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The nanoscale: where nature loves to hide

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The potential for nanotechnology to undermine our certainties about how matter behaves can also put into question our assumptions about how we assess risks. One thing is for certain: this is the start of a long and unusual journey.


It is a truism to say that we tend to be frightened of those things we can’t see; of things that go bump in the night and which trigger our imaginations to think the worst. Whether it is supernatural shape-shifters that defy our understanding or all-too-human psychopaths that hide in the shadows, our visual sense is fundamental to how we construct knowledge and a realistic appreciation of risk. 

Such atavistic fears would seem to have little role in the ultra-modern science of nanotechnology, which, after all, describes a huge variety of materials, techniques and uses. But in its short, 30 years of history and with headlines like ‘nanotubes may lead to cancer’ or ‘nanobots’ will eat up the world and turn it into ‘grey-goo’; with commentators calling it ‘spooky’ and doubting the public will accept it, nanotechnology has an image – and risk – problem.

With one nanometre (nm) equal to one billionth, or 10−9, of a metre, nanotechnology is the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometres, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering and technology, nanotechnology involves imaging, measuring, modelling and manipulating matter at this scale. To put that scale in another context, the comparative size of a nanometre to a metre is the same as that of a marble to the size of the earth.

There is a distinction between nanomaterials and nanotechnology. Nanoscale particles are not new in either nature or science. Many of the inner workings of cells naturally occur at the nanoscale. For example, hemoglobin, the protein that carries oxygen through the body, is 5.5 nanometres in diameter. A strand of DNA, one of the building blocks of human life, is only about two nanometres in diameter. Some nanomaterials are natural, while others are the by-products of human activities, or are specifically manufactured for a particular purpose.

The creation of tools to manipulate matter at this scale means to use of nanomaterials to engineer products at the nanoscale. These new products make nanotechnology distinct from devices which are merely miniaturised versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description of microtechnology.

The quantum realm
The revolutionary potential of nanomaterials is not really about these quantitative considerations of scale. What is important about nanotechnology is what it means for the properties that such matter exhibits. It is these qualitative changes that make nanotechnology such an exciting prospect.

Michael Riediker is director of operations at SAFENANO, Europe’s centre of excellence on nanotechnology hazard and risk, based at the Institute of Occupational Medicine, a centre that facilitates responsible development of safe nanomaterials and nanotechnology-enabled products. He explains that “nanomaterials often show physico-chemical properties that are different from individual atoms or the larger sized material. Since biology interacts with material on the basis of physico-chemical properties, there are also different biological effects possible as compared to atoms or larger sized material. Thus, many nanomaterials will behave like a new chemical substance.”

This means a number of physical properties of matter change at the nanoscale when compared to their macroscopic or bulk forms. Nanoscale materials have far larger surface areas than similar masses of larger-scale materials. As surface area per mass of a material increases, a greater amount of the material can come into contact with surrounding materials, thus radically altering the mechanical, optical, thermal and catalytic properties of materials. Things hard can behave like they’re soft and pliant; liquids act like solids; resistant substances become conductive, or vice versa. This development, Michael points out, means “many of the risks associated with nanotechnology are not related to the technology itself but to the direct health effects from nanomaterials.”

Commercialisation
These property-shifting or property-enhancing goals of nanotechnology create, of course, enormous commercial opportunities, but it would be a mistake to think of nanotechnology as a sector. It is in fact a set of tools and methods that in theory could be applied in any sector, or even creates new ones. A spokesperson from the European Agency for Occupational Safety and Health (EU-OSHA) said: “Nanomaterials offer new and exciting opportunities in areas such as engineering, information and communication technology, medicine and pharmaceuticals, to name but a few.” For instance, copper can become transparent; aluminium can turn combustible; gold may become soluble and though chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Huge areas of public policy such as securing the world’s energy needs or solving health problems are drawing on advances in nanotechnology.

In 2009 the European Commission estimated that 11m tonnes of nanomaterials were on the global market with a value of €200bn. The current direct employment in the nanomaterial sector is estimated at 300,000 to 400,000 people in Europe. In recent years, many new nanomaterial-related applications have been developed, including a number of consumer products such as UV-filters in sun creams and anti-odour textiles.

