Definition Of Nanomaterials Research Articles

Refinement of the acute inhalation limit test for inert, nano-sized dusts by an in silico dosimetry-based evaluation: case study for the dissolution of a regulatory dilemma.

This case study aims to describe the dilemma faced when exposing rats to very high concentrations of fine, pulverulent materials for acute inhalation studies and to address the regulatory question of whether the effects seen here are relevant to humans and the subject of classification according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS). Many powders match the definition of nanomaterials in the EU; therefore, information on acute inhalation testing of powders up to the GHS cutoff of 5mg/L is required. However, testing rats at such a high aerosol concentration can cause physical obstruction of the airways and even mortality by suffocation. Therefore, to evaluate whether the physical effects on airway obstruction in rats exposed to 5mg/L for 4hours and alternative exposures to 1 and 2mg/L are relevant for humans, an in silico evaluation of aerosol deposition was conducted using the multiple-path particle dosimetry (MPPD) model. For this evaluation, actual exposure conditions for an organic, nano-sized pigment which produced 100% lethality in rats at 5mg/L, but not at 1mg/L, were used to assess the potential for airway obstruction in rats and accordingly in humans. As an indicator of the potential for airway obstruction, the ratio of the diameter of the deposited, aggregated aerosol to airway diameter was calculated for each exposure condition. For rats exposed to 5mg/L for 4h, approximately 75% of tracheobronchial and 22% of pulmonary/alveolar airways were considered vulnerable to significant or complete obstruction (ratios >0.5). In humans, an equivalent exposure resulted in just over 96% of human tracheobronchial airways that received deposited mass to airway diameter ratios between 0.3 and 0.4 (nasal) or 0.4 and 0.5 (oral), with no airways with ratios >0.5. For the pulmonary/alveolar region, ∼88% of the airways following nasal or oral breathing were predicted to have deposited aerosol diameter to airway diameter ratios <0.1, with no airways with ratios >0.5. Thus, the in silico results obtained for rats are in line with the pathological findings of the animal test. The predicted results in humans, however, affirm the hypothesis of a rat-specific high dose effect which does not justify a classification according to GHS.

Challenges in Nanomaterial Characterization - From Definition to Analysis.

Nanomaterials have outstanding properties and have several applications, ranging from foods, cosmetics, pharmaceuticals to energy, construction, etc. As with all novel products, the benefits of nanomaterials use must be weighed against its health and environmental impact. They have different origins, natural, incidental, or engineered, they are widespread, and they need to be classified and characterized for various purposes, including nanotoxicology studies and risk assessment, workplaces and environment safety evaluation, consumer products evaluation, as well as manufacturing process control. To properly characterize nanomaterials, a consensual definition of nanomaterial is needed, and several analyses using the available characterization techniques must be performed. Various properties are relevant in the characterization process and many of them, namely size, are still a challenge that the research community is facing. The measurement of physical and chemical properties is very important in the case of nanomaterials. In view of this, in this chapter, available analytical techniques are reviewed based on nanomaterials classification, regulatory demands and toxicology assessment. Additionally, some of the current major challenges and gaps in nanomaterials characterization are identified and listed.

Assessing a national nanotechnology infrastructure for enforcing nanosafety in consumer food - Funding the infrastructure

Crucial to assessing any national risk assessment infrastructure is the development of keen insights into the funding landscape, the base skill set and expertise levels, risk prioritisation, and stakeholder determination. This paper presents an overview of the first of these criteria with respect to the Irish funding landscape for nanotechnology and nano-agri-food. It examines difficulties with policy enforcement due to a lack of clarity and varying interpretations of the EU definition of nanomaterials and how the funding landscape could potentially facilitate the necessary infrastructure, to underpin regulatory enforcement and risk assessment for nanotechnology in food. In 2008 an assessment of the potential risks associated with nanotechnologies was carried out in Ireland which resulted in a number of recommendations centred around the provision of funding. This study examines Exchequer/public investment over the last decade to develop research infrastructure and it identifies if such investment has helped enhance the enforcement of nano-food safety legislation in Ireland.

