Standardized experimental approaches for the quantification of the bioaccumulation potential of nanomaterials in general and in (benthic) invertebrates in particular are currently lacking. We examined the suitability of the benthic freshwater amphipod Hyalella azteca for the examination of the bioaccumulation potential of nanomaterials. A flow-through test system that allows the generation of bioconcentration and biomagnification factors was applied. The feasibility of the system was confirmed in a 2-lab comparison study. By carrying out bioconcentration and biomagnification studies with gold, titanium dioxide and silver nanoparticles as well as dissolved silver (AgNO3) we were able to assess the bioaccumulation potential of different types of nanomaterials and their exposure pathways. For this, the animals were examined for their total metal body burden using inductively coupled mass spectroscopy (ICP-MS) and for the presence of nanoparticulate burdens using single-particle ICP-MS. The role of released ions was highlighted as being very important for the bioavailability and bioaccumulation of metals from nanoparticles for both examined uptake paths examined (bioconcentration and biomagnification). In 2018 a tiered testing strategy for engineered nanomaterials was proposed by Handy et al. that may allow a waiver of bioaccumulation fish studies using inter alia invertebrates. Data gained in studies carried out with invertebrates like the developed Hyalella azteca test may be included in this proposed tiered testing strategy. © 2020 The Author(s)
Next to properties like persistence and ecotoxicity, the determination of chemical substances to bioaccumulate in organisms is essential to understand potential harmful interactions with the environment. Existing methods to determine bioaccumulation are mainly addressing soluble organic chemicals. If these methods are also applicable to investigate bioaccumulation of nanomaterials remains an open issue. Once released to surface waters, nanomaterials tend to agglomerate and sediment in dependence of their individual properties and the properties of the surrounding media. Thus, it has to be anticipated, that benthic and filtering organisms are most likely exposed by nanomaterials. Therefore, the ability of nanomaterials to bioaccumulate in these organisms is important in view of a comprehensive evaluation of potential environmental risks. In this project a method was developed which allows to investigate the bioaccumulation of nanomaterials in freshwater mussels. A new test system was established and necessary adaptions regarding inter alia test performance and analytics of nanomaterials in biota and aquatic media were carried out. The new method was examined using selected nanomaterials of different chemical nature and collected data were critically discussed in view of their regulatory applicability. Veröffentlicht in Texte | 18/2020.
Immer größer werdende Mengen an synthetischen Nanomaterialien (MNMs) werden für den industriellen Einsatz produziert und können während der Produktion, dem Einsatz der Produkte, sowie bei deren Entsorgung in die Umwelt gelangen. MNM mit hohen Produktionsvolumina unterliegen einer Bioakkumulationsbewertung im Rahmen der EU REACH Verordnung, um potentielle Umweltbelastungen abschätzen zu können. Die hierbei für die Chemikalienbewertung klassischerweise verwendeten Methoden, etwa Durchflussstudien mit Fischen gemäß OECD TG 305, sind für das Testen von MNMs in aquatischen Medien jedoch nur bedingt geeignet. So neigen die meisten MNMs dazu in aquatischen System nur metastabile Suspensionen zu bilden und direkt nach dem Eintreten in das Medium oder im zeitlichen Verlauf zu sedimentieren. Eine konstante homogene Exposition im Testsystem wird somit stark erschwert. Für Corbicula fluminea, eine weit verbreitete Süßwassermuschel, wurde bereits in früheren Studien gezeigt, dass sie MNMs aus der Wasserphase durch Filtration aufnehmen kann. Im Rahmen dieses Projekts wurde die Eignung von C. fluminea für Bioakkumulationsstudien mit MNMs geprüft. Hierzu wurde ein neues Durchflusssystem entwickelt, welches eine konstante und homogene Exposition von MNMs ermöglicht. Zur Überprüfung wurden synthetische Nanomaterialien gewählt, welche jeweils MNMs mit bestimmten Eigenschaften