Post by whiterose on Dec 7, 2007 13:12:25 GMT -5
THE GIANT RISKS IN NANOTECHNOLOGY
Waving a packet of carbon nanotubes accusingly at the assembled American politicians during a hearing last month in Congress, Andrew Maynard was determined to make a point. The nanotechnology expert at the Woodrow Wilson International Centre for Scholars in Washington, DC, had bought the tiny tubes on the internet. They had arrived in the post along with a safety sheet describing them as graphite and thus requiring no special precautions beyond those needed for a nuisance dust. Dr Maynard's theatrics were designed to draw attention to a growing concern about the safety of nanotechnology. The advice he had received was at best uncertain, and at worst breathtakingly negligent. For a start, describing carbon nanotubes as graphite was rather like describing a lump of coal
as a diamond. Graphite is made of carbon, just like the nanotubes, although the tubes themselves are about 1m times smaller than the graphite that makes up the “lead” in a pencil. Carbon nanotubes may be perfectly safe, but then again, they may have asbestos-like properties. Nobody knows. Indeed, industry, regulators and governments know little about the general safety of all manner of materials that are made into fantastically small sizes. Research on animals suggests that nanoparticles can even evade some of the body's natural defence systems and accumulate in the brain, cells, blood and nerves. Studies show there is the potential for such materials to cause pulmonary inflammation; to move from the lungs to other organs; to have surprising biological toxicity; to move from within the skin to the lymphatic system; and possibly to move across cell membranes. Moreover, these effects vary when particles are engineered into different shapes. There is currently no way of knowing how each shape will behave, except by experiment.
------------------------------
www.raidersnewsnetwork.com/
--------------------
little risky business
Nov 22nd 2007
From The Economist print edition
Illustration by Bill Butcher
The unusual properties of tiny particles contain huge promise. But nobody knows how safe they are. And too few people are trying to find out
Get article background
WAVING a packet of carbon nanotubes accusingly at the assembled American politicians during a hearing last month in Congress, Andrew Maynard was determined to make a point. The nanotechnology expert at the Woodrow Wilson International Centre for Scholars in Washington, DC, had bought the tiny tubes on the internet. They had arrived in the post along with a safety sheet describing them as graphite and thus requiring no special precautions beyond those needed for a nuisance dust.
Dr Maynard's theatrics were designed to draw attention to a growing concern about the safety of nanotechnology. The advice he had received was at best uncertain, and at worst breathtakingly negligent. For a start, describing carbon nanotubes as graphite was rather like describing a lump of coal as a diamond. Graphite is made of carbon, just like the nanotubes, although the tubes themselves are about 1m times smaller than the graphite that makes up the “lead” in a pencil. Carbon nanotubes may be perfectly safe, but then again, they may have asbestos-like properties. Nobody knows. Indeed, industry, regulators and governments know little about the general safety of all manner of materials that are made into fantastically small sizes.
This lack of knowledge is so great that research can paradoxically add to the problem. Vicki Colvin, a professor of chemistry at Rice University in Texas and one of the world's leading experts in nanotechnology-risk research, told the same hearing: “If you fund five teams to understand nanotube toxicity, and they get five different answers, your research investment hurts you, because it creates uncertainty. The bad news is that we have way over five different opinions about carbon-nanotube toxicity right now.”
In the past few years the number of consumer products claiming to use nanotechnology has dramatically grown—to almost 600 by one count. Patents are rapidly being filed (see chart 1). For a product to count as nanotechnology, it does not need to contain a tiny machine—though some seers imagine that as the field's ultimate aim. It is enough merely for some of the material to have been tinkered with at a small scale. Often that can involve grinding down a substance into particles that may be only a few nanometres big—a nanometre is a billionth of a metre—about 100,000th of the thickness of a sheet of paper. These particles can also be engineered into shapes that provide some functional property, like rigidity. The variety of shapes includes rings, shells, wires, beads, cages and plates. The particles and shapes can also be incorporated into other materials to bestow useful properties on them.
Honey, I shrunk the silver
Some nanotechnology products are applied directly to the skin, as cosmetics and sunscreens. Titanium dioxide is commonly used as the white pigment in sunscreen. When it is ground into nanoparticles it can still block harmful ultraviolet radiation, but it allows visible light to pass straight though, which means modern sunscreens can appear completely transparent, while offering the same protection as the old white stuff.