Agglomeration of titanium dioxide nanoparticles increases toxicological responses in vitro and in vivo

BackgroundThe terms agglomerates and aggregates are frequently used in the regulatory definition(s) of nanomaterials (NMs) and hence attract attention in view of their potential influence on health effects. However, the influence of nanoparticle (NP) agglomeration and aggregation on toxicity is poorly understood although it is strongly believed that smaller the size of the NPs greater the toxicity. A toxicologically relevant definition of NMs is therefore not yet available, which affects not only the risk assessment process but also hinders the regulation of nano-products. In this study, we assessed the influence of NP agglomeration on their toxicity/biological responses in vitro and in vivo.ResultsWe tested two TiO2 NPs with different primary sizes (17 and 117 nm) and prepared ad-hoc suspensions composed of small or large agglomerates with similar dispersion medium composition. For in vitro testing, human bronchial epithelial (HBE), colon epithelial (Caco2) and monocytic (THP-1) cell lines were exposed to these suspensions for 24 h and endpoints such as cytotoxicity, total glutathione, epithelial barrier integrity, inflammatory mediators and DNA damage were measured. Large agglomerates of 17 nm TiO2 induced stronger responses than small agglomerates for glutathione depletion, IL-8 and IL-1β increase, and DNA damage in THP-1, while no effect of agglomeration was observed with 117 nm TiO2.In vivo, C57BL/6JRj mice were exposed via oropharyngeal aspiration or oral gavage to TiO2 suspensions and, after 3 days, biological parameters including cytotoxicity, inflammatory cell recruitment, DNA damage and biopersistence were measured. Mainly, we observed that large agglomerates of 117 nm TiO2 induced higher pulmonary responses in aspirated mice and blood DNA damage in gavaged mice compared to small agglomerates.ConclusionAgglomeration of TiO2 NPs influences their toxicity/biological responses and, large agglomerates do not appear less active than small agglomerates. This study provides a deeper insight on the toxicological relevance of NP agglomerates and contributes to the establishment of a toxicologically relevant definition for NMs.

Is aggregated synthetic amorphous silica toxicologically relevant?

BackgroundThe regulatory definition(s) of nanomaterials (NMs) frequently uses the term ‘agglomerates and aggregates’ (AA) despite the paucity of evidence that AA are significantly relevant from a nanotoxicological perspective. This knowledge gap greatly affects the safety assessment and regulation of NMs, such as synthetic amorphous silica (SAS). SAS is used in a large panel of industrial applications. They are primarily produced as nano-sized particles (1–100 nm in diameter) and considered safe as they form large aggregates (> 100 nm) during the production process. So far, it is indeed believed that large aggregates represent a weaker hazard compared to their nano counterpart. Thus, we assessed the impact of SAS aggregation on in vitro cytotoxicity/biological activity to address the toxicological relevance of aggregates of different sizes.ResultsWe used a precipitated SAS dispersed by different methods, generating 4 ad-hoc suspensions with different aggregate size distributions. Their effect on cell metabolic activity, cell viability, epithelial barrier integrity, total glutathione content and, IL-8 and IL-6 secretion were investigated after 24 h exposure in human bronchial epithelial (HBE), colon epithelial (Caco2) and monocytic cells (THP-1). We observed that the de-aggregated suspension (DE-AGGR), predominantly composed of nano-sized aggregates, induced stronger effects in all the cell lines than the aggregated suspension (AGGR). We then compared DE-AGGR with 2 suspensions fractionated from AGGR: the precipitated fraction (PREC) and the supernatant fraction (SuperN). Very large aggregates in PREC were found to be the least cytotoxic/biologically active compared to other suspensions. SuperN, which contains aggregates larger in size (> 100 nm) than in DE-AGGR but smaller than PREC, exhibited similar activity as DE-AGGR.ConclusionOverall, aggregation resulted in reduced toxicological activity of SAS. However, when comparing aggregates of different sizes, it appeared that aggregates > 100 nm were not necessarily less cytotoxic than their nano-sized counterparts. This study suggests that aggregates of SAS are toxicologically relevant for the definition of NMs.

A Dose Metrics Perspective on the Association of Gold Nanomaterials with Algal Cells

A single-cell inductively coupled plasma mass spectrometry technique was used to explore the influence of particle properties on the association of nanomaterials (NMs) with algal cells. We investigated the effect of particle size, shape, and surface chemistry [citrate and natural organic matter (NOM) coating] on the association of gold (Au) NMs with algal cells using particle mass, particle number, surface area (SA), and volume-specific surface area (VSSA) as dose metrics. Particle number was found to be a better dose metric than particle mass, SA, and VSSA in view of the strong correlation obtained between the number of associated Au NMs with cells and the number of Au NMs in the exposure medium. When particle number was used as the dose metric, there was no selectivity of Au NM cellular association irrespective of particle size and shape, and the cellular association was proportional to the effective number of particles to which the cells were exposed. The surface chemistry of the Au NMs, however, decreased the level of cellular association of some NMs (60 nm spheres). Particle number is the main element used for the classification of NMs according to the recommended definition for NM by the European Commission. The key finding of our study supports the implementation of this definition for safety purposes.