repräsentieren. Das Silbernanopartikel NM 300K (AgNP) wurde als Repräsentant der Gruppe der gut dispergierbaren und ionenfreisetzenden MNMs getestet und mit AgNO3 als nicht nanopartikuläre Form desselben Elements verglichen. NM 105, ein Titandioxid NP, wurde für die Gruppe der nicht ionenfreisetzenden MNMs getestet. Für die Gruppe der MNMs, welche auf organischen Polymeren basieren, wurde das Polystyrol NP Fluoro-MaxTM getestet, welches mit einem Fluoreszenzfarbstoff markiert war. Somit konnte die Aufnahme und Verteilung des NPs im Weichkörper der Muscheln u.a. mittels Fluoreszenzmikroskop untersucht werden. Für die Ag und TiO2 Behandlungen konnten nach Messung der Gewebekonzentrationen BAF bzw. BCF Werte im Konzentrationsgleichgewicht ermittelt werden. BAFss Werte von 31 und 128 für die beiden NM 300K Konzentrationen (0.624 und 6.177 'Mikrogramm'Ag/L) und 6,150 und 9,022 für die beiden NM 105 Konzentrationen (0.099 und 0.589 'Mikrogram'TiO2/L) zeigten, dass BAFss Werte für die untersuchten MNMs abhängig von der jeweiligen Expositionskonzentration sind. Für die AgNO3 Behandlung wurden ebenso konzentrationsabhängige BCFss Werte von 31 und 711 für die höhere und niedrigere Konzentrationen ermittelt. Die Kinetik der gemessenen Partikelkonzentrationen in den Muschelgeweben (sp-ICP-MS) wie auch die ermittelten Distributionsfaktoren für einzelne Kompartimente lieferten Hinweise, dass die untersuchten MNMs zwar aufgenommen, aber nicht inkorporiert wurden. Quelle: Forschungsbericht
Detection of manufactured nanomaterials (NM) still features enormous challenges for environmental exposure assessment and management of NM. The expert opinion presents a comprehensive survey on existing experimental approaches to detect NM in the environment and analyses to what extent these approaches could be utilized and advanced to be used routinely for data collection to assess and manage environmental exposure. Recommendations for actions on a short and long term basis are deduced for the establishment of standardized protocols for sampling, sample preparation and analysis which can now be used to prioritize further action in improving measurement techniques of NM in the environment. Veröffentlicht in Texte | 133/2019.
Increasing amounts of manufactured nanomaterials (MNMs) are produced for their industrial use and released to the environment by the usage or disposal of the products. As depending on their annual production rate, substances are subjected to PBT assessment, the availability of reliable methods to evaluate these endpoints for (corresponding) nanoforms/MNMs becomes relevant. The classical method to elucidate the bioaccumulation potential of chemicals has been the flow-through study with fish, which has limitations as regards meeting the requirements of MNMs. Most MNMs tend to sediment in the aquatic environment. Thus, maintenance of stable exposure conditions for bioaccumulation testing with fish is nearly impossible to achieve when using MNMs. Corbicula fluminea, a freshwater filter-feeding bivalve distributed worldwide, has been previously shown to ingest and accumulate MNMs present in the water phase. To investigate the suitability of C. fluminea for bioaccumulation testing we developed a new flow-through system to expose mussels under constant exposure conditions. Two nanoparticles (NPs), the AgNP NM 300K and the TiO2NP NM 105, were applied. In addition, C. fluminea was exposed to AgNO3 as a source of dissolved Ag+ to compare the bioaccumulation of Ag in dissolved and nanoparticulate forms. For each MNM exposure scenario we were able to determine steady-state bioaccumulation factors. BAFss values of 31 and 128 for two NM 300K concentrations (0.624 and 6.177 (my)g Ag per L) and 6150 and 9022 for TiO2 (0.099 and 0.589 (my)g TiO2 per L) showed the exposure dependence of the BAFss estimates. The progression of metal uptake and elimination in the soft tissue provided clear indications that the uptake and thus accumulation is mainly driven by the uptake of NPs and less of dissolved ions. © The Royal Society of Chemistry
