title: Genotoxic and teratogenic effect of freshwater sediment samples from the Rhine and Elbe River (Germany) in zebrafish embryo using a multi-endpoint testing strategy.
abstract: The embryotoxic potential of three model sediment samples with a distinct and well-characterized pollutant burden from the main German river basins Rhine and Elbe was investigated. The Fish Embryo Contact Test (FECT) in zebrafish (Danio rerio) was applied and submitted to further development to allow for a comprehensive risk assessment of such complex environmental samples. As particulate pollutants are constructive constituents of sediments, they underlay episodic source-sink dynamics, becoming available to benthic organisms. As bioavailability of xenobiotics is a crucial factor for ecotoxicological hazard, we focused on the direct particle-exposure pathway, evaluating throughput-capable endpoints and considering toxicokinetics. Fish embryo and larvae were exposed toward reconstituted (freeze-dried) sediment samples on a microcosm-scale experimental approach. A range of different developmental embryonic stages were considered to gain knowledge of potential correlations with metabolic competence during the early embryogenesis. Morphological, physiological, and molecular endpoints were investigated to elucidate induced adverse effects, placing particular emphasis on genomic instability, assessed by the in vivo comet assay. Flow cytometry was used to investigate the extent of induced cell death, since cytotoxicity can lead to confounding effects. The implementation of relative toxicity indices further provides inter-comparability between samples and related studies. All of the investigated sediments represent a significant ecotoxicological hazard by disrupting embryogenesis in zebrafish. Beside the induction of acute toxicity, morphological and physiological embryotoxic effects could be identified in a concentration-response manner. Increased DNA strand break frequency was detected after sediment contact in characteristic non-monotonic dose-response behavior due to overlapping cytotoxic effects. The embryonic zebrafish toxicity model along with the in vivo comet assay and molecular biomarker analysis should prospectively be considered to assess the ecotoxicological potential of sediments allowing for a comprehensive hazard ranking. In order to elucidate mode of action, novel techniques such as flow cytometry have been adopted and proved to be valuable tools for advanced risk assessment and management.
authors.affiliation: Hydrotox GmbH, Bötzingerstr. 109, 79098, Freiburg, Germany. manuel.garcia-kaeufer@uniklinik-freiburg.de.|Department of Ecosystem Analysis, Institute for Environmental Research, ABBT-Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany. manuel.garcia-kaeufer@uniklinik-freiburg.de.|Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Centre Freiburg, Breisacherstr. 115b, 79106, Freiburg, Germany. manuel.garcia-kaeufer@uniklinik-freiburg.de.|Department of Environmental Health Sciences, University Medical Centre Freiburg, Breisacherstr. 115b, 79106, Freiburg, Germany. manuel.garcia-kaeufer@uniklinik-freiburg.de.
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Käufer
authors.affiliation: Hydrotox GmbH, Bötzingerstr. 109, 79098, Freiburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Gartiser
authors.affiliation: Hydrotox GmbH, Bötzingerstr. 109, 79098, Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hafner
authors.affiliation: Department of Ecosystem Analysis, Institute for Environmental Research, ABBT-Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schiwy
authors.affiliation: Department of Ecosystem Analysis, Institute for Environmental Research, ABBT-Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.|Man-Technology-Environment Research Centre, School of Science and Technology, Örebro University, 70182, Örebro, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Keiter
authors.affiliation: Center for Complementary Medicine, Department of Environmental Health Sciences, University Medical Centre Freiburg, Breisacherstr. 115b, 79106, Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Gründemann
authors.affiliation: Department of Ecosystem Analysis, Institute for Environmental Research, ABBT-Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.|School of Environment, Nanjing University, Nanjing, China.|Key Laboratory of Yangtze River Environment of Education Ministry of China, College of Environmental Science and Engineering, Tongji University, Shanghai, China.|College of Resources and Environmental Science, Chongqing University, Chongqing, China.
authors.forename: H
authors.initials: H
authors.lastname: Hollert
mesh_terms: D000818:Animals; D020552:Comet Assay; D004249:DNA Damage; D054750:Ecotoxicology; D004625:Embryo, Nonmammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D019015:Geologic Sediments / Q000737:chemistry*; D005858:Germany; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D060753:Water Quality; D015027:Zebrafish
chemical_list: D014874:Water Pollutants, Chemical
keywords: Apoptosis; Comet assay; Cytotoxicity; Dioxin-like toxicity; Embryotoxicity; Freshwater sediment; Genotoxicity; Zebrafish