Auflistung nach Autor:in "Zalm, Esther van der"

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Closing gaps for environmental risk screening of engineered nanomaterials
(2019) Kühnel, Dana; Hellack, Bryan; Nickel, Carmen; Kussatz, Carola; Zalm, Esther van der; Zalm, Esther van der
Engineered nanomaterials (ENM) have a widespread presence in human life and are components of many products and applications. This warrants an easy and fast evaluation of potential environmental risks. However, so far this is hampered by the multitude of different nanomaterials on the markets in addition to the many variations in form, size and surface modifications. Testing of each variation of ENM is not manageable, and hence the development and application of fast risk screening tools for ENMs is discussed. Here, we present the development of a scoring scheme with regard to ENM environmental risks under consideration of the two compartments water and soil. It allows for the ranking of ENM according to their environmental fate and hazard by taking into account criteria that are meaningful and relevant for ENM. The selection of the criteria is based on conceptual considerations, existing knowledge, and experimental work including transport and transformation studies as well as aquatic and terrestrial toxicity tests. The allocation of the ENM to the scores informs on the potential for transport and transformation and the hazard potential. Fate and hazard scores are subsequently combined into one risk score (1â€Ì10 for aquatic compartment, 1â€Ì7 for terrestrial compartment). The risk score has the intention to indicate which ENM may need prioritization for further action, i.e. with regard to the degree of detail for further testing or modelling. The applicability and consistency of the scoring schemes were assessed by taking different chemical species (e.g. of Ag, TiO2, SiO2, Cu, Fe) of ENM in various modifications (e.g. different shapes and coatings) into account. In conclusion, the established scoring schemes were found to be applicable to rank ENM according to their environmental fate and hazard potential, and thus to their environmental risk potential. © 2019 The Authors. Published by Elsevier B.V.
Das BMBF Projekt nanoGRAVUR - Gruppierung von Nanomaterialien
(2019) Zalm, Esther van der; Schwirn, Kathrin
Grouping of nanomaterials regarding their ecotoxicity
(2017) Kühnel, Dana; Zalm, Esther van der; Kussatz, Carola; Schwirn, Kathrin; Hund-Rinke, Kerstin
Given the numerous manufactured nanomaterials (NM) already on the market and expected in future, the effort for the individual investigation and assessment would be enormous. Therefore, it is necessary to develop approaches that allow an adequate hazard assessment of NM while avoiding individual testing of a large number of the different forms. Approaches to meet data requirements in deviation from performing standard test requirements are already established for chemical substances. One of these is the grouping and read-across/analogue approach. In comparison to soluble organic substances, nanomaterials of the same chemical substance differ in their physicochemical parameters (e.g. surface chemistry, size, shape) and can potentially differ in their hazard profiles. But also fate related physicochemical properties which are influenced by surrounding conditions, like dispersion stability or dissolution rate, influence bioavailability and effects of NM. Annotation of NM to specific hazard groups or read-across based on their physical-chemical (PC) properties will be a great advantage to reduce the amount of testing necessary for an adequate risk assessment. To identify PC properties which are relevant predictors for ecotoxicity, a literature research was performed. It was found that sparsely or non-soluble, and ion-releasing NM need to be considered differently. We have found that ecotoxicity correlates with more than one PC characteristic. Based on this finding the tool ECOTOX BOND was developed. ECOTOX BOND was tested for robustness with experimental data on eight NM in 23 modifications. The predicted and measured ecotoxicity of the NM tested mostly fit, but the ecotoxicity of green algae for TiO2, CeO2 and Fe2O3 is higher than predicted. This effect could be caused by shading and is investigated in more detail. Quelle: Poster abstacts
Grouping of nanomaterials regarding their ecotoxicity - are hypotheses based on literature data robust enough?
