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From 2020 Science: I’m
looking at an electron microscope image of a carbon nanotube - as I
cannot show it here, you’ll have to imagine it. It shows a long,
straight, multi-walled carbon nanotube, around 100 nanometers wide and
10 micrometers long. There is nothing particularly unusual about
this. What is unusual is that the image also shows a section of the
lining of a mouse’s lung. And the nanotube is sticking right through the lining, like a needle through a swatch of felt.
The image was shown at the annual Society of Toxicology meeting in Baltimore last week, and comes from a new study by researchers at the National Institute for Occupational Safety and Health (NIOSH) on the impact of inhaled multi-walled carbon nanotubes on mice.
It’s highly significant because it
takes scientists a step closer to understanding whether carbon
nanotubes that look like harmful asbestos fibers, could cause
asbestos-like disease. Questions were raised about carbon nanotubes and their superficial similarity to asbestos fibers as far back as 1992. Yet it wasn’t until last year that research was published suggesting carbon nanotubes that look like harmful asbestos fibers could possibly also cause asbestos-like diseases—specifically the disease of the lungs’ lining mesothelioma.
The Poland study, published in the journal Nature Nanotechnology,
indicated that development of the disease mesothelioma was
theoretically possible following inhalation exposure. But it didn’t
establish whether exposure could occur to asbestos-like carbon
nanotubes in practice or, if they were inhaled, whether the nanotubes
could move to and penetrate the sensitive outer layer of the lungs.
Both steps would have to occur for there to be a chance of mesothelioma developing.
The current study from NIOSH seems to
close the loop on one of those steps. Some caution is needed here as
the research has yet to be peer reviewed (see Richard Denison’s comments for instance). Yet the findings are so significant that NIOSH thought it important to keep people abreast of developments before the work is finally reviewed and published.
In the study, a suspension of carbon nanotubes was introduced into the mice lungs using the pharyngeal aspiration
technique, and the movement of the nanotubes through the lungs
subsequently tracked. The researchers found that some of the nanotubes
migrated from the alveoli in the lungs (the tiny sacs where oxygen
passes form the air to the blood) to the pleura—the delicate membrane
surrounding the lungs. As seen in the image described above, there was
direct evidence that some of these needle-like fibers physically
penetrated through the lung lining, into the region where mesothelioma
can develop.
The researchers are at pains to point
out that these data are preliminary, and are not conclusive. The
results could have been influenced by the way the nanotubes were
delivered to the lungs, the amount of material applied, or the types of
animals used. Nevertheless, they demonstrate that, in principle, some
forms of carbon nanotubes have the potential to migrate to the outer
layer of the lungs. And this, combined with the data from Poland et
al., raises the stakes considerably regarding potential health impacts.
The data from this study will be
peer-reviewed and published shortly, allowing a more critical
evaluation. But given the significance of the preliminary findings, it
seems there is an urgent need for a more extensive strategic research
program to establish how harmful different types of carbon nanotubes
are, and how they can be handled safely.
Without this, it’s hard to see how
manufacturers will be able to make informed choices on good practices
that don’t either endanger workers and users, or place an overwhelming
burden on production processes.
In the meantime, the best advice seems
to be: Take great care to avoid airborne exposures when working with
carbon nanotubes that bear a physical resemblance to asbestos. [Read the original article at http://2020science.org/2009/03/26/new-carbon-nanotube-study-raises-the-health-impact-stakes/]
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So you want to make or use carbon nanotubes, but you are worried about handling then safely. What do you do? The good news is that the UK Health and Safety Executive has just published an information sheet that addresses just this question. Risk management of carbon nanotubes is (according to the blurb) “specifically about the manufacture and manipulation of carbon nanotubes, and has been prepared in response to emerging evidence about the toxicology of these materials.”
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From 2020science: Ten years ago to the month, one of the first research reports detailing the challenges of ensuring the safe use of engineered nanomaterials was delivered to the UK Health and Safety Executive. The report wasn’t for general release, and you’ll be hard pressed to find a copy of it in the public domain. But as a co-author, I have a copy skulking around in my archives. And given it’s ten year anniversary, I’ve been browsing through it, to find out how much has progressed - or not, as the case may be!
The report focused on ultrafine aerosols, and the Health and Safety Laboratory’s ability to respond to then-current, and future, research needs. As such it was pretty wide ranging, and focused extensively on exposure to incidental nanoscale aerosols - such as welding fume and engine emissions - in the workplace. But it did encompass the then-nascent field of nanotechnology and “nanophase material synthesis.” And some of these early assessments of the field bear revisiting.
For anyone interested in what was being written about the potential health and safety issues raised by engineered nanomaterials ten years ago, I’ve extracted a few sections of the report below - for the full thing, you’ll have to go to the UK Health and Safety Executive.
My apologies that the post is so long - I’m only expecting a dedicated few to plough through it. But at the least, you might want to skip to the end to see how the research recommendations of 1999 compare to those of today - you might be surprised!
A scoping study into ultrafine aerosol research and HSL's ability to respond to current and future research needs. IR/A/99/03
Kenny, Maynard et al. 1999
The introduction to the report starts:
Over the past few years a number of epidemiological studies have indicated a tentative link between ambient particulate concentrations, and morbidity and mortality rates (e.g. Dochery et al. 1993, Pope 1996, Schwartz et al. 1993, Schwartz et al. 1991). In all studies, particles with an aerodynamic diameter less than 10 µm (the PM10 fraction) have been implicated as the key agents. The lack of an apparent association between particles of specific composition and health effects has indicated the observed effects to be due to some physical aspect of the inhaled particles. A further link between particle size and health has been indicated by Dochery et al. (1993) who showed a more positive correlation between ill health and particles smaller than 2.5 µm than was seen than with the PM10 fraction. The possibility of correlations between particle size and number concentration and toxicity has been demonstrated by Oberdörster et al. (1995) by exposing rats to PTFE particles ~20 nm in diameter. At concentrations of 106 particles cm-3 (corresponding to an equivalent mass concentration of approximately 60 µg m-3) rats exposed for 30 minutes died within 4 hours. At lower concentrations a steep dose response curve was observed between pulmonary inflammatory responses and particle number. More recent research has begun to indicate a possible material-independent link between inhaled particle surface area and selected toxicological endpoints (e.g. Lison et al. 1997). The possibility of a relationship between fine inhaled particles and ill health is now readily accepted, although research is still at a very early stage and most published data to date are open to a wide range of interpretations. Tentative hypotheses concerning possible mechanisms leading to toxicity have been proposed (e.g. Schlesinger 1995, Seyton et al. 1995, Donaldson and McNee 1998), and the impact of inhaling ultrafine particles on both the respiratory and cardiovascular systems have been speculated on. The US EPA have already acted, partially as a response to earlier epidemiological studies, and introduced the PM2.5 sampling standard for environmental particulates. Whether the UK is to follow this lead is still under discussion. However, despite these steps, research so far has raised more questions than answers. There is debate over the interpretation of the epidemiological studies, and the appropriateness of chosen endpoints in toxicology tests. Contradictory experimental results are beginning to be published regarding ultrafine particle impact on health (e.g. Pekkanen et al. 1997). There also appear to be widely conflicting views on what constitutes an ultrafine particle, with implicit cut-off points ranging from 10 µm down to a few nm!
In amongst all the current confusion is the question of whether the alleged health implications of inhaling ultrafine aerosols are of relevance to the workplace. Much has been made of the apparent health problems amongst vulnerable sectors of the general population following environmental exposures, and the argument is followed through to the conclusion that within a healthy workforce similar problems are unlikely to be seen (backed up by a lack of evidence of severe health problems that are clearly linked to ultrafine aerosols). However, in part the current uncertainty over the toxicity of ultrafine particles is due to the very limited information available on the nature of so-called ultrafine particles. Inhaled particles associated with health in epidemiology studies have been very poorly defined, and even the particles used in most well controlled in vitro and in vivo experiments have been poorly characterised. Without basic information on particle size, morphology, composition and structure, it is clearly not feasible to make value judgements on the nature of inhaled particles, either in the general environment or in the workplace. In the light of the scarcity of information on particle characteristics, the Committee on the Medical Aspects of Air Pollutants has recommended the monitoring of such parameters at a number of environmental locations (COMEAP 1996). Similar measurements will be essential within the workplace before further speculations on the importance of ultrafine aerosols are made.
In reading this, it is important to remember that the state of the science is ten years on from when this was written—there are now a wealth of publications on the potentially health-relevant behavior of nanometer-scale particles. Yet the framework of questions set out largely remains as relevant now as it did then.
Perhaps more interestingly, in 1999 the discussion was focused on understanding and managing the health impacts of inhaled particles, NOT whether those particles could be classified as arising from nanotechnology or not. As a result, the document tends to be more grounded in the science of how fine particles potentially impact on health, rather than how the poorly defined field of “nanotechnology” might lead to health effects.
