetraglyme in the Oder River were between 20–185 ng L–1 (n = 4) and 273¬–1576 ng L–1 (n = 4). Monoglyme, diglyme, and 1,4-dioxane were analyzed only during the two last sampling campaigns. At that time, the concentration of diglyme in Oder River was 65¬–94 ng L-1 (n = 2) and 1,4-dioxane 1610¬–3290 ng L–1 (n = 2). In the drainage ditch, following bank filtration, concentrations of ethers ranged between 1090 ng L–1 and 1467 ng L–1 for 1,4-dioxane, 23¬ng L–1 and 41 ng L–1 for diglyme, 37 ng L–1 and 149 ng L–1 for triglyme, and 496 ng L–1 and 1403 ng L–1 for tetraglyme. In the anoxic aquifer, 1,4-dioxane showed the greatest persistence during the groundwater passage. At the distance of 1150 m from the river and an estimated groundwater age of 41.9 years, a concentration above 200 ng L−1 was detected. A positive correlation was found for the inorganic tracer chloride (Cl−) with 1,4-dioxane and tetraglyme. Similarities in the behavior of Cl− and the organic compound suggested that 1,4-dioxane and tetraglyme are controlled by the same hydraulic process and therefore can be used as additional tracers to study the dynamics of the groundwater system. These results show that high concentrations of ethers are present in the surface water and are not removed during bank filtration processes. Moreover, the hydrophilic ethers persist in the anoxic aquifer and little or no degradation is expected, supporting, their possible application as organic tracers.
A separate sampling project was conducted for 1,4-dioxane that focused primarily on its fate in the aquatic environment. This study provided missing information on the extent of water pollution with 1,4-dioxane is Germany. Numerous waste-, surface-, ground- and drinking water samples were collected in order to determine the persistence of 1,4-dioxane in the aquatic environment. The occurrence of 1,4-dioxane was determined in wastewater samples from four municipal sewage treatment plants (STP). The influent and effluent samples were collected during weekly campaigns. The average influent concentrations in all four plants ranged from 262 ± 32 ng L−1 to 834 ± 480 ng L−1, whereas the average effluents concentrations were between 267 ± 35 ng L−1 and 62,260 ± 36,000 ng L−1. The source of increased 1,4-dioxane concentrations in one of the effluents was identified to originate from impurities in the methanol used in the postanoxic denitrification process. Spatial and temporal distribution of 1,4-dioxane in the river Main, Rhine, and Oder was also examined. Concentrations reaching 2,200 ng L−1 in the Oder River, and 860 ng L−1 in both Main and Rhine River were detected. The average load during the sampling was estimated to be 6.5 kg d−1 in the Main, 34.1 kg d−1 in the Oder, and 134.5 kg d−1 in the Rhine River. In all of the sampled rivers, concentrations of 1,4-dioxane increased with distance from the mouth of the river and were found to negatively correlate with the discharge of the river. In order to determine if 1,4-dioxane can reach drinking water supplies, samples from a Rhine River bank filtration site and potable water from two drinking water production facilities were analyzed for the presence of 1,4-dioxane in the raw water and finished potable water. The raw water (following bank filtration) contained 650 ng L−1 to 670 ng L−1 of 1,4-dioxane, whereas the concentration in the finished drinking water fell only to 600 ng L−1 and 490 ng L−1, respectively.
During the final project, investigations of the source identification of high glyme concentrations in the Oder River were carried out. During four sampling campaigns between January, 2012 and April, 2013, 50 samples from the Oder River in the Oderbruch region and Poland were collected. During the first two samplings in the Oderbruch polder, glymes were detected at concentration reaching 0.07 µg L-1 (diglyme), 0.54 µg L−1 (triglyme) and 1.73 µg L−1 (tetraglyme) in the Oder River. The extensive sampling campaign of the Oder River (about 500 km) in Poland helped to identify the area of possible glyme entry into the river. During that sampling the maximum concentrations of triglyme and tetraglyme were 0.46 µg L−1 and 2.21 µg L−1, respectively. A closer investigation of the identified area of pollution, helped to determine the possible sources of glymes in the Oder River. Hence, the final sampling focused on the Kaczawa River, a left tributary of the Oder River and Czarna Woda, a left tributary of Kaczawa River. Moreover, samples from an industrial wastewater treatment plant were collected. Samples from Czarna Woda stream and Kaczawa River contained even higher concentrations of diglyme, triglyme, and tetraglyme, reaching 5.18 µg L−1, 12.87 µg L−1 and 80.81 µg L−1, respectively. Finally, three water samples from a wastewater treatment plant receiving influents from a copper smelter were analyzed. Diglyme, triglyme, and tetraglyme were present at an average concentration of 569 µg L−1, 4300 µg L−1, and 65900 µg L−1, respectively in the wastewater. Further research helped to identify the source of the glymes in the wastewater. The gas desulfurization process – Solinox implemented in the nearby copper smelter uses glymes as physical absorption medium for sulfur dioxide.