Given the numerous manufactured nanomaterials already on the market and expected in future, the effort for the individual investigation of hazard and risk would be enormous. To overcome this challenge, grouping of nanomaterials has been identified as one critical issue by the European Commission as well as the Organisation for Economic Co-operation and Development (OECD). In that context, several research projects have been carried out to deliver scientific input and develop approaches. This publication discusses experiences from several cases of two scientific projects with the aims to develop and review analogy hypotheses for grouping of different nanoforms of same substances for endpoints related to aquatic ecotoxicity from a regulatory point of view. Furthermore, by presenting examples of grouping attempts, it outlines the need for considerations of further aspects beside key physicalâ€Ìchemical parameters for grouping nanomaterials regarding environmental endpoints. The results substantiate previous educated guesses with strategically collected experimental data on issues that needs to be considered for grouping nanomaterials in regulatory context. Still, grouping of nanomaterials for the aim of joint assessment of ecotoxicity of nanoforms in a regulatory context is in its infants compared to grouping approaches of nanoforms for human health assessment. This publication features important aspects on possibilities and challenges of grouping nanomaterials for environmental hazard assessment. Quelle: https://enveurope.springeropen.com
Derzeit befindet sich eine Vielzahl von Produkten auf dem Markt, die so genannte synthetische Nanomaterialien enthalten. In den kommenden Jahren ist mit einem weiteren Anstieg zu rechnen, wodurch auch vermehrt Abfälle mit einem erhöhten Anteil an Nanomaterialien anfallen werden. Allerdings ist der Kenntnisstand über den Verbleib von nanomaterialhaltigen Abfällen in der Entsorgungsphase gering. Dies wurde zum Anlass genommen, um innerhalb des Projektes die Emissionspfade bei der thermischen Abfallbehandlung eingehend zu untersuchen. Veröffentlicht in Texte | 37/2016.
The Sponsorship Programme is the central testing programme of the OECD Working Party on Manufactured Nanomaterials (WPMN) launched in 2007. It was called into being to create the conditions for a coordinated approach between the member countries with regard to the safety of manufactured nanomaterials. The WPMN brings together 30 member countries of the OECD and the EU Commission. Some non-member countries are also represented, as are organisations from industry and from standardisation and environmental associations. The idea behind the OECD Sponsorship Programme was to collate data on selected and precisely described manufactured nanomaterials. The intention was thereby to obtain information on their physicochemical properties, behaviour and effects on humans and the environment, and to demonstrate the relationships between them. In this process Germany joined forces with France as joint “Lead Sponsors” for nTiO2. This report summarizes the results of the Sponsorship Programme on ecotoxicology and environmental behavior of nanoscale titanium dioxide of the OECD Working Party on Manufactured Nanomaterials (WPMN). Veröffentlicht in Texte | 69/2016.
Das Sponsorship Programm ist das zentrale Testprogramm der 2007 gegründeten OECD Working Party on Manufactured Nanomaterials (WPMN). Diese wurde ins Leben gerufen, um einen zwischen den Mitgliedsstaaten koordinierten Ansatz zu Sicherheitsfragen (z.B. die Anwendbarkeit von OECD Prüfrichtlinien) für technisch hergestellte Nanomaterialien zu ermöglichen. An der WPMN sind neben 30 OECD-Mitgliedsstaaten auch die Europäische Kommission, BIAC und verschiedene andere Nichtregierungsorganisationen beteiligt. Die Idee des OECD Sponsorship Programms war es, Daten zu ausgewählten und präzise beschriebenen, technisch hergestellten Nanomaterialien zusammen zu tragen. Auf diese Weise erhielt man Informationen zu physikalisch-chemischen Eigenschaften und Verhalten und Effekten auf Mensch und Umwelt. Deutschland war in diesem Prozess zusammen mit Frankreich hauptverantwortlich für die Datenerhebung zu nanoskaligem Titandioxid. Dieser Bericht stellt die Ergebnisse des Sponsorship Programms zur Ökotoxikologie und zum Umweltverhalten von nanoskaligem Titandioxid der OECD WPMN zusammen. Veröffentlicht in Texte | 45/2016.
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
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