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International audience ; Nanotechnologies are becoming a larger presence in everyday life and are viewed by governments and economic actors as a key area for development. The theory of social representations suggests that specialist views eventually disseminate to shape representations among the public. Yet nanotechnologies remain relatively little known to the general public. The media emphasize potential benefits, while potential risks get less attention. The literature has not yet addressed whether representations by a well-informed population (scientists) are indeed structured in terms of the risk–benefit polarity that dominates research framing to date. We attempted a systematic assessment of how background knowledge about nanotechnology may influence experts' perception. Study 1 delivered the first demonstration derived from a qualitative analysis confirming the existence of a polarized representation of nanotechnologies, contrasting opportunity (medical, economic, and technological) and risk. Interestingly, risk was distinguished at two levels: that associated with nanomaterial characteristics (toxicity, reactivity) and at the larger scale of impact (health, environment, leg- islation). Does this polarity indicate a 'yes, but' logic (nanotechnology carries opportunity but also risk), or two clusters of specialists (sensitive, respectively, to opportunity or to risk)? Study 2 surveyed a larger sample of experts who self- described their scientific background and role viz. nanotechnology. Role had no influence. Specialists consensually viewed that nanotechnology represents opportunity, but depending on scientific background they did not agree to the same extent that nanotechnology also constitutes a risk. Participants with a phy- sics and chemistry background tended to represent nanotechnologies predomi- nantly in terms of opportunities and not in terms of inherent risks or impacts. In contrast, toxicologists, life and social scientists appeared to explicitly incorporate both benefits and risks in their ...

A substance may have one or more nanoforms, defined for regulatory purposes under EU chemicals legislation REACH based on differences in physicochemical properties such as size, shape, specific surface area and surface chemistry including coatings. To reduce the burden of testing each unique nanoform for the environmental risk assessment of nanomaterials, grouping approaches allow simultaneous assessment of multiple nanoforms. Nanoforms with initially different intrinsic properties, could still be considered similar if their environmental fate and effects can be demonstrated to be similar. One hypothesis to group nanoforms with different organic surface modifications is to use parameters linked to biodegradation of the organic surface. The hypothesis contends that nanoforms with a similar core chemistry, but different organic surface treatments may be grouped, if the surface treatment is likely to be lost through biodegradation rapidly upon entering an environmental compartment, such that it no longer modulates fate, exposure and toxicity of the nanoform. To implement grouping according to surface treatment biodegradability, a robust approach to measure the breakdown of particle surface treatments is needed. We present a tiered testing strategy to assess the biodegradation of organic surface treatments used with nanomaterials that can be implemented as part of an Integrated Approach to Testing and Assessment (IATA) for grouping based on surface treatment stability. The tiered approach consists of an initial pre-screening MT2 colorimetric carbon substrate utilisation assay, to provide a rapid assessment of coating degradation, and a second tier of testing using OECD Test Guideline 301F for assessing organic chemical biodegradability. Six common surface treatment substances are assessed using the tiered testing strategy to refine rules for escalating between tiers. Similarity assessment using absolute Euclidean distances and x-fold difference concluded that the Tier 1 assessment can be used as conservative binary ...