Abteilung Umweltchemie

Den Schadstoffen auf der Spur

Unser Forschungsteam untersucht Vorkommen, Verteilung und Verbleib von organischen Schadstoffen in der aquatischen Umwelt. Der Fokus liegt auf den Stoffflüssen aus den Siedlungsgebieten sowie der Landwirtschaft. Zentrale Werkzeuge dabei sind die Spurenanalytik, Feld- und Laborstudien sowie die Modellierung.

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Letzte Publikationen

Simultaneous exposure to a pulsed and a prolonged anthropogenic stressor can alter consumer multifunctionality

Ecosystems face multiple anthropogenic threats globally, and the effects of these environmental stressors range from individual‐level organismal responses to altered system functioning. Understanding the combined effects of stressors on process rates mediated by individuals in ecosystems would greatly improve our ability to predict organismal multifunctionality (e.g. multiple consumer‐mediated functions). We conducted a laboratory experiment to test direct and indirect, as well as immediate and delayed effects of a heat wave (pulsed stress) and micropollutants (MPs) (prolonged stress) on individual consumers (the great pond snail Lymnaea stagnalis) and their multifunctionality (i.e. consumption of basal resources, growth, reproduction, nutrient excretion and organic‐matter cycling). We found that stressful conditions increased the process rates of multiple functions mediated by individual consumers. Specifically, the artificial heat wave increased process rates in the majority of the quantified functions (either directly or indirectly), whereas exposure to MPs increased consumption of basal resources which led to increases in the release of nutrients and fine particulate organic matter. Moreover, snails exposed to a heat wave showed decreased reproduction and nutrient excretion after the heat‐wave, indicating the potential for ecologically relevant delayed effects. Our study indicates that the immediate and delayed effects of stressors on individual organisms may directly and indirectly impact multiple ecosystem functions. In particular, delayed effects of environmental stress on individual consumers may cumulatively impede recovery due to decreased functioning following a perturbation. Reconciling these results with studies incorporating responses at higher levels of biological complexity will enhance our ability to forecast how individual responses upscale to ecosystem multifunctionality.
Salo, T.; Räsänen, K.; Stamm, C.; Burdon, F. J.; Seppälä, O. (2018) Simultaneous exposure to a pulsed and a prolonged anthropogenic stressor can alter consumer multifunctionality, Oikos, doi:10.1111/oik.05310, Institutional Repository

A proteomics approach to trace site-specific damage in aquatic extracellular enzymes during photoinactivation

Extracellular enzymes are major drivers of biogeochemical nutrient and carbon cycling in surface water. While photoinactivation is regarded as a major inactivation process of these enzymes, the underlying molecular changes have received little attention. This study demonstrate how light exposure leads to a rapid loss of phosphatase, aminopeptidase and glucosidase activities of biofilm samples and model enzymes. Here, an optimized proteomics approach allowed simultaneous observation of inactivation and molecular changes. Site-specific fingerprints of degradation kinetics have been generated and visualized in the three-dimensional proteins. Oxidation of tryptophan, the chromophoric target, initiated secondary reactions. Evidence was obtained that tyrosine residues act as intramolecular antioxidants, reflected in decelerated decay of tryptophan- and enhanced decay of tyrosine-containing peptides. In addition, subsequent methionine oxidation and disulfide reduction contribute to heterogeneous photodamage. The proximity to tryptophan residues explains >95% of the photodamage across the protein structures. The presence of redox-active organic matter or a model antioxidant in solution quenched not only photoinactivation and tryptophan oxidation but also all subsequent damage. The developed analytical approach can be applied to other research questions in environmental sciences where site-specific damage in a protein is essential.
Egli, C. M.; Janssen, E. M. L. (2018) A proteomics approach to trace site-specific damage in aquatic extracellular enzymes during photoinactivation, Environmental Science and Technology, doi:10.1021/acs.est.7b06439, Institutional Repository

Non-target screening to trace ozonation transformation products in a wastewater treatment train including different post-treatments

