domingo, abril 02, 2006

NRDC on nano

You may have seen the TV commercials, or you may have read about it in the clothing catalogs that clog your mailbox. You now can buy wrinkle-free clothes.

How do they make it wrinkle-free? With nanotechnology: the science of manipulating tiny particles that are one-billionth of a meter in size -- larger than an atom but smaller than a cell -- which in this case are impregnated into cotton. But nanotechnology isn't only for pants. It already has a number of other commercial applications, from high-capacity computer drives to food packaging, shampoos, sunscreens and cosmetics. And it is being hailed as the next industrial revolution, likely to change everything from the cars we drive to the clothes we wear to the medical treatments doctors can offer. Scientists expect these invisible nanoparticles, or ultra-fine particles, will enable them to create new cancer therapies, pollution-eating compounds, more durable consumer products, advanced detectors for biohazards like anthrax, and higher-efficiency fuel cells, among other things.

While nanotechnologies promises much, very little is known about the risks it may pose to people, wildlife or the environment. The limited research on nanotechnologies indicates that there is a very real potential for harm. Likewise, there are no adequate federal or state regulations governing its use, so there is nothing holding back the nanotechnology industry from continuing to market products containing nanoparticles, which are likely to wind up in our bodies or the environment.

Nanomaterials Are Not Benign

Nano, which comes from the Greek word for "dwarf," is used by scientists to indicate 10-9, or one billionth. Nanometer-sized materials are one-billionth of a meter in size; larger than atoms, but much smaller than a cell. As a comparison, there are as many nanometers in an inch as there are inches in 400 miles -- 25,344,000. Molecules in the range of 1 to 100 nm are considered nano-sized. The width of a human hair, for example, is 80,000 nm.

Nanotechnology describes the engineering of nano-size materials from such elements as carbon, iron or titanium. While nano-sized materials are not new, scientists' ability to construct geometric arrays of elements on a nano-scale has become increasingly sophisticated over the last decade.

Nanomaterials come in a number of shapes and sizes, such as buckeyballs (60 carbon atoms in the shape of a soccer ball named after R. Buckminster Fuller, the designer of the geodesic dome), fibers and dots, and have different properties than their normal-size counterparts. At nano-size, opaque materials may become transparent, chemically stable materials may become reactive, and electrical insulators may become conductors, or vice-versa.

Laboratory animal studies suggest that nanoparticles can cause inflammation, damage brain cells, and cause pre-cancer lesions. Early research also has found that nanoparticles easily move from one area of the body to another. A nanoparticle may easily penetrate a cell, while the normal-size form of the same chemical may not be able to enter.

There are three main ways people can be exposed to nanomaterials: inhaling them, ingesting them, or absorbing them through their skin. A June 2005 study by researchers at Rice University found that carbon buckeyballs will clump together and become soluble in water. This is disconcerting given that buckeyballs can damage the brain cells of fish, according to a 2004 Duke University study. Meanwhile, scientists at the New Jersey Institute of Technology found that high levels of nano-alumina oxide stunts the growth of five plant species, which include corn, cucumbers, cabbage, carrots and soybeans. Nano-alumina already is used to make scratch-resistant coatings and sunscreen lotions, and to neutralize water pollution, where it could be released directly into waterways.

Industry response to these early warnings has been mixed. Some large manufacturers and many small start-ups welcome safety testing and adequate regulation if they are not overly costly or burdensome. But other manufacturers are either avoiding conducting safety tests or are keeping their test data confidential. At the same time they are reassuring the public that the technology is safe.

The insurance industry, meanwhile, is worried about nanotechnology's potential health and environmental hazards; it does not want to face another asbestos liability debacle. Reinsurance companies such as Swiss Re, and financial investment advisers such as Innovest and Allianz, have called for strict safety testing and regulatory oversight.


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