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Context - Nanotechnologies and nanomaterials use tiny particles of nanometre size (millionths of a millimetre) and have a great deal to offer to improve our quality of life.
However, new scientific methods have to be developped since current methods may not be relevant to testing nanomaterials.
This is a faithful summary of the leading report produced in 2015 by Dutch National Institute for Public Health and the Environment (RIVM): "Assessing health and environmental risks of nanoparticles: Current state
of affairs in policy, science and areas of application
Nanotechnologies and nanomaterials use tiny particles of nanometre size (millionths of a millimetre) and have a great deal to offer to improve our quality of life. However, as for any emerging technology or development, there are potential downsides.
A challenge posed by nanomaterials is to determine in what way their physical, chemical and biological properties are different to conventional materials, and how this influences potential harmful effects. In practice, new scientific methods have to be developped since current methods may not be relevant to testing nanomaterials.
Continuously new nanomaterials are being developed for a multitude of products. In parallel, our scientific understanding and ability to explain and describe the observed properties of nanomaterials is growing, but is still relatively limited. More importantly, our knowledge of the potential harmful effects of nanomaterials is progressing more slowly than the technological developments.
Scientific understanding is growing, but has not yet been able to provide general descriptive models; more practical data and understanding of the mechanisms are necessary to support this process.
When considering if nanomaterials can cause harm – if they present a hazard1 – an elementary but important observation is that nanomaterials and nanoparticles are in the size range of our biological machinery. Therefore, nanomaterials are a class of compounds that is toxicologically ‘new’, because it may interact with biological systems in a way which we now only partly understand. However, size is not the only parameter responsible for a possible toxic effect of a given nanoparticle.
Inhaling certain nano-sized particules may result in local lung inflammation, allergic responses or harmful effects on genes. Some specific types of nano-fibres may cause similar reactions as asbestos including chronic inflame mation. Additional concerns are related to internal exposure, as some particles may enter the bloodstream and accumulate in organs like the liver and spleen. Nanoparticulate matter is able to enter cells, which might in turn lead to direct and indirect genotoxic effects.
Meanwhile, new generations of complex and sophisticated nanomaterials are specifically designed for bio-interactions or have a self-assembling nature. These nanomaterials may behave in complex dynamic ways, which fundamentally complicates the process of scientific understanding. This novel class of nano-particulates notably includes nano-encapsulates that have been developed to be used in food and feed products and are already used for medical purposes.
When it comes to assessing the risk associated with exposure to nanoparticles in real-life conditions, the methods normally used, also need to be adapted because of the specific properties of some nanomaterials. This is time consuming and still requires considerable effort. For exposure at the workplace, pragmatic approaches have been developed in order to aid the assessment and subsequent control of nano-particles exposure.
The diversity of impact data and nanomaterials makes it difficult to draw conclusions on environmental risks of specific nanomaterials.
Most of the available information concerns the aquatic environment and virtually no information exists on the hazards of nanoparticles in soils and sediments. Increasing attention is being paid to potential harmful effects of transformation products which are formed after the introduction of a nanomaterial into the environment.
Models that describe the release of nonoparticles, their distribution in the environment and exposure of living organisms to them, are still scarce and so is the data to validate the models. Progress in the development of the analytical tools and methods to determine and measure nano-characteristics in complex media are needed, to gain insights into the presence of nanomaterials and exposure to them.
An environmental risk assessment for metallic particles of zinc has shown that the gap between effect levels and exposure levels is relatively large, so that as yet, no risk for organisms in EU waters is anticipated. However, a similar assessement for nano-silver does not exclude the occurrence of adverse effects on the environment.
Four main areas require progress :
First of all, we seriously need data – i.e. nanomaterial and nanoparticle specific data but also information on the use of nanomaterials/particles in products and their release from products.
Secondly, we need to improve our scientific understanding of nano-toxicological behaviour to enable the step towards generalisation and abstraction.
Thirdly, we need to address not only simple existing nanomaterials but also monitor and assess developments of new and emerging generations of nanomaterials.
Fourthly, we need to consider aspects of risk governance and how to deal with the difference in pace between nanomaterial innovations and our scientific and regulatory capacity to assess the uncertainties and risks, and ways of dealing with these potential risks and uncertainties.
Government, society in general, the scientific community, and the business community need to cooperateto find ways of dealing with fundamentally new and innovative developments in both materials and risks. This would add a firm foundation for increased data availability and mutual understanding.
In general, the European Commission concluded that the current EU-legislative framework, to a large extent, covers potential risks in relation to nanomaterials. Yet current legislation may have to be modified in the light of remaining gaps and new information becoming available, for example regarding thresholds.
1 For an explanation of the important difference between a « hazard » and
a » risk » in this context, see the short GreenFacts video on the subject:
www.youtube.com/watch?v=PZmNZi8bon8
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