Many products are now embedded with silver nanoparticles. At such small sizes, silver can have antimicrobial properties. Silver nanoparticles may come in handy wherever you want to kill germs—for instance, in things as diverse as children's dummies (comforters to Americans), teddy bears, washing machines, chopsticks and bed linen. Hence nanotechnology can be used in food production, most often as nanoparticles of silver in food-preparation equipment. The food industry is also trying to restructure ingredients at the nanoscale so as to include particles of trace metals in food supplements and to produce less-fattening foods.
All that sounds alarming, but assessing the risks calls for perspective. Humans are already surrounded by nanoparticles of one sort or another. Much of the food people eat is made of naturally occurring nanoscaled components. Each person breathes in at least 10m nanoparticles a minute. Most of them do no harm.
The trouble is that some—such as the particles from a diesel-engine exhaust—are known to cause serious health problems. Moreover, despite hundreds of years of experience in chemistry, it is not easy to predict how a substance will behave when it is made extremely small. That means, you cannot be sure how it will affect health.
Nanoparticulate versions of a material can act in novel ways—indeed, as with silver, that is what makes them so useful. When they are very, very small, materials, such as copper, that are soft can become hard. Materials, such as gold, that would not react to other substances become reactive. And when they have been shrunk, materials, such as carbon, that are perfectly safe might become unsafe. Plenty of research suggests that nanoparticles of harmless substances can become exceptionally dangerous.
One reason for this change is that a tiny thing has a large surface area relative to its mass. Atoms on the surface of a material are generally more reactive than those inside (which is why powders dissolve more quickly than solids do). Half of the atoms in a five-nanometre particle are on its surface, which can make it many times more toxic than expected by weight alone. Nanoparticles are small enough to be transported into the human body more easily and into the environment in new ways.
Research on animals suggests that nanoparticles can even evade some of the body's natural defence systems and accumulate in the brain, cells, blood and nerves. Studies show there is the potential for such materials to cause pulmonary inflammation; to move from the lungs to other organs; to have surprising biological toxicity; to move from within the skin to the lymphatic system; and possibly to move across cell membranes. Moreover, these effects vary when particles are engineered into different shapes. There is currently no way of knowing how each shape will behave, except by experiment.
Britain's Royal Society was concerned enough about all this to recommend in 2004 that nanoparticles be treated as entirely new substances. The European Commission concluded that each new material should be assessed on a “case by case basis”. However, understanding the environmental, health and safety (collectively known as EHS) risks is difficult.
Many governments take the view that, in terms of product-safety, nanotechnology changes nothing. The responsibility for managing EHS risk remains with companies themselves. Firms must make sure that the goods they produce are safe for consumers, that their workers are healthy and that their factories and products do not cause damage to the environment. On the whole, that is the right approach in a market economy, but the uncertainties make it hopelessly over-optimistic for nanoparticulates.
In the absence of any firm guidance from governments as to exactly what tests are needed to ensure a product is safe, businesses are devising their own. Michael Holman, an analyst with Lux Research, an emerging-technology consultancy based in New York, says that larger companies can probably cope with the research because they are more familiar with the risks of liability and regulation. But the task is beyond some small companies. “We talk to them and they say they are just doing titanium dioxide and they are not concerned, because it is a safe material, and we think they're whistling to the graveyard on EHS risks,” he says.
The analysts at Lux reckon that the applications that are likely to cause most (real and perceived) concern are those intended to go into or onto the body: cosmetics, food additives, pharmaceutical-delivery systems, novel therapeutics and textile coatings and treatments. But Lux says there is also a lot of uncertainty over what happens to these substances at the end of their lives. Carbon nanotubes have been used for years in industry. They have been embedded in materials like plastics to increase their toughness and provide electrical conductivity for components that are electrostatically painted. But it remains unknown, for instance, if they can enter groundwater when the products that contain them are dumped or broken up.
Businesses have good reason to make safe products. But the temptation for a company, especially a small one, is to spend its precious research budget on new products rather than basic investigations into the safety of nanotechnology that would benefit everyone, including its competitors. The risks may end up being carried by insurers. However, Swiss Re, one of the biggest insurers and one that has taken an early interest in nanotechnology, reckons insurers are not yet fully able to assess the risks. At the moment, firms with product-liability insurance are implicitly insured for their nanoparticles.
One hope is that the insurers will demand more certainty. Another, given the fundamental principles that have still to be established, is that some of the money governments are pouring into nanotechnology (see chart 2) will be diverted into the basic safety research the technology needs to thrive.
