Towards Safe and Sustainable Advanced (Nano)materials: A proposal for an early awareness and action system for advanced materials (Early4AdMa)

It is of utmost importance to develop an anticipatory risk governance approach and to proactively avoid the occurrence of potential unexpected risks of advanced (nano)materials. Addressing safety and sustainability issues early in the innovation chain can support innovation by preventing problems later on. Towards this goal, we propose a novel Early4AdMa system to systematically identify emerging issues of advanced nanomaterials. This system can be applied by regulators, risk assessors, as well as innovators

Multiple controls affect arsenite oxidase gene expression in Herminiimonas arsenicoxydans

<p>Abstract</p> <p>Background</p> <p>Both the speciation and toxicity of arsenic are affected by bacterial transformations, i.e. oxidation, reduction or methylation. These transformations have a major impact on environmental contamination and more particularly on arsenic contamination of drinking water. <it>Herminiimonas arsenicoxydans </it>has been isolated from an arsenic- contaminated environment and has developed various mechanisms for coping with arsenic, including the oxidation of As(III) to As(V) as a detoxification mechanism.</p> <p>Results</p> <p>In the present study, a differential transcriptome analysis was used to identify genes, including arsenite oxidase encoding genes, involved in the response of <it>H. arsenicoxydans </it>to As(III). To get insight into the molecular mechanisms of this enzyme activity, a Tn<it>5 </it>transposon mutagenesis was performed. Transposon insertions resulting in a lack of arsenite oxidase activity disrupted <it>aoxR </it>and <it>aoxS </it>genes, showing that the <it>aox </it>operon transcription is regulated by the AoxRS two-component system. Remarkably, transposon insertions were also identified in <it>rpoN </it>coding for the alternative N sigma factor (σ⁵⁴) of RNA polymerase and in <it>dnaJ </it>coding for the Hsp70 co-chaperone. Western blotting with anti-AoxB antibodies and quantitative RT-PCR experiments allowed us to demonstrate that the <it>rpoN </it>and <it>dnaJ </it>gene products are involved in the control of arsenite oxidase gene expression. Finally, the transcriptional start site of the <it>aoxAB </it>operon was determined using rapid amplification of cDNA ends (RACE) and a putative -12/-24 σ⁵⁴-dependent promoter motif was identified upstream of <it>aoxAB </it>coding sequences.</p> <p>Conclusion</p> <p>These results reveal the existence of novel molecular regulatory processes governing arsenite oxidase expression in <it>H. arsenicoxydans</it>. These data are summarized in a model that functionally integrates arsenite oxidation in the adaptive response to As(III) in this microorganism.</p

Spatially Explicit Analysis of Metal Transfer to Biota: Influence of Soil Contamination and Landscape

Concepts and developments for a new field in ecotoxicology, referred to as “landscape ecotoxicology,” were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn) in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi) and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula). Total and CaCl2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging) were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc.) are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our understanding of pollutant transfer and effects in ecosystems

Evaluation system new substances: Transformation rates

Binnen het raamproject "Beoordelingssysteem Nieuwe Stoffen" (BNS) worden methoden ontwikkeld voor een systematische beoordeling van de risico's voor mens en milieu die verbonden zijn aan de produktie en het gebruik van "nieuwe stoffen". Voor het schatten van blootstellingsconcentraties wordt tot op heden voornamelijk gebruik gemaakt van schattingssystemen voor stofuitwisselingssnelheden. Voor realistische schattingen van de te verwachten stofconcentraties dienen echter ook formuleringen van omzettingssnelheden bekend zijn. Een korte literatuurstudie is uitgevoerd met als doel het beschikbaar maken van methodes voor het berekenen van deze omzettingssnelheden. Gebleken is dat de volgende processen voldoende in de literatuur worden beschreven om in het BNS gebruikt te kunnen worden: 1. Oxidatie van organische verbindingen door hydroxylradicalen. 2. Reductie van gehalogeneerde alifatische koolwaterstoffen in water-sediment systemen. 3. Hydrolyse van organische verbindingen. Naast de voor gebruik in het BNS in aanmerking komende procesformuleringen worden in dit rapport databases voor stofeigenschappen aangegeven. Daarnaast zijn ook de beperkingen in de procesformuleringssets weergegeven.DGM/SR / Broekhuizen

