« Some materials develop new physico-chemical properties if the particle size is reduced below a certain value. What potentially delights scientists in research and development causes serious worries for those evaluating safety issues of such materials, since not only useful properties but also hazardous ones might result.
Because the size range in question lies in the range of nanometers (nm), such materials are nowadays called nanomaterials. To address the possibility of a material developing new or enhanced risks, if used in the nanoform, producers demand additional safety data on the primary nanomaterials, industries which are processing them, consumers of the final product, as well as the respective authorities supervising them. But how do we define a nanomaterial ?
The most detailed basis for regulatory “nano” definitions has been developed, and is constantly revised, by the International Organisation for Standards (ISO). The ISO TS 80004 (part two of 13) defines a “nano-object” as a material with one, two or three external dimensions in the nanoscale and also distinguishes different types, like nanotubes or nanoparticles. For the European Union, a recommendation for a definition has been given by the European Commission (EC). It was updated in 2011 and is relatively broad, and while it is not legally binding in itself will be adapted for relevant product or sector specific legislation.
The main criterion is the size of the particles that a material is composed of. To be considered a nanomaterial, this has to be 1- 100 nm in at least one external dimension, and this should apply to at least 50 % (based on number) of all the particles constituting the material. If adequate, the threshold may even be lowered to 1%, in case of special environmental or health safety considerations, for example. Due to their large volume specific surface area (VSSA), most nanomaterials tend to form (loose) agglomerates or (inseparable) aggregates. Nevertheless, those are also considered nanomaterials if the constituent particles fall into the scope of the definition.
In addition, the VSSA is given as a criterion, but one which is only applicable for a positive decision (if greater than or equal to 60 m ²/cm ³) if the particle size distribution does not lie in the defined range. Furthermore, fullerenes, carbon nanotubes and graphene flakes are explicitly included though not covered by the size range given (all, two or one dimension(s) below 1 nm, the other(s) above 100 nm). This definition applies to intentionally or unintentionally manufactured materials as well as naturally occurring ones.
Though easy to understand, this definition has become subject to many discussions. On the one hand, it only refers to particulate materials, thus embedded nanomaterials, most nanostructured materials or colloids are not covered. On the other hand, the definition applies for a very wide range of materials, including many powders which unintentionally contain a relevant number of nanosized particles due to the production process. Also materials, which have been on the market for decades, may now be considered nanomaterials. An amendment of the recommended definition was planned by December 2014, but the process is still ongoing.
Some specific EU legislations have implemented their own (legally binding) nano definition, namely the biocidal product Regulation, the cosmetics Regulation and the Regulation on food information for consumers (FIC), adapting parts of the recommendation and/or adding new criteria, respectively. Important additional criteria, not mentioned in the recommendation, are the occurrence of new physico-chemical properties, which are not present for the bulk form (FIC), as well as the restriction of intentionally manufactured materials (FIC, cosmetics Regulation). The cosmetics Regulation, furthermore, restricts the materials of interest to biopersistent, insoluble particles, but includes nanostructured materials.
For some legislations, there are proposed amendments not yet implemented, such as fo the novel food Regulation: to adapt the definition given in the FIC Regulation, or for the medical devices Directive: to adapt the recommendation, but leaving the possibility of setting the particle-size distribution threshold below 50%. Without giving an explicit nano definition, the Regulation on plastic materials demands a case-by-case decision on nanomaterials, and only those listed in Annex 1 are allowed for the exact use specified (for example, titanium nitride nanoparticles for the use in PET bottles).
There are other relevant sectors, where nanomaterials are not (yet) mentioned explicitly, such as the Regulation on food contact materials or the chemicals regulations REACH and CLP. According to CLP, hazardous substances should be notified with Echa specifying the exact form they are put on the market (such as a nanomaterial), regardless of their production volume. Echa published guidance on nanomaterials for REACH registrants in 2013. It does not provide an overall definition, but proposes rather a case-by-case assessment, based on the registrants’ expert judgement on “the most appropriate metric” to be considered. According to the Second Regulatory Review on Nanomaterials, amendments of the REACH Annexes are planned.
