| 1. |
- Grund, Stefanie, et al.
(författare)
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Assessment of fish health status in the Upper Danube River by investigation of ultrastructural alterations in the liver of barbel Barbus barbus
- 2010
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Ingår i: Diseases of Aquatic Organisms. - Luhe, Germany : Inter-Research. - 0177-5103 .- 1616-1580. ; 23, s. 235-248
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Tidskriftsartikel (refereegranskat)abstract
- Despite intensive efforts and tightened guidelines for improvement of water quality over the last 2 decades, declines of fish populations have been reported for several rivers around the world. The present study forms part of a comprehensive weight-of-evidence approach, which aims to identify potential causes for the decline in fish catches observed in the Upper Danube River. The major focus of the present study is the investigation of the health status of wild barbel Barbus barbus L. collected from 3 locations along the Danube River, which experienced different levels of contamination. Whereas the comparison of the condition factor (CF) of field fish with that of control fish revealed no differences, ultrastructural investigations indicated severe disturbance of hepatic cell metabolism in field fish from the more contaminated sites Rottenacker and Ehingen, compared to both control fish and field fish from the less contaminated site Riedlingen. The ultrastructural analysis provided information about reactions of e.g. the rough endoplasmic reticulum, peroxisomes, andmitochondria, indicating an impaired health status of barbel at the sampling sites Rottenacker and Ehingen. Even though a straightforward cause-effect relationship between sediment contamination and ultrastructural alterations could not be established, based on a meta-analysis and toxicity assays it may be suggested that sediment-bound xenobiotics at least partly account for the hepatocellular changes. A relationship between impaired fish health status and the decline of fish catches along the Upper Danube River cannot be excluded.
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| 2. |
- Hollert, Henner, et al.
(författare)
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Eine Weight-of-Evidence-Studie zur Bewertung der Sedimentbelastung und des Fischrückgangs in der Oberen Donau [Assessing sediments and fish health using a weight-of-evidence approach : in search for the causes of fish decline in the Danube river]
- 2009
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Ingår i: Umweltwissenschaften und Schadstoff-Forschung. - Berlin : Springer. - 0934-3504 .- 1865-5084. ; 21:3, s. 260-263
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Tidskriftsartikel (refereegranskat)abstract
- Background and aim Despite intensive and continuous stocking and improvement of water quality since the 1970s, fish populations, especially those of the grayling (Thymallus thymallus), have declined over the last two decades in the upper Danube River (Germany). In order to assess 1) possible links between molecular/biochemical responses and ecologically relevant effects, and 2) if ecotoxicological effects might be related to the decline in fish catches in the upper Danube river, sediment samples and fish were collected at different locations and analyzed using a weight-of-evidence (WOE) approach with several lines of evidence. The objective of the presentation is to introduce the conceptual framework and to review results of the ongoing study. As previously addressed by Chapman and Hollert (2006) a variety of lines of evidence can be used in WOE studies. Briefly, 1) a comprehensive battery of acute and mechanism-specific bioassays was used to characterize the ecotoxicological hazard potential. 2) Histopathological investigations and the micronucleus assay with erythrocytes were applied, analyzing in situ parameters. 3) Diversity and abundance of benthic macroinvertebrates and fish as well as 4) persistent organic pollutants, endocrine disrupting substances, limnochemical parameters and the concentration of heavy metals were recorded. To identify organic contaminants a spotential causes of sediment toxicity assays, 5) effect directed analysis was applied. © 2009 Springer-Verlag.
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| 3. |
- Keiter, Steffen, 1971-, et al.
(författare)
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Ecotoxicological assessment of sediment, suspended matter andwater samples in the upper danube river : a pilot study in search for the causes for the decline of fish catches
- 2006
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 13:5, s. 308-319
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Tidskriftsartikel (refereegranskat)abstract
- Goals, Scope and Background. Fish populations, especially thoseof the grayling (Thymallus thymallus), have declined over thelast two decades in the upper Danube River between Sigmaringenand Ulm, despite intensive and continuous stocking and improvementof water quality since the 1970s. Similar problems havebeen reported for other rivers, e.g. in Switzerland, Great Britain,the United States and Canada. In order to assess if ecotoxicologicaleffects might be related to the decline in fish catchat the upper Danube River, sediment, suspended matter andwaste water samples from sewage treatment plants were collectedat selected locations and analyzed in a bioanalytical approachusing a battery of bioassays. The results of this pilotstudy will be used to decide if a comprehensive weight-of-evidencestudy is needed.Methods. Freeze-dried sediments and suspended particulate matterswere extracted with acetone in a Soxhlet apparatus. Organicpollutants from sewage water were concentrated usingXAD-resins. In order to investigate the ecotoxicological burden,the following bioassays were used: (1) neutral red assaywith RTL-W1 cells (cytotoxicity), (2) comet assay with RTLW1cells (genotoxicity), (3) Arthrobacter globiformis dehydrogenaseassay (toxicity to bacteria), (4) yeast estrogen screen assay(endocrine disruption), (5) fish egg assay with the zebrafish(Danio rerio; embryo toxicity) and (6) Ames test with TA98(mutagenicity).Results and Discussion. The results of the in vitro tests elucidateda considerable genotoxic, cytotoxic, mutagenic, bacteriotoxic,embryotoxic and estrogenic burden in the upper DanubeRiver, although with a very inhomogeneous distribution of effects.The samples taken from Riedlingen, for example, inducedlow embryo toxicity, but the second highest 17β-estradiol equivalentconcentration (1.8 ng/L). Using the fish egg assay with nativesediments, a broad range of embryotoxic effects could beelucidated, with clear-cut dose-response relationships for theembryotoxic effects of contaminated sediments. With nativesediments, embryotoxicity was clearly higher than with correspondingpore waters, thus corroborating the view that – atleast for fish eggs – the bioavailability of particle-bound lipophilicsubstances in native sediments is higher than generally assumed. The effect observed most frequently in the fish egg assay was a developmental delay. A comparison of our own results with locationsalong the rivers Rhine and Neckar demonstrated similaror even higher ranges of ecotoxicological burdens in theDanube River.Conclusions. The complex pattern of ecotoxicological effectscaused by environmental samples from the Danube River, whenassessed in an in vitro biotest battery using both acute and morespecific endpoints, showed that integration of different endpointsis essential for appropriate hazard assessment. Overall, theecotoxicological hazard potential shown has indeed to be consideredas one potential reason for the decline in fish catches atthe upper Danube River. However, based on the results of thispilot study, it is not possible to elucidate that chemically inducedalterations are responsible for the fish decline.Recommendations and Perspectives. In order to confirm the ecologicalrelevance of the in vitro results for the situation in thefield and especially for the decline of the grayling and otherfishes, further integrated investigations are required. For linkingthe weight of evidence obtained by in vitro assays and fishpopulation investigations, the application of additional, morespecific biomarkers (e.g. vitellogenin induction, EROD and micronucleusassay) has been initiated in fish taken from the fieldas well as in situ investigations.
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