Medical and technical applications such as tumour therapies, lithium-ion batteries that can drive electrical cars or solar panels also exist. It can even make tennis balls last longer or golf balls fly straighter. Trousers and socks have been infused with nanotechnology so that they will last longer and keep people cool in the summer. Bandages are being infused with silver nanoparticles to heal cuts faster. Carbon nanotubes are important – we will come back to these when we look at the risks to health – and these are widely used for their mechanical strength, light weight, heat-dissipation properties and electrical conductivity in applications such as electronics, energy storage, spacecraft and vehicle structures and sports equipment.

Those applications have the potential to create major technological breakthroughs, and the market is expected to grow, and quickly. The European Commission estimates that products underpinned by nanotechnology are forecast to grow from a global volume of €200bn in 2009 to €2 trillion by 2015.

Risks and the asbestos question 
Nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials. Its ability to fundamentally rewire matter also brings concern about its effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted. EU-OSHA recognise large gaps in our knowledge of nanotechnology.

Size and emerging, divergent properties are the two main aspects of nanotechnology that present the greatest challenge to any efforts to manage risk from a health and toxicity perspective. These risks extend across workers and public. Epidemiological responses are being led by the relevant authorities; including HSE and DEFRA in the UK and EU-OSHA at European level.

An EU-OSHA spokesperson explains: “Following the entry of nanomaterials into the body, some have been found in the lungs, liver, kidneys, heart, reproductive organs, fetus, brain, spleen, skeleton and soft tissues. The cardiovascular system may also be affected. Open questions remain concerning the bioaccumulation of nanomaterials and elimination mechanisms from cells and organs.

An additional issue is that, while a nanomaterial itself may not be toxic, it could act as a Trojan horse, meaning that a more toxic material may attach itself to the nanomaterial and gain entry to the body, organs or cells.”

When it comes to the risks associated with the size and properties of a nanomaterial, Michael thinks the biggest concern “is with those that are reactive, bio-persistent and at the same time very small, which allows them to translocate from the lungs or the gut into other parts of the body”. Not surprisingly, the ones to watch are those that get into the lungs, and the concern is that they will trigger cancers. A two-year study (2008/10) at UCLA’s School of Public Health into nano-titanium dioxide showed DNA and chromosome damage to a degree linked to all the major illnesses, namely cancer, heart disease, neurological disease and aging.

Concern about cancer is particularly applicable to carbon nanotubes, where comparisons to asbestos have been made. A report by the Royal Society and Royal Academy of Engineering in 2004 suggested that nanotubes might deserve special toxicological attention, largely due to their potential to induce similar health effects to asbestos.

According to the EU-OSHA spokesperson, “researchers subsequently emphasised that fibre-shaped nanomaterials may present a potent inhalation hazard that should be evaluated as a matter of urgency”.

Other researchers have also suggested similar health implications of carbon nanotubes. Professor Anthony Seaton, honorary senior consultant at the Institute of Occupational Medicine in Edinburgh, has indicated that some nanotubes have the potential to cause mesothelioma and has asked for regulations to be in place to ensure that they are handled in the right way to minimise exposure.

Carbon nanotubes are hollow and 10,000 times smaller than a human hair. The huge surface area of carbon nanotubes makes them ideal to be used as electrodes in capacitors, meaning that energy can be stored throughout the whole ‘tube’, not just at the ends, as in conventional capacitors.

There is already a growing commercial market for these products. According to the article ‘Carbon Nanotubes: Present and Future Commercial Applications’, published in Science magazine in 2013, the production of nanotubes presently exceeds several thousand tons per year. Currently, bulk carbon nanotube powders are incorporated in diverse commercial products, ranging from rechargeable batteries to automotive parts; sporting goods to water filters.

Michael reminds us to keep things in perspective. For him comparing nanotechnology to asbestos is “as useful as claiming that chemicals are harmful, for instance think of water as an example of a chemical”. According to him the comparison comes from two issues: “firstly, there is a small class of nanomaterials that are bio-persistent long fibres. The best known are long stiff carbon nanotubes which show in animals similar health effects as asbestos; and, secondly, there is a worry that it may take us many years to discover unknown effects of nanomaterials, in a comparable way to how asbestos went from a miracle material to being banned.”

An HSE spokesperson says that any comparison to asbestos must take into account the different historical contexts. “It should be remembered that, historically, asbestos was used in a wide range of industries and products, with little consideration for protecting workers or understanding of the long term health effects. In the UK there is a regulatory framework in place to ensure that workers are not exposed to harmful materials as they were in the past.”