As a consequence of the inconsistency of definition and lack of information on nanomaterials (and because no joint European approach is available), several countries have developed, or plan, their own registers, including France, Belgium, Denmark and Sweden. France’s register, launched in 2012, only covers the substances, not consumer products containing them. Required information includes the identity of the declarant, information about the properties of the nanomaterial, uses of the substance and the identity of the professional users (confidential information).
In Belgium, data collection will start on 1 January next year. Danish registration opened on 20 June 2014 and is compulsory for producers and importers of mixtures and products containing nanomaterials. The first registration period ended on 30 August with few registrations. The Belgium and Danish nano registers contain a long list of exemptions for registration among other substances that are exempt from REACH registration. It seems that an EU-wide decision on how to handle nanomaterials would be helpful to prevent (well-intentioned) national initiatives, resulting in additional work for registrants, as well as for authorities.
Consequences on workload and labelling
Furthermore, due to the differences in nanomaterial definitions according to specific legislation, a material may be considered a nanomaterial in one kind of product, but not in another. This may result in a higher workload for manufacturers and downstream users of possible nanomaterials, because depending on their application, different kinds of data may have to be collected and evaluated.
What are the consequences, if a material falls under the definition of a nanomaterial? Cosmetic products containing nanomaterials shall be notified to the European Commission (EC) by the responsible person, six months prior to being placed on the market, including toxicological information, for example. If considered necessary, additional data may be requested and the Scientific Committee for Consumer Safety (SCCS) will publish an opinion on behalf of the EC. Nanomaterials considered as hazardous may be prohibited or restricted (Annexes II and III). For biocides, the simplified authorisation procedure is not possible if the product contains nanomaterials, irrespective of whether the active substance itself or some other constituent is considered as nano. If a bulk material has been authorised as a biocide, this does not automatically apply to the nanoform if not explicitly mentioned. Nanoscale ingredients are to be indicated as “nano” in brackets on the ingredient list ( titanium dioxide (nano) for example) for food, biocides and cosmetics.
But nanomaterials are, of course, not only a European phenomenon. How are they handled overseas? The US Environmental Protection Agency (EPA) currently proposed a reporting rule for nano-scale materials under the Toxic Substances Control Act (TSCA). An important difference to European definitions is the weight-based instead of number-based percentage threshold. Due to the small size and, thus, low weight of nanoparticles, 50 % number-based, may be much less than 10% weight-based. The proposed rule would require processors and manufacturers (including importers) of nano-scale materials to report information about the nanomaterial, including properties, composition, uses and production volumes together with existing exposure and health and safety information.
It was also stated that there is no intention to publish a nano register, although non-confidential information will be published online. Until finalisation of the proposed rule, the EPA continues to regulate numerous nano-scale materials under its existing TSCA section 5 authority to require notification for significant new uses of chemical substances, for which new chemical notifications have been received. Producers of plant protection products have to notify the agency if using nanomaterials.
The EPA will then determine on a case-by-case basis whether a nanoscale active or inert ingredient is a “new” one for the purposes of the Federal Insecticide, Fungicide, and Rodenticide Act (Fifra) and the Pesticide Registration Improvement Act (PRIA). The Food and Drug Administration (FDA) distributed guidance documents on what to consider if a FDA-regulated product (for example food, drug, medical devices and cosmetics) involves the application of nanomaterials giving a non-official definition. And like in the EU, US states have begun to take unilateral actions regarding nanomaterials. These range from gathering informal data to formal regulations.
Asian countries also have definitions for nanomaterials but no specific regulations yet. They seem to wait for EU-wide decisions and regulations and make them the basis for their own. In further countries in South America or Africa initiatives regarding EHS issues dealing amongst others with nanomaterials are founded and may push the development of regulatory frameworks. In conclusion, a comprehensive EU-wide regulation for nanomaterials seems to be preferable for EU-member states and may be a benchmark/trigger for non-EU states.
Article of Jörg Wagner and Julia Donauer
Cet article n’engage que son auteur/ This article is the sole responsibility of the author