Nanotechnology – we need a precautionary approach to this rising tech


6
Jun 2014

Manipulation of substances at the scale of a molecule – the nanoscale – will result in a wave of new materials with unheard-of-before properties during this century. Although some nano particles have been around for a while many more are still just in the research phase, their potential yet to be fully realised.

Nanotechnology is the ‘science of designing, producing, and using structures and devices having one or more dimensions of about 100 millionth of a millimetre (100 nanometres) or less.’ A nanoparticle is the size of an individual molecule – and such particles or materials behave differently at this scale – the nanoscale.

…there are many risk-related knowledge gaps to be filled and that the emissions of graphene, the fate of graphene in the environment, and the toxicity of graphene should be further studied

In terms of our environment, nanomaterials offer many opportunities for achieving greater energy efficiencies, reducing pollution and aiding recycling, but such new materials, like any newly developed chemical, might also pose a risk to our environment and health.

In the past many materials were touted as safe, ‘wonder’ or ‘miracle’ materials have turned out to be extremely, and some irreversibly, problematic to health and the environment – DDT, asbestos, PVC’s and phthalates are just some examples. How do we minimise the potential negative impacts of these new materials on our environment and health? Should they be assessed differently to other chemicals? And instead of just a risk assessment shouldn’t we be asking at this early stage, whether these new materials on the horizon will contribute to our goals for sustainable development, a carbon-neutral, cradle-cradle or circular economy of zero-waste material efficiency?

Three such nanomaterials that have been in the news recently are – graphene, pollution-eating nano-titanium dioxide (nano-TIO2) and carbon nanotubes (CNTs). What do they offer, are they safe and how are they regulated?

Graphene

Graphene is definitely the nanomaterial attracting most attention due to its ‘super’ properties. Prized for its strength, conductivity and flexibility its potential applications are extraordinary. Synthetically engineered, graphene is a one atom thick, nearly transparent sheet of pure carbon molecules. Ultra thin, ultra strong – 100 times stronger than steel (based on weight).

First created in 2004, graphene is not yet on the market but is being extensively manufactured and researched by many companies for potential applications ‘as diverse as battery electrodes, super-capacitors, nano-electronics (e.g. transistors and sensors), inks, anti-bacterial paper, and many biomedical uses for imaging, drug delivery, tissue engineering, and biosensors’ (SAFENANO).

Wow, graphene sounds cool and unbelievable! But… recent research indicates that graphene isn’t that clean. Its toxicity in the environment could be substantial and therefore it requires further research, and potentially more stringent regulation, to limit the material’s negative impacts. According to one study graphene:

‘…could exert a considerable toxicity and that considerable emission of graphene from electronic devices and composites are possible in the future. It is also suggested that graphene is both persistent and hydrophobic. Although these results indicate that graphene may cause adverse environmental and health effects, the results foremost show that there are many risk-related knowledge gaps to be filled and that the emissions of graphene, the fate of graphene in the environment, and the toxicity of graphene should be further studied’ (Research Gate).

Furthermore, researchers from the University of California found that graphene oxide nanoparticles are highly mobile in lakes and streams, raising concern that when released into the aquatic environment such particles could have negative environmental impacts. The study also recommended the need for further research to really ascertain the full impact graphene could have on the environment.

Looking at the biological effects of graphene, studies suggest that graphene might be genotoxic because it is so small it can interact with our DNA. Additionally, because of its tiny size, on inhalation during for example its manufacture, it could badly impact respiratory and lung health (SAFENANO).

Titanium dioxide nanoparticles (nano-TiO2)

Titanium dioxide nanoparticles (nano-Tio2) are so small they do not reflect visible light, so cannot be seen. Nano-Tio2 has been used in sun creams as UV filters for decades, and they can be found in cosmetics and in household products such as paints. The nano-TiO2 is distinguishable from regular/bulk TiO2 which is used in pigments for paints, plastics and paper, amongst other applications.

The tiny nanoparticles of nano-TiO2 are now being used as a means to reduce air pollution. It has been shown that by incorporating or covering surfaces with nano-TiO2, concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides can be substantially reduced. Such ‘photocatalytic cement’ is incorporated in outdoor buildings as well as pavements to keep them clean as well as acting as air cleaners. The nano-TiO2 reacts with pollutants preventing them from discolouring the surface, making defunct the use of chemical cleaners.

Most recently a professor at the University of Sheffield created a large poster glazed with nano-TiO2. It is said that it can convert the pollutants from 20 cars into compounds harmless to health such as carbon dioxide and water.

Use of nanoparticles of TiO2, for example in sunscreens, was approved in the EU and US with supposedly minimal risk assessment. The US Food and Drug Administration (FDA) reviewed the immediate health effects of exposure to the particles for consumers. However, they did not review its impacts on aquatic ecosystems (when the sunscreen rubs off), nor did the US Environmental Protection Agency (USEPA). Impacts of TiO2 on more vulnerable groups such as the use on children of sunscreen over long periods of time was also not assessed.

More recent research has suggested that nano-TiO2 might be of greater risk to health than previously thought. Due to this the US National Institute for Occupational Safety and Health have recommended occupational exposure limits of nano-TiO2 as science indicates that the nano version of Titanium Dioxide could be a potential carcinogen.

