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- 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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| 2. |
- Klee, Nina, et al.
(författare)
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Changes in toxicity and genotoxicity of industrial sewage sludge samples containing nitro- and amino-aromatic compounds following treatment in bioreactors with different oxygen regimes
- 2004
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Ingår i: Environmental Science and Pollution Research. - 0944-1344 .- 1614-7499. ; 11:5, s. 313-320
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Tidskriftsartikel (refereegranskat)abstract
- GOALS, SCOPE AND BACKGROUND: From 2005, deposition of organic waste will be banned in Sweden. Likewise, in Germany and Austria, similar bans are being planned, and further countries will probably follow. Thus, there is a need to develop new methods and to refine established techniques for sludge management in the whole of the European Union. For this end, there is also an urgent need for appropriate ecotoxicological approaches to elucidate and assess the hazard potential of sewage sludge. Therefore, the present study was designed to assess the capacity of various established sludge treatment methods using different oxygen regimes to degrade recalcitrant nitro-substituted organic compounds and reduce their toxicity. Sewage sludge samples from a wastewater treatment plant in Sweden (Cambrex Karlskoga AB, industrial area Björkborn) receiving wastewater from industries manufacturing pharmaceutical substances, chemical intermediates and explosives were processed with different sludge treatment methods. Among other treatment methods, bioreactors (for anaerobic and aerobic sludge treatment) were used. In the present investigation, a battery of in vitro bioassays was employed to compare the cytotoxic and genotoxic potentials of different fractions of sludge samples in order to elucidate whether the treatments were suitable to reduce the toxicity of the sludge. METHODS: In order to investigate the cytotoxicity of the extracts of treated and untreated sludge samples, the acute cytotoxicity test with the permanent cell line RTL-W1 was used. Genotoxicity was tested by means of the comet assay (single cell gel electrophoresis) with RTL-W1 cells, and mutagenicity was assessed with the Ames test using the Salmonella typhimurium strains TA98, TA98NR and TA100. Sludge toxicity was tested in different fractions of organic extracts produced by acetone and hexane extractions. The subsequent clean-up procedure (silica gel chromatography and elution with hexane and dichloromethane) resulted in two fractions, a lipophilic hexane-fraction and a semi-lipophilic dichloromethane-fraction. For the genotoxicity and mutagenicity tests, these fractions were reunited at equal ratios. RESULTS AND DISCUSSION: The acute cytotoxicity test with RTL-W1 cells revealed a high cytotoxic potential for the semi-lipophilic DM-fractions of all sludge samples with NR50 values (= effective concentration for 50% cell death in the neutral red test) from 8.9 up to 20 mg sludge d.w./ml medium. A low cytotoxic potential for the hexane fractions of the untreated sludge samples (NR50 400 to > 400 mg sludge d.w./ml medium) was observed, whereas the hexane fractions of the treated sludge samples showed elevated cytotoxicity increasing further with treatment in the bioreactors. The comet assay indicated that three out of eight of the reunited fractions had a significant genotoxic potential. Whereas the genotoxic potential of one sample treated anaerobically was very high with an induction factor of 11.6, a similar sample (taken from the same anaerobic reactor four months later) and one untreated sample showed lower potentials. The samples treated in another anaerobic bioreactor as well as the samples treated aerobically showed no genotoxic potential. Results indicate that aerobic treatment was basically adequate for reducing the genotoxicity of the sludge, whereas anaerobic treatment was only partly useful for reduction of genotoxicity. The Ames test revealed a very high mutagenic potential for the reunited fractions of the untreated sludge samples with strain TA98 (maximum induction factors (IFmax) up to 45) and a relatively high potential for one of the samples treated aerobically (S2, IFmax = 18 (TA98, S9-)), thus documenting the suitability of both anaerobic and aerobic treatments to reduce the mutagenicity of the samples, however, with the aerobic treatment being less effective. CONCLUSIONS: Overall, none of the microbiological treatments for wastewater sludge in bioreactors was found to be ideal for general toxicity reduction of the sludge samples. Whereas cytotoxicity of the sludge increased or levelled off in most cases following either treatment, genotoxicity both increased or decreased after anaerobic treatment, depending on the specific sample. However, mutagenicity could generally be reduced by anaerobic treatment and, to a lesser degree, by aerobic treatment. RECOMMENDATIONS AND PERSPECTIVES: The complex modification of the diverse damage potentials of sludge sample extracts by use of an in vitro biotest battery following treatment for toxicity reduction in bioreactors showed that considerations of different toxicological endpoints is essential for an adequate hazard assessment. Whereas in the case of cytotoxicity reduction, the reactors proved ineffective, mutagenicity could be reduced significantly at least in some cases in this case study.
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