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Bioaccumulation of organic pollutants in aquatic organisms: linking exposure and effects

English title Bioaccumulation of organic pollutants in aquatic organisms: linking exposure and effects
Applicant Hollender Juliane
Number 184878
Funding scheme Project funding
Research institution Umweltchemie Eawag
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Other disciplines of Environmental Sciences
Start/End 01.07.2019 - 30.06.2023
Approved amount 919'968.00
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Keywords (6)

biotransformation; exposure ; organic trace analysis; invertebrates; bioaccumulation; organic pollutants

Lay Summary (German)

Lead
Kenntnisse über die Anreicherung von organischen Schadstoffen in Gewässerorganismen sind wichtig, um die Belastung in den Gewässern durch Landwirtschaft und Kläranlagen mit den Wirkungen auf Gewässerorganismen zu verknüpfen.
Lay summary

Ziel des Projektes ist es, die Relevanz der Anreicherung von polaren organischen Schadstoffen in Flohkrebsen sowie den Einfluss verschiedener Faktoren darauf besser zu verstehen. Diese Faktoren umfassen Konzentrationsveränderungen im Gewässer, die Bedeutung der Futterquelle und die chemische Struktur sowie Eigenschaften der Schadstoffe. Hierzu werden Versuche im Labor unter definierten Bedingungen mit einzelnen Stoffen durchgeführt als auch Proben von Wasser, Sediment, Blättern und Flohkrebsen im Feld während des Einsatzes von Pflanzenschutzmitteln und unterhalb von Kläranlagen genommen. Die Mischung an Schadstoffen und ihre Abbauprodukte werden mit analytischen Methoden (Flüssigchromatographie gekoppelt an die hochauflösende Massenspektrometrie) in den verschiedenen Proben quantitativ bestimmt. Die Verteilung zwischen den verschiedenen Gewässerbestandteilen wird mit den Eigenschaften der Schadstoffe verglichen. Mit einer räumlich aufgelösten massenspektrometrischen Methode wird auch bestimmt, in welchen Organen die Schadstoffe sich anreichern. Labor- und Feldergebnisse werden in einem mathematischen Modell zusammengeführt, um damit die Dynamik der Konzentrationen im Gewässer mit den Konzentrationen in den Flohkrebsen zu verknüpfen und mögliche Wirkungen abzuschätzen. Die Ergebnisse können nützlich sein für eine verbesserte Gewässerbewertung als auch die zukünftige Zulassung von Chemikalien mit ähnlichen Eigenschaften unterstützen.

Direct link to Lay Summary Last update: 30.05.2019

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Associated projects

Number Title Start Funding scheme
165935 Bioaccumulation and biotransformation of organic xenobiotics in aquatic organisms 01.04.2016 Project funding

Abstract

Knowledge on the bioaccumulation and biotransformation of anthropogenic pollutants in aquatic organisms is essential to mechanistically link the environmental exposure with ecotoxicological effects. It is also relevant for the derivation of environmental quality standards within the Water Framework Directive mandate and for the evaluation of the bioaccumulation potential as required by REACH for new chemical registration. In the proposed project, we aim to further improve exposure assessment and add key links between exposure and effects with a team of two PhD students and two postdoctoral scientists. The overall question addresses the relevance of bioaccumulation and biomagnification of polar organic pollutants in aquatic organisms in the environment and its modulation by compound concentration dynamic, uptake pathways, and chemical structure. Laboratory experiments (PhD student 1) with the aquatic invertebrates Gammarus pulex and Hyalella azteca will be conducted to mechanistically evaluate specific bioaccumulation and bio-transformation processes such as methylation, a process associated with increased bioaccumulation of hy-drophobic and neutral biotransformation products (BTPs). Food such as plant detritus will be investigated as additional source for pesticides such as neonicotinoids. To determine organ-specific bioaccumulation factors that are more relevant for toxicity assessment, the spatial distribution of selected compounds in inverte-brates will be investigated using spatially resolved high resolution tandem mass spectrometry. The results of the lab experiments and their relevance in a multi-compartment environment with varying pollutant sources and dynamics will be tested in a field study where water, sediment, leaves, biofilms, aquatic invertebrates, and fish at three sites up- and downstream of a wastewater treatment plant will be sampled at high temporal resolution (7-10 days during the pesticide application period) (PhD student 2). To get a comprehensive pic-ture on the bioaccumulation and biomagnification of polar pollutants (~60 compounds), exposure-relevant suspected compounds (e.g. pharmaceuticals & pesticides), BTPs of selected compounds and additional un-known pollutants will be identified in the biota samples using high resolution tandem mass spectrometric (HRMS/MS) data, statistical approaches and structure elucidation methods. The partitioning of the com-pounds in water, sediment, food, and aquatic organisms will be compared with physical-chemical properties using polyparameter linear free energy relationships. In addition, fold-changes of endogenous metabolites will be compared up- and downstream to indicate impact on metabolic pathways and be correlated with the contamination pattern and results of in-situ feeding assays (postdoc 1). Finally, the field and lab data will be used to develop a model that links the fate of organic pollutants in several environmental compartments (wa-ter, sediment, and food) to the concentration dynamics within aquatic organisms. The internal concentra-tions will be simulated using toxicokinetic modelling and the risk of effects will be estimated based on those concentrations (postdoc 2). This research plan will make significant contributions toward a more mechanistic approach to risk assessment that not only employs several tools in exposure science but also sheds new light on the mechanisms of pollutant bioaccumulation.
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