Nanotechnology's Double-Edged Sword

Posted: 09-May-2005; Updated: 26-Sep-2007

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This micrograph shows a looped nanowire against the backdrop of a human hair. (credit: Limin Tong/Mazur Group/Harvard University)

It turns out space isn't quite the final frontier. Scientists are exploring a whole new world, much closer to home and much, much smaller: nanotechnology.

The science of the very small has big potential: improved energy generation, information technology, health care delivery and a wide range of other applications, including some with potentially enormous environmental benefits. But as with any potentially revolutionary technology, it only makes sense to look before we leap.  And the results of preliminary studies on some nanomaterials are less than entirely reassuring.

The prefix nano (from the Greek for "dwarf") refers to one billionth of a meter. To put into perspective just how small this is, a human hair is about 80,000 nanometers wide. On such a tiny scale scientists have discovered that things behave much differently than their counterparts in our regular-sized world. The aluminum in an ordinary soda can, for instance, can become explosive when reduced to nano-sized particles. Gold compounds scaled down to nano levels can become red, black or blue. Carbon goes from becoming pencil lead to a semiconductor. Suddenly elements and compounds we understand quite well in our physical world become effectively new substances in the nanosphere.

Looking Before We Leap
These new physical and chemical properties represent what's both exciting and worrisome about nanotechnology. While the ability of some nano particles to pass through a cell or skin could lead to breakthroughs in a cure for cancer or in the detection of Alzheimer's, these same features can pose environmental and health risks. Studies on some nano materials, for example, have found adverse effects in species as diverse as rats and fish.

Nanotechnology's sword has the potential to cut both ways. Environmental Defense is starting to work with companies looking into this important new technology to make sure both positives and negatives are considered beforehand. We're also advocating to increase federal funding for research into nanotechnology's potential risks, and pushing to enhance safety regulations to ensure that nanotechnology products are properly evaluated before getting to market.

"We see our role as guiding people to carefully consider and manage the potential implications of nanotechnology," says Scott Walsh, project manager for Environmental Defense's Corporate Partnerships group. "We are advocating for a proactive approach, both by working with companies to establish standards of care and by seeking to enhance government regulations to identify and address risks, even as more is learned about the various exciting possibilities of this emerging science."

Learning From History
New technologies have often ushered in solutions to vexing problems while adding entirely new, sometimes even more dire, ones. When x-rays were discovered in the 1890s, radioactive materials began popping up in a host of medical applications and beyond, from acne and cancer cures to smoke alarms, devices to measure shoe size and glow-in-the-dark watches. Since we have become aware of the adverse health effects related to radiation exposure, use of radioactive materials has shrunk. In the 1920s, a new family of relatively non-toxic chemicals called chlorofluorocarbons (CFCs) became the standard for refrigerants. Decades later we learned these CFC "wonder" chemicals were doing more than we bargained for, dissolving the Earth's ozone layer.

Environmental Defense's pioneering effort -- and first success -- was the banning of aerial spraying of DDT after we discovered the pesticide was not just helping eradicate mosquitoes; it was devastating bird species such as ospreys, peregrine falcons and bald eagles.

Lead additives for gasoline, asbestos fire retardants and PCB electrical insulators are just a few more examples of initially promising technologies whose negative consequences were only discovered long after they were widely commercialized.

"With nanotechnology, we have a unique opportunity to figure out if some of these new materials will harm ecosystems, wildlife and humans before the products actually hit the market," says Dr. John Balbus, director of Environmental Defense's Health Program. "We have the chance to avoid repeating mistakes of the past through a commonsense, look-before-you-leap approach. Well-funded, strategic research and appropriate interim risk management plans are the first steps."

Probing this new technology before its products gain widespread use, creating adequate regulatory structures and setting appropriate standards are key to avoiding the kinds of adverse health and environmental pitfalls new technologies have introduced in the past.

"We are cautiously optimistic that our society can shepherd nanotechnology's benefits while identifying and managing its risks," says Walsh.

A Big Future Promised in Tiny Building Blocks
A new and fascinating branch of science, nanotechnology is an umbrella term for the design and manipulation of materials at the molecular and atomic scale. But the vast range of science and applications the field covers also presents a wide range of potential hazards. All nano particles are not the same. They act very differently from one another and have their own unique properties.

