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- Keiter, Susanne, et al.
(author)
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Does perfluorooctane sulfonate (PFOS) act as chemosensitizer in zebrafish embryos?
- 2016
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In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 548-549, s. 317-324
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Journal article (peer-reviewed)abstract
- Earlier studies have shown that perfluorooctane sulfonate (PFOS) increases the toxicity of other chemicals by enhancing their uptake by cells and tissues. The present study aimed at testing whether the underlying mechanism of enhanced uptake of chemicals by zebrafish (Danio rerio) embryos in the presence of PFOS is by interference of this compound with the cellular efflux transporter Abcb4. Modifications of uptake/clearance and toxicity of two Abcb4 substrates, the fluorescent dye rhodamine B (RhB) and vinblastine, by PFOS were evaluated using 24 and 48. h post-fertilization (hpf) embryos. Upon 90. min exposure of 24. hpf embryos to 1. μM RhB and different PFOS concentrations (3-300. μM) accumulation of RhB in zebrafish was increased by up to 11.9-fold compared to controls, whereas RhB increases in verapamil treatments were 1.7-fold. Co-administration of PFOS and vinblastine in exposures from 0 to 48. hpf resulted in higher vinblastine-caused mortalities in zebrafish embryos indicating increased uptake of this compound. Interference of PFOS with zebrafish Abcb4 activity was further studied using recombinant protein obtained with the baculovirus expression system. PFOS lead to a concentration-dependent decrease of the verapamil-stimulated Abcb4 ATPase activity; at higher PFOS concentrations (250, 500. μM), also the basal ATPase activity was lowered indicating PFOS to be an Abcb4 inhibitor. In exposures of 48. hpf embryos to a very high RhB concentration (200. μM), accumulation of RhB in embryo tissue and adsorption to the chorion were increased in the presence of 50 or 100. μM PFOS. In conclusion, the results indicate that PFOS acts as inhibitor of zebrafish Abcb4; however, the exceptionally large PFOS-caused effect amplitude of RhB accumulation in the 1. μM RhB experiments and the clear PFOS effects in the experiments with 200. μM RhB suggest that an additional mechanism appears to be responsible for the potential of PFOS to enhance uptake of Abcb4 substrates.
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| 2. |
- Dulio, Valeria, et al.
(author)
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The NORMAN Association and the European Partnership for Chemicals Risk Assessment (PARC) : let’s cooperate!
- 2020
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In: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 32:1
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Journal article (peer-reviewed)abstract
- The Partnership for Chemicals Risk Assessment (PARC) is currently under development as a joint research and innovation programme to strengthen the scientific basis for chemical risk assessment in the EU. The plan is to bring chemical risk assessors and managers together with scientists to accelerate method development and the production of necessary data and knowledge, and to facilitate the transition to next-generation evidence-based risk assessment, a non-toxic environment and the European Green Deal. The NORMAN Network is an independent, well-established and competent network of more than 80 organisations in the field of emerging substances and has enormous potential to contribute to the implementation of the PARC partnership. NORMAN stands ready to provide expert advice to PARC, drawing on its long experience in the development, harmonisation and testing of advanced tools in relation to chemicals of emerging concern and in support of a European Early Warning System to unravel the risks of contaminants of emerging concern (CECs) and close the gap between research and innovation and regulatory processes. In this commentary we highlight the tools developed by NORMAN that we consider most relevant to supporting the PARC initiative: (i) joint data space and cutting-edge research tools for risk assessment of contaminants of emerging concern; (ii) collaborative European framework to improve data quality and comparability; (iii) advanced data analysis tools for a European early warning system and (iv) support to national and European chemical risk assessment thanks to harnessing, combining and sharing evidence and expertise on CECs. By combining the extensive knowledge and experience of the NORMAN network with the financial and policy-related strengths of the PARC initiative, a large step towards the goal of a non-toxic environment can be taken.
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| 3. |
- Hollert, Henner, et al.
