There is enormous public support for investment in sustainable, renewable energy alternatives to coal or nuclear power. There is also growing support for ‘green’ substitution of toxic chemicals. But all too often industry and governments are prepared to promote new (or old) technologies with a thick veneer of ‘greenwash’, presenting them as environmental saviours despite evidence of serious environmental risks or challenges. The green hype around nanotechnology fits this pattern.
Nanotechnology, the ‘science of the small’, enables materials, systems and even living organisms to be manipulated at extremely small scales. Public awareness about nanotechnology remains low. But ‘nanoparticles’ are already being used – unlabelled and largely unregulated – in sunscreens, cosmetics, food packaging and health supplements, fertilisers and pesticides, clothing, electrical goods, household appliances, fuel catalysts, industrial processing and manufacturing.
Nanotechnology is promoted as an unprecedented techno-fix to our climate and energy woes, enabling unfettered economic expansion and consumption while dramatically reducing our environmental footprint. The Howard government’s "Smaller, Cleaner, Cheaper, Faster, Smarter" nanotechnology report is just one example of the enthusiasm with which nanotechnology’s putative environmental credentials have been used in its promotion.
The CSIRO has gone so far as to suggest that by enabling greatly increased production of cheap solar energy, greater energy and resource efficiency in ‘clean’ manufacturing, and atomic scale recycling of all inputs, nanotechnology will enable us to ‘decouple’ resource use from economic expansion.
It is rarely acknowledged that manufacturing nanoparticles and nano-films used in solar cells and elsewhere is extremely energy-intensive; the chemicals required for nano-manufacturing are often highly toxic, as are many nanoparticles themselves; and the carbon nanotubes mooted for use in lightweight superstrong plane parts cause mesothelioma (the deadly cancer previously thought to be caused only by asbestos).
Friends of the Earth has argued that in addition to introducing a new generation of toxic chemicals, nanotechnology is also likely to underpin a new wave of industrial expansion and economic globalisation that will magnify existing resource and energy use.
Future nanotechnology-based environmental gains are often touted in an effort to win public ‘hearts and minds’ and to head off unease about the health and environmental risks of nanoproducts that are now entering homes, workplaces and ecosystems. The problem is that while a very high level of proof is demanded of those calling for regulation of nanotechnology’s environmental risks, claims of environmental benefits have largely passed unchallenged and unassessed.
There is yet to be any life-cycle assessment comparing the sustainability of conventional and nanotechnology-based products. However there is emerging evidence that any environmental gains achieved by nanotechnology may be outweighed by the environmental costs of production.
Here is a brief summary of nanotechnology’s environmental pros and cons in a few key areas.
Energy and environmental costs
Nanotechnology proponents have claimed that nanoparticles will lower energy and resource use. This is because small quantities of more potent nanoparticles can theoretically accomplish the tasks of much larger amounts of conventional materials, and because carbon nanotubes are predicted to enable lighter industrial components whose use will require less energy.
However academics at the University of Illinois at Chicago have found that the manufacture of nanoparticles has an unexpectedly high environmental footprint. This was related to highly specialised production environments, high energy and water demands of processing, low yields, high waste generation, the production and use of greenhouse gases such as methane and the use of toxic chemicals and solvents such as benzene.
In a separate life-cycle study of carbon nanofibre production, academics at Ohio State University found that their potential to contribute to global warming, ozone layer depletion, environmental or human toxicity may be as much as 100 times greater per unit of weight than those of conventional materials like aluminium, steel and polypropylene.
Nanoparticles are likely to be used in far smaller quantities than conventional substances, so a life-cycle assessment of the products they are used in (which has yet to be performed on any nano-products) would give a more accurate estimate of total energy and environmental impacts. Nonetheless, these early findings led the scientists to conclude that any environmental gains of nanoparticles may be outweighed by the environmental costs of production.
Friends of the Earth Australia (FoEA) and others have voiced concern that nanoparticles themselves constitute a new generation of toxic chemicals. As particle size decreases, in many nanoparticles the production of free radicals increases, as does toxicity.
Test tube studies have shown that nanoparticles now in commercial use can damage human DNA, negatively affect cellular function and even cause cell death. There is a small but growing body of scientific studies showing that some nanoparticles are toxic to algae, invertebrate and fish species that regulators use as environmental indicators.There is also evidence that some nanoparticles could impair the function or reproductive cycles of bacteria, fungi or earthworms which play a key role in nutrient cycling that underpins ecosystem function.
The argument is often made that the potential environmental impact of potent nanoparticles will be greatly reduced because of the relatively small quantities in which they will be used. However, in 2006 the Woodrow Wilson International Center for Scholars’ Project on Emerging Nanotechnologies (PEN) estimated that 58,000 tonnes of nanoparticles will be produced world-wide from 2011 to 2020. The Center stated its concerns that given the potency of nanoparticles, this could have an ecological impact equivalent to five million up to 50 billion tonnes of conventional materials.
Nano solar
Amidst the hype that nano solar will soon deliver energy half the price of oil, coal or gas, last year the CEO of nanotechnology analyst Cientifica warned that we needed to take a "reality check" about its promise. "The companies using nanotechnology to produce thin film solar systems have burned through a quarter of a billion dollars of venture capital money over six years, and still haven’t cracked the manufacturing and reliability issues which will make the technology economic."
