Big Surprises Come in Nano Packages
There's nothing nano about the projected economic impact of nanotechnology in the near future. Even though in 2002 the demand for U.S. nanomaterials was approximately $200 million, the National Science Foundation recently estimated that by 2015, nanotechnology applications may be valued at more than $1 trillion in the worldwide economy.
To get a handle on what some are hailing as one of science's hottest and most rapidly evolving fields, it important to learn the terminology. Nanoscience describes our attempts to understand the unique and potentially useful properties that occur on the nanoscale (one billionth of a meter), where the properties of materials become defined by their size and shape as well as their composition. Nanotechnology is the application of this science and includes the wide range of methods being used to manipulate atoms and molecules with the goal of developing new substances that often have unique properties and fewer impurities than substances developed in a conventional manner.
In a recent interview, Paul Burrows, manager of the Pacific Northwest National Laboratory's (PNNL) Nanoscience and Technology Initiative, explained the difference between normal molecules and their nano counterparts. "If you make a nanoparticle out of silicon, it no longer behaves like bulk silicon. Its behavior depends on the size, shape, and environment of the nanoparticle," Burrows said, "If it's long and skinny, it will chemically behave differently than if it's round, square, or cubic. That's because you're exposing different crystal planes of the nanoparticle to the environment. There also will be the chemical functionality of the surface; generally, a material's surface characteristics will be different from its bulk characteristics and nanoparticles are almost all surface." Two examples of nanotechnolgy are quantum dots and fullerenes. Quantum dots, which are nanometer sized crystals, are designed to use the energy of electrons for applications such as semiconductors. Fullerenes are molecular forms of pure carbon. One type of fullerene called a carbon annotate is highly conductive and 30 times stronger than steel.
In addition to using this new technology in the health sciences, many scientists are developing nanotechnolgy to be used to clean up industrial pollution and conserve energy. For example, recently Lehigh University researchers found that nanoscale iron particles may remediate contaminated groundwater. They discovered that nanoparticles injected into groundwater polluted with trichloroethylene (TCE), a chemical mainly used as a solvent to remove grease from metal parts, broke down the TCE into more benign products when palladium or platinum was added to the iron nanoparticles to enhance the degradation rate.
In another example of an environmentally related application, PNNL researchers are using nanoscale materials to create a thermoelectric device to harvest and recover waste heat from diesel and gasoline engines, exhaust systems, and industrial manufacturing processes, including glass, aluminum, and chemical processes. The thin-film thermoelectric devices show high conductivities. Their goal is to achieve 20 percent efficiency -- an accomplishment that will make thermoelectric power generation using waste heat economically feasible. This energy would be useful in powering electrical accessories on vehicles, which reduces the load on the main engine, as well as for many stationary applications.
While the economic potential of nanotechnolgy looks very promising, many are concerned that the new technology may have adverse effects on human health and the environment. Their goal is to avoid nano nightmares by being proactive about researching nanotechnology's potential risks and regulating its use if warranted. One of the few studies to focus on nanotech health and safety created controversy in March 2004 when it showed that fullerine nanoparticles caused brain damage and genetic changes in fish. Dr. Eva Oberdorster, an environmental toxicologist and biology lecturer at Southern Methodist University in Dallas, and several colleagues conducted the research, which was the first to demonstrate toxic effects from nanoparticles.
At a national nanotechnology conference held in April 2004, E. Clayton Teague, director of the National Nanotechnology Coordination Office, described some of the laws that could be used to regulate nanotechnology in the event that it is considered necessary. The Toxic Substances Control Act, which gives the U.S. Environmental Protection Agency (EPA) the authority to regulate new chemicals, could be used. In addition, according to Teague, EPA could use the Clean Air Act to control emissions from nanotechnology companies. Nanotech materials are about the same size as inadvertently created ultra-fine particles that can be formed through combustion.
Teague added that other strategies that could be invoked to control nanotech materials include permissible exposure limits set by the U.S. Occupational Safety and Health Administration, recommended exposure levels developed by the National Institute for Occupational Safety and Health, and threshold limit values established by the American Conference of Governmental Industrial Hygienists.
Nanotechnolgy has the potential to dramatically change our lives. We need, however, to look at past examples of chemical products that were introduced into the marketplace and later found to have troubling downsides, such as asbestos and DDT, and proceed with caution before we rush into an unknown nanotech future.
This editorial originally appeared in the November/December 2004 issue Environmental Protection, Vol. 15, No. 10.
This article originally appeared in the 11/01/2004 issue of Environmental Protection.