On the uses of predictive toxicology to approve the use of engineered nanomaterials as biocidal active substances under the Biocidal Products Regulation

To date only two engineered nanomaterials (ENMs) have been approved to be used as biocidal active substances in the formulation of biocidal products under product type 18 (insecticides, acaricides and products to control other arthropods). Such materials are silicon dioxide (as a nanomaterial formed by aggregates and agglomerates) and synthetic amorphous silicon dioxide (nano). The use of non-animal alternative test methods has been foreseen in the Biocides Product Regulation, Regulation (EU) 258/2012 (BPR). Further, the BPR is one of the existing regulations that includes a specific definition of nanomaterials. On the present article, a review is made on the potential uses of Quantitative Structure-Activity Relationship approach (Nano-QSARs) to be used as a non-testing method for the generation of ecotoxicological data required for the approval of new active substances in the nanometric scale. Relevant challenges are to be faced in the application of computational chemistry but it could meet the needs imposed by the BPR in relation to the use of non-testing methods. However nanospecific adaptations need to be implemented further on ecotoxicological testing so that obtained results are considered a suitable input for models’ building. The BPR, thus, sets the framework for innovative approaches in the regulatory approval of new chemicals that integrate special considerations derived from the chemical nature of ENMs and the application of non-testing methods but, to date, the implementation of such actions is not feasible in practical terms.

Reliable nanomaterial classification of powders using the volume-specific surface area method

The volume-specific surface area (VSSA) of a particulate material is one of two apparently very different metrics recommended by the European Commission for a definition of “nanomaterial” for regulatory purposes: specifically, the VSSA metric may classify nanomaterials and non-nanomaterials differently than the median size in number metrics, depending on the chemical composition, size, polydispersity, shape, porosity, and aggregation of the particles in the powder. Here we evaluate the extent of agreement between classification by electron microscopy (EM) and classification by VSSA on a large set of diverse particulate substances that represent all the anticipated challenges except mixtures of different substances. EM and VSSA are determined in multiple labs to assess also the level of reproducibility. Based on the results obtained on highly characterized benchmark materials from the NanoDefine EU FP7 project, we derive a tiered screening strategy for the purpose of implementing the definition of nanomaterials. We finally apply the screening strategy to further industrial materials, which were classified correctly and left only borderline cases for EM. On platelet-shaped nanomaterials, VSSA is essential to prevent false-negative classification by EM. On porous materials, approaches involving extended adsorption isotherms prevent false positive classification by VSSA. We find no false negatives by VSSA, neither in Tier 1 nor in Tier 2, despite real-world industrial polydispersity and diverse composition, shape, and coatings. The VSSA screening strategy is recommended for inclusion in a technical guidance for the implementation of the definition.Graphical abstractWe evaluate the extent of agreement between classification by electron microscopy (EM) and classification by Volume-Specific Surface Area (VSSA) on a large set of diverse particulate substances. These represent the challenges anticipated for identification of nanomaterials by the European Commission recommendation for a definition of nanomaterials for regulatory purposes.

Regulatory Aspects of Nanomaterials in the EU

AbstractNanomaterials are present in almost any industrial sector and addressed in corresponding legislation. The EC has developed a recommendation of the term nanomaterial for regulatory purposes. Due to uncertainties regarding the safety of nanomaterials, it is necessary to develop best practices and facilitate harmonization of assessment practices. However, more research with specific relevance for regulatory questions is still needed, in particular regarding the implementation of the definition of nanomaterials, the enforcement of product labeling, the development of methods for safety testing and risk assessment, and a better availability of quality data on nanomaterials for regulatory purposes.

Comments on the article by A. J. Lecloux (J Nanopart Res (2015) 17:447) regarding the use of volume-specific surface area (VSSA) to classify nanomaterials.

