Engineered nanomaterials (ENMs) are intentionally designed in different nano-forms of the same parent material in order to meet application requirements. Different grouping and read-across concepts are proposed to streamline risk assessments by pooling nano-forms in one category. Environmental grouping concepts still are in their infancy and mainly focus on grouping by hazard categories. Complete risk assessments require data on environmental release and exposure not only for ENMs but also for their nano-forms. The key requirement is to identify and to distinguish the production volumes of the ENMs regarding nano-form-specific applications. The aim of our work was to evaluate whether such a grouping is possible with the available data and which influence it has on the environmental risk assessment of ENMs. A functionality-driven approach was applied to match the material-specific property (i.e. crystal form/morphology) with the functions employed in the applications. We demonstrate that for nano-TiO2, carbon nanotubes (CNTs), and nano-Al2O3 the total production volume can be allocated to specific nano-forms based on their functionalities. The differentiated assessments result in a variation of the predicted environmental concentrations for anatase vs. rutile nano-TiO2, single-wall vs. multi-wall CNTs and α- vs. γ-nano-Al2O3 by a factor of 2 to 13. Additionally, the nano-form-specific predicted no-effect concentrations for these ENMs were derived. The risk quotients for all nano-forms indicated no immediate risk in freshwaters. Our results suggest that grouping and read-across concepts should include both a nano-form release potential for estimating the environmental exposure and separately consider the nano-forms in environmental risk assessments.

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Material-specific properties applied to an environmental risk assessment of engineered nanomaterials - implications on grouping and read-across concepts

The biological effects of airborne particulate matter (PM) in humans stimulated many research activities in recent years. One type of particles contributing to PM are those derived from combustion processes. By using in vitro test systems for assessing the toxic effects of those particles, the transfer into liquid media is necessary. Thus the question arises, how the transfer of airborne particles into liquid suspensions should be realized and how the exposure of test organisms/cells to the particles can be done and monitored with regard to concentration and stability. Further, the characterization of the airborne particles regarding their composition seems to be of importance in order to understand the induced biological effects. Hence, this review gathers and evaluates results from in vitro and ecotoxicity studies, where the introduction of airborne particles into liquids is required. The aim was to learn on the current practice and recommend on the design of toxicity studies in the future. In total, about 80 papers were retrieved by literature search that deal with the assessment of biological effects of combustion-derived particles or their constituents. The papers were evaluated in detail with regard to the methodology applied. From this evaluation and based on expert knowledge regarding nanoparticle testing, recommendations for the assessment of PM applying toxicological assays were developed. To provide guidance, essential criteria are developed that should help in preparation, testing, and during the evaluation phase of toxicological assays. We further advise whole particle testing, complemented by testing of particle extracts and washed particles.

https://link.springer.com/content/pdf/10.1007%2Fs13399-017-0295-1.pdf

From the air to the water phase: implication for toxicity testing of combustion-derived particles

Sowohl Wissenschaftler als auch der Burger brauchen verlassliche Informationen, wenn sie faktenorientiert uber die Sicherheit von Nanomaterialien diskutieren wollen. Nicht alle Artikel zu diesem Thema eignen sich fur eine Risikoabschatzung. Deshalb ist es notwendig, geeignete von ungeeigneten Artikeln zu trennen. Dies ist das Ziel des vom Bundesministerium fur Bildung und Forschung geforderten Projekts DaNa 2.0. Hier werden wissenschaftliche Veroffentlichungen in einem transparenten Verfahren unter Verwendung eines Literatur-Kriterienkatalog evaluiert und die Ergebnisse in Form von allgemeinverstandlichen Artikeln auf der Projekt-Website publiziert.

Sarah Reithel

Papers

DaNa 2.0 – verlässliche Informationen zur Sicherheit von marktüblichen Nanomaterialien