The report goes on to consider the generation of ultrafine aerosols in the workplace:
In general, very little is known about any aspect of ultrafine aerosols in the workplace. There are a number of processes such as welding and soldering where intuitively one would expect large numbers of sub-µm particles. However even in these areas, detailed measurements of particle size do not appear to have been made. There is a general feeling that in situations where large concentrations of particles are generated, agglomeration will remove ultrafine particles from the aerosol before it is inhaled, thus removing the need to consider ultrafines. However this has not been verified, and evidence exists for significant mass concentrations of ultrafines existing close to generation sources. Interestingly, researchers are currently speculating that agglomerates with ultrafine primary particles may have the equivalent impact on the lungs as the individual primary particles. More is known about the products of internal combustion engines, although mainly from the view point of monitoring and reducing environmental emissions. However very little information on the nature of individual particles in the workplace exists.
Ultrafine aerosols tend to be formed either through nucleation (in particular homogeneous nucleation), gas to particle reactions or through the evaporation of liquid droplets. The majority of workplace ultrafine particles are likely to arise from the nucleation route, either as combustion products, or within saturated vapours arising from other sources (e.g. welding, smelting, laser ablation). Evaporation of sub-micron and even micron sized droplets of relatively high purity solvents will result in very small particles. Where the initial particles are highly charged, there is the possibility of any resulting fine particles exceeding the Rayleigh charge limit and fragmenting into even finer particles. This is a recognised method of generating ultrafine particles through electrospraying. To what extent this generation route is present in the workplace is unknown, although it is used for the specific generation of ultrafine particles during nanofabrication. Gas to particle generation of ultrafine aerosols accounts for the majority of non-combustion particles in the environment, although again the significance of this route within the workplace is unclear.
Following current interest in nanophase technology, and the use of ultrafine particles as precursors in nanophase materials, it is likely that the next few years will see an increase in the industrial generation and use of ultrafine particles. At present the planned generation of particles tends to be isolated to the production of ultrafine metal oxides such as TiO2, ZnO and fumed silica. Ultrafine carbon black is also currently generated on a commercial scale. Although the full extent to which ultrafine aerosols are generated as an unwanted by-product within industry is still largely unknown, there are clear cases where the generation rate is high, such as in welding and from internal combustion engines. Even so, data on the nature of generated aerosols in these areas are sparse.
There follows an assessment of different sources of nanoscale particles in the workplace, from welding to plastic fumes from laser cutting, and a range of other sources. This is all interesting information, but here I want to focus on the section on ultrafine aerosol precursors in nanophase technology:
Over the last ten years, interest in the unique properties associated with materials having structures on a nanometer scale has been increasing at something approaching an exponential rate. By restricting ordered atomic arrangements to increasingly small volumes, materials begin to be dominated by the atoms and molecules at the surfaces of these ‘domains’, often leading to properties that are startlingly different from the bulk material. As the domains become smaller, and hence more dominated by surface atoms and surface energies, so the properties become increasingly unique from either the bulk material or the constituent atoms. So for instance, a relatively inert metal or metal oxide may become a highly effective catalyst when manufactured as ultrafine particles; opaque materials may become transparent when composed of nanoparticles, or vice versa; conductors may become insulators, and insulators conductors; nanophase materials may have many times the strength of the bulk material. All of these effects and many more have been observed with various materials. Such material properties that are unique to nanostructured materials that have excited both the scientific and industrial communities in recent years.
Most nanophase materials are fabricated either from the liquid state, or the aerosol state, although some routes combine the two. The liquid route perhaps gives more control over the process in some cases. However there is a general feeling at the present that using aerosols is an inexpensive and versatile route to constructing these materials. Although there are many different production methods being explored, the general approach is to generate, capture and process an aerosol of particles with the dimensions of the final nanostructure. Typically this requires the generation of particles from 1 to 2 nm in diameter up to around 20 – 30 nm in diameter, depending on the required properties of the final material. Generation rates in research laboratories tend to be low (of the order of mg/hour), although where industrial production of nanoparticles has commenced, production rates of the order of tonnes per hour are seen.
At present, nanophase materials are an emerging technology, with the emphasis most definitely still on the research lab. However, there is considerable commercial commitment to the field, and it is certain that as scale-up problems are overcome, the mass production of both nanoparticles and nanophase materials will increase rapidly world-wide. When this occurs, the unique health problems associated with a unique product that can neither be treated as a bulk material or on a molecular level will have to be fully addressed. In the meantime, there is a clear need to keep up to date with both developments in the technology, and any health concerns that may be associated with it.
Over the past ten years, commercial-scale production of nanoscale materials has moved on significantly, although perhaps not as much as some would have predicted. Yet the issues surrounding their safety still reflect (by on large) the issues raised here.
The report summarizes the state of nanotechnology research in 1999—which I’ll skip over—and goes on to consider where the rather quaintly termed nanophase technology was heading:
The indication from the scientific press is that there are as many potential applications for nanophase technology as there are groups working in the field. However a relatively small number of areas can be identified where commercial production of materials is most likely to be seen in the next 5 - 10 years. To understand the commercial pressure behind the progress of nanophase technology and its likely integration into industry, you only have to consider the potential market for successful applications. In the electronics industry in particular, the revenue arising from nanotechnology is likely to be well in excess of hundreds of billions of dollars. In other areas, such as coatings and catalysts, similar markets exist for successful applications. The market for ‘intelligent’ drug delivery systems, if successful, is likely to be immense. Reflecting this, the pharmaceutical industry is currently investing in excess of $14B per annum into advanced delivery systems.
Electronic applications
The reduction in particle size has a profound effect on electronic structure as nanometre dimensions are reached, leading to a number of unique electronic properties seen in individual and groups of nanoparticles. As an illustration, Si, which is semiconducting in the bulk solid, may be used to form nanometre sized pseudo-crystals with one of two types of atomic structure dominating its faces. Particles with one structure are fully conducting. Those with the other are good insulators. What does this mean/what are the general implications?
Perhaps the most widely recognised electronic property of nanoparticles is their ability to act as quantum dots. In arrays of such particles, the overall electronic characteristics are dominated by quantum effects within the particles, leading to novel applications. For instance, quantum dot devices can be used to create high efficiency LED’s and electroluminescent plastics. High frequency solid state lasers based on quantum dot technology are expected to form the basis of a major breakthrough in telecommunications, leading to significantly higher communication bandwidths. High speed and high capacity computer memory will also be possible using quantum dot technology. Success in fabricating viable quantum dot devices will bring about a major technological step within the electronics industry, leading to a $B production industry, although progress at present is limited by the need to fabricate very precise arrays of well characterised particles. Current approaches include the use of colloids, nanolithography and aerosols.
Porous nanostructured semiconductors such as silicon have recently been shown to have electroluminescent properties. If this can be fabricated into integrated circuits, the basis for the next generation of high speed optoelectronic computers will be laid. Nanoparticles are also being found to lead to improved properties in resistors and capacitors. Ultrafine conducting particles embedded in an insulating matrix have been shown to give a great range of resistances as well as showing very high temperature stability. Similarly, the use of nanoparticles in capacitors has been shown to give a high dielectric permitivity and a low dissipation factor, making them ideal for high speed computer memory.
A particularly interesting phenomenon seen in nanophase materials is that of electrochromism; the modification of optical properties by the application of an electric field. Windows or mirrors coated with thin layers of these materials show variable light transmittance or reflection based on the magnitude of an applied electric field. It has also been found that nanophase materials may be used to form thin transparent films with high conductivity.
A number of other important areas relating to electronics are increasingly relying on the use of nanostructured materials. Solid state gas sensors show improved sensitivity when using films of sintered nanometre particles; high temperature superconductors have a higher performance when formed of nanostructured materials; thermocouples benefit from nanostructure and the magnetic properties of some nanostructured materials is already exploited to the full in magnetic storage media.
Coatings
Using nanophase materials to coat a wide range of substrates is being explored, and has been exploited in a wide range of applications. Hard nanophase coatings are important in the construction industry. The use of coatings with specific optical properties is of interest within the glass and photographic film industries. Dry coating technology is also benefiting from nanophase materials. It has been shown that the transport properties of large particles may be radically altered by the addition of a thin coating of fine particles of a suitable material. For instance, coating starch grains with fumed silica results in a highly flowable powder. In many cases, this coating need only be of the order of nanometres thick, and the use of nanoparticles in dry coating processes is already under investigation.
Chemical-mechanical polishing using nanoparticle slurries.
Surface polishing is a critical step in the processing of silicon wafers prior to semiconductor chip fabrication. Surface blemishes are a major source of both wafer and chip rejection in the electronics industry. By using polishing slurries consisting of nanoparticles, planarisation of wafer surfaces with fewer blemishes is possible.
Drug delivery systems.
A key goal in current drug delivery system research is the development of ‘intelligent’ systems that will deliver doses to specific sites within the body. One approach being actively considered is the use of coated nanoparticles. These would be capable of penetrating capillaries and being transported directly to the target site. The coating would include the drug to be delivered, components to prevent an immune response from the body and components to achieve site-specific or condition-specific delivery.
Nanoparticle catalysts
The modified surface chemistry of nanoparticles is well recognised for its catalytic properties in many materials. This, together with the associated surface area to mass ratio for such particles, has led to intense interest in nanostructured catalysis within many fields.
