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| 2. |
- 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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| 3. |
- Seitz, Nadja, et al.
(författare)
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A novel statistical approach for the evaluation of comet assay data
- 2008
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Ingår i: Mutation Research. - : Elsevier. - 1383-5742 .- 1388-2139. ; 652:1, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- The present study forms part of a weight-of-evidence framework including genotoxicological studies in the upper Danube River basin, which aim at elucidating the reasons for the decline in fish catch. The major focus of this paper is the assessment of genotoxicity of sediments from the Danube River basin by use of the comet assay with RTL-W1 cells and with embryos of zebrafish (Danio rerio). A frequently discussed question in this type of approach is how to aggregate and compare the data obtained from genotoxicity testing. There is a need to develop mathematical method combining the information from dose–response curves and level of effectiveness (maximum genotoxic effect). For comparison and ranking of the genotoxic potential of samples from different locations along the Danube River, several methods based on EC50, Lowest Observed Effect Concentration (LOEC), and maximum induction factor were compared with respect to their validity. An evaluation system termed the “3-step, analysis” was developed to facilitate consideration of a maximum number of aspects of the raw data. The so-called “concentration-dependent induction factor” (CDI) introduces an index for a straightforward, precise and realistic assessment of the genotoxic potential of any kind of field sample or genotoxic agent.
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| 4. |
- 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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| 5. |
- Keiter, Steffen, 1971-, et al.
(författare)
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A fuzzy logic-classification of sediments based on data from in vitro biotests
- 2009
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Ingår i: Journal of Soils and Sediments. - Heidelberg, Germany : Springer. - 1439-0108 .- 1614-7480. ; 9:3, s. 168-179
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Tidskriftsartikel (refereegranskat)abstract
- Background, aim, and scope: Ecotoxicological risk assessment of sediments is usually based on a multitude of data obtained from tests with different endpoints. In the present study, a fuzzy logic-based model was developed in order to reduce the complexity of these data sets and to classify sediments on the basis of results from a battery of in vitro biotests.Materials and methods: The membership functions were adapted to fit the specific sensitivity and variability of each biotest. For this end, data sets were categorized into three toxicity levels using the box plot and empirical methods. The variability of each biotest was determined to calculatethe range of the gradual membership. In addition, the biotests selected were ranked according to the biological organisation level in order to consider the ecological relevance of the endpoints measured by selected over- or underestimation of the toxicity levels. In the next step of the fuzzy logic model, a rule-base was implemented using if...and...then decisions to arrive at a system of five quality classes.Results: The results of the classification of sediments fromthe Rhine and Danube Rivers showed the highest correlation between the biotest results and the fuzzy logical ternative based on the empirical method (i.e. the classification of the data sets into toxicity levels).Discussion: Many different classification systems based on biological test systems are depending on respective datasets; therefore, they are difficult to compare with other locations. Furthermore, they don‘t consider the inherent variability of biotests and the ecological relevance of these test systems as well. In order to create a comprehensive risk assessment for sediments, mathematical models should be used which take uncertainties of biotest systems into account, since they are of particular importance for areliable assessment. In the present investigation, the variability and ecological relevance of biotests were incorporated into a classification system based on fuzzy logic. Furthermore, since data from different sites and investigations were used to create membership functions ofthe fuzzy logic, this classification system has the potential to be independent of locations.Conclusions: In conclusion, the present fuzzy logic classification model provides an opportunity to integrate expert knowledge as well as acute and mechanism-specific effects for the classification of sediments for an ecotoxicological risk assessment.Recommendations and perspectives: In order to achieve amore comprehensive classification, further investigation is needed to incorporate results of chemical analyses and in situ parameters. Furthermore, more discussions are necessary with respect to the relative weight attributed to different ecological and chemical parameters in order too btain a more precise assessment of sediments.
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| 6. |
- Keiter, Steffen, et al.
(författare)
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Activities and identification of aryl hydrocarbon receptor agonists in sediments from the Danube river
- 2008
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Ingår i: Analytical and Bioanalytical Chemistry. - Berlin / Heidelberg : Springer. - 1618-2642 .- 1618-2650. ; 390:8, s. 2009-2019
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Tidskriftsartikel (refereegranskat)abstract
- This study is a consequence of a distinct fish decline in the Danube river since the beginning of the 1990s. In contrast to the decline of fish population, former studies have repeatedly documented that the water quality along the Danube river is improving. However, the conclusion of a pilot study in 2002 was that a high hazard potential is associated with local sediments. The present study documents that sediment samples from the Danube river showed comparatively high aryl hydrocarbon receptor mediated activity in biotests, using the cell lines GPC.2D.Luc, H4IIE (DR-CALUX®) and RTL-W1. The combination of chemical analysis, fractionation techniques and different in vitro tests revealed that priority pollutants could not explain the main induction, even though the concentrations of priority polycyclic aromatic hydrocarbons (PAHs) were very high (maximum in the tributary Schwarzach, sum of 16 EPA PAHs 26 μg/g). In conclusion, this investigation shows that nonpriority pollutants mainly mediate the high induction rates. Nevertheless, owing to the effects of PAHs towards fish and the connection between dioxin-like activity and carcinogenicity, the link between contamination and the fish population decline cannot be ruled out.