In November 2015, an article by A. J. Lecloux was published in this journal (J Nanopart Res, 17:447, 2015). The article focused on the use of volume-specific surface area (VSSA) for the implementation of the European Commission’s recommended definition of “nanomaterial”. In that paper, VSSA values were calculated for polydisperse particulate materials using a particle number-based averaging method which do not agree with earlier results of VSSA simulations of polydisperse materials reported in 2014 by the Joint Research Centre (JRC) of the European Commission (EC). In this contribution, we explain the difference between traditional view of VSSA which was used by the JRC and the proposed model of Lecloux. Through the use of some simple examples for polydisperse materials, it is demonstrated that the latter produces values which neither correspond to the generally accepted definition of VSSA nor relate to the commonly used experimental methods for determining VSSA using gas adsorption. Lecloux’s model therefore does not constitute a basis for practical implementation of the EC’s definition of nanomaterial using gas adsorption techniques.

THE ROLE OF NANOMATERIALS IN COSMETICS: NATIONAL AND INTERNATIONAL LEGISLATIVE ASPECTS

Nanotechnology is currently one of the fastest growing scientific fields. The products of this science have become part of our everyday lives. However, to date, regulatory agencies have not yet established a single definition for nanomaterials and nanotechnology. Therefore, each country has its own definitions and legislation to control products containing nanomaterials. Being relatively new materials, there are no long-term studies showing their impact on human health and the environment. Consequently, countries control the amount of nanomaterials present in cosmetics, allowing the end consumer to choose which cosmetic to use, by choosing products with or without nanomaterials. Therefore, the primary objective of this study was to identify the most used nanomaterials in cosmetics and verify whether these formulations are in accordance with the laws in force in the United States, the European Union and Brazil, thereby determining if the cosmetics on the market are in line with the existing laws in these three economic powers. This study is unique and will contribute to furthering the discussion on existing laws pertinent to the use of nanotechnology in cosmetics.

Size measurement uncertainties of near-monodisperse, near-spherical nanoparticles using transmission electron microscopy and particle-tracking analysis

Particle-tracking analysis (PTA) in combination with systematic imaging, automatic image analysis, and automatic data processing is validated for size measurements. Transmission electron microscopy (TEM) in combination with a systematic selection procedure for unbiased random image collection, semiautomatic image analysis, and data processing is validated for size, shape, and surface topology measurements. PTA is investigated as an alternative for TEM for the determination of the particle size in the framework of the EC definition of nanomaterial. The intra-laboratory validation study assessing the precision and accuracy of the TEM and PTA methods consists of series of measurements on three gold reference materials with mean area-equivalent circular diameters of 8.9 nm (RM-8011), 27.6 nm (RM-8012), and 56.0 nm (RM-8013), and two polystyrene materials with modal hydrodynamic diameters of 102 nm (P1) and 202 nm (H1). By obtaining a high level of automation, PTA proves to give precise and non-biased results for the modal hydrodynamic diameter in size range between 30 and 200 nm, and TEM proves to give precise and non-biased results for the mean area-equivalent circular diameter in the size range between 8 and 200 nm of the investigated near-monomodal near-spherical materials. The expanded uncertainties of PTA are about 9 % and are determined mainly by the repeatability uncertainty. This uncertainty is two times higher than the expanded uncertainty of 4 % obtained by TEM for analyses on identical materials. For the investigated near-monomodal and near-spherical materials, PTA can be used as an alternative to TEM for measuring the particle size, with exception of 8.9 nm gold, because this material has a size below the detection limit of PTA.

The Law of the European Union on Nanotechnologies: Comments on a Paradox

European Union (EU) law and policy on nanotechnologies reveals what might seem like a paradox. Even if the EU acts as a leading investor in this area, there is no regulation specifically targeting nanotechnologies. While a great number of European regulations could be applicable to nanomaterials, these still require further examination. However, the adaptation of current provisions has not been successful so far due to terminological inconsistencies, which have not been completely resolved by the adoption of the recommendation of the European Commission on a definition for nanomaterials.