More at this link:
www.economist.com/PrinterFriendly.cfm?story_id=10171212
Waving a packet of carbon nanotubes accusingly at the assembled American politicians during a hearing last month in Congress, Andrew Maynard was determined to make a point. The nanotechnology expert at the Woodrow Wilson International Centre for Scholars in Washington, DC, had bought the tiny tubes on the internet. They had arrived in the post along with a safety sheet describing them as graphite and thus requiring no special precautions beyond those needed for a nuisance dust. Dr Maynard's theatrics were designed to draw attention to a growing concern about the safety of nanotechnology. The advice he had received was at best uncertain, and at worst breathtakingly negligent. For a start, describing carbon nanotubes as graphite was rather like describing a lump of coal
as a diamond. Graphite is made of carbon, just like the nanotubes, although the tubes themselves are about 1m times smaller than the graphite that makes up the “lead” in a pencil. Carbon nanotubes may be perfectly safe, but then again, they may have asbestos-like properties. Nobody knows. Indeed, industry, regulators and governments know little about the general safety of all manner of materials that are made into fantastically small sizes. Research on animals suggests that nanoparticles can even evade some of the body's natural defence systems and accumulate in the brain, cells, blood and nerves. Studies show there is the potential for such materials to cause pulmonary inflammation; to move from the lungs to other organs; to have surprising biological toxicity; to move from within the skin to the lymphatic system; and possibly to move across cell membranes. Moreover, these effects vary when particles are engineered into different shapes. There is currently no way of knowing how each shape will behave, except by experiment.
------------------------------
www.raidersnewsnetwork.com/
--------------------
little risky business
Nov 22nd 2007
From The Economist print edition
Illustration by Bill Butcher
The unusual properties of tiny particles contain huge promise. But nobody knows how safe they are. And too few people are trying to find out
Get article background
WAVING a packet of carbon nanotubes accusingly at the assembled American politicians during a hearing last month in Congress, Andrew Maynard was determined to make a point. The nanotechnology expert at the Woodrow Wilson International Centre for Scholars in Washington, DC, had bought the tiny tubes on the internet. They had arrived in the post along with a safety sheet describing them as graphite and thus requiring no special precautions beyond those needed for a nuisance dust.
Dr Maynard's theatrics were designed to draw attention to a growing concern about the safety of nanotechnology. The advice he had received was at best uncertain, and at worst breathtakingly negligent. For a start, describing carbon nanotubes as graphite was rather like describing a lump of coal as a diamond. Graphite is made of carbon, just like the nanotubes, although the tubes themselves are about 1m times smaller than the graphite that makes up the “lead” in a pencil. Carbon nanotubes may be perfectly safe, but then again, they may have asbestos-like properties. Nobody knows. Indeed, industry, regulators and governments know little about the general safety of all manner of materials that are made into fantastically small sizes.
This lack of knowledge is so great that research can paradoxically add to the problem. Vicki Colvin, a professor of chemistry at Rice University in Texas and one of the world's leading experts in nanotechnology-risk research, told the same hearing: “If you fund five teams to understand nanotube toxicity, and they get five different answers, your research investment hurts you, because it creates uncertainty. The bad news is that we have way over five different opinions about carbon-nanotube toxicity right now.”
In the past few years the number of consumer products claiming to use nanotechnology has dramatically grown—to almost 600 by one count. Patents are rapidly being filed (see chart 1). For a product to count as nanotechnology, it does not need to contain a tiny machine—though some seers imagine that as the field's ultimate aim. It is enough merely for some of the material to have been tinkered with at a small scale. Often that can involve grinding down a substance into particles that may be only a few nanometres big—a nanometre is a billionth of a metre—about 100,000th of the thickness of a sheet of paper. These particles can also be engineered into shapes that provide some functional property, like rigidity. The variety of shapes includes rings, shells, wires, beads, cages and plates. The particles and shapes can also be incorporated into other materials to bestow useful properties on them.
Honey, I shrunk the silver
Some nanotechnology products are applied directly to the skin, as cosmetics and sunscreens. Titanium dioxide is commonly used as the white pigment in sunscreen. When it is ground into nanoparticles it can still block harmful ultraviolet radiation, but it allows visible light to pass straight though, which means modern sunscreens can appear completely transparent, while offering the same protection as the old white stuff.