(2017) Kühnel, Dana; Zalm, Esther van der; Kussatz, Carola; Schwirn, Kathrin; Hund-Rinke, Kerstin
Nanomaterials (NM) offer a great innovation potential and are assumed to be beneficial to mankind and the environment by e.g. reducing material usage and energy consumption. However, the large variety of synthetic nanomaterials represents a major challenge for scientists and regulators in terms of measuring and assessing the potential hazard caused by the materials and the products over the whole life-cycle. Currently, the assessment of potential hazards posed by NM towards environmental organisms is assessed on a case-by-case basis, which is considered as not practicable to be performed for the many different variations of NM, which involve differences in composition, size, shape, crystalline structure and surface modifications. In order to overcome the need for extensive testing grouping and read across approaches for NM are discussed, enabling risk assessors to predict the hazard of an NM based on existing knowledge on similar NMs. This requires the identification of relationships between nanomaterials̷ physicochemical properties and their ecotoxicological behavior. To gain knowledge on this relationship, we performed an extensive literature research taking into account ecotoxicological studies either involving several organisms and / or several modifications of the same type of NM. This allowed us to reveal parameters crucial for the emergence of specific ecotoxicological effects. The set of parameters identified as relevant included the surface properties (charge, zeta potential, surface modifications), the size and shape of a NM, and the release of ions. Based on these findings, a test set of NM, involving in most cases several subtypes of a given NM was compiled, which underwent testing in the ecotoxicological relevant aquatic (algae, daphnia and zebrafish embryo) and terrestrial organisms (earth worm, microorganisms). Subsequently, the initial grouping hypotheses were compared to the actual results obtained in the tests in order to verify or falsify initial grouping hypotheses. Even though several predictions could not be confirmed, a first evaluation of results shows that inert and ion-releasing NM needs to be considered differently. Acknowledgement - Funding of the project nanoGRAVUR by the German Federal Ministry of Education and Research (BMBF), Grant No. 03XP0002 is acknowledged. Quelle: http://www.ime.fraunhofer.de/
Grouping/ranking of nanomaterials regarding environmental risk
(2017) Hund-Rinke, Kerstin; Nickel, Carmen; Kühnel, Dana; Zalm, Esther van der
Grouping/Read Across approaches to reduce the testing of nanomaterials regarding their environmental hazard
(2017) Kühnel, Dana; Kussatz, Carola; Zalm, Esther van der; Schwirn, Kathrin; Völker, Doris; Hund-Rinke, Kerstin
Nanomaterials (NM) offer a great innovation potential and are assumed to be beneficial to mankind and the environment by e.g. reducing material usage and energy consumption. However, the large variety of synthetic nanomaterials represents a major challenge for scientists and regulators in terms of measuring and assessing the potential hazard caused by the materials and the products over the whole life-cycle. Currently, the assessment of potential hazards posed by NM towards environmental organisms is performed on a case-by-case basis, which is considered as not practicable for the many different variations of NM, which involve differences in composition, size, shape, crystalline structure and surface modifications. In order to overcome the need for extensive testing, grouping and read across approaches for NM are considered helpful. The prediction of NM hazard based on existing knowledge requires the identification of relationships between nanomaterials̷ physicochemical properties and their ecotoxicological behavior. To gain knowledge on this relationship, we used several approaches involving extensive literature research, the formulation of grouping hypotheses based on physical-chemical parameters, as well as systematic toxicity testing. For the latter purpose, a test set of NM was compiled, involving in most cases several subtypes of a given nanoscaled substance, which differed in the parameter considered as driver for a specific effect. The NM test set underwent testing in the ecotoxicological relevant aquatic (algae, daphnia and zebrafish embryo) and terrestrial organisms (earth worm, microorganisms). All organism tests were conducted according to OECD guidelines under consideration of NM-specific modifications. The NM selected for testing were extensively characterized regarding their properties and their behavior in the respective ecotoxicological test media. The talk will provide an overview on the most crucial results obtained so far. Basically it became obvious that an identification of groups consisting of NM with comparable ecotoxicity based on literature data is of limited value, because of fragmented reporting on nanomaterials̷ physical-chemical properties, the application of different methods to characterize the NM as well as a high variability in the applied test procedures. Further, as the systematic testing showed, there are no mono-causal relationships between one physical-chemical parameter and an ecotoxic effect. Our current proposal for a qualitative grouping scheme therefore considers various parameters. The reliability of the grouping scheme was tested by applying it to a further data set not used for the development of the scheme. It became obvious that not all NM exerting a comparable ecotoxicity grouped into the same group and accordingly, further parameters beyond the ones already considered in the grouping scheme need to be taken into account. Hence, in order to facilitate grouping with focus on environmental effects, further steps need to be taken. Quelle: Platform presentations - Abstracts
Nanostrukturierte Materialien - Gruppierung hinsichtlich Arbeits-, Verbraucher- und Umweltschutz und Risikominimierung (nanoGRAVUR)
(2019) Zalm, Esther van der; Völker, Doris; Schwirn, Kathrin; Zalm, Esther van der ; Deutschland. Umweltbundesamt
Überprüfung von Gruppierungshypothesen zur ökotoxikologischen Wirkung von NM
(2017) Hund-Rinke, Kerstin; Zalm, Esther van der; Schwirn, Kathrin; Kussatz, Carola; Kühnel, D.