Results of this doctoral research provide important information about the occurrence, distribution, and behavior of hydrophilic ethers: 1,4-dioxane, monoglyme, diglyme, triglyme, and tetraglyme in the aquatic environment. A method capable of analyzing a wide range of ether compounds: from a volatile ETBE to a high molecular weight tetraglyme was validated. 1,4-Dioxane and tetraglyme were found to be applicable as organic tracers, since they are not easily attenuated during bank filtration and the anoxic groundwater passage. The extent of water pollution with 1,4-dioxane was shown in waste-, surface-, ground-, and drinking waters. One source of extremely high concentrations of 1,4-dioxane in a municipal sewage treatment plant applying postanoxic denitrification was identified, however more information is needed on the entry of 1,4-dioxane into surface waters. Moreover, 1,4-dioxane was present in drinking water samples from river bank filtration, which demonstrates its persistence in the aquatic environment and its low degradation potential during bank filtration and subsequent water treatment. Furthermore, this was the first study that focused primarily on identifying sources of glymes in surface waters. Glymes find a widespread use in industrial sectors, hence establishing their origin in the surface water is difficult (as with 1,4-dioxane). In this work, a gas desulphurization process was identified to be a dominating source of glyme pollution in the Oder River.
Stratigraphy and properties of soil profiles along transects in Burkina Faso and Benin and their influence on phytodiversity
Cheikh Amadou Tidiane Anne
- This thesis aims to analyse in a first step the physical and chemical properties of soil profiles along pedomorphological transects in different land used conditions (protected, partly protected as well as cultivated and pastured areas) in North West Benin and in South East Burkina Faso. The information about soils, which are carried out in consideration of the pedogenesis processes like weathering types, saprolitisation, formation of laterite crusts and denudation within the planation surfaces are therefore correlated in a second step with the structure and dynamic of woody plant around individual soil profiles. The relationship soil properties and woody plant is investigated in order to assess the reciprocal influence between the diversity of woody plants and soil characteristics within a small scale study and under different land use conditions.
A common vertical and lateral differentiation of physical and chemical properties regardless of the partly protected, protected and cultivated status of the sites can be noticed. Thus, in the cultivated site of Kikideni and in the partly protected zone of Natiabouani (South East Burkina Faso) sandy loam and sandy clay loam soil surfaces are widespread because of the occurrence of similar erosion processes like sheet wash, rill and gully erosion while in the central part of the Pendjari National Park loamy soil textures are prevailing. In fact, the steepness of the relief and the length of the slopes in the Pendjari Park seem to limit the development of some erosion forms as gully. Furthermore, the classification of soils reflects the variation of pedological processes along the transects and thus the occurrence of different soil types. The status of the sites may play an insignificant role in the differentiation of soil properties within the scale of small pedomorphological transects. A direct comparison of the vegetation type in the land use respectively partly protected and in the total protected sites (National Park of Pendjari) reveals a transition from the shrub savanna to the tree savanna. In conclusion it is important to insist on the fact that the variations of soil parameters within small slopes and the different sites are more conditioned by varying erosion processes and drainage conditions than the status protected or land use sites while the composition and diversity of plants is influenced by the status of the sites, the prevailing management tools, the pedogenetic conditions as well as the presence of wild animals like elephants. The ordination diagram shows that the organic matter is better correlated to the subgroup representing principally the sites of the hunting zone of the Pendjari Park and might be an explaining factor to the distribution of these sample sites groups. CEC ratios in the partly protected site of Natiabouani represent the highest measured in all sites. Nevertheless, statistical analysis of the CCA (canonical correspondence analysis) indicates generally a low correlation. This tendency is consolidated by the Monte Carlo test (p=0.14) which is a good indicator of species and environmental conditions. The detailed analysis of soil properties and the vegetation dynamic as well as their relationship within small pedomorphological transects represent an important pedological and botanical data collection involving different compartments. This thesis contributes to the better understanding of the savanna landscapes of West Africa and may provide essential scientific background for each development project directed towards interdisciplinary and integrative researches.
Automatische Bestimmung von Doppelbrechungsparametern in regionalseismischen Netzwerken (ADORE) für Aufzeichnungen des Deutschen Seismologischen Regionalnetzes
- In dieser Arbeit wird die Richtungsabhängigkeit seismischer Geschwindigkeiten im Erdmantel unterhalb Deutschlands und angrenzender Gebiete durch die Analyse der teleseismischen Kernphase SKS auf Doppelbrechung untersucht (Scherwellen-Splitting). Die Anisotropie wird durch die Splittingparameter Φ und δt beschrieben und erlaubt Rückschlüsse auf geodynamische Prozesse.