Beoordelingssysteem nieuwe stoffen: Schattiangsroutines voor omzettingssnelheden

Binnen het raamproject "Beoordelingssysteem Nieuwe Stoffen" (BNS) worden methoden ontwikkeld voor een systematische beoordeling van de risico's voor mens en milieu die verbonden zijn aan de produktie en het gebruik van "nieuwe stoffen". Voor het schatten van blootstellingsconcentraties wordt tot op heden voornamelijk gebruik gemaakt van schattingssystemen voor stofuitwisselingssnelheden. Voor realistische schattingen van de te verwachten stofconcentraties dienen echter ook formuleringen van omzettingssnelheden bekend te zijn. Een korte literatuurstudie is uitgevoerd met als doel het beschikbaar maken van methodes voor het berekenen van deze omzettingssnelheden. Gebleken is dat de volgende processen voldoende in de literatuur worden beschreven om in het BNS gebruikt te kunnen worden: 1. Oxidatie van organische verbindingen door hydroxylradicalen. 2. Reductie van gehalogeneerde alifatische koolwaterstoffen in water-sediment systemen. 3. Hydrolyse van organische verbindingen. Naast de voor gebruik in het BNS in aanmerking komende procesformuleringen worden in dit rapport databases voor stofeigenschappen aangegeven. Daarnaast zijn ook de beperkingen in de procesformuleringssets weergegeven.DGM/SR /Leeuwen CJ va

An investigation on the feasibility of developing an expert system for calculating environmental transport and transformation processes

In this report the results are presented of an investigation on the feasibility of developing an expert system for calculating compound specific physical-chemical parameters and predicting the rates of intercompartimental transport processes and abiotic and biotic transformations on the basis of the structure formula of a given compound. The most important applications of an expert system environmental chemistry are the assessment of the fate and behaviour of both new and existing chemicals within the framework of the legislation on chemical substances considered dangerous tot the environment and the derivation of standards for maximal allowed concentrations of chemical substances in all environmental compartments. First of all an inventarisation is made of the information that is available on: a-databases containing information on mainly physical-chemical parameters, b-Quantitative structure-activity relationships (QSARS) and c-Additional data needed for setting up the expert system. Thereupon, a possible outline of such a system is briefly discussed. It is concluded that at the moment sufficient data are available to enable the development of an expert system environmental chemistry ; the performance of such a system can most likely be increased by using QSARS based on elementary structural parameter, most of which at the moment need further development.RIV

The importance of categorization of nanomaterials for environmental risk assessment.

Nanotechnology is a so-called key-emerging technology that opens a new world of technological innovation. The novelty of engineered nanomaterials (ENMs) raises concern over their possible adverse effect to man and the environment. Thereupon, risk assessors are challenged with ever decreasing times-to-market of nano-enabled products. Combined with the perception that it is impossible to extensively test all new nanoforms, there is growing awareness that alternative assessment approaches need to be developed and validated to enable efficient and transparent risk assessment of ENMs. Associated with this awareness, there is the need to use existing data on similar ENMs as efficiently as possible, which highlights the need of developing alternative approaches to fate and hazard assessment like predictive modelling, grouping of ENMs, and read across of data towards similar ENMs. In this contribution, an overview is given of the current state of the art with regard to categorization of ENMs and the perspectives for implementation in future risk assessment. It is concluded that the qualitative approaches to grouping and categorization that have already been developed are to be substantiated, and additional quantification of the current sets of rules-of-thumb based approaches is a key priority for the near future. Most of all, the key question of what actually drives the fate and effects of (complex) particles is yet to be answered in enough detail, with a key role foreseen for the surface reactivity of particles as modulated by the chemical composition of the inner and outer core of particles. When it comes to environmental categorization of ENMs we currently are in a descriptive rather than in a predictive mode.Comment: 10 pages, 5 figures, This article is one of a collection of articles about the categorization of nanomaterials, generated by research and workshop discussions under the FutureNanoNeeds project funded by EU FP