After laying out the state of the science regarding the potential risks of inhaling nanoscale particles (which has advanced considerably over the past ten years), the report summarises (on the health impacts):
There has been little work in this field to date, so it is difficult to draw meaningful general conclusions from the published data. One of the reasons for this lack of data appears to be the difficulty in generating particles of standard and known size for use in in vitro studies. Particles used in both in vitro and in vivo studies have also tended to be relatively poorly characterised. Different effects both in vitro and in vivo have been observed with different sources of ultrafine particles, so the responses measured may be a function of the particle constituents rather than the particles per se. The differences observed have been attributed to the ability of particles with a particular composition to have different levels of free radical activity at their surface. Whilst there has been some work investigating synergy between acid aerosols and ultrafine particles (see below), there has been no work investigating the synergy between ultrafine particles and other potential airborne contaminants, e.g. allergens, VOC’s and bacteria. Some of the animal models used to demonstrate toxicological endpoints require exposure regimes which are far in excess of any possible exposure in humans (e.g. 6 hours a day, 5 days a week for 3 months). Therefore, the extrapolation of such health effect data to humans should be treated with some caution. … Interest in possible health effects following inhalation of ultrafine particles is high at present, and research is beginning to follow this interest. Inhalation toxicology has taken over from epidemiology over the past few years, and dominates the field at present. Dose response relationships in rodents are being seen that indicate particle number or surface area to be more appropriate metrics than mass. The possibility of ultrafine particles acting as vectors to transport acids and metals to the alveolar region of the lung is also being explored. However it is recognised that many of the current approaches being taken are lacking in various aspects, particularly regarding the significance of chosen endpoints and the characterisation of particle exposure, and a number of groups are now beginning to address these issues. This is an area that is particularly ripe for good research proposals to sympathetic funding bodies. The need to fully characterise the particles used in exposure and inhalation tests, as well as those that people are exposed to in the workplace and environment, is well understood, although the right combination of technical skills to achieve this seems to be lacking in many establishments. In particular there would appear to be significant scope for transferring analytical electron microscopy skills used in materials science and nanostructure analysis to the analysis of ultrafine aerosol particles. There is also a recognised need for in-vitro test systems that allow cell cultures to be exposed to the aerosol, rather than a particulate suspension. A small number of research groups are currently developing test systems allowing direct aerosol deposition. Funding for fine particle research (PM2.5 sampling, and mass-based aerosol sampling) still dominates, but all aspects of ultrafine particle research are on the increase, and it is likely that the next few years will see significant funding opportunities and research in this area. Driven by concerns over environmental exposure, together with the need to address exposure limits for nuisance dusts, there is increasing interest in examining the impact of ultrafine particle exposure in the workplace.
The report covers a lot of ground on exposure measurement and control, which I won’t duplicate here (although a lot of the information remains highly pertinent). Instead, I’ll jump right to the end of the report, where a number of research recommendations are made. Remembering that these are focused specifically on inhalation exposure in the workplace, they sound surprisingly contemporary, being written 10 years ago:
Full quantification of ultrafine aerosol exposure in the workplace:
- Measurement of number, size, surface area, composition, morphology, structure
- Investigation of the surface properties of workplace particles.
- Investigation of surface enrichment, role of modified surface activity below 10 nm, relevance of internal structure.
- Development of instrumentation and analytical techniques for surface area
- measurement and individual particle characterisation (Analytical Electron Microscopy)
Targeted epidemiology and toxicology studies.
- Epidemiological evidence for ultrafine particle toxicity in the workplace
- Toxicity of well defined particles, and of particles characteristic of those found in the workplace.
- Investigation of mechanisms resulting in toxic responses, in relation to the known physical and chemical attributes of workplace particles.
Instrumentation
- Identification of deficiencies in instrumentation and monitoring requirements, and development of new technologies and methods.
Control
- Reassessment of the applicability of conventional control systems (including RPE) to reduce exposure to ultrafine particles, and the development of new approaches to exposure control.
Exposure Limits
- Assessment of current exposure limits in the light of available data on ultrafine particle toxicity, and the development of more appropriate approaches to exposure limits.
Ten years on, it is surprising how relevant this document still is. The major issues facing the safe use of nanomaterials were reasonably clear ten years back. And many of the research needs raised then remain today. Progress certainly has been made since then, and an understanding of the types of nanomaterials of greater concern has increased—the 1999 report doesn’t mention carbon nanotubes for instance. But on the flip side, this is a report that was clearly unencumbered by the politics of nanotechnology that seem to have diffused through things today
Perhaps most surprisingly though, is that governments and others are still talking about the same issues - often as if they have discovered them for the first time - without doing that much about them. It would be churlish to ask where we might have been now if some of those 1999 recommendations were listened to. But at least I can ask where we might be in 2019, if only we can break out of this endless cycle of re-inventing the nanotech risk report!
Endnote
Because this was an internal report, I have been careful to extract only parts of it that are of general interest and are not in any sense proprietary. That said, there is a lot of information in the full report that would be helpful to anyone grappling with addressing and managing potential occupational risks arising from nanoscale particle exposure in the workplace. It would be great if the UK Health and Safety Executive could release it for public use!
References
COMEAP (1996). Non-biological particles and health. HMSO Publications.
Dochery, D. W., Pope, C. A., Xu, X., Spengler, J. D., Ware, J. H., Fay, M. E., Ferris, B. G. and Speizer, F. E. (1993). An association between air pollution and mortality in six U.S. cities. N. Engl. J. Med, 329, 24, 1753-1759.
Donaldson, K. and McNee, W. (1998). The mechanics of lung injury caused by PM10. In: Air Pollution and Pealth. Eds: Hester and Harrison. Royal Society of Chemistry. ISBN 0-85404-245-8. pp21-32.
Lison, D., Lardot, C., Huaux, F., Zanetti, G. and Fubini, B. (1997). Influence of particle surface area on the toxicity of insoluble manganese dioxide dusts. Arch. Toxicol. 71, 725-729
Oberdörster, G., Gelein, R. M., Ferin, J. and Weiss, B. (1995). Association of particulate air pollution and acute mortality: involvement of ultrafine particles? Inhal. Toxicol., 7, 111-124.
Pekkanen J, Timonen KL, Ruuskanen J, Reponen A, Mirme A (1997) Effects of ultrafine and fine particles in urban air on peak expiratory flow among children with asthmatic symptoms. Environ Res 74: 24-33
Pope, C. A. (1996). Adverse health effects of air pollutants in a nonsmoking population. Toxicology, 111, 149-155.
Schlesinger, R. B. (1995). Toxicological evidence for health effects from inhaled particulate pollution: does it support the human experience? Inhal. Toxicol., 7, 99-109.
Schwartz, J., Spix, C., Wichmann, H. E. and Malin, E. (1991). Air pollution and acute respiratory illnessin five German communities. Environ. Res., 56, 1-4.
Schwartz, J., Slater, D., Larson, T. V., Pierson, W. E. and Koenig, J. Q. (1993). Particulate air pollution and hospital emergency room visits for asthma in Seattle. Am. Rev. Respir. Dis., 147, 826-831.
Seyton, A., MacNee, W., Donaldson, K. and Godden, D. (1995). Particulate air pollution and acute health effects. The Lancet, 345, 176-178.
Read more: "Nanotechnology risk research, ten years on" - http://2020science.org/2009/03/02/nanotechnology-risk-research-ten-years-on/#ixzz08iLutTS0
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From 2020science.org: Introducing MINChar—a new community initiative to support effective material characterization in nanotoxicity studies.
Here’s
a tough one: Imagine you have a new substance—call it substance X—and
you run some tests to see how toxic it is. But you’re not quite sure
what substance X is.
You
know that it is a powder, and it is supposed to have chemicals x y and
z somewhere in it. But you don’t know how small the particles are,
what shape they are, whether chemical z is on the surface of the
particles or inside them, whether the particles all clump together when
shoved into the test system or whether they can’t get far enough away
from each other after being administered, or whether there is something
else present in substance X that really shouldn’t be there.
Now
imagine your tests show that substance X looks like it could be rather
dangerous. How do identify which aspect of the material is causing the
problem, so you can go about fixing it?
Or
imagine someone else wants to repeat your work. Or they want to
compare your data with another study. How do you know that the
substance being used in other studies is the same as substance X, and
not simply a crude approximation?
The
scenario is somewhat hypothetical, but the issues are very real. And
they have dogged the field of nanotoxicology for over a decade.
The
problem is, toxicologists are used to working with substances where
chemical identity and mass of material are all that are needed to
establish the concentration at which the material becomes harmful.
These folks aren’t used to dealing with materials that “do what they
do” because of a complex set of physical and chemical characteristics,
and that may change from one environment to another.
But the
toxicology community is becoming increasingly aware of the new
challenges of studying the harmfulness of engineered nanomaterials.
Which is why a new grass-roots initiative has just been launched to try
and change things for the better.
The Minimum Information on Nanomaterial Characterization initiative—MINChar for short—has its roots in a workshop held in Florida back in 2004.
At the time, materials scientists and toxicologists were well aware of
the disconnect between conventional toxicology and the new challenges
presented by engineered nanomaterials. But they weren’t clear what to
do about it. And it rapidly became apparent that the research
community wasn’t ready to take radical action to change the habits of a
lifetime—the ideas were there, but the timing wasn’t right.