Untersucht werden Aufzeichnungen des Deutschen Seismologischen Regionalnetzes (GRSN) und assoziierter Stationen aus dem Zeitraum von 1993 bis 2009. Für drei Stationen des Gräfenberg-Arrays (GRF-Array) sind Wellenformen ab 1976 verfügbar, welche damit einen weltweit einmaligen Datensatz liefern.
Auf Grund des stetigen Ausbaus der seismologischen Netze und des langen Beobachtungszeitraumes können über 3.000 Seismogramme ausgewertet werden. Der Hauptteil dieser Arbeit besteht daher in der Entwicklung einer automatischen Methodik zur Analyse von SKS-Splitting: ADORE ("Automatische Bestimmung von DOppelbrechnungsparametern in REgionalseismischen Netzwerken"). Für regionale Netze wie das GRSN gewährleistet ADORE eine objektive Bestimmung der Splittingparameter. Zunächst wird das seismologische Netzwerk als seismisches Array aufgefasst, um durch eine Frequenz-Wellenzahl-Analyse den Einsatz der SKS-Phase ohne manuellen Eingriff zu bestimmen. Die Berechnung der Splittingparameter erfolgt durch eine Inversion nach der Methode der Minimierung des transversalen Energieanteils. Automatisch wird das optimale Fenster um den SKS-Einsatz positioniert, für jede Beben-Stations-Kombination werden dazu 3.600 Einzelinversionen durchgeführt.
Um diese Vielzahl von Auswertungen in akzeptabler Zeit zu berechnen, nutzt ADORE moderne Rechnerarchitekturen aus, verteilt die Berechnungen auf mehrere Computer im lokalen Netzwerk und erzielt damit eine Beschleunigung um einen Faktor 60.
Die Analyse des gesamten Datensatzes ergibt folgende Ergebnisse: An allen analysierten Stationen wurde ein Scherwellen-Splitting festgestellt, der Stationsuntergrund weist somit überall Anisotropie auf. Für 240 Erdbeben können insgesamt 494 Wertepaare mit höchster Qualität bestimmt werden.
Unter der Annahme einer homogenen ungeneigten anisotropen Schicht unterhalb der jeweiligen Station können die Einzelmessungen pro Station gemittelt werden. Damit sind Regionen mit ähnlichen Merkmalen gut zu identifizieren: Im Norden Deutschlands herrschen NW-SO-, in der Mitte W-O-Richtungen und im Süden SW-NO-Richtungen vor.
Die Verzögerungszeiten liegen im Bereich zwischen 1.0 (Station Taunus) und 2.2 Sekunden (Tannenbergsthal, TANN). Auf Grund des hohen Wertes sind die Ursachen für die hier beobachteten Zeiten dem Erdmantel und nicht der Kruste zuzuordnen. Die bevorzugte Ausrichtung von anisotropen Kristallen auf Grund von Fließprozessen von Mantelmaterial ist Quelle der beobachteten Anisotropie. Rezente Fließprozesse von Mantelmaterial sind vor allem an der Unterkante der Lithosphäre wahrscheinlich. Durch Gebirgsbildungsprozesse, vorhandene Gebirgswurzeln oder regionale Veränderungen in der Mächtigkeit der Lithosphäre entstehen Barrieren für viskoses Mantelmaterial.
Als tektonische Ursachen für die hier gemessenen Orientierungen ist im Norden die Tornquist-Teisseyre-Linie (TTZ), in der Mitte die Variszische Gebirgsbildung und im Süden Einflüsse des Alpenbogens anzusehen. Ausnahmen bilden die Stationen Clausthal-Zellerfeld (CLZ), Rügen und Black-Forest-Observatory (BFO). Während bei letzterer ein Einfluss der Spreizungszone des Oberrheingrabens zu vermuten ist, scheint die Intrusion des Brockengranits die Beobachtungen an CLZ zu prägen. Rügen liegt in einer Übergangszone zwischen Sorgenfrei-Tornquist-Zone und TTZ.
Durch die Vielzahl von vorhandenen Einzelmessungen lassen sich an manchen Stationen komplexe Modelle untersuchen. Dazu zählen neben Gradientmodellen auch die geneigte Schicht und Zwei-Schicht-Modelle. Für sechs Stationen kann ein Zwei-Schicht-Modell erstellt werden: BFO, Gräfenberg A1, Fürstenfeldbruck (FUR), Rüdersdorf (RUE), TANN und Unterbreitzbach (UBBA). Die Interpretation der Richtungen von oberer und unterer Schicht gelingt für einen Teil der genannten Stationen: An BFO liegt die Orientierung der unteren Schicht parallel zur Vorzugsrichtung der variszischen Gebirgsbildung, jene der obere Schicht antiparallel zur Spreizungsrichtung des Rheingrabens. Für die Station FUR ist eine Überlagerung mit der Streichrichtung des Alpenmassivs zu beobachten. An GRA1 wird die untere Schicht offenbar durch rezente oder eingefrorene Anisotropie des Böhmischen Massivs bzw. des Eger-Riftsystems beeinflusst. Eine vergleichbare Wirkung ist durch die TTZ an der Station RUE zu erkennen.