Michael also supports this view, pointing out that the assessment and control of risks will be the same in place for any chemical. “The risk of a nanomaterial is a function of its hazard and the potential for exposure. For example, nanomaterials inside a computer chip are very unlikely to ever get in contact with humans, whereas nanomaterial on textiles or even in free powder form are more likely and thus need more attention.”

The other aspect of nanotechnology is of course the emerging and unique properties of materials that ‘operate’ in the quantum field. This of course makes any predictions about the health implications of nanotechnology very difficult. The HSE spokesperson concurs that “there are uncertainties as to whether the unique properties of engineered nanomaterials pose an occupational health risk. There are gaps in knowledge in predicting health risks and the interaction of the nanomaterial with the body’s biological systems are not yet fully understood. More data is needed on the potential health risks associated with exposure to engineered nanomaterials and this is the position for all regulators, not just HSE in the UK.”

Research and regulation in the face of uncertainty 

Clearly, research must be carried out to build the evidence to create or update regulations that will be effective. For EU-OSHA, this work must not be at the expense of action now. “Given that not all nanomaterials have a toxic effect, a case-by-case approach is necessary while ongoing research continues.” They are concerned though that for workers – either involved in production or those exposed at different stages of the supply chain – it is unlikely that sufficient measures are being put in place to prevent exposure. ”The complexity of the supply chain means that many workers may not be aware they are being exposed to nanomaterials and may inhale them, or for them to come into contact with the skin.”

In the face of such rapid developments – particularly in the last 10 years as nanotechnology has grown commercially – it is very difficult for a regulator to stay up to date. HSE explains that since 2003 collaboration across government and industry has been important; HSE has also provided joint funding into research, principally through scientific input into large EU joint funded projects, to maximise the benefits from expenditure on research. Also in 2003 the Royal Society recommended that HSE carry out a review of the adequacy of existing regulations to assess and control workplace exposure to nanoparticles and nanotubes.

Findings from a study by the UK NanoSafety Group (a group that brings together key experts in the field of nanotechnology) showed that research groups in university departments are on the whole more than adequately controlling exposure to nanomaterials in laboratories.

At the same time, HSE is confident that the current UK regulatory framework – underpinned by the Health and Safety at Work Act 1974 – is adequate to control the risks to workers arising from nanotechnology. “The framework includes the Control of Substances Hazardous to Health (COSHH), and the principles of risk assessment embedded in COSHH apply to the use of nanomaterials”, explains the spokesperson.

Importantly, though, the framework also sets out what to do when we don’t have all the facts at our disposal. “As data gaps exist, the regulatory response is to take a precautionary approach, and this would include using equipment that fully encloses the process at source, for example carrying out all tasks, including packaging for disposal, in a ducted fume cupboard with a HEPA filter, or by using other suitable effective local exhaust ventilation (LEV) fitted with a HEPA filter.”

EU-OSHA points out that the primary source of information for workers on nanomaterial risk management is that “contained in material safety data sheets (SDS). Unfortunately, the quality and usefulness of the information is not often sufficient for the purposes of effective risk communication and management, since it is often not specific to nanoscale versions of the material but relies on unjustified extrapolations from the bulk form of the chemical.”

The EU-OSHA spokesperson further clarifies that “directive 98/24/EC on chemical agents at work imposes more stringent provisions on the management of risks from substances at work, in particular the hierarchy of prevention measures that strengthens elimination or substitution as priority measures – which also apply to nanomaterials, as these fall within the definition of ‘substances’.

“Consumer products that are not a subject of specific legislation have to meet the requirements of the General Product Safety Directive. Community regulation in these areas contains provisions in relation to health and safety of consumers, workers, patients and users. As nanomaterials contained in such products are a subject of REACH legislation, an assessment on their environmental impact must be conducted. All product legislation imposes a risk assessment and the adoption of risk management measures. Nanomaterials are not excluded from this obligation.”

Though the European Commission concluded that on the basis of its second regulatory review on Nanomaterials, REACH sets the best possible framework for the risk management of nanomaterials, there is a danger that such a patchwork of laws can look a little bit like ‘catch up’. Of course, legislators and regulators have to wait for research to produce the evidence, a process that undoubtedly takes longer than heavily financed innovation to speedily bring products to market.