Four
years on though, the landscape has changed—an increasing amount of
nanotoxicology research is being funded and published, and more people
are realizing that for the work to be useful, the materials being
tested need to be characterized appropriately.
But
there is a problem: what constitutes “appropriate.” Or rather, to the
toxicologist who is easily scared by long lists of incomprehensible
parameters that require fancy (and expensive) instruments to
measure—what is the minimum material characterization that is
achievable in practice.
This is what the MINChar initiative set out to address. Over the course of two days in October,
a group of people involved with generating, assessing and using
toxicology data got together and hashed out a minimum set of
information they thought was necessary for effective studies. The idea
was to put something in place as a community that would compliment
initiatives from more august bodies—and start to improve the quality of
nanotoxicology studies from the laboratory outward.
The result was a list of nine physical and chemical parameters, and three overarching considerations—available on the MINChar website.
But
just as importantly, the meeting spawned a community of people
interested in improving the state of material characterization in
nanotoxicology studies.
And if you are involved in any way with nanotoxicology—as a researcher, a reviewer, a program manager, a data-user—you can sign up as a member of MINChar Community.
This is something that is being strongly recommended by the organizers
of the October workshop—because the more people there are involved in
improving the quality of nanotoxicology research, the more likely it is
that approaches to using new and potentially useful nanomaterials
safety will be developed.
And understanding how to use substance X safely will no longer be like groping in the dark.
_______________________________
Endnotes
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From 2020science.org: The
National Research Council of the National Academies releases its review
of the National Nanotechnology Initiative Strategy for
Nanotechnology-Related Environmental, Health, and Safety Research. And
it’s not pretty.
Most people acknowledge that innovation is vital to economic and
social prosperity. But what do you do when science and technology
innovation are in danger of being stymied by bad habits and misguided
thinking? One solution: apply a little tough love. Something a new report from the US National Academies does in spades.
By the end of the next US administration, there will be an estimated
seven billion people on the planet, all wanting food, shelter, and
water, and most of them striving for a first-world quality of life.
With dwindling natural resources and an environment struggling to
absorb humanity’s assaults, old technologies are coming to the end of
their shelf life. Energy security, curing cancer, quality of life in
old age, plentiful clean water, climate change—none of these challenges
will be met without science and technology innovation.
More to the point, without a constant stream of science and
technology innovation, the economy will be starved of the
knowledge-capital so desperately needed for stability and growth.
Given this backdrop, you would think that the US federal government
would be on top of spotting and navigating around potential barriers to
innovation. Yet according to a new report
from the National Research Council of the National Academies, the feds
seem to have their collective heads in the sand when it comes to
ensuring investment in science and technology research delivers
sustainable results...
The new report specifically addresses nanotechnology. And it
focuses on federal government plans to address potential risks
associated with this emerging technology. But the cracks in the system
it reveals are most likely endemic across all areas of science and
technology innovation. [Continue reading...]
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From 2020science:
Nanotechnology—like
other emerging technologies—presents a dilemma: If you're making new
substances with uncertain health risks, how low is low enough when it
comes to managing exposure?
The issue is raised in the current edition of Nature Nanotechnology by Vladimir Murashov of the National Institute for Occupational Safety and Health (NIOSH), and former NIOSH-director John Howard. But the question has been bubbling along for some time.
And it’s an important one. Uncertainty over safe workplace
practices is bad news for nanotech businesses trying to do the right
thing—especially small start-ups that don’t have the resources to work
out their own bespoke solutions. It’s not much better for
regulators—as the gap between emerging technologies and solid
information on their safe use widens, how do you craft new approaches
to protecting people’s health and the environment?
Back in 2007, the Environmental Defense Fund and DuPont released their Nano Risk Framework... The Framework
places a heavy emphasis on pragmatic exposure-based decision-making.
In a nutshell, the message was: Use the best information available. And
when that runs out, use every trick in the book to come up with the
best possible benchmarks for qualitatively managing risk—until better
information is available. And do all this under “reasonable
worst-case” assumptions.
But the Nano Risk Framework stops short of providing practical guidelines on developing benchmarks for exposure assessment.
This gap was neatly filled by a guidance document from BSI Inc—the British Standards Organization—in January 2008. The “Guide to safe handling and disposal of manufactured nanomaterials” (BSI PD 6699-2:2007)
takes the bold step of recommending starting exposure values for four
different classes of nanomaterials—benchmarks for establishing exposure
decision-points in the absence of anything else. PD 6699-2 refers to them as Benchmark Exposure Levels, and couches them in enough caveats to make the most hardened lawyer proud. A better moniker might have been Lifeline Exposure Levels—because
they quite literally throw a lifeline to anyone completely at sea when
it comes to making practical decisions on making sense of airborne
nanomaterial exposure measurements.
But the Benchmark Exposure Levels are based on assumptions and
speculation, not hard science. And while they are firmly grounded in
recommendations within the Nano Risk Framework—using available
information and reasonable worst-case solutions—they are, in the
long-run, no substitute for quantitative risk assessment.
This is one of the main concerns that Murashov and Howard have about the BSI guidelines in their Nature Nanotechnology commentary.
They argue that exposure limits should be based on generally accepted
principles of risk assessment—and I agree with them. But something is
needed in the interim while these limits are established, otherwise the
whole emerging technology enterprise is on dodgy ground!
This is exactly what the Nano Risk Framework and PD 6699-2
address, and hopefully what additional guidance from organizations like
the International Standards Organization, and even government agencies,
will grapple with.
But this brings us back to the original question—how low is low
enough? Because recommendations like “keep exposures as low as
reasonably practicable” simply don’t cut the mustard without some sense
of how to evaluate exposure, and what the numbers mean.
PD 6699-2 makes a good stab at helping industries develop
internal pragmatic guidelines on how to use airborne exposure
measurements when working with new nanomaterials. Earlier this year, I
took a stab at assessing the validity and utility of the Benchmark
Exposure Limits for BSI—the full assessment is available here (PDF, 168 KB). My conclusions: the benchmark levels are far from perfect, but they are a great starting point.
Assuming that most readers will have better things to do than read through the 12-page assessment, here are the conclusions:
If effective health and safety plans are to be
implemented in research laboratories and workplaces generating and
using nanomaterials, guideline exposure limits are essential. In the
absence of further information, the benchmark exposure levels presented
in BSI PD 6699-2:2007 appear reasonable. Furthermore, the context
surrounding the levels—which is clearly stated in the document—allows
people following the recommendations to adapt the levels to their
specific circumstances, depending on the best available information.
In other words, they are not binding, but rather present a clear
starting point for an informed process of setting relevant exposure
levels. And thus, where evidence exists to suggest that the benchmark
exposure levels are overly stringent or not measurable for a given
material, it is left to the discretion of the person setting the levels
to adjust the accordingly.
These suggested levels are not a substitute for workplace exposure
limits, and do not remove the need for targeted research leading to the
development of evidence-based limits. But until such levels are
developed, they fulfil a role that is essential to underpinning the
development of safe and successful nanotechnologies. As such, BSI
should be applauded for publishing them.
The bottom line here is that industry needs practical guidelines on
safe workplace practices where hard information on risks is lacking,
and at some point this will mean grasping the bull by the horns and
providing advice on how to measure exposures, and what the numbers mean.
Giving meaning to the numbers might simply require establishing
rules of thumb for developing bespoke exposure levels. Or it might
require clear benchmark exposure levels to be suggested for different
classes of materials (with suitable caveats of course). Either way,
there will be exposure data, and people will want to know what they mean, and what action to take as a result.
In the long run however, hard data are still needed to underpin
quantitative and authoritative risk assessment that will supersede
interim qualitative measures. And this of course means there needs to
be a research plan, plenty of funding, and a willingness to translate
new information into informed oversight.
But that is a story for another day... ___________________________
Note: See also Rob Aitken's blog on the Murashov/Howard Nature Nanotechnology Commentary
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From 2020science.org: First impressions of the ICON EHS Database Analysis Tool
What do you do this holiday season when the turkey’s lost its
appeal, you’ve seen every movie worth watching ten times over, and
conversational déjà-vu sets in? If you are really desperate, you could
play “nano-trivia”—and thanks to the fine folks at the International Council On Nanotechnology
(ICON) you now have the perfect widget to help craft those cunning
questions that will have your nearest and dearest wracking their brains.
Questions like “between 2000 and 2006, what percentage of scientific
papers addressing the toxicity of carbon-based nanomaterials considered
exposure via mucous membranes (or the skin)?”
OK, so maybe playing “toxic particle trivial pursuits” is the last
resort of the desperate, and likely to result in an ever-decreasing
circle of close friends. But for all that, the new ICON Environmental Health and Safety Database Analysis Tool has its merits...
Most importantly, it provides a fascinating insight into how new
knowledge on nanomaterial safety is progressing—or not, as the case may
be.
Backtracking a little, the EHS Database Analysis Tool (lets just call it “the widget”) is an add-on to the ICON nanoEHS Virtual Journal.