ADORE wurde weiterhin auf einen Datensatz des temporären RIFTLINK-Projektes angewandt.
Paleoenvironmental and paleoecological changes during deposition of the late eocene kiliran oil shale, Central Sumatra Basin, Indoniesia
Agus Haris Widayat
- Forty two samples of the Late Eocene Kiliran oil shale, Central Sumatra Basin, Indonesia were collected from a 102 m long drill core. Palynofacies and geochemical analyses have been carried out to reconstruct the paleoenvironmental conditions and paleoecology during deposition of the oil shale. Amorphous organic matter (AOM) is very abundant (>76%). B. braunii palynomorph is present (3-16%) as the only autochtonous structured organic matter and generally more abundant in middle part of the profile. The stable carbon isotopic composition of organic matter (δ13C) varies from -27.0 to -30.5‰ and is generally more depleted in middle part of the profile. The ratio of total organic carbon to sulfur (TOC/S), used as salinity indicator, ranges from 2.5 to 15.8 and shows variations along the profile. Relatively less saline environments are observed in the middle part profile. Fungal remains are generally present only in middle part of the profile with distinct peak of abundances. The presence of fungal remains is regarded as an indication for a relatively warmer climate during deposition of middle part of the profile. The warmer climate is thought to influence the establishment of a thermocline, limiting the supply of recycled nutrients to the epilimnion. Consequently, the primary productivity in the Kiliran lake decreased during deposition of the middle part of the profile as indicated by the relatively depleted δ13C and the blooming of B. braunii. The chemocline was also shoaling during deposition of the middle part of the profile according to the higher abundance of isorenieratene derivatives of green sulfur bacteria origin. The warmer climate affected also to increase of water supply and thus less saline environments.
Tectonic subsidence is also thought to be a significant factor for the development of the Kiliran lake. The Zr/Rb ratio, an indicator for grain size, ranges from 0.4 to 1.3 and generally increases upwards along the profile. Three sudden decreases of the ratio are observed, indicating rapid change to finer grain size. These decreases are interpreted to indicate rapid deepening events of the lake due to mainly periodic subsidence. During deposition of lower part of the profile, the subsidence rates might have been relatively higher than sediment and water supply rates, resulting in a higher autochtonous fraction in the oil shale. During deposition of middle part of the profile, the sediment and water supply rates were relatively higher promoting distinct progradational sedimentation. Subsequently, the lake became more shallow and smaller during deposition of the upper part of the profile, leading to a relatively higher terrigenous input to the oil shale.
Norneohop-13(18)-ene and neohop-13(18)-ene derived from methanotrophic bacteria are the dominant hopanoid hydrocarbons. The sum of their concentrations varies from 40.6 to 360.0 μg/g TOC. The δ13C of these compounds are extremely depleted (-45.2 to -50.2‰). The occurrence of abundant bacteria including methanotrophic bacteria was responsible for the recycling of carbon below the chemocline of the lake. The effect of the recycling of carbon is observed by the presence of a concomitant depletion (about 7-9‰) in 13C of some specific biomarkers derived from organisms dwelling in the whole phototrophic zone.
4-Methylsterane and 4-methyldiasterene homologues occur in the oil shale as the predominant biomarkers. The sum of the concentrations of all homologues are about 40.3-1,009.2 μg/g TOC with generally higher values in uppermost and lower parts of the profile. Ca accounts as the predominant element in the oil shale, ranging from 5.0 to 16.7%. This element shows generally parallel variation with the 4-methylsterane homologues along the profile. This suggests that the 4-methylsteranes were derived from biological sources favoring more alkaline and more trophic environments. On the other hand, these compounds were less abundant in middle part of the profile which is consistent with less alkaline and less trophic environments promoting B. braunii to bloom.
The 4-methylsterane homologues are considered to originate from Dinoflagellates. Alternation between Dinoflagellates and B. braunii in Paleogene lake systems due to water chemistry changes are known from previous studies. Moreover, freshwater Dinoflagellates have been frequently reported to occur in the basin depocenters. In the present case, distinct alternation between B. braunii abundances and concentrations of 4-methylsterane homologues along the studied oil shale profile suggest that the 4-methylsterane homologues were derived from freshwater Dinoflagellates although dinosterane is not present in the sediment extracts. Water alkalinity and trophic level changes were most likely responsible for the alternation of Dinoflagellates and B. braunii blooming.
