EC adopts cross-cutting definition of nanomaterials to be used for all regulatory purposes

by Andrew Maynard on October 18, 2011

The European Commission had just adopted a “cross-cutting designation of nanomaterials to be used for all regulatory purposes” (link). The definition builds on a draft definition released last year, but includes a number of substantial changes to this.

Here’s the full text of the definition:

1. Member States, the Union agencies and economic operators are invited to use the following definition of the term “nanomaterial” in the adoption and implementation of legislation and policy and research programmes concerning products of nanotechnologies.

2. “Nanomaterial” means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm.

In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50 % may be replaced by a threshold between 1 and 50 %.

3. By derogation from point 2, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials.

4. For the purposes of point (2), “particle”, “agglomerate” and “aggregate” are defined as follows:

(a) “Particle” means a minute piece of matter with defined physical boundaries;

(b) “Agglomerate” means a collection of weakly bound particles or aggregates where the resulting external surface area is similar to the sum of the surface areas of the individual components;

(c) “Aggregate” means a particle comprising of strongly bound or fused particles.

5. Where technically feasible and requested in specific legislation, compliance with the definition in point (2) may be determined on the basis of the specific surface area by volume. A material should be considered as falling under the definition in point (2) where the specific surface area by volume of the material is greater than 60 m2 / cm3. However, a material which, based on its number size distribution, is a nanomaterial should be considered as complying with the definition in point (2) even if the material has a specific surface area lower than 60 m2/cm3.

6. By December 2014, the definition set out in points (1) to (5) will be reviewed in the light of experience and of scientific and technological developments. The review should particularly focus on whether the number size distribution threshold of 50 % should be increased or decreased.

7. This Recommendation is addressed to the Member States, Union agencies and economic operators.

Particular points of interest here include:

1.  The inclusion of incidental and natural materials in the definition.  The inference is that any product containing or associated with nanomaterials from any of these sources will potentially be regulated under this definition.  Strict enforcement of this definition would encompass many polymeric materials and most heterogeneous materials currently in use.  And the lack of distinction between “hard” and “soft” nanoparticles means that the definition applies to any substance containing small micelles or liposomes – someone needs to check the micelle size distribution in homogenized milk.

2.  The focus on unbound nanoparticles and their agglomerates and aggregates.  This makes sense in terms of targeting materials with the greatest exposure potential.  But it may be hard to apply to complex nanostructured materials which nevertheless present unusual health and environmental risks – such as materials with biologically active structures that are not based on unbound nanoparticles (patterned surfaces, porous materials and nano-engineered micrometer-sized structures come to mind).

3.  The threshold of 50% of a material’s number distribution comprising of particles with one or more external dimension between 1 nm – 100 nm.  This is a laudable attempt to handle materials comprised of particles of different sizes.  But it is unclear where the scientific basis for the 50% threshold lies, how this applies to aggregates and agglomerates, and how diameter is defined (there is no absolute measure of particle diameter – it depends on how it is defined and measured).

4.  The “grandfathering” in of materials such as fullerenes, graphene flakes and carbon nanotubes with one or more dimensions below 1 nm.  This makes little sense – carbon 60 fullerenes are around 1 nm in diameter, and single walled carbon nanotubes typically have a lower diameter just above 1 nm.  Unless this is a typo, and should have read “100 nm”.  Surely not.

This seems very much like a definition of convenience – and one that I worry will detract from developing evidence-based regulation (see my previous comments on this).  Of course, the critical question is, how will the definition be used.  According to the EC,

Nanomaterials are not intrinsically hazardous per se but there may be a need to take into account specific considerations in their risk assessment. Therefore one purpose of the definition is to provide clear and unambiguous criteria to identify materials for which such considerations apply. It is only the results of the risk assessment that will determine whether the nanomaterial is hazardous and whether or not further action is justified.

In other words, there is no clear evidence of risk here, but provisions are being made to regulate a notional class of materials, just in case evidence should indeed emerge.

The desire to identify materials that require further action makes sense.  But I do worry that this definition is a significant move toward requiring industry action and providing consumer information in a way that creates concern and raises economic barriers, without protecting health (and possibly taking the focus off materials that could present unusual risks) – in the “do no harm” and “do good” stakes, it seems somewhat lacking.

1 LaVerne Poussaint October 18, 2011 at 5:34 pm

Re 3 “But it is unclear where the scientific basis for the 50% threshold lies, how this applies to aggregates and agglomerates…”

The 50% benchmark appears not to be arbitrary: SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise. It has been proven possible to protect half of an SWNT from oxygen exposure, while exposing the other half to oxygen, so this control measure seems to one of flammability risk mitigation.

Also, nanoviruses scale within the 30-50nm range and commercial nanofilters are successful at retaining larger (80-110nm) viruses, but nanofiltration clearance challenges of smaller viruses (18-30nm) have proven less comforting.

As to aggregation: “Viruses derived from crude preparations, such as tissue culture lysates, may be aggregated. As such, viral clearance can be achieved with filters having pore sizes many times larger than the known diameter of the virus in question. Virus aggregation can therefore result in a significant overestimation of viral clearance during filter validation experiments.”
See: http://americanpharmaceuticalreview.com/ViewArticle.aspx?ContentID=5

What I see is a real “rubber meets the road” effort to move industry viably forward while remaining circumspect, closer to a substantial somewhere, and much farther away from the nearer to nowhere previous impasse and legislative lethargy.

Re 4 “The “grandfathering” in of materials such as fullerenes, graphene flakes and carbon nanotubes with one or more dimensions below 1 nm… […] “Unless this is a typo, and should have read “100 nm”. “

Not a typo, I think, but a taking into account of the pico -> nano charge transfer (transport phenomenon) and related variables and factors other than size during testing of eNPs and processing of artificially- engineered nanosystems.

While these adoptions and implementations may not satisfy some critics, it surely shall survive Court dismissability procedures in any current and future health/medical disability insurance and workers’ compensation claims and it also points to a particular way forward towards productive nanotox research and documentation.

This is right, and right on time.

Towards tomorrow, by orders of magnitude!
-LLP

2 LaVerne Poussaint October 18, 2011 at 5:46 pm

If a product or a therapeutic process cannot pass the pico -> nano test, surely that obviates the need for certain micro/macro discussions and contestations, yes?

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