I'm a long-time fan of the Virtual Journal, which is probably the
foremost repository of information on scientific papers addressing the
potential health and environmental impacts of engineered
nanomaterials. Established and maintained by ICON, it links to
close-to every paper published that has some relevance to understanding
and addressing the possible impacts of nanomaterials, and is an
essential resource for anyone doing work in this area.
But those clever people down at Rice University didn’t just stop at cataloging the constant stream of publications coming out of
researchers around the world. They went one step further and added
some useful information—such as what material was studied in the
published research, how it was studied, which aspects of hazard or risk
were addressed, who the publication was aimed at, and so on.
And that opened up the way for “the widget.”
What the widget does is enable sophisticated searches on the
database, and then displays the information graphically (as well as
giving direct access to the source-paper records). Imagine for a moment you are interested in the relative numbers of
papers that have been published to date on different routes for
carbon-based particles to get into the body—ingestion, inhalation, or
through the skin or mucous membranes. Plug the desired information
into a reasonably easy to use matrix on the widget’s web page, select a “Simple Distribution Analysis” plot for the years 1961 through to the end of 2008, and press “Generate Report.”
Hey presto, the widget creates a neat little pie chart clearly
showing the requested information. (For the interested, across these
three exposure routes and for the years and material in question, 86%
of papers address inhalation, 11% dermal/mucous membrane penetration,
and 3% ingestion).
This analysis gives you a sense of how research has balanced out
over different areas over a number of years. But what if you want to
know how things are changing—whether more is being published now on
carbon nanoparticles for instance than was being published five years
ago? You should not be surprised to hear that the widget can handle
this also... (More...)
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From 2020science.org: The Royal Commission on Environmental Pollution report on Novel Materials
Imagine for one naïve moment that we have a pretty good handle on
managing the environmental impact of existing manufactured “stuff”.
Then someone comes along and invents some “new stuff” that behaves very
differently from the “old stuff.”
How can we be sure that the frameworks and mechanisms in place for
preventing harm to the environment will work for the new stuff? And
where they are strained to breaking point, how do we go about fixing
the system?
These are two questions addressed in a new report from the Royal Commission on Environmental Pollution—an
independent British standing body established in 1970 to advise the
Queen, government, Parliament and the public on environmental issues...
Of course, because this is for the Her Majesty The Queen, phrases like
“old stuff” and “new stuff” are conspicuous by their absence in the
report—which instead addressed the rather more sophisticated-sounding
issue of “Novel Materials in the Environment.”
This is, in effect, a report on the challenges of avoiding adverse
environmental impacts of engineered nanomaterials. Coming four years
after the seminal report from the Royal Society and Royal Academy of Engineering
on nanoscience and nanotechnologies, it reflects both how thinking on
the challenges and opportunities presented by engineered nanomaterials
has advanced, and actions to ensure their safe use have not! The report itself draws on extensive interviews with experts around the
world, and the depth and quality of the writing reflects this. Perhaps
not surprisingly, many of the recommendations arising from this process
will be familiar to readers—the challenges haven’t changed that much
over the years, and solutions still seem few and far between in many
cases... [Follow the link to read more]
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From 2020science.org: UK Consumer Organization Which? Releases New Report
Who needs an emerging technologies blog when you have The Daily Mail? For those of you that missed it, Wednesday’s on-line issue of the British tabloid newspaper highlighted
“The beauty creams with nanoparticles that could poison your body”
I’m so glad someone’s tracking this issue, while us folks over on
the other side of the pond are dealing with the considerably
less-interesting issues surrounding the incoming Obama administration.
The only trouble is, the Mail didn’t quite get it right. In fact on a
scale of 1 – 10, I’m not even sure they even make it to first base...
The article is based on a new report from the UK-based consumer organization Which? The report “Small Wonder? Nanotechnology and Cosmetics”
[PDF, 3.9 MB] takes a clear-eyed view of nanotechnology-based cosmetics
on the market, and asks what information is available about them, and whether or
not users can be sure they are safe.
Unlike The Daily Mail story, this is an exceedingly good report. If you are at all interested in nanotechnology and cosmetics, read it—it’s
only a few pages long, but conveys the issues with clarity and style.
And by building on perspectives from industry, researchers and
consumers, it presents a well-balanced overview.
The report is so accessible that it’s hardly worth summarizing it.
But here anyway are the take-home messages—Which?’s 10 point action
plan:
- CO-ORDINATION: The Government should establish a strategic
stakeholder group to ensure there is effective input from all sectors
of society and that the necessary measures are implemented and progress
monitored.
- DEFINITIONS: International agreement is needed on definitions for nanotechnologies.
- PRODUCTS: The Government and EU need to understand what products
are already on the market, in the pipeline or at the research stage and
identifying those likely to raise most concerns based on current
understanding.
- RESEARCH: The Government and EU need to ensure that uncertainties
around the environmental and health risks presented by some
manufactured nano materials are urgently addressed – and ensure that
research to enable this is funded.
- ASSESSMENT: The Government and EU must provide clarity over how
the safety of nano materials should be assessed given the current
knowledge gaps.
- PRECAUTION: The precautionary principle should be applied to
products where there are potential risks, but where it is not currently
possible to assess their safety, so that consumers are not put at risk.
- TRANSPARENCY: Government and industry should be open about the
uncertainties that some nano materials may raise, the research
underpinning safety assessments as well as claims about potential
benefits.
- REGULATION: The EU needs to address the loopholes in regulations
so that nano materials are included and there is clear guidance on how
the regulations apply.
- INFORMATION: The Government must ensure consumers, industry and
regulators have clear information about where nano materials are being
used and that any claims they make are true.
- ENGAGEMENT: The public should be involved in meaningful
discussions, at all levels, about the development of the technology,
priority applications and any no-go areas.
This is a reasonable action plan, and a far cry from the scare-mongering pervading The Daily Mail story.
And unlike many of the reports that appeared in the popular press,
Which? do an admirable job of fitting the story to the facts—rather than
the other way around!
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From 2020Science.org: Twelve months ago today I held a bag of multi-walled carbon nanotubes up
before a hearing of the U.S. House Science Committee. I wanted to
emphasize the discrepancy between the current state of the science on
carbon nanotubes, and a tendency to classify this substance as the
relatively benign material graphite from a safety perspective. So it
is perhaps fitting that on the anniversary of that congressional
hearing, the US Environmental Protection Agency is making it clear that
carbon nanotubes are in fact, a new substance—and should be regulated as such.
Carbon nanotubes are often described as sheets of graphite—the stuff
that makes pencil lead black—wrapped into a tube; leading to
nanometre-thin “fibres” that are incredibly strong for their weight,
and highly conducting—thermally as well as electrically. But perhaps
because of this simple imagery, they are often handled as if they are
graphite—especially when it comes to using them safely.
Given the amount of time and money researchers and industry are
pouring into producing and using carbon nanotubes, you would think that
they are at least marginally different from their flat-sheeted
cousins. In fact the differences are anything but marginal: Wrapping
the sheets associated with graphite into tubes radically changes the
physical chemical and biological properties of these carbon-based
materials—just like re-arranging the carbon atoms that make up soot
into diamonds leads to the formation of a fundamentally different
material.
Yet many companies continue to persist in claiming “it’s just
graphite” when questions arise over the possible health impacts of
being exposed to carbon nanotubes.
But all that is about to change. Hot on the heels of clarification from the European Commission
that carbon nanotubes (and other novel forms of carbon) need to be
registered under the new REACH chemicals regulations, the US EPA has
clarified their position on the material. According to a just-released notice in the Federal Register, the EPA
“generally considers [carbon nanotubes] to be chemical
substances distinct from graphite or other allotropes of carbon listed
on the TSCA Inventory.”
In effect, this means that any company wanting to manufacture or
import carbon nanotubes in the United States needs to submit a Pre
Manufacturing Notice (PMN) to the EPA—unless the material can be shown
to be on the Toxic Substances Control Act (TSCA) Chemical Substances
Inventory. And the chances of that are pretty slim—at present.
EPA actually established their position on carbon nanotubes back in
2007, in a document clarifying how the agency saw TSCA applying to
engineered nanomaterials [available here].
But the agency’s stance was so unclear that the Federal Register notice
clarifying the situation was felt necessary. In the words of the
notice just published:
“current pre-notice inquiries to the Agency and questions in public forums still indicate a lack of clarity on this issue.”
This is a significant step forward for the US EPA, and a very
welcome one. Research is continuing to show that some forms of carbon
nanotubes are potentially dangerous if inhaled in sufficient
quantities. Earlier this year, Craig Poland and colleagues
showed that long thin multiwalled carbon nanotubes are potentially able
to cause the disease mesothelioma if inhaled. And more recently Anna Shvedova and co-researchers confirmed that inhaled single walled carbon nanotubes can have a unique impact on the lungs of mice.
Neither of these studies suggests that carbon nanotubes behave
anything like graphite if they get into the lungs. Yet companies
persist with treating this material like graphite.
I’ve previously noted that carbon nanotube distribution companies like CheapTubes Inc. consider all forms of the material as being like graphite for health and safety purposes. In fact, as of October 31, the Materials Safety Data Sheet posted on the CheapTubes website noted of carbon nanotubes:
“This material is listed on the US Toxic Substances Control Act (TSCA) Inventory”
There is little doubt now that this is, in fact, not the case.