The formation and the geochemical and thermal evolution of the lithospheric mantle beneath the Kaapvaal craton recorded by subcalcic garnets from harzburgites and by pristine eclogites and garnet-pyroxenites
- The mantle xenoliths collected by kimberlites indicate that the subcratonic mantle underneath the Archean crust is mostly a residue of high degrees of partial melting which was subsequently reenriched. The majority of the xenoliths show cryptic metasomatism and only few modal metasomatism.
Much effort has been put into deciphering different kinds of enrichment processes within the mantle. Here, we take the approach to look into the inventory of subcalcic garnets which stem from cpx-free harzburgites and dunites. These subcalcic garnets, commonly with sinusoidal REE patterns, carry the major budget of the trace elements of their host rock. Thus, they are promising objects to study both depletion and enrichment. Most importantly, the analysis of a single grain subcalcic garnetwill provide almost all important information of the bulk rock. Our aim is to gain detailed information mainly on metasomatism on a craton wide scale by combining major, trace elements and Lu-Hf and Sm-Nd isotopic signatures from subcalcic garnets. Eventually, we will summarize the metasomatic agent(s) and processes and possibly the timing of the enrichment within the lithospheric mantle underneath the Kaapvaal craton.
Insights into rifting from seismic noise variations, shear wave splitting and b value analyses: case study beneath the Rwenzori Region, East African Rift System
Arthur Godfrey Batte
- This research was conducted in the Rwenzori Region of the Western Branch, East African Rift System (EARS). The EARS is a tectonic structure extending over a length of more than 3000 km from the Afar Triple Junction, in Ethiopia, to Lake Malawi in the south. The Western Rift System is a roughly NE to ENE trending sector of the EARS, which runs along the western boundary of Uganda and the neighboring Democratic Republic of Congo (D.R.C). It stretches 2100 km from Nimule, NW on Uganda-Sudan border, extending to Lake Malawi in the SE of Africa. The unusual uplift of the Rwenzori Mountains within an extensional regime and the mechanisms associated with the high frequency of seismic activity in the region was hardly understood and therefore, had remained a subject of contention that needed to be critically addressed in detail. To my knowledge, this was probably the first study to be performed and documented in great depth within the domains of seismic noise variation, seismic anisotropy and b value analyses beneath the Rwenzori Region. After about six years of operation (2006-2012), the seismology group of the RIFTLINK Research Project (www.riftlink.org) acquired a vast amount of high-quality, digital data that were collected using a seismic network of well calibrated seismic equipment. The project was divided into two phases. Phase I, that operated between February 2006 - September 2007, consisted of thirty-two temporary seismic stations, which were selectively spread out in the Rwenzori Region on the Ugandan side, to detect and record extremely weak as well as strong naturally occurring earthquakes. The seismic equipment used included EDL and REFTEK digitizers, which were coupled with Güralp and MARK sensors respectively (REFTEKS: only short-period MARK sensors, EDLs: short-period MARK plus few broadband Güralp Sensors). Exactly 22375 earthquakes were recorded. The data were processed using the SEISAN software package. About 14413 earthquakes were carefully localized using the velocity model of Bram (1975) that implements a Vp=Vs ratio fixed at 1.74. Phase II, that extended between 2009-2012 consisted of thirty-two seismic stations, which were spread out around the Rwenzori Mountains, both on the Ugandan side and the neighboring D.R.C. Only Taurus digitizers that were coupled with Trillium sensors were used in the D.R.C. On the Ugandan side however, both EDL and Taurus digitizers, which were coupled with Trillium and Güralp sensors were used. ...