(author)
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Wasserrahmenrichtlinie : Fortschritte und Defizite
- 2007
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In: Umweltwissenschaften und Schadstoff-Forschung. - : Springer. - 0934-3504 .- 1865-5084. ; 19:1 Suppl., s. 58-70
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Journal article (peer-reviewed)abstract
- Background: The water protection policy of the European Union sits on new footings since the end of 2000: The Water FrameworkDirective (WFD). By replacing, merging and renewing all parts of the European water protection policy from the 1970s, the WFD provides a consistent, transparent and comprehensive concept of what water management should be in the Europe of the coming decades. The new directive is aimed at a holistic approach towards integrated water protection. It sets ambitious high-quality goals to achieve a good status for European lakes and rivers primarily in ecological terms, gives details about the essential processes as well as instruments, and includes everything into a strict time schedule.Aim: This article adresses progress and shortcomings at the implementation of the WFD in general and with reference to two selected case studies (Rivers Elbe and Upper Danube).Results and Discussion: After introducing the WFD, its aims and exceptions, a policy summary and background document ‘Environmental objectives und the Water Framework Directive’ and the use of Environmental Quality Standards (EQS) for single ‘priority substances’ as well as ‘hazardous priority components’ is discussed. The initial characterization undertaken by the German states revealed that only about 14% of all surface waters are considered to meet the WFD objectives by the year of 2015. Approximately 60% of the water bodies assessed are at risk of failing the WFD objectives, if not systematic efforts are made to improve the quality. Screenings of sources and paths of exposure for ‘priority substances’ and ‘priority hazardous substances’ according WFD identified one distinct pollution source for surface waters: ‘Historical pollution from sediments’. Because of industrial emissions in the past several river catchment areas are expected to fail the standards demanded by the WFD, due to a risk of remobilization of contaminants from sediments. This holds true for the Rhine river with high loads of hexachlorobenzene (HCB) as well as for Elbe river, where contaminated sediments can be a severe problem. Therefore, integration of sediments into the holistic river basin management approach and their consideration within the ‘programmes of measures’ scheduled for 2009 is highly recommended. At present, a comprehensive weight-of-evidence study verifies whether the observed fish decline at the Upper Danube. River is caused by ecotoxicological hazard potentials of contaminated sediments.Outlook: Combined investigations of sediment contamination and mobility as well as acute and mechanism specific biotests in effect directed analyses/weight-of-evidence studies show grent potential for the assessment of chemically polluted rivers and should be included into the ‘programmes of measures’ within future management concepts.
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| 4. |
- Jernbro, Susanne, et al.
(author)
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Perfluorooctane Sulfonate Increases the Genotoxicity of Cyclophosphamide in the Micronucleus Assay with V79 Cells : Further Proof of Alterations in Cell Membrane Properties Caused by PFOS
- 2007
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In: Environmental Science and Pollution Research. - : Ecomed. - 0944-1344 .- 1614-7499. ; 14:2, s. 85-87
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Journal article (peer-reviewed)abstract
- Perfluorooctane sulfonate (PFOS; C8F17SO3–) is a fully fluorinated organic compound which has been manufactured for decades and was used widely in industrial and commercial products. The recent toxicological knowledge of PFOS mainly concerns mono-substance exposures of PFOS to biological systems, leaving the potential interactive effects of PFOS with other compounds as an area where understanding is significantly lacking. However, a recent study, reported the potential of PFOS to enhance the toxicity of two compounds by increasing cell membrane permeability. This is of particular concern since PFOS has been reported to be widely distributed in the environment where contaminants are known to occur in complex mixtures. In this study, PFOS was evaluated alone and in combination with cyclophosphamide (CPP) to investigate whether a presence of PFOS leads to an increased genotoxic potential of CPP towards hamster lung V79 cells. Genotoxicity was investigated using the micronucleus(MN) assay according to the recent draft ISO/DIS 21427-2 method. PFOS alone demonstrated no genotoxicity up to a concentration of 12.5 μg/ml. However, PFOS combined with two different concentrations of CPP, with metabolic activation, caused a significant increase in the number of micronucleated cells compared to treatments with CPP alone. These results provide a first indication that PFOS has the potential to enhance the genotoxic action of CPP towards V79 cells, suggesting, together with the alterations in cell membrane properties shown previously, that genotoxicity of complex mixtures may be increased significantly by changes in chemical uptake. Together with an earlier study performed by the own working group, it can be concluded that PFOS alone is not genotoxic in this bioassay using V79 cells up to 12.5 μg/ml, but that further investigations are needed to assess the potential interaction between PFOS and other substances, in particular regarding the impact of membrane alterations on the uptake of toxic substances.
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| 5. |
- Keiter, Steffen, 1971-, et al.
(author)
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A fuzzy logic-classification of sediments based on data from in vitro biotests
- 2009
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In: Journal of Soils and Sediments. - Heidelberg, Germany : Springer. - 1439-0108 .- 1614-7480. ; 9:3, s. 168-179
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Journal article (peer-reviewed)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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