The EPA’s clarification will certainly help ensure that this
innovative material is used safely, and its full potential is realized
without causing undue harm. There are though, perhaps inevitably,
still some unresolved issues. These include various material use and
production quantity exemptions that could be used by some companies to
justify not applying TSCA to their nanotubes (see for instance the series of articles by Richard Denison
on TSCA and nanomaterials). But smart companies are realizing that
compliance is the best way to ensuring safe and sustainable
products—which is why a number of PMN’s for carbon nanotubes have
already been submitted to EPA (again, Richard Denison’s blog at the Environmental Defense Fund has useful comments on this point).
There are however two rather large flies in the ointment:
The EPA clarification doesn’t add anything to the question of where
many other engineered nanomaterials stand on the regulations front.
Carbon nanotubes are chemically distinct from other forms of carbon,
and so are easily defined under TSCA as news substances. But if you
take something like titanium dioxide or silver and form it into
nanoparticles, current regulations make no distinction between the nano
and non-nano forms of the material—even though research suggests the
nano-form may be more harmful.
Just as importantly, submitting a PMN for a specific type of carbon
nanotube material opens the way for that material being added to the
TSCA Chemical Substances Inventory. And once there, other companies
are free to make, use and sell the material. As Richard Denison writes,
“Once reviewed and placed on the TSCA Inventory, any
company can manufacture and use the nanomaterial without even having to
notify EPA it is doing so.” (unless EPA simultaneously issue a
Significant New Use Rule)
Yet researchers are only just beginning to discover what might make
different carbon nanotubes harmful, and how to avoid that harm. What
are the chances therefore of carbon nanotubes being added to the TSCA
inventory before we have a good handle on how to use them safely?
The bottom line here is that resolving the regulatory status of
carbon nanotubes is an important step forward. But there is still some
way to go before this material is regulated in a way that will
encourage innovation while preventing undue harm—whether to people or
the environment.
And while carbon nanotubes can perhaps leave the couch feeling a
little more confident about themselves, we shouldn’t forget that there
are still plenty of other materials out there that are suffering from a
nano-induced identity crisis.
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First posted on 2020science.org, 20th October 2008: Is the RBC Life Sciences® nanotechnology product Slim Shake approved for use by the US Food and Drug Administration (FDA)? According to the BBC Radio 4 science program Frontiers—broadcast on Monday evening—there may be some doubt. But I get ahead of myself.
The US-based company RBC Life Sciences® sells a range of dietary
supplements and food products allegedly based on nanotechnology—8 of
them are listed in the Project on Emerging Nanotechnologies public inventory of nanotech-enabled consumer products.
As with many of the products in the inventory, it’s hard to tell
whether they are truly using nanotechnology, and even harder to tell
what steps have been made to assure their safety. But Monday’s edition of Frontiers shed a little light on this issue...
Monday’s program, called very simply “Nanofoods,” provided a
thoughtful and balanced perspective on the development and use of
nanotechnology in the UK food industry, and included interviews with
representatives from the companies Unilever and Leatherhead Foods
International, as well as the UK’s Institute for Food Research, the
Central Science Laboratory and the Food Standards Agency.
Presenter Sue Broom started off looking into what nanotech can do
for food—from futuristic drinks with dial-up flavours to low-fat
mayonnaise that still manages to taste… well, tasty. But as the
program progressed, the discussion gradually turned to the issue of
safety. And when it got there, things began to get interesting.
Asked whether nanotech food additives that can be metabolized—i.e.
broken down by the body—present a greater safety risk than their
non-nano counterparts, most of the interviewees suggested that they
probably did not. But Sandy Lawrie of the Food Standards Agency did caution that these assumptions really need to be tested in the laboratory.
However, when it came to nanoparticles that aren’t
metabolized—nanoparticles that retain their particle-ness after being
eaten and as they pass through the gut—there was less confidence that
nanoscale ingredients could be assumed to be safe. Qasim Chaudhry from
the UK’s Central Science Laboratory
was particularly concerned about the possibility of such particles
being transported to normally inaccessible parts of the body, and
perhaps causing harm because of their small size and their durability.
These concerns are echoed in a draft report on nano and food published by the European Food Safety Agency (EFSA) last week.
At this point, the RBC Life Sciences® product Slim Shake was
introduced—to a backdrop of eerie music (OK, so I guess radio producers
are allowed a little dramatic license in setting the sound-stage.). As
explained by Kimberly Lloyd of RBC, the Slim Shake Chocolate
contains “cocoa clusters”—individual particles of silica 4 – 6 nm in
diameter, that are coated with the molecules responsible for giving
chocolate its flavour. The high surface area of these nanoparticles
supposedly gives an over-sized taste-hit when you drink the shake,
which masks the taste of other ingredients in the drink (whatever they
may be)—the point being that the Slim Shake tastes good without using too many of the ingredients that any self-respecting dieter would prefer to avoid.
The science actually makes sense, and RBC Life Sciences® should be
applauded for actually coming out and explaining it. But there is a
possible problem with those nanoscale silica particles—which are
described on the program as being discrete particles, not aggregates.
The folks producing Frontiers got in touch with the US Food and Drug Administration to see whether these silica nanoparticles were approved for use in Slim Shake. This is what they got back from the FDA:
“we are not aware of any tests that have been carried
out to specifically demonstrate the safety of nanosized silica for this
use. For those uses that FDA has determined to be safe, the silica is
generally a fine powder but no lower limits on size exist other than
those encompassed by good manufacturing practice.”
Mmm, so is RBC Life Sciences® using an unapproved food ingredient, or is life more complicated than this?
Amorphous silica has been used for decades as a food additive, and
for specific applications it is Generally Regarded As Safe (a
designation referred to as GRAS) by the FDA. But GRAS status depends
on how a material is used, as well as what it is made of. And reading
between the lines of the FDA statement, RBC have not established that
their particular use of nano-silica as a food additive is GRAS; nor
have FDA worked out whether existing determinations of silica safety
apply to nanoscale forms of the material.
To be fair, much of the amorphous silica used in foods these days does have a nanostructure (the material Aerosil®
is a good example). But it is typically used as large aggregates of
nanoparticles—i.e. the resulting particles in the additive are much
larger than the nanoparticles they are made up from. In contrast, RBC
is claiming that their product contains individual nanoparticles—a
departure that could alter the transport of the material within the
body, and possibly its subsequent behavior.
Is it possible that RBC Life Sciences® think they are selling an
FDA-approved product because of confusion over how existing regulations
apply to nanomaterials? I shouldn’t speculate, but I would like to
give them the benefit of the doubt. (It should also be noted that the
company would be well within its rights to determine whether their
nano-silica was GRAS without input from FDA—you don’t need prior FDA
approval to put something like this on the market, but deciding to go
it alone is often ill-advised.)
If this is the case, the faster guidance is developed by the FDA on
how nanotechnology fits into existing regulations, the better. Because
as Slim Shake seems to demonstrate, nanotech-enabled foods are
appearing in the US that seem to be slipping through the regulatory net.
____________________________________
Postscript (added on 21st October)
For an illuminating discussion on the UK Food Standards Agency response to Slim Shake in particular, and nanotechnology-based ingredients in food in general, fast forward to 23 minutes and 35 seconds into the Frontiers program - available on the web here.
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From 2020science.org: Whoever would have thought a science juggling act could be so much
fun? Or so informative? Yet a couple of weeks back I found myself
grinning like a ten year-old as I sat reviewing a new set of nanotech
DVDs. The culprit: "The Amazing Nano Brothers Juggling Show;" one of the highlights of Talking Nano-a just-released set of six professionally produced educational DVDs on nanotechnology from the Nanoscale Informal Science and Engineering (NISE) Network.
Talking Nano attempts to bring the mysteries of nanotechnology to the masses. And it does this pretty well...
Each of the six DVDs is aimed at a different audience; some will appeal
to younger children, while others provide meat for older and more
sophisticated viewers. Taken together, the set provides a
comprehensive and valuable resource-whether introducing kids to
nanotechnology, walking people through the great potential and real
challenges of this emerging area, or providing a more in-depth
background on nanotech for decision-makers.
The DVD set opens with an accessible introduction to nanotechnology from Boston Museum of Science
educator Tim Miller. Filmed as a presentation at the Museum of
Science, the content is aimed fair and square at young kids with an
interest in science and technology. This would make a great teaching
resource for middle school kids, and an even better one for adults who
still feel like middle schoolers when it comes to nanotech. It isn't Mythbusters,
but considering the slightly smaller production budget available to the
Boston Science Museum, it does what it sets out to do well.
Dig further into the box of DVDs and you reach "Guiding Light With Nanowires;" an illuminating lecture from Harvard physicist Eric Mazur
on using fibre optics and optical nanowires to direct the flow of
light. Eric does a competent job of describing how and why light can
be transmitted down fibres and wires, moving from the macroscale of
swimming pools to the nanoscale of some of the thinnest and most
unusual fibre optics around. And the case is well made for the
importance of being able to transmit information using light rather
than electricity is-especially at the nanoscale. This DVD is pitched
at a higher level than Miller's introduction, and will appeal most to
older children and adults. Recommended as a good introduction to
manipulating light at the nanoscale for anyone with an interest in the
field.