Entwicklung der transdisziplinären Methode "Akteursbasierte Modellierung" und ihre Anwendung im Problemfeld der mobilen, organischen Fremdstoffe : die Verknüpfung von Akteurswahrnehmungen, partizipativer Szenarienentwicklung und sequentieller Modellierung von Handlungsentscheidungen
- Die vorliegende Arbeit wurde im Rahmen des Forschungsprojekts „Integrierte Analyse von mobilen, organischen Fremdstoffen in Fließgewässern“ (INTAFERE) am Institut für Physische Geographie an der Goethe-Universität Frankfurt erstellt. In INTAFERE wurde das Gefährdungspotenzial von mobilen, organischen Fremdstoffen (MOF) für aquatische Ökosysteme und die natürlichen Wasserressourcen in integrierter und partizipativer Art und Weise untersucht. MOF sind chemische Substanzen, die in Alltagsprodukten enthalten sind und durch unterschiedliche Eintragsfade in unbekannten Mengen in Oberflächengewässer eingetragen werden. Problematisch sind aus Umweltgesichtspunkten ihre Eigenschaften: sie besitzen im Wasser eine hohe Mobilität und sind schwer abbaubar. Dies führt zu einer Persistenz über lange Zeiträume. Für einige dieser Substanzen wurde zudem gezeigt, dass sie in sehr geringen Konzentrationen biologisch aktiv sind und für aquatische Ökosysteme eine Gefahr darstellen. In INTAFERE wurden drei zentrale Ziele verfolgt: Charakterisierung des Problemfeldes MOF, Erzeugung von praxisrelevantem Wissen für das Management von MOF und Entwicklung einer Softwareanwendung, die gesellschaftliche Aushandlungsprozesse durch eine transparente Darstellung der Wirkungszusammenhänge im Problemfeld unterstützt. Um einen Beitrag für die Erfüllung der Ziele zu leisten, war es die Aufgabe der Verfasserin, eine Akteursanalyse und -modellierung durchzuführen sowie Zukunftsszenarien im Bereich der MOF zu entwickeln. Dafür existierte keine adäquate Methodik, daher verfolgt die Dissertation zum einen die Entwicklung einer Methodik und zum anderen deren Anwendung im Kontext des Projektes INTAFERE. Da im Forschungsprozess die Durchführung von Analysen, die wissenschaftliche und gesellschaftliche Sichtweise der Problematik sowie die Erarbeitung von praktischen Lösungen im Mittelpunkt standen, wurde eine transdisziplinäre Herangehensweise gewählt. Ziel war es, eine Methodik zu entwerfen, die sowohl eine Entwicklung von Szenarien als auch eine Modellierung von Handlungsentscheidungen umfasst. Eine Modellierung und Visualisierung von Handlungsentscheidungen ist notwendig, um Strategien für ein Umweltproblem für verschiedene Szenarien zu ermitteln, und damit einen Lernprozess der Stakeholder zu initiieren. Dies wurde mit der transdisziplinären Methode „Akteursbasierte Modellierung“ umgesetzt. Hierbei wurden insbesondere Aspekte der Problemwahrnehmung von Akteuren und deren Darstellung, der partizipativen Szenarienentwicklung sowie der semi-quantitativen Modellierung von Handlungsentscheidungen berücksichtigt. Die Verfasserin hat mit der semi-quantitativen akteursbasierten Modellierung eine Methode erarbeitet und getestet, die bisher unverbundene Komponenten (wie die Software Dynamic Actor Network Analysis (DANA) und die Szenarienentwicklung) zusammenführt. Um Handlungsentscheidungen unter verschiedenen Szenarien zu modellieren hat die Autorin eine sequentielle Modellierung entwickelt, die mit der Software DANA durchgeführt werden kann. Die dafür notwendige Weiterentwicklung von DANA wurde von Dr. Pieter Bots (TU Delft) umgesetzt. Die akteursbasierte Modellierung läuft in drei methodischen Schritten ab: 1. Modellierung von Akteurs-Sichtweisen in Form von Wahrnehmungsgraphen und deren Analyse, aufbauend auf Ergebnissen von qualitativen, leitfaden-gestützten Expertengesprächen (= Akteursmodellierung), 2. partizipative Szenarienentwicklung mit den Akteuren und 3. Zusammenführung der Ergebnisse der Akteursmodellierung und der Szenarienentwicklung und darauf aufbauend eine sequentielle Modellierung von Handlungsentscheidungen und deren Auswirkungen auf Schlüsselfaktoren. Im Zuge der Anwendung auf das Problemfeld der MOF wurde für folgende Akteure jeweils ein Wahrnehmungsgraph modelliert: Obere Wasserbehörde, Umweltbundesamt, Umwelt- und Verbraucherschutzorganisationen, Wasserversorger sowie für die Hersteller von verschiedenen MOF, weiterhin für die European Flame Retardants Association und die Weiterverarbeitende Industrie. Das Ergebnis der Szenarienentwicklung waren vier Szenarien: ein Gesundheitsszenario, unter der Annahme von hohen lokalen Umweltstandards durch nachhaltigkeitsorientierte KonsumentInnen, ein Umweltszenario, in dem eine starke Regulierung und nachhaltigkeitsorientierter Konsum Hand in Hand gehen, ein Globalisierungsszenario, in dem Wirtschaftsmacht und preisbewusste KonsumentInnen statt staatliche Regulierung vorherrschen und ein Technikszenario, unter der Annahme, dass Kläranlagen, bedingt durch eine starke Regulierung, aufgerüstet werden. Bei der Modellierung von Handlungsentscheidungen wurden die Wahrnehmungsgraphen und die vier Szenarien miteinander verknüpft. Pro Substanz wurde ein Modell entwickelt, welches die wichtigsten Systemkomponenten in einer angemessenen Komplexität umfasst und die von den Akteuren gemeinsam getragene Einschätzung der Wirkungsbeziehungen darstellt. Insgesamt wurden 16 Modelle entwickelt. Basierend auf den simulierten Akteurshandlungen wurden relativen Veränderungen der Schlüsselfaktoren Produktion, Import und Leistungsfähigkeit der Kläranlagen für die vier genannten Szenarien berechnet. In Zusammenarbeit mit Pieter Bots konnten algorithmische Beiträge zur Analyse- und Modellierungssoftware DANA getestet und verbessert werden. Da keine vollständige und zugleich leicht verständliche Einführung zu DANA vorlag, wurde für Nutzer im Rahmen dieser Dissertation eine Anleitung verfasst, die die Modellierung von Wahrnehmungsgraphen und deren Analyse sowie alle Schritte der akteursbasierten Modellierung mit DANA erläutert.
