"On the issue of nanomaterials, we have to questions about their utility in view of the health risks"- Aurélie Niaudet.

What are the characteristics of nanomaterials?

Their very small size gives them novel properties such as resistance, conductivity and an ability to transport other substances. These properties are highly sought after and increasingly exploited, but can also induce specific types of behaviour when interacting with humans or the environment. For example, we know that they can pass through physiological barriers such as skin and the respiratory tract, while some of them also have specific types of toxicity. Once the human body has been exposed, there is then the question of the distribution and possible accumulation of these nanomaterials in the various organs.

What kind of difficulties do you face when assessing the effects of nanomaterials?

Depending on their shape and characteristics, nanomaterials interact with living organisms in different ways. A wide variety of parameters can influence their toxicity: their chemical nature – for example silica, titanium or silver – but also their size, shape, surface area and the characteristics of any coating they may have . In general, assessing the risks associated with nanomaterials involves three steps: agreeing on criteria for defining them, describing the main types of exposure, and understanding their behaviour and effects.  In fact today there is still no single clear definition of nanomaterials. Apart from their size, few physico-chemical parameters are taken into account in the definition currently proposed by the European Commission. So in order to protect people, we need to be pragmatic and above all understand the nanomaterials to which we are most exposed.

What is the focus of ANSES's work on nanomaterials?

We have been working on this issue for a long time at ANSES. We assess the risks of nanomaterials to the general population, to workers handling these substances – for example in product manufacturing – and to the environment.
Among other substances, our work covers titanium dioxide, which is used as a food additive, and nano-silver, which is used for its antibacterial properties. We have also been working on methodologies to offer alternatives to the assessment methods traditionally used and better integrate the different behaviours of these compounds. We recently published a review of the presence of engineered nanomaterials in food and recommended a suitable method for assessing the health risks of these materials when found in food.

ANSES also manages the "R-Nano" register. This mandatory declaration scheme was set up in 2013 to improve the traceability of nanoparticle substances produced, imported and distributed in France. In 2020, an analysis of the scheme highlighted the poor quality of the reported data and led ANSES to issue recommendations to declaring companies and to the ministries to consolidate this register and increase its usefulness.

Lastly, through the National Research Programme for Environmental and Occupational Health (PNR EST), coordinated by ANSES, we also fund research projects on the effects and environmental fate of nanomaterials, as well as on monitoring population exposure, etc.

To conclude, what are your recommendations to protect people?

It is clear that there are still many grey areas regarding population exposure to nanomaterials and the potential impact on health and the environment. In addition to strengthening the regulatory framework, it is also important to limit exposure of the population and the environment as a precautionary measure, by choosing safe products that are equally effective but free of nanomaterials. Moreover, given the persistent unknowns about nanomaterials, some uses seem artificial, and the Agency reiterates its recommendation to restrict the use of products containing nanomaterials that are of little benefit to the population