The sediments of surface waters are temporary or final depository of many chemical compounds, including trace metals and metalloids (metal(loid)s) from natural and anthropogenic sources. Whether they act as a source or sink of metal(loid)s depends strongly on the dynamics of the biogeochemical processes that take place at the sediment-water interface (SWI). Important information on biogeochemical processes as well as on the exposure, the fate and the transport of pollutants at the SWI can be obtained by determining chemical concentration profiles in the sediment pore water. A major challenge is to conduct experiments with a spatial resolution, which allows to adequately record existing gradients and to log all the parameters needed, to describe and better understand the complex processes at the SWIs. At the same time, it is from major importance to prevent the formation of any artifacts during sampling, which may occur due to the labile nature of the SWIs and the very steep biogeochemical gradients. In this context, in the first part of this work, a system was developed and tested that enables the automated, minimal invasive sampling of sediment pore water of undisturbed or manipulated sediments while simultaneously recording parameters such as redox potential, oxygen content and pH value. In an incubation experiment the impact of acidification and mechanical disturbance (re-suspension) on the mobility of 13 metal(loid)s was investigated using a triple quadrupole inductively coupled plasma-mass spectrometry (ICP-QQQ-MS) multi-element approach. Most metals were released as consequence of sulfide weathering whereas mechanical disturbance had a major impact on the mobility of the oxide forming elements As, Mo, Sb, U and V. Additionally, options were demonstrated to address with the system the size fractionation of metal(loid)s in pore water samples and the speciation of As(III/V) and Sb(III/V). In the second part, the focus, with a similar experimental design, was placed on the processes leading to the release of metal(loid)s. For this purpose, two incubation experiments with different oxygen supply were conducted in parallel. For the first time the nonmetals carbon, phosphorus and sulfur were analyzed simultaneous to 13 metal(loid)s in sediment pore water by ICP-QQQ-MS. Throughout the experiment metal(loid) size fractionation was monitored. It was confirmed that resuspension promotes the mobility of metalloids such as As, Sb and V, while the release of most metals was largely attributed to pyrite weathering. The colloidal (0.45-16 μm) contribution in terms of mobilization was only relevant for a few elements. Finally, the sampling system was used as part of a new approach to sediment risk assessment. Undisturbed sediment cores from differently contaminated positions in the Trave estuary were examined, considering 16 metal(loid)s, the non-metals C, P and S and the ions NH4+, PO43- and SO42-. By the first in-depth comparison with in-situ dialysis-based pore water sampling the ability of the suction-based approach to represent field conditions was proven. The pore water studies together with supplementing resuspension experiments in bio-geochemical microcosms and sequential extraction identified the most “pristine” sediment of the study area as posing the greatest risk of metal(loid) release. However, the potentially released amounts per kg of sediment are only a few parts per thousand of the average daily loads of the Trave river.

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