Following Mazur there is a change of pace, with Project on Emerging Nanotechnologies director David Rejeski
talking about nanotechnology, consumer products and public
perceptions. This DVD is billed as being suitable for high schoolers
and up, and I have to agree. While the content is informative, it
delves reasonably deeply into where nanotech is turning up and what the
social and policy implications are. A great resource for stimulating
discussions on nanotechnology and society in high schools and college
classes. I would also count this DVD a must-have resource for anyone
seriously interested in the interface between nanotechnology and
everyday people.
There follows the longest DVD in the set-50 minutes of George Whitesides
from Harvard University providing his own personal and inimitable
perspective on nanotechnology. This is a little dry in places, and
probably more palatable to a relatively mature audience (although
anyone from senior high upward should be able to handle it). But the
chance to listen to one of the leading thinkers in nanotechnology
talking about the history and future of this area-from the science to
the social implications-is not to be missed. Highly recommended for
anyone (nano-novice or nano-expert) interested in a big-picture
perspective on the science and technology of working at the nanoscale.
The final disk in the set is the aforementioned "Amazing Nano Brothers Juggling Show."
To be honest, I was cringing when I put this in the DVD player-remember
those "educational" shows you saw as a kid that were supposed to be
funny, but were just plain embarrassing? This is what I was expecting,
and for the first minute or so, this is what I thought I was getting.
But all credit to jugglers Dan and Joel (and some savvy
behind-the-scenes producers), the show actually works! This is a
class-act that actually manages to convey something useful about
nanotechnology. Without giving too much away, my guess is that most
people between 8 and 80 would find it hard to get more fun out of
nanotechnology than this 40 minute DVD provides.
At this point, you may be wondering when I lost my ability to
count-having compressed a review of six DVDs into five brief
paragraphs. The reason for the discrepancy is that I have saved my
favourite disk 'till last.
The second disk in the set is surely the highlight in an already great product, and features IBM's Don Eigler talking about his work on single atom imaging and manipulation.
For those not in the know, Don has been at the cutting edge of
single atom manipulation since the late 1980's, and is responsible for
some of the most stunning images to come from a scanning probe
microscope.
This DVD is something special. Don's delivery is unassuming,
accessible and engaging, and I suspect it will appeal to nano novices
and established nano hacks alike. Filmed in front of a live audience,
Eigler elegantly takes the audience through the basics of scanning
probe microscopy, and explains what the technique shows and what it can
do. And at the end of the 24-minute DVD comes a Eureka moment: Done
with talking about what the science can do, Don demonstrates it by
picking up and moving single atoms in real time, in front of the live
audience. And not content with this, he proceeds to let audience
members loose on the equipment (which is linked by internet to his lab
back on the West Coast).
Watching this and seeing the audience reaction, you can't help thinking "wow-so that's what nano is all about!"
All in all, Talking Nano
has something for everyone. Not all the DVDs will appeal to all
audiences, but there are some gems here that make the set worthwhile.
A great resource for teaching adults and kids alike about nanotech,
bringing decision-makers up to speed on some of the finer points of the
emerging technology, and pretending for a few minutes you are a
wide-eyed child again!
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From 2020science.org: After three years of hard work, International Standards Organization (ISO) Technical Committee TC229—set
up in 2005 to develop nanotechnology-related standards—has finally
begun delivering the goods. And the first documents off of the blocks
tackle head-on the challenges of working safely with engineered
nanomaterials.
September saw the publication of the Technical Specification 27687—“Nanotechnologies—Terminology and definitions for nano-objects—Nanoparticle, nanofibre and nanoplate” (ISO/TS 27687). True to its title, TS 27687 does exactly what it promises...
what you get is beautifully crafted definitions of the terms
“nanoparticle” , “nanofibre” and “nanoplate”. But what is clever about
this document is that it develops a systematic hierarchy of terms under
the umbrella of “nano-objects”. Clever, because it neatly resolves the
question of “when is a nanoparticle not a nanoparticle” that so often
paralyzes discussions on handling nanomaterials safely.
According to TS 27687, a nano-object is a material with
either one, two or three dimensions in the nanoscale (roughly, but not
exclusively, 1 nm – 100 nm). Under this overarching term come
nanoparticles (having all three external dimensions in the nanoscale),
nanoplates (with only one external dimensions in the nanoscale) and
nanofibres (nano-objects with two similar dimensions in the nanoscale,
and a third dimension that is significantly larger).
Nanofibres are further subdivided into three categories: Nanowires
(electrically conductive nanofibres), nanotubes (hollow nanofibres) and
nanorods (rigid nanofibres).
The result is a neat and logical way of describing nanoscale
materials that differentiates between objects that have previously all
been lumped together as nanoparticles.
TS 27687 is not directly focused on health and safety—this is
a general Technical Specification designed to aid the development and
application of nanotechnologies. Yet I suspect that the primary
utility of this document will be to establish a common language for
addressing health and safety concerns when handling nanomaterials that
could become airborne when handled. In recognition of this, the
introduction to the Technical Specification states:
“It is … essential that regulators and health and environmental
protection agencies have available reliable measurement systems and
evaluation protocols supported by well-founded and robust standards”
My guess is that TS 27687 will help a great deal in developing such systems and protocols.
But there is clearly more to working safely with engineered
nanomaterials than being able to tell a nano-rod from a nano-plate.
The international nanotechnology standards community obviously though
the same, because hot on the heels of TS 27687 comes ISO Technical Report 12885, “Nanotechnologies—Health and safety practices in occupational settings relevant to nanotechnologies” (ISO/TR 12885). Published in early October, TR 12885
presents an in-depth assessment of the issues surrounding and possible
solutions to working safely with engineered nanomaterials. At 79 pages
long, it is perhaps the most weighty document addressing nanotechnology
to come out of a standards organization to date!
TR 12885 is heavily based on the NIOSH document “Approaches to Safe Nanotechnology: An Information Exchange with NIOSH”
(originally published in 2005, and updated in 2006). While much of the
information presented closely reflects that in the NIOSH document, the
ISO Technical Report expands significantly on the original document in
a number of areas. For instance, TR 12885 goes into far greater depth on exposure monitoring and exposure control than the NIOSH document.
This new report isn’t perfect. For instance, I was surprised to see no mention of the DuPont/Environmental Defence Nano Risk Framework
in the Product Stewardship section. And it would have been useful to
have a fuller discussion on risk management techniques such as control
banding and how they might be applied to working with engineered
nanomaterials [see end notes for more information]. But as a
comprehensive review of the issues relevant to working safely with
engineered nanomaterials, it’s not bad.
However, this new guide on health and safety practices for nanotechnologies is entering an already-crowded marketplace. ASTM International were the first standards kids on the block with E 2535-07 (Standard Guide for Handling Unbound Engineered Nanoscale Particles in Occupational Settings), published in October 2007. This was followed a few weeks later by BSI guide PD 6699-02:2007 (Nanotechnologies – Part 2: Guide to safe handling and disposal of manufactured nanomaterials), published in December 2007. And of course, you have the original NIOSH document, that beat all the others in its first incarnation by two years—having hit the streets in October 2005.
So does this new document from ISO add anything to the mix?
Having looked through the new Technical Report, I have to say yes.
But this is a qualified yes: The ISO document is great for laying out
the current state of knowledge and offering options and possibilities
for working safely with engineered nanomaterials, but it falls short on
clear and concise advice. In contrast, BSI PD 6699-02 offers what I have previously described as a “shop-floor manual for making decisions where the rubber hits the road.” ASTM E 2535-07 is similarly more direct in its guidance, although more narrowly focused on what are termed “unbound nanoparticles.”
At the end of the day, these three documents complement each other. ISO TR 12885 is the reference manual, while BSI PD 6699-02 and ASTM E 2535-07
provide on-the-job advice that is unencumbered with over-much
background and analysis. None of them are perfect—the ISO document is
perhaps too reticent in providing guidance, and struggles to keep up
with the latest developments (perhaps belying it’s origins in a
document published originally three years ago), while the BSI and ASTM
International guides could be described as too simplistic in places.
Yet together, they form a firm foundation for ensuring safer workplaces
when handling engineered nanomaterials. And as such they are all
highly recommended.
But back to the ISO documents. These are both strong documents to come out of ISO TC229,
and will be extremely useful in helping to develop the knowledge,
protocols and methodologies necessary for working safely with
engineered nanomaterials.
All we need now is a new guide to make sense of the alphabet soup
that these standards organization documents seem to emerge from!
________________________________________________________
End Notes
The work programme of ISO TC229 can be accessed here.
It should be noted that you have to pay for the privilege of owning
ISO TS 27687, ISO TR 12885 and ASTM E 2535-07. BSI PD 6699-02 on the
other hand, is free.
And on this note, I cannot resist but point out that the core of ISO
TS 27687 is twelve defined terms. I make that just over $4 per term if
you purchase the document! But for $4, you couldn’t get a more
beautifully crafted term ☺
Control banding remains an interesting option when it comes to
making practical judgements on minimizing exposure to engineered
nanomaterials in the absence of good information, which is why I was
surprised not to see more discussion of it in the ISO document. A
fuller discussion on the utility of the concept for working with
nanomaterials can be found here, and a possible implementation, developed by the Nanotechnology Industries Association, can be accessed here.