Carbon Nanotubes (CNTs)

Carbon nanotubes are hexagonal arrangements of carbon atoms built up to form a fibre. CNTs are already being used in cosmetics, sunscreens, sporting goods, clothing, electronics, baby and infant products, in food and food packaging. But their potential applications are much greater and more advanced – in biosensors, robotics, super strong sticky tape, improved computer and TV displays, to repair broken bones, in medicine to deliver drugs directly to cells in the body, supercapacitors, strengthen and change material properties, electricity generation and distribution and water filtration. Phew – that is a list and a half!

But like graphene and nano-TiO2 their health and environmental impacts are still not fully understood, and latest research is calling their safety into question.

As early as 2004, scientists picked up on the possibility that some CNTs – depending on size and dimension – could exhibit asbestos-like behaviour. The concerning CNTs are called HARNS - High Aspect Ratio Nano Structures.

In 2009, a consortium of scientists in the UK released a report identifying the potential health risks of HARNs, and further corroborating research published in 2011 strongly suggested that it is likely that some HARNs will act like asbestos in sufficient quantities with potential severe respiratory-related health impacts.

More recent research into CNTs in our environment has indicated that CNTs could potentially be released into our environment during breakdown of nanocomposites, such as plastics (containing CNTs), under normal conditions such as general wear and tear in sunlight. The study highlighted that ‘there remains a need to confirm whether the environmentally degraded nanocomposite is non-toxic, given the observation of free form of CNTs on the degraded nancomposite surfaces’.

Regulation

Currently in the EU, nanomaterials are covered by the same legislation entitled REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances) as ‘normal’ chemicals as they are considered the same, so are assessed accordingly – each new nanomaterial must go through a risk assessment on a case-by-case basis as some will be toxic while others will not. Under REACH there is a ‘no data, no market’ requirement and each new chemical for commercial use must be registered. Additionally, the precautionary principle is a recognised approach when there is lack of data.

Sounds good but the hitch is that nanomaterials are still not considered different to regular versions of the same material. Although there is ongoing discussion by the European Commission as to whether this ought to change. Additionally, the responsibility lies with the manufacturer to provide details on the safety of the particular substance under question.

In the US the Food and Drug Administration (FDA) only regulates on the basis of voluntary claims made by the product manufacturer. If no claims are made by a manufacturer, then the FDA may be unaware of nanotechnology being employed. While in the UK, when existing substances are produced in nanoparticulate form regulations don’t require additional testing!

So, neither engineered nanoparticles nor the products and materials that contain them are subject to any special regulation regarding production, handling or labelling.

Is this good enough?

Based on the three examples above, it is easy to argue that it isn’t. Firstly it seems that nanomaterials have been approved for commercial use before their full potential health and environmental impact has been properly assessed. The precautionary principle has not been applied. Secondly, the size of a compound matters. Bulk titanium dioxide is different from nano-titanium dioxide and therefore the latter should be treated as a new substance, requiring a new form of risk assessment. Graphene should go through a more vigorous and custom assessment prior to full commercial approval!

In 2012, a group of civil organisations – The Center for International Environmental Law (CIEL), ClientEarth, and Friends of the Earth Germany (BUND) – called for the EU to address the risks of nanomaterials more effectively. They argued that ‘more specific requirements for nanomaterials within the framework have proven necessary’; and that further regulatory action is necessary, recommending a “nano patch” for REACH, including an obligation for all nanomaterials to be considered distinct from their non-nanoscale counterparts and substantially lower volume thresholds for registration of nanoscale substances.’

This sounds prudent. No?!

One could claim that nanotechnology is still in its infancy, and regulation is just catching up. But it is more likely that nanotechnology promises so much from a commercial and economic point of view that politicians and businesses alike do not want to see innovation thwarted and thereby slowed by overly prudent – precautionary – regulation.

As regards REACH, on the one hand it has to ensure a ‘high level of health, safety and environmental protection’ while at the same time ‘permit access to innovative products and promote innovation and competitiveness’. According to the EU commission the applications for nano materials and tech have: ‘…the potential to create major technological breakthroughs, and therefore nanomaterials have been identified as a key enabling technology. Products underpinned by nanotechnology are forecast to grow from a global volume of €200 billion in 2009 to €2 trillion by 2015.’ There is a huge economic incentive to assume that the products from nanotechnology are safe.

We are at a juncture now where it would make sense to be precautionary because of  – rather than in spite of – the technology’s infancy. Is it not better to restrain our excitement before we create a legacy we regret? Do we really want to find out in due course that the impacts on our health from certain nanoparticles are similar to that of asbestos?

Nanotechnology promises some interesting solutions to both environmental and health issues. Pollution-eating nano-particles is the least spectacular (just check out the ninja-polymers which IBM have been exploring). But we should be careful. Firstly about treating the symptom with a new, untested solution rather than focussing on tackling the cause (e.g. ); secondly about unrestrained innovation without common sense. We don’t need nanoparticles for everything just where the technology actually improves the world we live in.

What we need is a set of guidelines that will direct nanotechnology to solve the appropriate problems, and which will ensure that the technology is applied with sustainable development, circular-economic thinking and the good of humanity in mind.