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| 7. |
- Wölz, Jan, et al.
(författare)
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Changes in toxicity and Ah receptor agonist activity of suspended particulate matter during flood events at the rivers Neckar and Rhine - a mass balance approach using in vitro methods and chemical analysis
- 2008
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Ingår i: Environmental Science and Pollution Research. - Berlin / Heidelberg : Springer. - 0944-1344 .- 1614-7499. ; 15:7, s. 536-553
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Tidskriftsartikel (refereegranskat)abstract
- Background, aim, and scope As a consequence of flood events, runoff and remobilized sediments may cause an increase of ecotoxicologically relevant effects from contaminant reservoirs. Aquatic and terrestrial organisms as well as cattle and areas of settlement are exposed to dislocated contaminants during and after flood events. In this study, the impacts of two flood events triggered by intense rain at the rivers Neckar and Rhine (Southern Germany) were studied. Effects in correlation to flood flow were assessed at the river Neckar using samples collected at frequent intervals. River Rhine suspended particulate matter (SPM) was sampled over a longer period at normal flow and during a flood event. Three cell lines (H4L1.1c4, GPC.2D.Luc, RTL-W1) were used to compare Ah receptor agonist activity in different biotest systems. Multilayer fractionation was performed to identify causative compounds, focusing on persistent organic contaminants. Materials and methods Native water and SPM of flood events were collected at the river Neckar and at the monitoring station (Rheinguetestation, Worms, Germany) of the river Rhine. Water samples were XAD-extracted. SPM were freeze-dried and Soxhlet-extracted using acetone and finally dissolved in dimethyl sulfoxide. Resulting crude extracts were analyzed for cytotoxicity with the neutral red assay. Aryl hydrocarbon receptor (AhR) agonist activity was measured in a set of biological test systems (DR-CALUX, GPC.2D, and ethoxyresorufin-O-deethylase (EROD) assay) and different cell lines. In addition, crude extracts were fractionated using a combined method of multilayer (sequence of acidified silica layers) and carbon fractionation. Fractions from the multilayer fractionation contained persistent organic compounds (polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and some polycyclic aromatic hydrocarbon (PAHs)); fractions from the carbon fractionation were separated into a PCDD/F and a PCB fraction. Dioxin-like activity of multilayer and carbon fractions was determined in the EROD assay and expressed as biological toxicity equivalency concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (bio-TEQs). The calculation of chemical equivalency concentrations (chem-TEQs) and comparison to bio-TEQ values allowed the determination of the contribution of the analyzed persistent compounds to the total biological effects measured. Results Soluble compounds in native and extracted water samples resulted in no or minor activity in the toxicity tests, respectively. Filter residues of native water caused increased AhR-mediated activity at the peak of the flood. Activities of SPM of the river Neckar correlated well with the flow rate indicating a flood-dependent increase of toxicity culminating at the peak of flow. River Rhine SPM showed a decrease of activity regarding an SPM sample of the flood event compared to a long-term sample. Excellent correlations with AhR agonistic activity were determined for DR-CALUX and EROD assay, while the GPC.2D assay did not correlate with both other biotests. The activity of persistent dioxin-like acting compounds in multilayer and carbon fractionated PCDD/F and PCB fractions was low if compared to corresponding crude extracts. The congener pattern of PCDD/F revealed that the contaminations mainly originated from products and productions of the chlorine and organochlorine industries. Discussion Native and extracted water samples could be shown to contain little or no cytotoxic or AhR agonistic compounds. In contrast, particle-bound compounds were shown to be the relevant effect-causing fraction, as indicated by the activities of filter residues of native water and SPM. Compounds other than fractionated persistent PCBs and PCDD/Fs were more relevant to explain AhR-mediated activities of crude flood SPM at both rivers assessed. Biologically detected activities could at least in part be traced back to chemically analyzed and quantified compounds. Conclusions The calculation of the portion of persistent PCBs and PCDD/Fs in multilayer fractions causing the high inductions in the EROD assay in combination with chemical analysis provides a suitable tool to assess dioxin-like activity of persistent compounds in SPM sampled over the course of flood events. Depending on the catchment area and annual course of flood events, end points may either indicate an increase or a decrease of activity. In order to determine the ecological hazard potential of mobilized contaminants during flood events, the focus should be set on particle-bound pollutants. Furthermore, PCDD/Fs and PCBs, commonly expected to be the most relevant pollutants in river systems, could be shown to contribute only to a minor portion of the overall AhR-mediated activity. However, they might be most relevant for human exposure when considering persistence and bioaccumulation–biomagnification in the food chain. Recommendations and perspectives As a consequence of climate change, flood events will increase in frequency and intensity at least in some regions such as Central Europe. Thus, it is crucial to identify the potential hazard of (re-)mobilized contaminants from reservoirs dislocated via floods and threatening especially aquatic organisms and cattle grazing in flood plains. Since other less persistent compounds seem to be more relevant to explain AhR-mediated activities in flood SPM, nonconventional PAHs and more polar compounds also need to be considered for risk assessment. Effect-directed analysis using broad-range fractionation methods taking into account compounds from polar to nonpolar should be applied for identification of pollutants causing biological effects, thus integrating biological and chemical parameters.
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