Nanotechnologies and Novel Foods in European Law

Food is a big business in the EU and nanofood products are beginning to be placed on the market. It is still unclear whether the absence of minimum regulation at a global level promotes or prevents the growth of a market in nanofood. However, the development of an adequate risk management policy in relation to food safety is a key concern for consumers. Importantly, the European Parliament in its 2009 Resolution on “Legal aspects on nanomaterials” called for more in-depth scientific research on the toxicity of compounds in nanomaterials, and for the adoption of an EU definition of nanomaterials for regulatory purposes. Unfortunately, in 2011, nanotechnology led to inconclusive debates in the context of the revision of Novel Food Regulation. General Food Law applies to nanofood in terms of safety requirements, and specific rules also apply to food contact materials containing nanoparticles as well as to to additives, vitamins and minerals. The EU legislator also introduced mandatory labelling in respect of products derived from nanotechnologies. The legal framework is evolving according to the so-called “incremental approach”, a governance model that creates the risk of fragmentation. But the main problem is the inconsistent definition of the terms “nanotechnology” and “nanomaterials” when looking at the enforcement of regulations and the provision of a wide range of specific tools for different nanofoods: for example the use of positive lists of authorised substances applying only to food contact materials, additives and supplements. This contribution aims to review the regulations in force in respect to nanofood and novel foods and to highlight the problems that are still unresolved.

Novel Foods: Regulation, Health and Safety Considerations

Abstract Under the Novel Food Regulation (258/97/EC), a novel food is defined as a food or food ingredientthat does not have a significant history of consumption within the European Union prior to 15May 1997. Novel foods are required to undergo a pre-market safety assessment and must beauthorised before they can legally be marketed in the EU. A proposal to revise and update the EUNovel Food Regulation was published in 2008. This proposed a definition for nanomaterials, acentralised and faster authorisation procedure and specific measures for traditional foods fromthird countries. As a result of disagreement on the inclusion of foods from cloned animals, theEuropean Parliament and Council were unable to reach agreement on the new regulation beforethe deadline of 30 March 2011. New discussions on the updated Regulation are expected to takeplace in 2012. So far 66 novel foods and food ingredients have been authorised for use in the EU.The most popular products are Noni juice (juice of the fruits of Morinda citrifolia) and phytosterolsin a number of foodstuffs

Measuring nanoparticles size distribution in food and consumer products: a review

Nanoparticles are already used in several consumer products including food, food packaging and cosmetics, and their detection and measurement in food represent a particularly difficult challenge. In order to fill the void in the official definition of what constitutes a nanomaterial, the European Commission published in October 2011 its recommendation on the definition of ‘nanomaterial’. This will have an impact in many different areas of legislation, such as the European Cosmetic Products Regulation, where the current definitions of nanomaterial will come under discussion regarding how they should be adapted in light of this new definition. This new definition calls for the measurement of the number-based particle size distribution in the 1–100 nm size range of all the primary particles present in the sample independently of whether they are in a free, unbound state or as part of an aggregate/agglomerate. This definition does present great technical challenges for those who must develop valid and compatible measuring methods. This review will give an overview of the current state of the art, focusing particularly on the suitability of the most used techniques for the size measurement of nanoparticles when addressing this new definition of nanomaterials. The problems to be overcome in measuring nanoparticles in food and consumer products will be illustrated with some practical examples. Finally, a possible way forward (based on the combination of different measuring techniques) for solving this challenging analytical problem is illustrated.

Detection of nanomaterials in food and consumer products: bridging the gap from legislation to enforcement

This paper describes the requirements and resulting challenges for the implementation of current and upcoming European Union legislation referring to the use of nanomaterials in food, cosmetics and other consumer products. The European Commission has recently adopted a recommendation for the definition of nanomaterials. There is now an urgent need for appropriate and fit-for-purpose analytical methods in order to identify nanomaterials properly according to this definition and to assess whether or not a product contains nanomaterials. Considering the lack of such methods to date, this paper elaborates on the challenges of the legislative framework and the type of methods needed, not only to facilitate implementation of labelling requirements, but also to ensure the safety of products coming to the market. Considering the many challenges in the analytical process itself, such as interaction of nanoparticles with matrix constituents, potential agglomeration and aggregation due to matrix environment, broad variety of matrices, etc., there is a need for integrated analytical approaches, not only for sample preparation (e.g. separation from matrix), but also for the actual characterisation. Furthermore, there is an urgent need for quality assurance tools such as validated methods and (certified) reference materials, including materials containing nanoparticles in a realistic matrix (food products, cosmetics, etc.).