And finally, for future reference, this blog entry should be referred to as TTS-AM:23A4FD5PO245FF6/TTFN-2008
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From 2020Science.org: The silent rave
might seem a rather bizarre social phenomenon; a group of strangers
converging in a public place and dancing to their own individual iPod
soundtracks. But I have a sneaking suspicion that the emerging
technology community has been indulging in the new tech-equivalent of
silent raves for some time now.
These suspicions are probably the delusional by-product of jetlag.
But travelling back from the latest in a long line of multi-stakeholder
nanotechnology meetings last week, the analogy hit a chord...
Imagine a meeting room where people are plugged into their own
personal mental iPods: The scientists immersed in Avril Lavigne’s "Complicated" (apart from the toxicologists, who are playing "Another One Bites the Dust"); the industry folk tuned in to "I Did It My Way"; with the NGO’s rocking along to "Holding Out for a Hero"
(with either Bonnie Tyler or Jennifer Saunders taking the lead,
depending on how “hip” the group is). And all the while the policy
makers in the room listening to Bob Geldof and "I Don’t Like Mondays"—over and over again...
This is a recipe for a great time (for some), little progress, and a
lot of noise. And it seems to be one that is followed at many meetings
designed to address the broader social, health and environmental issues
of emerging technologies.
The problem is twofold I suspect: People in different discipline
and with different agendas find it hard to listen to and understand
other perspectives. And in the absence of a clear focus for dialogue,
it is near-impossible to find a common language to facilitate
communication. In the silent rave analogy: People find it really hard
to unplug their mental iPods and listen to other tunes; especially if
there isn’t a strong communal tune to replace their personal
soundtracks.
This is hardly a blinding revelation. But the point is nevertheless
an important one if real progress is to be made in developing
sustainable emerging technologies. The question is: how can people be
encouraged to unplug and join the conversation?
I’m not sure what the answer is, but I’m pretty sure one of the
first steps will be to find that clear focus for dialogue—not just a
woolly desire to talk about ill-defined implications of emerging
technologies, but a clear statement of what the challenges are to
making progress. And that might mean dropping pre-conceived ideas of
what defines any particular emerging technology (like nanotechnology),
and focusing instead on what the science is revealing—and how this
challenges conventional approaches to ensuring safe, environmentally
sound and socially acceptable use. Perhaps if this focus is found, it
will lead to a communal tune so irresistible that people will start
turning off their mental iPods, and tuning in to the group conversation.
In fairness, the meeting that sparked off these thoughts was more
productive than many I have participated in. But more is needed if we
(as stakeholders in getting emerging technologies right) are to stop
going round in circles and start making some serious headway into a
technologically secure future.
And as for what is playing on my mental iPod: Fortunately, I
unplugged myself a long time back. Funny thing though, no matter which
meeting I’m at, I keep hearing strains of Pink Floyd’s “Is There Anyone Out There?” Strange that!
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From 2020science.org:So, you have a cool new science that could make a major impact on
global challenges like energy, disease and pollution and you want to
make sure it reaches its full potential. What do you do? At some
point, having a heart to heart with “the public” might be a good idea.
Especially if your “cool new science” involves playing around with the
very building blocks of life!
A just-released national survey on awareness of and attitudes toward nanotechnology and synthetic biology from the Wilson Center Project on Emerging Nanotechnologies
should help kick-start this conversation. For the first time, this
annual telephone poll has included questions on synthetic biology—the
use of advanced science and engineering to make or re-design living
organisms (such as bacteria) so that they can carry out specific
functions. The results are intriguing, and should help inform the path
toward responsible and socially acceptable uses of synthetic biology.
But more on this later…
I have been eagerly awaiting the results of the survey for some
time. Would people’s awareness and attitudes match those found for
nanotechnology, or would the extension of nanometer-scale manipulation
to the biological world raise new fears and hopes? And how would the
concept of making new life from dead chemicals resonate with the
religiously inclined?
Impatient for results, I tried out a quick experiment on my
eleven-year-old son. Presented with a one-line definition of synthetic
biology similar to the one above, I asked what his first thoughts
were. The results: “Isn’t that against the Bible?” Followed
immediately by “Isn’t that like Frankenstein’s monster?”
At this point I should establish that the reason for using such a
young and naïve subject was to gauge how accessible the definition for
synthetic biology was that we were developing. But his responses
intrigued me. He is not overtly religious (although he does attend
church regularly), and he is untainted by the Frankenfood debates
surrounding genetically modified foods. Yet he immediately focused in
on two key areas that seem to dog attitudes toward biological
manipulation. Understandably therefore, I was keen to see whether the
results of the current telephone poll—conducted across the United
States by Peter D. Hart Research Associates Inc.—matched these concerns.
The results of the poll weren’t as clear-cut as my son’s response, but they did highlight some interesting points.
First off, synthetic biology is not on the radar for most people.
67% of the thousand people polled had never heard of the field, while a
mere 2% claimed they had heard a lot about it. Yet when asked whether
they thought the benefits would outweigh the risks (or vice versa), 60%
of people who had never previously heard of synthetic biology voiced an
opinion. That’s right—they didn’t know what it was, but they sure knew whether they liked it or not!
This has echoes of Dan Kahan’s work at the Cultural Cognition Project
at Yale Law School. Dan has shown previously that when people are
initially introduced to nanotechnology, their attitudes are driven by
an emotional response—their gut feeling. Such a gut-response to
nanotechnology is seen in the current poll. But in this case, more
people were willing to make an initial judgment on synthetic biology
than nanotechnology.
I mention Dan’s work because he found that when people leaned more
about nanotechnology, their opinions were heavily influenced by their
value systems; moral, political, religious, or otherwise; and not just
by the science. If this holds true for synthetic biology, people with
strong religious beliefs might be expected to respond differently to
more information on synbio than those less-inclined to a religious
perspective—the “Isn’t that against the Bible?” response.
To gauge poll participants’ informed responses to synthetic biology,
they were read two short paragraphs—one discussing its potential
benefits and the other discussing its potential risks (see the PEN report
for the paragraphs). The order in which these were read was randomly
rotated. Participants were then asked again whether they thought the
risks of synbio would be greater, the benefits greater, or whether the
two would be about equal.
I was particularly interested in this question of how religious
values affected people’s informed response. Delving into the data,
respondents who never attend religious services were ambivalent on the
risks and benefits of synthetic biology—there was no statistical
difference between the numbers of people who thought benefits would
outweigh risks, and vice versa. But people who attended
religious services once or more per week were on balance more likely to
feel that potential risks would dominate potential benefits.
Of course, it may be that this trend simply reflects a more
risk-averse attitude amongst the religiously active. But comparing the
synthetic biology data with the informed attitudes to nanotechnology
counters this suggestion. In the case of nanotechnology, people who
attended religious services once or more per week were ambivalent on
whether the risks and benefits of the technology would dominate, while
the religiously un-engaged clearly felt on balance that the benefits
outweighed the risks.
A similar comparison between attitudes toward synthetic biology and
nanotechnology was seen when poll subjects were separated out by
gender, education and income.
Men on balance felt the benefits of nanotechnology would outweigh the
risks, while women were on the fence. But when it came to synthetic
biology, men were on the fence, and on balance women felt the risks
would dominate.
College graduates anticipated the benefits of nanotechnology would
dominate the risks on balance, while people educated to high school or
less were ambivalent. For synbio, the graduates were undecided on
whether risks or benefits were greater, while on balance those who only
reached high school education or less thought the risks would be
greater.
People earning more than $75 thousand a year thought the benefits of
nanotechnology would be more significant on balance, while those
earning less than $30 thousand per year weren’t sure. In the case of
synthetic biology, the participants earning $75 thousand or more
weren’t so sure about risks and benefits, while those earning less than
$30 thousand were sure on balance that the risks would be greater.
Overall, there were plenty of people within each gender, education,
income and religious observance group who bucked the
trends—anticipating more benefits when the majority were expecting
higher risks, and vice versa. But the overall picture is one
of nanotechnology as an area where people are on balance either
ambivalent about risks and benefits or anticipating the benefits to
dominate, and synthetic biology as an area where people are either on
the fence or anticipating the risks to dominate.
This is critical information to anyone trying to chart a course to
successful and sustainable uses of synthetic biology. Clearly, there’s
something about the conjunction of “synthetic” and “biology” that
drives an emotive and values-driven response in people that isn’t seen
for nanotechnology. But what to do about this? If synthetic biology
is truly as important as its proponents believe, there’s a lot of work
to do ahead in engaging with people to help develop socially acceptable
applications.
Fortunately, this “new cool science” is still in its infancy, and
the opportunities to engage with “the public” are still there. But it
is growing up fast—The J. Craig Venter Institute is racing ahead
towards creating the first artificial bacteria, and “biohackers” are learning how to re-engineer life at an increasingly rapid pace.
Some deep soul-searching between synthetic biologists and the public
may not be in the making yet. But a serious heart to heart will be
needed sooner rather than later, if synbio is to reach its full
potential without major growing pains.
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