Many products are now embedded with silver nanoparticles. At such small sizes, silver can have antimicrobial properties. Silver nanoparticles may come in handy wherever you want to kill germs—for instance, in things as diverse as children's dummies (comforters to Americans), teddy bears, washing machines, chopsticks and bed linen. Hence nanotechnology can be used in food production, most often as nanoparticles of silver in food-preparation equipment. The food industry is also trying to restructure ingredients at the nanoscale so as to include particles of trace metals in food supplements and to produce less-fattening foods.
All that sounds alarming, but assessing the risks calls for perspective. Humans are already surrounded by nanoparticles of one sort or another. Much of the food people eat is made of naturally occurring nanoscaled components. Each person breathes in at least 10m nanoparticles a minute. Most of them do no harm.
The trouble is that some—such as the particles from a diesel-engine exhaust—are known to cause serious health problems. Moreover, despite hundreds of years of experience in chemistry, it is not easy to predict how a substance will behave when it is made extremely small. That means, you cannot be sure how it will affect health.
Nanoparticulate versions of a material can act in novel ways—indeed, as with silver, that is what makes them so useful. When they are very, very small, materials, such as copper, that are soft can become hard. Materials, such as gold, that would not react to other substances become reactive. And when they have been shrunk, materials, such as carbon, that are perfectly safe might become unsafe. Plenty of research suggests that nanoparticles of harmless substances can become exceptionally dangerous.
One reason for this change is that a tiny thing has a large surface area relative to its mass. Atoms on the surface of a material are generally more reactive than those inside (which is why powders dissolve more quickly than solids do). Half of the atoms in a five-nanometre particle are on its surface, which can make it many times more toxic than expected by weight alone. Nanoparticles are small enough to be transported into the human body more easily and into the environment in new ways.
Research on animals suggests that nanoparticles can even evade some of the body's natural defence systems and accumulate in the brain, cells, blood and nerves. Studies show there is the potential for such materials to cause pulmonary inflammation; to move from the lungs to other organs; to have surprising biological toxicity; to move from within the skin to the lymphatic system; and possibly to move across cell membranes. Moreover, these effects vary when particles are engineered into different shapes. There is currently no way of knowing how each shape will behave, except by experiment.
Britain's Royal Society was concerned enough about all this to recommend in 2004 that nanoparticles be treated as entirely new substances. The European Commission concluded that each new material should be assessed on a “case by case basis”. However, understanding the environmental, health and safety (collectively known as EHS) risks is difficult.
Many governments take the view that, in terms of product-safety, nanotechnology changes nothing. The responsibility for managing EHS risk remains with companies themselves. Firms must make sure that the goods they produce are safe for consumers, that their workers are healthy and that their factories and products do not cause damage to the environment. On the whole, that is the right approach in a market economy, but the uncertainties make it hopelessly over-optimistic for nanoparticulates.
In the absence of any firm guidance from governments as to exactly what tests are needed to ensure a product is safe, businesses are devising their own. Michael Holman, an analyst with Lux Research, an emerging-technology consultancy based in New York, says that larger companies can probably cope with the research because they are more familiar with the risks of liability and regulation. But the task is beyond some small companies. “We talk to them and they say they are just doing titanium dioxide and they are not concerned, because it is a safe material, and we think they're whistling to the graveyard on EHS risks,” he says.
The analysts at Lux reckon that the applications that are likely to cause most (real and perceived) concern are those intended to go into or onto the body: cosmetics, food additives, pharmaceutical-delivery systems, novel therapeutics and textile coatings and treatments. But Lux says there is also a lot of uncertainty over what happens to these substances at the end of their lives. Carbon nanotubes have been used for years in industry. They have been embedded in materials like plastics to increase their toughness and provide electrical conductivity for components that are electrostatically painted. But it remains unknown, for instance, if they can enter groundwater when the products that contain them are dumped or broken up.
Businesses have good reason to make safe products. But the temptation for a company, especially a small one, is to spend its precious research budget on new products rather than basic investigations into the safety of nanotechnology that would benefit everyone, including its competitors. The risks may end up being carried by insurers. However, Swiss Re, one of the biggest insurers and one that has taken an early interest in nanotechnology, reckons insurers are not yet fully able to assess the risks. At the moment, firms with product-liability insurance are implicitly insured for their nanoparticles.
One hope is that the insurers will demand more certainty. Another, given the fundamental principles that have still to be established, is that some of the money governments are pouring into nanotechnology (see chart 2) will be diverted into the basic safety research the technology needs to thrive.
More at this link:
www.economist.com/PrinterFriendly.cfm?story_id=10171212