Filtern
Schlagworte
- Cloud Point Extraction (1)
- Größenfraktionierung (1)
- Kolloide (1)
- Kolloids (1)
- Metalle/Matalloide (1)
- Metals/metalloids (1)
- Nanoparticles (1)
- Nanopartikel (1)
- Sediment-Water-Interfaces (1)
- Size-fractionation (1)
- Wasser-Sediment-Grenzschichten (1)
In der aquatischen Umwelt stellen Wasser-Sediment-Grenzschichten (WSG) die wichtigsten Bereiche bezüglich der Austauschprozesse zwischen dem Wasserkörper und dem Sediment dar. Diese räumlich begrenzten Regionen sind durch starke biogeochemische Gradienten charakterisiert, die die Speziierung und den Verbleib natürlicher und artifizielle Substanzen maßgeblich bestimmen. Abgesehen von biologischen Prozessen (z.B. grabende Organismen oder Photosynthese) ist der Austausch zwischen Wasser und Sediment von Diffusion oder Kolloid-gesteuerten Transport bestimmt. Dies erfordert Methoden, die es ermöglichen, die feinen Strukturen der Grenzschichten abzubilden und zwischen den unterschiedlichen Prozessen zu unterscheiden.
Hinsichtlich neu entwickelter Substanzen, die voraussichtlich in die aquatische Umwelt gelangen werden, sind artifizielle Nanomaterialien (engineered nanomaterials; ENMs) aufgrund ihrer zunehmenden Nutzung in Produkten und Anwendungen von großer Relevanz. Da sie auf der Grundlage ihrer Größe definiert werden (<100 nm), umfassen sie eine Vielzahl verschiedenster Materialien mit unterschiedlichem Verhalten in der Umwelt. Erreichen sie aquatische Systeme, mischen sie sich mit natürlich vorkommenden Kolloiden (<1 μm), die nanoskalige Partikel beinhalten.
Ausgehend von existierenden methodischen Lücken bezüglich der Charakterisierung von ENMs (als neu aufgekommene Substanzen) und WSG (als betroffene Umweltkompartimente) war das Ziel der vorliegenden Dissertation, die Entwicklung, Validierung und Anwendung einer geeigneten analytischen Basis, um ENMs an WSG untersuchen zu können. Die Herausforderungen lagen dabei in i) der Entwicklung von Methoden, die eine räumlich hochaufgelöste Beprobung von Sedimentporen-wasser erlauben. ii) Der Bereitstellung routinetauglicher Methoden zur Charakterisierung metall-basierter ENMs und iii) der Entwicklung von Methoden zur Größenfraktionierung von Porenwässern, um größenbezogene Elementverteilungsmustern an WSG erhalten zu können.
Im ersten Teil erfolgte die Entwicklung von Filter-Probenahmesonden, die in ein neuartiges Probenahmesystem integriert wurden, welches mit einem kommerziell verfügbaren Microprofiling-system kombiniert wurde (microprofiling micro sampling system; missy). Nach umfangreicher Validierung konnte in Experimenten die Tauglichkeit des missy für eine minimal-invasive und auto-matisierte Beprobung von Sedimentporenwasser bei parallelen Messungen mittels Mikrosensoren gezeigt werden. Es wurde somit erstmal möglich, im Millimetermaßstab Multielementinformationen für Sedimenttiefenprofile zu erhalten und diese in einen direkten Zusammenhang mit verschiedenen Sedimentparametern zu setzten.Aufgrund der zu erwartenden Freisetzung von ENMs in die Umwelt, war es das Ziel, Methoden bereitzustellen, die eine Untersuchung von Transportprozessen und dem Verbleib von ENMs an WSG ermöglichen. Da standardisierte Methoden noch immer fehlen, erfolgte die Entwicklung routinetauglicher Ansätze zur Bestimmung der Massenkonzentration sowie der gelösten Fraktion von ENM-Suspensionen. Somit konnten erstmals Methoden bereitgestellt werden, die eine routinetaugliche Bestimmung von zwei der wichtigsten Eigenschaften kolloidaler Systeme ermöglichen, die ebenfalls für die Entwicklung geeigneter Risikoabschätzungen und Regularien benötigt werden.
Basierend auf dieser methodischen Grundlage erfolge die Entwicklung geeigneter Verfahren zur Bestimmung der gelösten und kolloidalen Fraktionen in Sedimentporenwässern. Dies ermöglichte es erstmalig, fraktionsbezogene Elementinformationen für Sedimenttiefenprofile in millimetergenauer Auflösung zu erhalten, was eine Unterscheidung zwischen Diffusion und kolloid-gesteuerten Transportprozessen gestattet.
Zusätzlich zu den forschungsorientierten Teilen der vorgelegten Dissertation wurden in einer weiteren, als Anhang beigefügten Publikation (Appendix III) Fragen zu einem möglichen Eintrag nanoskaliger Stoffe in Oberflächengewässer vor dem Hintergrund des aktuell gültigen Deutschen Wasserrechtes adressiert.