"Carbon nanotubes could be the titanium of the future," says Walsh. "Stronger than steel but much, much lighter, they are potentially new building blocks for everything from vehicles to construction materials, but they have also been shown to cause lung damage."

Carbon nanotubes are not just durable; they exhibit intriguing electrical properties.

"They could also be the silicon of the future," says Walsh.

Intel is considering nanotubes among other technologies as a possible replacement for the computer chip and potential key to sustaining the relevancy of Moore's law. Proposed forty years ago by the company's co-founder Gordon Moore, the law observes that the number of transistors fitting on a chip doubles about every 18 months. The infinitesimal nature of nano means Moore's law could continue being a guiding principal of the computing world for decades to come.

Still Many Questions
Buckyballs are another carbon-based building block. Discovered in 1985 and named after Buckminster Fuller, inventor of the geodesic dome, they have the potential to take electrical and optical applications to the next level. Faster Internet speeds or more rapid delivery of communications down phone lines, cable lines and through cellular networks could result from buckyballs, making today's split-second delivery seem horse-and-buggyish. But preliminary studies suggest that these same materials can kill waterborne bacteria and break down brain cells in fish. So what happens when buckyballs wash out of consumer products and into sewage plants that discharge into lakes, rivers, or coastal waters? Or when factories that produce or use buckyballs discharge wastes directly into waterways? Right now, we simply don't know.

"Until the many questions about what these new materials will do in the environment are addressed, it's best to avoid uses that would lead to wide dispersion," explains Dr. Balbus. "We don't know how quickly they'll degrade, or how microorganisms, many of which rely on natural nanoparticles as food sources, will fare on a feast of buckyballs. Because bacteria are an essential part of natural ecosystems, we have to pay attention to the fact that a few nanomaterials, like carbon nanotubes and nano-sized titanium dioxide, have been shown to be potent bactericides.  Killing bacteria is fine in a hospital bed, but not so great in a river bed."

Risk Management Over Risky Business
Some of the environmental risks associated with certain nanoparticles can stem from their extraordinary mobility. Because they are so small, nano particles can even get inside cells.  That can be extremely useful in designing substances to deliver drugs; for example, getting cancer-fighting drugs into cancer cells is a perennial problem. But if nanoparticles are similarly mobile and spread in the environment, this could harm unintended targets.

One promising environmental application is cleaning hazardous waste with nano iron particles.

"Nano-scale iron could be very effective in breaking down toxic chemicals and common contaminants found in groundwater," says Walsh. "But problems could arise if these particles can't be retrieved. They're very reactive, and what makes them effective in decontaminating hazardous materials is what makes them potentially dangerous to the healthy ecosystem base."

In other words, it's critical to ask the classic question: could the cure be worse than the disease?

Nanotechnology Today
There is a flurry of activity around nanotechnology in government agencies and at scientific conferences. The U.S. government alone is investing approximately $1 billion per year in nanotechnology research and development.  We are pushing government to allocate at least 10% of that investment towards understanding the implications of the nanotechnology applications being developed. We are working with the International Council on Nanotechnolgy, the American National Standards Institute and the American Society for Testing and Materials, as they begin to develop consensus standards for several aspects of nanotechnology; such standards may help shape government regulations down the road. We're also exploring partnering with individual companies to develop risk management to develop standards, and sharing information with a wide array of scientific and environmental organizations.

Already there are applications of the technology on the market, though they are more evolutionary than revolutionary: ultra lightweight but durable materials for car bumpers, coatings for scratch resistant sunglasses, "jumbotron" lamps lighting athletic stadiums, sunscreens and stain resistant pants.

"Today's nanotechnology applications are only a few steps better than their conventional predecessors. The really revolutionary applications are several years from launch," says Walsh. "We're not seeing the cures for cancer or pollution-free energy production yet."

But this is the promising future of this exciting new science, and our hope is to ensure that with proper attention paid now to the risks, we can avoid the mistakes of the past while reaping the benefits that nanotechnology may bring.