Updating our language: why should not paint all nanoforms with the same brush

2021-05-31

One of the most important functions of language is the ability to describe reality in increasing degrees of precision. For example, what many of us would simply call “red” can be vermilion, carmine, crimson or scarlet to a painter. Similar levels of accuracy also exist for what most people would still simply call “nanomaterials”. To continue with our colour metaphor, this helps us to identify red. But what if we need to be more precise than that?

The EU definition originally adopted in 2011 describes a nanomaterial as a material at the nanoscale i.e. smaller than 100 nanometres (to put this in context, our red blood cells typically measure 7-8 nanometres).

Just as an artist does not treat all shades of a colour the same way, assessing the behaviour of substances at the nanoscale requires a greater degree of precision than that allowed for by the term “nanomaterial” as defined by the EU. This is because talking about a specific “nanomaterial” only tells us about its elemental composition and size; however, at the nanoscale, that substance can adopt more than one different form (i.e. a nanoform), and, most importantly, those nanoforms can behave differently in terms of their physico-chemical properties. If we just call them all a nanomaterial, we’re erasing those differences.

Why is this important? The EU REACH Regulation lays out the requirements that companies have to meet to lawfully place their chemicals on the market, including the registration of any substance produced, imported or used in a quantity above one tonne/year, as well as a Safety Data Sheet (SDS) which must be provided to every customer with the first delivery of a chemical. This way, the customer can prepare accordingly and put in place adequate worker protection procedures, as well as environment protection measures where needed.

Remember what we just said about different nanoforms of a chemical having different properties and behaviours? SDS are where those differences come into play. Let’s take for example nanosilver, one of the most studied substances at the nanoscale, which is used in a variety of applications including medicine, textile, and cosmetics: to talk about nanosilver simply tells us that we’re looking at the chemical element silver, at a size smaller than 100 nanometres. Nanosilver, however, comes in different nanoforms that have different properties. This means that, while one form of nanosilver can be used as an effective anti-microbial agent, another one may be used in tagging and imaging applications, and both will be associated with different (if any) toxicities: it seems obvious that we would not treat them in the same way.

To go back to our artistic metaphor, imagine you’re a contemporary Rubens working on the portrait of Emperor Maximilian, and want to add some rich red velvet in the background; you know that different shades will create very different effects and that crimson will be much better than vermilion. Now imagine that your paint delivery arrives, and the can only says “Red”. It could be crimson, it could be vermilion, it could be yet another shade. You’re probably not going to risk ruining your work, so you’ll decide to stay away from the colour red altogether and paint that background grey.

If we apply this to nanoforms, the impact can be damaging: if the language we use does not allow us to capture their differences in terms of hazard profiles, we risk ending up with a blanket approach that attributes to all nanoforms of a same substance the risk profile of the most hazardous of them, misleading us into avoiding or even banning them altogether. This in turn can hamper the development and use of novel materials, missing out on the opportunities they afford.

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EUON, 31 May 2021
; https://euon.echa.europa.eu/nanopinion/-/blogs/updating-our-language-why-we-should-not-paint-all-nanoforms-with-the-same-brush