Thousands of chemicals from daily use are being discharged from civilization into the water cycle via different pathways. Ingredients of personal care products, detergents, pharmaceuticals, pesticides, and industrial chemicals thus find their way into the aquatic ecosystems and may cause adverse impacts on the ecology. Pharmaceuticals for instance, represent a central group of anthropogenic chemicals, because of their designed potency to interfere with physiological functions in organisms. Ecotoxicological effects from pharmaceutical burden have been verified in the past. Therapeutic groups with pronounced endocrine disrupting potentials such as steroid hormones gain increasing focus in environmental research as it was reported that they cause endocrine disruption in aquatic organisms even when exposed to environmentally relevant concentrations. This thesis considers the comprehensive investigation of the occurrence of corticosteroids and progestogens in wastewater treatment plant (WWTP) effluents and surface waters as well as the elucidation of the fate and biodegradability of these steroid families during activated sludge treatment. For the first goal of the thesis, a robust and highly sensitive analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed in order to simultaneously determine the occurrence of around 60 mineralocorticoids, glucocorticoids and progestogens in the aquatic environment. A special focus was set to the compound selection due to the diversity of marketed synthetic steroids. Some analytical challenges have been approved by individual approaches regarding sensitivity enhancement and compound stabilities. These results may be important for further research in environmental analysis of steroid hormones. Reliable and low quantification limits are the perquisite for the determination of corticosteroids and progestogens at relevant concentrations due to low consumption volumes and simultaneously low effect-based trigger values. Achieved quantification limits for all target analytes ranged between 0.02 ng/L and 0.5 ng/L in surface water and 0.05 ng/L to 5 ng/L in WWTP effluents. This sensitivity enabled the detection of three mineralocorticoids, 23 glucocorticoids and 10 progestogens within the sampling campaign around Germany. Many of them were detected for the first time in the environment, particularly in Germany and the EU. To the best of our knowledge, this in-depth steroid screening provided a good overview of single steroid burden and allowed for the identification of predominantly steroids of each steroid
type analyzed for the first time. The frequent detection of highly potent synthetic steroids (e.g. triamcinolone acetonide, clobetasol propionate, betamethasone valerate, dienogest, cyproterone acetate) highlighted insufficient removal during conventional Summary wastewater treatment and indicated the need for regulation to control their emission since the steroid concentrations were found to be above the reported effect-based trigger values for biota. Overall, the study revealed reliable environmental data of poorly or even not analyzed steroids. The results complement the existing knowledge in this field but also providednew information which can beused particularly for compound prioritization in ecotoxicological research and environmental analysis. Based on the data obtained from the monitoring campaign, incubation experiments were conducted to enable the comparison of the biodegradability and transformation processes in activated sludge treatment for structure-related steroids under aerobic and standardized experimental conditions. The compounds were accurately selected to cover manifold structural moieties of commonly used glucocorticoids, including non-halogenated and halogenated steroids, their mono- and diesters, and several acetonide-type steroids. This approach allowed for a structure-based interpretation of the results. The obtained biodegradation rate constants suggested large variations in the biodegradability (half-lifes ranged from < 0.5 h to > 14 d). An increasing stability was identified in the order from non-halogenated steroids (e.g. hydrocortisone), over 9α-halogenated steroids (e.g. betamethasone), to C17-monoesters (e.g. betamethasone 17-valerate, clobetasol propionate), and finally to acetonides (e.g. triamcinolone acetonide), thus suggesting a strong relationship of the biodegradability with the glucocorticoid structure. Some explanations for this behavior have been received by identifying the transformation products (TPs) and elucidating individual transformation pathways. The results revealed the identification of the likelihood of transformation reactions depending on the chemical steroid structure for the first time. Among the identified TPs, the carboxylates (e.g. TPs of fluticasone propionate, triamcinolone acetonide) have been shown persistency in the subsequent incubation experiments. The newly identified TPs furthermore were frequently detected in the effluents of full-scale wastewater treatment plants. These findings emphasized i) the transferability of the lab-scale degradation experiments to real world and that ii) insufficient removals may cause adverse effects in the aquatic environment due to the ability of the precursor steroids and TPs to interact with the endocrine system in biota. For the last goal, the conceptual study for glucocorticoids was applied to progestogens.
Here, two sub-types of the steroid family frequently used for hormonal contraception were selected (17α-hydroxyprogesterone and 19-norstestosterone type). The progestogens showed a fast and complete degradation within six hours, and thus empathizes pronounced biodegradability. However, cyproterone acetate and dienogest Summary have been found to be more recalcitrant in activated sludge treatment. This was consistent with their ubiquitously occurrence during the previous monitoring campaign. The elucidation of TPs again revealed some crucial information regarding the observed behavior and highlighted furthermore the formation of hazardous TPs. It was shown that 19-nortestosterone type steroids are able to undergo aromatization at ring A in contact with activated sludge, leading to the formation of estrogen-like TPs with a phenolic moiety at ring A. In the case of norethisterone the formation of 17α-ethinylestradiol was confirmed, which is a well-known potent synthetic estrogen with elevated ecotoxicological potency. Thus, the results indicated for the very first time an unknown source of estrogenic compounds, particularly for 17α-ethinylestradiol. In conclusion, some steroids were found to be very stable in activated sludge treatment, others degrade well, and others which do degrade but predominantly to active TPs depending on their chemical structure. Fluorinated acetal steroids such as triamcinolone acetonide and fluocinolone acetonide are poorly biodegradable, which is reflected in high concentrations detected ubiquitously in WWTP effluents. Endogenous steroids and their most related synthetic once such as hydrocortisone, prednisolone or 17α-hydroxyprogesterone are readily biodegradable. Regardless their high influent concentrations, they are almost completely removed in conventional WWTPs. Steroids between this range have been found to form elevated quantities of TPs which are partially still active, which particularly the case for betamethasone, fluticasone propionate, cyproterone acetate or dienogest. The thesis illustrates the need for an extensive evaluation of the environmental risks and carried out that corticosteroids and progestogens merit more attention in environmental regulatory and research than it is currently the case