Coupling of geological processes in the Earth’s crust and mantle
On the interaction between thermal tides and gravity waves in the middle atmosphere
Occurrence and sources of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) in the aquatic environment
Arlen Guedez Orozco
- The aim of the present study was to identify the sources of 2,4,7,9-tetramethyl-5-decyne-4,7-
diol (TMDD) into the aquatic environment and to investigate its occurrence in rivers and
wastewater treatment plants (WWTPs). Therefore, TMDD was analyzed in 441 wastewater
samples from influents and effluents of 27 municipal WWTPs, in 6 sludge samples, in 52
wastewater samples from 3 sewage systems of municipal WWTPs, in 489 surface samples
from 24 rivers, in 9 wastewater samples of 3 paper-recycling industries and in 65 groundwater
samples. TMDD was also analyzed in household paper products, in 23 samples of toilet
papers, in 5 types of paper towels and in 12 types of paper tissues. The samples were collected
between 2007 and 2011. The water samples were extracted with solid phase extraction (SPE)
and the household paper samples with Soxhlet extraction. Gas chromatography-mass
spectrometry (GC-MS) was used for quantification purposes.
Between November 2007 and January 2008, TMDD was detected in the river Rhine at Worms
with permanent high concentrations (up to 1330 ng/L). The results showed that TMDD is
uniformly distributed across the river at Worms. An increase of the mean TMDD
concentration from approximately 500 ng/L to 1000 ng/L was registered in January 2008. Due
to the minor fluctuations of the TMDD concentration during the sampling period it is
expected that the input of TMDD into the river is continuous. Therefore, TMDD might rather
originate from effluents of municipal WWTPs than from temporal sources. The mean TMDD
load based on the analysis of 147 water samples collected in the River Rhine was 62.8 kg/d
which is equivalent to 23 t/a suggesting that TMDD must be used and/or produced in high
quantities in order to be found in those high concentrations. To determine if TMDD is
discharged by effluents of municipal WWTPs into the rivers, 24 hours influent and effluent
samples of four municipal WWTPs in the Frankfurt/Rhine-Main metropolitan region were
collected during November 2008 and February 2010 and analyzed for TMDD. The TMDD
influent concentrations varied between 134 ng/L and 5846 ng/L and the effluent
concentrations between <LOQ (limit of quantitation) and 3539 ng/L. The TMDD elimination
rates in the four WWTPs varied between 33% and 68%. The results showed that effluents of
municipal WWTPs are an important source of TMDD in the aquatic environment because
TMDD is not completely removed from the sewage during the wastewater treatment. Weekly
and daily variations of the TMDD concentration in the influents of two municipal WWTPs
indicated that both private households and indirect industrial dischargers contribute to the
introduction of TMDD into the municipal sewage systems. A more detailed study of the
TMDD elimination rate in the different wastewater treatment stages was carried out in the
WWTP Niederrad/Griesheim in Frankfurt am Main. The results showed that the removal of
TMDD is mainly carried out during the aerobic biological treatments, where the elimination
rate was 46%. In contrast, during the anoxic treatment the removal efficiency was only 1.4%
and during the mechanical treatment the elimination rate was 19%.
To determine the sources of TMDD in the sewage, household paper products (paper tissues,
toilet papers and paper towels) were analyzed for TMDD using Soxhlet extraction. TMDD
was detected in 83% of the samples (n=40). The highest mean TMDD concentrations were
found in recycled toilet paper (0.20 μg/g) and in paper towels (0.11 μg/g). In paper tissues and
non-recycled toilet paper the mean TMDD concentrations were lower 0.080 μg/g and
0.025 μg/g respectively. According to these results the high TMDD influent concentrations
found previously in municipal WWTPs (mean 1.20 μg/L) cannot be explained due to
migration of TMDD from the household paper products into the sewage. Thus indirect
industrial dischargers are the cause of the high influent TMDD concentrations. Effluents of
municipal WWTPs with different indirect industrial dischargers (textile-, metal processing-,
food processing-, electroplating-, paper-recycling- and printing ink factories) were analyzed.
