Molecular responses of European flounder (Platichthys flesus) chronically exposed to contaminated estuarine sediments

• Published in: Chemosphere (Oxford) Vol. 108; pp. 152 - 158
• Main Authors: Williams, Tim D., Davies, Ian M., Wu, Huifeng, Diab, Amer M., Webster, Lynda, Viant, Mark R., Chipman, J. Kevin, Leaver, Michael J., George, Stephen G., Moffat, Colin F., Robinson, Craig D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2014; Elsevier
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; DNA Damage - drug effects; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Estuaries; Female; Flounder; Flounder - genetics; Flounder - physiology; Fundamental and applied biological sciences. Psychology; Genotoxicity; Geologic Sediments - analysis; Liver - drug effects; Liver - metabolism; Male; Metabolomics; Metals, Heavy - analysis; Metals, Heavy - toxicity; Microarray; Mutagens - analysis; Mutagens - toxicity; Polychlorinated Biphenyls - analysis; Polychlorinated Biphenyls - toxicity; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - toxicity; Sediments; Toxicogenomics; Transcription, Genetic - drug effects; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Metabolomics; Sediments; Microarray; Toxicogenomics; Flounder; Genotoxicity; Brackish water environment; Toxicity; Metabolite; Liver; Estuaries; Platichthys flesus; Persistent organic pollutant; Marine environment; Tissue; Pisces; Toxicogenetics; Ecotoxicology; Hydrocarbon; Bioavailability; Polycyclic aromatic compound; Vertebrata; Chronic; DNA; Degradation product
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2014.01.028

•Flounders were exposed to contaminated sediments in mesocosms for 7months.•Little differential accumulation of contaminants was found by chemical analysis.•1-Hydroxypyrene and DNA damage increased in exposed fish.•Metabolic and transcriptional changes were detected in fish livers.•Molecular alterations were consistent with chronic PAHs exposure. Molecular responses to acute toxicant exposure can be effective biomarkers, however responses to chronic exposure are less well characterised. The aim of this study was to determine chronic molecular responses to environmental mixtures in a controlled laboratory setting, free from the additional variability encountered with environmental sampling of wild organisms. Flounder fish were exposed in mesocosms for seven months to a contaminated estuarine sediment made by mixing material from the Forth (high organics) and Tyne (high metals and tributyltin) estuaries (FT) or a reference sediment from the Ythan estuary (Y). Chemical analyses demonstrated that FT sediment contained significantly higher concentrations of key environmental pollutants (including polycyclic aromatic hydrocarbons (PAHs), chlorinated biphenyls and heavy metals) than Y sediment, but that chronically exposed flounder showed a lack of differential accumulation of contaminants, including heavy metals. Biliary 1-hydroxypyrene concentration and erythrocyte DNA damage increased in FT-exposed fish. Transcriptomic and 1H NMR metabolomic analyses of liver tissues detected small but statistically significant alterations between fish exposed to different sediments. These highlighted perturbance of immune response and apoptotic pathways, but there was a lack of response from traditional biomarker genes. Gene-chemical association annotation enrichment analyses suggested that polycyclic aromatic hydrocarbons were a major class of toxicants affecting the molecular responses of the exposed fish. This demonstrated that molecular responses of sentinel organisms can be detected after chronic mixed toxicant exposure and that these can be informative of key components of the mixture.