Ozonation and subsequent post-treatments are increasingly implemented in wastewater treatment plants (WWTPs) for enhanced micropollutant abatement. While this technology is effective, micropollutant oxidation leads to the formation of ozonation transformation products (OTPs). Target and suspect screening provide information about known parent compounds and known OTPs, but for a more comprehensive picture, non-target screening is needed. Here, sampling was conducted at a full-scale WWTP to investigate OTP formation at four ozone doses (2, 3, 4, and 5 mg/L, ranging from 0.3 to 1.0 gO3/gDOC) and subsequent changes during five post-treatment steps (i.e., sand filter, fixed bed bioreactor, moving bed bioreactor, and two granular activated carbon (GAC) filters, relatively fresh and pre-loaded). Samples were measured with online solid-phase extraction coupled to liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS) using electrospray ionization (ESI) in positive and negative mode. Existing non-target screening workflows were adapted to (1) examine the formation of potential OTPs at four ozone doses and (2) compare the removal of OTPs among five post-treatments. In (1), data processing included principal component analysis (PCA) and chemical knowledge on 31 possible oxidation reactions to prioritize non-target features likely to be OTPs. Between 394 and 1328 unique potential OTPs were detected in positive ESI for the four ozone doses tested; between 12 and 324 unique potential OTPs were detected in negative ESI. At a specific ozone dose of 0.5 gO3/gDOC, 27 parent compounds were identified and were related to 69 non-target features selected as potential OTPs. Two OTPs were confirmed with reference standards (venlafaxine N-oxide and chlorothiazide); 34 other potential OTPs were in agreement with literature data and/or reaction mechanisms. In (2), hierarchical cluster analysis (HCA) was applied on profiles detected in positive ESI mode across the WWTP and revealed 11 relevant trends. OTP removal was compared among the five post-treatments and 54–83% of the non-target features that appeared after ozonation were removed, with the two GAC filters performing the best. Overall, these data analysis strategies for non-target screening provide a useful tool to understand the behavior of unknown features during ozonation and post-treatment and to prioritize certain non-targets for further identification.
Schollée, J. E.; Bourgin, M.; von Gunten, U.; McArdell, C. S.; Hollender, J. (2018) Non-target screening to trace ozonation transformation products in a wastewater treatment train including different post-treatments, Water Research, 142, 267-278, doi:10.1016/j.watres.2018.05.045, Institutional Repository

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Biotransformation of sulfonamide antibiotics in activated sludge: the formation of pterin-conjugates leads to sustained risk

The presence of antibiotics in treated wastewater and consequently in surface and groundwater resources raises concerns about the formation and spread of antibiotic resistance. Improving the removal of antibiotics during wastewater treatment therefore is a prime objective of environmental engineering. Here we obtained a detailed picture of the fate of sulfonamide antibiotics during activated sludge treatment using a combination of analytical methods. We show that pterin-sulfonamide conjugates, which are formed when sulfonamides interact with their target enzyme to inhibit folic acid synthesis, represent a major biotransformation route for sulfonamides in laboratory batch experiments with activated sludge. The same major conjugates were also present in the effluents of nine Swiss wastewater treatment plants. The demonstration of this biotransformation route, which is related to bacterial growth, helps explain seemingly contradictory views on optimal conditions for sulfonamide removal. More importantly, since pterinsulfonamide conjugates show retained antibiotic activity, our findings suggest that risk from exposure to sulfonamide antibiotics may be less reduced during wastewater treatment than previously assumed. Our results thus further emphasize the inadequacy of focusing on parent compound removal and the importance of investigating biotransformation pathways and removal of bioactivity to properly assess contaminant removal in both engineered and natural systems.
Achermann, S.; Bianco, V.; Mansfeldt, C. B.; Vogler, B.; Kolvenbach, B. A.; Corvini, P. F. X.; Fenner, K. (2018) Biotransformation of sulfonamide antibiotics in activated sludge: the formation of pterin-conjugates leads to sustained risk, Environmental Science and Technology, 52(11), 6265-6274, doi:10.1021/acs.est.7b06716, Institutional Repository

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Aktuelles

Blaualgen vertilgen Glyphosat

Wasserproben für Glyphosatmessungen im Greifensee, Foto: Sebastian Stötzer
Die Wasserproben für die Glyphosatmessungen im Greifensee wurden im Rahmen der kantonalen Gewässerüberwachung vom Amt für Abfall, Wasser, Energie und Luft (AWEL) entnommen. Foto: Sebastian Stötzer

12. Juli 2018, Forschende von Agroscope und Eawag entdeckten im Greifensee, dass Glyphosat unter bestimmten Bedingungen schnell abgebaut wird. Alles deutet darauf hin, dass Bakterien dafür verantwortlich sind, die das Pflanzenschutzmittel als alternative Phosphorquelle nutzen. [mehr Info]

Aktuelles Historie

Ausgewählte, repräsentative Forschungsprojekte

Demonstration of promising technologies to address emerging pollutants in water and wastewater.

DEMEAU
Die umfassende Messung organischer Spurenstoffe in Gewässern ist aufwändig. Das Projekt NAWA SPEZ liefert Daten und Analysen zur Belastungssituation.

NAWA SPEZ
Predicting environment-specific biotransformation of chemical contaminants

PROduCTS - ERC
Die Überwachung von Oberflächengewässern hinsichtlich polarer und semipolarer organischer Mikroschadstoffe ist stark an die chemische Analytik gekoppelt...

Computergestützte Detektion von Mikroschadstoffen in Oberflächengewässern mittels hochauflösender Massenspektrometrie

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