Law and innovation in the context of nanomaterials: Barriers to sustainable development? Results of an empirical study

According to Art. 3(3) of the Treaty on the European Union, the Community is working towards the sustainable development of Europe – this constitutes the overriding long-term goal of the European Union. The guiding principle of sustainable development aspires towards the reduced exploitation of natural resources aimed at their long-term preservation and a reduced pollutant burden for protected natural resources. The target for 2020 is that "chemicals are used and produced in ways that lead to the minimization of significant adverse effects on human health and the environment" (’Johannesburg goals’). In addition, the guiding principle pursues the safeguarding of the basis for survival and economic production in order to maintain an adequate quality of life. These aims can only be achieved by far-reaching changes to the economic and social structures and also to patterns of consumption and production – consequently innovations are required. This requires specific regulatory strategies – particularly for product or process innovations – in order to create adequate incentives so that actors from trade and industry get innovations for sustainability off the ground. In connection with this the question arises as to how nanomaterials are to be regulated so that the innovation processes linked to these substances are aligned with the guiding principle of sustainable development. Nanomaterials are substances in terms of the REACH Regulation and therefore fall within its scope. However, REACH does not contain any provisions directed specifically at nanomaterials. The regulatory omissions arising from this – no definition for nanomaterials; tonnage quantity thresholds may be inappropriate for nanoscale substances; transitional periods for existing substances (phase-in substances, Art. 23) also apply to certain nanomaterials; test procedures are not designed to nanomaterial specifications, etc. – are discussed in depth in the literature. This article takes a different perspective. It examines to what degree REACH promotes innovations for sustainability through nanomaterials. The question of how the regulation affects the manufacturers' approach to nanomaterials was the subject of a survey sent to companies which manufacture and/or use nanomaterials. The survey questioned 37 companies based in Germany. Besides the issues of registering for REACH and carrying out safety assessments, the main focus of interest was on the relationships between substance risks and innovation and between REACH and innovation. The findings obtained from the survey were augmented by telephone interviews on this subject and by the results of a workshop held in Darmstadt, Germany, in December 2011 with representatives from companies and industry associations and experts on the regulation of nanomaterials. Finally, this contribution refers to the results of a study carried out for the European Commission on the innovative effects of REACH on emerging technologies. This document summarises the most important results from the empirical data and, where the data permits, draws some preliminary conclusions for a possible adaptation of the legal framework for nanomaterials.

Determination of the volume-specific surface area by using transmission electron tomography for characterization and definition of nanomaterials

BackgroundTransmission electron microscopy (TEM) remains an important technique to investigate the size, shape and surface characteristics of particles at the nanometer scale. Resulting micrographs are two dimensional projections of objects and their interpretation can be difficult. Recently, electron tomography (ET) is increasingly used to reveal the morphology of nanomaterials (NM) in 3D. In this study, we examined the feasibility to visualize and measure silica and gold NM in suspension using conventional bright field electron tomography.ResultsThe general morphology of gold and silica NM was visualized in 3D by conventional TEM in bright field mode. In orthoslices of the examined NM the surface features of a NM could be seen and measured without interference of higher or lower lying structures inherent to conventional TEM. Segmentation by isosurface rendering allowed visualizing the 3D information of an electron tomographic reconstruction in greater detail than digital slicing. From the 3D reconstructions, the surface area and the volume of the examined NM could be estimated directly and the volume-specific surface area (VSSA) was calculated. The mean VSSA of all examined NM was significantly larger than the threshold of 60 m2/cm3.The high correlation between the measured values of area and volume gold nanoparticles with a known spherical morphology and the areas and volumes calculated from the equivalent circle diameter (ECD) of projected nanoparticles (NP) indicates that the values measured from electron tomographic reconstructions are valid for these gold particles.ConclusionThe characterization and definition of the examined gold and silica NM can benefit from application of conventional bright field electron tomography: the NM can be visualized in 3D, while surface features and the VSSA can be measured.

The European Commission Tries to Define Nanomaterials

In 2010, the European Commission held a short consultation on a proposed definition for nanomaterials, to be used in European Union legislation and programmes. This was in response to a European Parliament resolution, and the definition followed a proposal by one of the Commission's scientific committees. The definition has three parts: on size distribution, size of internal structural elements, and surface area; a material caught by any of these parts meets the definition. There are a number of problems. The definition seems to be written with engineered nanomaterials in mind but as written applies to non-supplied materials, such as smokes. The structural element component seems to capture items such as sunscreen and tennis rackets, which include nanomaterials. Use of the definition will require some international standards, which have yet to be written and which will involve some difficult decisions. It is understandable why there are both size and surface area requirements, but they are not wholly consistent. The Commission plans a further consultation in 2012, but it might be better to delay this until after the standardisation work.