It is true that some of nano solar’s more exciting predicted applications are still at ‘early stage’ research, like energy generating plastic-based paint that can harvest infrared (non-visible) light. It remains to be seen whether or not such early stage research can be turned into practical products. However, other applications are reaching the market.
Nanoparticles like titanium dioxide, silver, quantum dots and cadmium telluride are being applied to thin film solar cells to boost their efficiency to as high as 14%, while quantum-dot based semiconductors are being developed to increase the currently low efficiency (around 6%) of polymer-based ‘organic’ photovoltaic plastics. A few US-based companies have recently claimed to be getting close to producing one gigawatt of solar energy annually. Company Nano Solar produces thin film cells at up to 14% efficiency (most other firms claims 6-12%) and claims to be nearing economic production at US$1/watt. Konarka has recently opened the world’s largest roll-to-roll flexible plastic film solar manufacturing facility.
First Solar, which produces cadmium-telluride nano film, currently has around 10% efficiency. In short, nano solar does not appear to be about to either deliver huge efficiency gains or to halve the cost of energy any time soon, although commercial production is slowly scaling up.
Efficiency gains in solar harvesting and manufacturing are certainly being made using nanotechnology – but they are modest gains. There is not yet any life-cycle assessment of nano solar products so it’s hard to tell what energy efficiency gains will exist once the energy required for manufacturing is taken into account. Furthermore, many thin film technologies are using nanoparticles that pose quite serious toxicity problems (e.g. cadmium, quantum dots, silver and titanium dioxide nanoparticles).
First Solar has committed to operate an end-of-life collection scheme, which is to be commended. However this is not the norm and there is still no safe method for disposal of waste nanoparticles.
Carbon nanotubes
Carbon nanotubes – cylinders made of carbon atoms which are 10,000 times thinner than a strand of human hair – are one of the nanoparticles generating the most excitement among industry. They are the stiffest and strongest fibres known and also have unique electrical properties.
Carbon nanotubes are already being used to reinforce specialty parts for planes and cars and high performance plastics, in fuel filters, electronic goods and carbon-lithium batteries. Their future use has been predicted to enable super lightweight planes and cars that will use much less fuel, dramatically reducing the environmental costs of air travel. They are also mooted for use in textiles, pharmaceuticals, food packaging and a range of other applications.
It is possible the huge energy demands of nanotubes manufacture could offset any efficiency gains from their enabling production of lightweight components. Lightweight planes could also simply lead to bigger planes or more flights being taken. However there are also serious concerns about their health and environmental risks, in particular, that some carbon nanotubes can cause asbestos-like harm if inhaled.
In 2004, the United Kingdom’s Royal Society, and risk specialists at the world’s second largest reinsurance agent Swiss Re, warned that nanotubes may behave like asbestos once in our lungs. Since then, a series of experiments have demonstrated that when introduced into the lungs of rodents, carbon nanotubes cause inflammation, granuloma development, fibrosis, artery ‘plaque’ responsible for heart attacks, and DNA damage.
Two independent studies have shown that carbon nanotubes can also cause the onset of mesothelioma – a cancer previously thought to be only associated with asbestos exposure.
Nano-geoengineering
Geoengineering is an emerging field where proponents hope to mitigate environmental problems by using technology to ‘re-engineer’ the environment, for example by ‘fertilising’ the ocean to produce huge algal blooms to absorb carbon dioxide, or by releasing nanoparticles into the upper atmosphere in an attempt to stop global warming.
Friends of the Earth is concerned that it is difficult to accurately model or predict the ecological consequences of such activities and that there is potential for large-scale ecological harm. The intentional mass release of nanoparticles into the environment has attracted opposition from senior scientists internationally.
In June, the UN Convention on Biological Diversity (CBD) supported a de facto moratorium on ocean fertilisation – despite Australia, China and Brazil blocking the moratorium until the eleventh hour. The moratorium came as several companies were planning to dump large quantities of tiny, perhaps nanoscale, iron filings into the ocean to produce a huge algal bloom that could supposedly suck up carbon dioxide – enabling the companies to claim lucrative carbon credits.
In the wake of the decision, research has been presented finding that in the ocean, iron encourages the growth of large populations of some algae species that produce domoic acid – a potent neurotoxin. German Environment Minister and CBD president Sigmar Gabrielle told Reuters, "It’s a very strange idea that technology can solve everything. It’s very risky and shows what humans are ready to do. I’m glad we came to a de facto moratorium."
However despite the moratorium, leading nano-geoengineering companies are gearing up to convince governments to support nano-geoengineering projects as a response to climate change.
Environmental life-cycle assessment
Early evidence of the much greater energy demands of producing nanoparticles, the significant quantities of potentially toxic waste their production generates, and the ecotoxic behaviour of many nanoparticles themselves have cast doubt on industry claims that nanotechnology offers ‘green’ solutions to ecological problems.
In many ways, nanotechnology offers the ultimate attempted techno-fix to problems that require social, economic and political solutions. In addition to questioning the energy demands and toxicity of nanoparticle production, we need to question the logic that underpins the quest for economic growth at all costs.
Without a change in the growth mentality, there is little possibility any efficiency gains made by nanotechnology will deliver environmental benefits rather than simply underpinning greater economic expansion.
This article was written by Georgia Miller for FoEA’s quarterly magazine "Chain Reaction" Issue 104.