Michael states that the EU does provide significant funding for research on materials and risk assessment. “Hopefully in the near future, the EU will also start funding epidemiological research that will be needed to document that the safety, health and environmental measures put in place are indeed meeting the protective goals.” In 2013 the Commission did look at more specific requirements for nanomaterials within the existing framework, but this was limited to some modifications of the REACH annexes.

Risk perception: dread, suspicion and proceeding with caution 
Beyond the question of whether the regulatory regime is, or is not, up to date, does nanotechnology itself call into question of how we create regulations and assess risk? In other words, can any directive or regulation deal with matter operating under the influence of quantum mechanics?

The EU-OSHA spokesperson says: “The fact that materials with essentiality the same name can have vastly different properties at the nanoscale can cause confusion and misunderstanding.”

The answer to this question is to give risk-perception sufficient importance and think how, as a society, we decide to embrace complex developments in scientific discovery. As long as there is insufficient evidence to carry out robust risk assessments of many existing nanomaterials, it will be important strategically to understand risk perception.

Influencing public opinion will be crucial to the success of this technology, not dissimilar to debates around biotechnology.

“Many of the factors that can heighten dread, develop conflict and delay appropriate prevention measures are present in nanomaterials,” the EU-OSHA spokesperson adds. “We know from risk perception theory that lack of knowledge, lack of transparency, the involuntary nature of exposure or delayed or uncontrollable effects can cause the public to judge it as being too high risk.”

Michael explains the origin of this perception: “In the beginning of nanotechnology, there were many fears that nanoproducts were boosted by fiction writers, such as the fear that ‘nanobots’ would ‘eat up’ the entire world. Fortunately, this is physically not possible. The smallest self-reproducing units are cells, which are several micrometres in size. Nanotechnology cannot go smaller because the information storage cannot go smaller than what the cells are using, i.e. DNA.”

The problem was that instead of being open about the new technology and dissipating fears, “some industries denied originally that many nanomaterials have different physico-chemical properties compared to larger material and tried to downplay justified worries. Also, even nanomaterials that were designed to be safe for users, for example nano-TiO2 in sunscreen, would not be declared on packaging labels for a very long time. The impact of this of course was suspicion and the perception that the industry had something bad to hide. But in fact, as I saw in Switzerland, being open about the composition of a product has the opposite, trust-building effect.”

Nonetheless, according to EU-OSHA, nanotechnology is, at the moment, most often framed by both the media and general public in terms of benefits. Public awareness of the issue, though, is a concern, as the EU-OSHA spokesperson goes on to explain: “A large fraction of the public still knows very little about nanotechnology.

“The Eurobarometer survey carried out at the beginning 2010 showed that a majority of Europeans, 54%, have never heard of nanotechnology. Comparable surveys in North America and Japan showed that more than 51% of all participants who were asked about their knowledge of nanotechnology reported knowing ‘nothing at all’, and nearly 30% ‘just a little’. Only 20% claimed to know ‘some’ or ‘a lot’ about nanotechnology.” It also doesn’t help to spread the knowledge that literature is mostly in English and intended for a specialist audience rather than the general public or workers.

The way forward 
Improved risk communication and a precautionary approach as research catches up seems to be the way forward. Most regulators agree that this should take the form of tightly controlling the release of nanomaterials into the environment and the exposure of both workers and the general public “to ensure that if serious hazards are subsequently identified, exposure has been minimised. It will also be important to communicate and discuss not only the potential risks of nanomaterials with workers, but also the uncertainties currently surrounding the field of their hazard characterisation.” This is something HSE agrees we are seeing more of.

So, information to influence the public’s perception of risk, a precautionary approach, more research along with existing regulations, openness and labelling are all part of the package of measures to ensure we benefit from this technology while constraining its risks.

Given that ‘nature loves to hide’ in the face of scientific discoveries that seek to slowly peel back the layers of what is real, the worst response by regulators and industry will be to conceal what emerges. In doing so, public opinion will only conspire with nature and quickly demand ‘no more,’ a situation we saw in large parts of the world to the genetic modification of our food.

Health and safety is not in opposition to nanotechnology (no matter what the ‘red-tape’ brigade say); it is a key enabler to its success. The tragedy of getting it wrong – both at a regulatory response and risk-communication level – will not be just the loss of commercial opportunities, it will be the loss of potential that this technology has to realise some of our most pressing needs.

 

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