The highest mean TMDD concentrations were found in the effluents of municipal WWTPs
that have paper-recycling (71.3 μg/L) and printing ink factories (138 μg/L) as indirect
industrial dischargers. These results were confirmed by analyzing process wastewater of three
paper-recycling factories located in Germany. High TMDD concentrations were detected and
fluctuated between 1.83 μg/L and 113 μg/L. TMDD was also analyzed in the wastewater of a
non-recycling-paper factory but its concentration was much lower (0.066 μg/L) indicating that
TMDD is introduced into the processing water during the papermaking process due to the use
of waste paper. Analyses of wastewater samples from different parts of the sewage pipes of a
municipal WWTP in Hesse, which receives the wastewater from a printing ink factory, were
carried out. The TMDD concentration in the wastewater sample from the sewage pipe of the
printing ink factory was much higher (3,300 μg/L) than the TMDD concentration detected in
the other wastewater samples from the sewage system (0.030 μg/L – 0.89 g/L). These results
confirm the printing ink production as one of the principal sources of TMDD in the sewage.
Analysis of surface water samples of the River Modau downstream from the effluent of the
WWTP Nieder-Ramstadt showed TMDD concentrations of up to 28.0 μg/L. These high
TMDD concentrations might be caused by the indirect wastewater discharges of a paint
factory connected to the municipal sewage system. These results indicate that TMDD is
introduced into the municipal WWTPs principally by indirect industrial dischargers and they
are mainly paint and printing ink factories. The paper-recycling factories also represent an
important source of TMDD in municipal WWTPs but indirectly. According to statements
given by the representatives of two paper recycling factories neither TMDD or any other
TMDD containing product is used or added during the papermaking process. Therefore,
TMDD is washed out from the printing inks of the coloured waste paper and concentrated in
the process wastewater in the closed water circuits of paper-recycling factories reaching rivers
and municipal WWTPs.
The occurrence and distribution of TMDD in surface waters in Germany was also studied.
The results showed that TMDD is widely distributed across different rivers systems in the
federal states of Hesse, North-Rhine-Westphalia, Bavaria, Baden-Wuerttemberg and
Rhineland-Palatinate. In Hesse, TMDD was detected in the some of main rivers with mean
concentrations of 812 ng/L (Schwarzbach, Hessian Ried), 374 ng/L (Kinzig), 393 ng/L (Main,
at Frankfurt), 539 ng/L (Werra), 326 ng/L (Fulda), 151 ng/L (Emsbach) and 161 ng/L
(Nidda). In small rivers (creeks) the mean TMDD concentrations varied between <LOQ
(Diemel, Urselbach) and 1890 ng/L (Darmbach). The results showed that the TMDD
concentrations in creeks are highly influenced by both effluents of WWTPs and by the
distance between the sampling point and the nearest WWTP. Surface samples from sampling
locations downstream from WWTPs dischargers showed higher TMDD concentrations (mean
518 ng/L) than sampling locations upstream from WWTPs dischargers (mean 35.1 ng/L).
The behavior of TMDD during bank filtration was investigated at two locations, at a water
utility company at the Lower River Rhine (urban area) and at the Oderbruch polder (rural
area). The results indicated that TMDD is removed from the surface water by bank filtration
at both sampling locations. The removal process is probably carried out in the first meters of
the aquifer (hyporheic zone) by biodegradation processes, since TMDD does not tend to be
absorbed by sediments and it was not found in the groundwater of monitoring wells. In
groundwater samples from the Hessian Ried (n=23) TMDD was found only in five samples
and the highest TMDD concentration was 135 ng/L. According to these results, TMDD does
not represent a concern for drinking water in Germany, since it does not reach the
groundwater with high concentrations and it has a low toxicity potential.
The input of TMDD into the North Sea was estimated to be 60.7 t/a by considering the mean
transported loads of TMDD by the River Rhine at Wesel (58.3 t/a) and Meuse in the
Netherlands (2.40 t/a). The estimated discharge of TMDD by German municipal WWTPs
(8.19 t/a) and paper-recycling factories (9.24 t/a) into rivers seems to be too low considering
that the mean TMDD load in the River Rhine downstream from Wesel is 58.3 t/a. However,
due to the high density of population and industries at the Lower Rhine it is expected that
more relevant sources of TMDD are located along the Rhine River increasing the transported
According to the results of this PhD project TMDD is a non-ionic surfactant contained in
products, which are applied on surfaces (printing inks and paints) and has the potential to
reach the aquatic environment. Therefore, TMDD should fulfill the requirement of a
biodegradability of 80% established by the “Law on the Environmental Impact of Detergents
and Cleaning Products” in Germany. However, due to the partial elimination rates of TMDD
obtained in municipal WWTPs (between 33% and 68%) and to the absence of information
about the execution of the biodegradation test on TMDD, it is unknown if TMDD is in
accordance with this law. Otherwise, its use as surfactant in such products is questionable.