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Expert Calls for Retooling Environmental Regulations for the Emerging Age of Nanotechnology
Given some of the surprises and unintended consequences that have resulted when new materials are introduced into the environment, there is a compelling argument for nimbler regulation of nanomaterials with new analytical tools, a historian of science told a 5 March seminar at AAAS.
Jody Roberts, program manager at the Chemical Heritage Foundation in Philadelphia, sought to dispel some of the scarier visions that have been proposed by critics of the technology, including the possibility that runaway nanorobots might somehow turn the surface of the Earth into a gray goo.
But he also noted that there are serious issues to be addressed as the technology emerges, including the fundamental question of how to regulate something that can't be seen. The unprecedented scale of nanomaterials will require a significant retooling of the ways regulators monitor substances in the environment, Roberts said.
"We need a revolution in analytical chemistry as well as nanotechnology," he said.
Roberts spoke at the first of three seminars at AAAS on contemporary issues in science, technology and policy. The series is organized by the Chemical Heritage Foundation's Center for Contemporary History and Policy and the AAAS Archives.
In his talk—"What's So Scary About Nano?"—Roberts focused on concerns about the potential toxicity of particles that are, on average, 100 to 1000 times smaller than the width of a human hair. Nanoparticles, which are a billionth of a meter in diameter or less, already are being used in cosmetics, automobile tires, and other products. They are being studied for their ability to cross biological membranes to enter cells, tissues and organs (including the brain) that larger particles normally cannot reach.
There remain questions about the extent to which nanomaterials may pose risks to the environment and human health. Studies have suggested, for example, that carbon nanotubes—thin, strong molecular cylinders of carbon atoms—have some of the same effects in mice as asbestos fibers, raising concern that exposure to such particles could cause similar cancers as asbestos.
To assess such questions, Roberts said, it will be important for scientists and regulators to come up with new tools for measuring the impact of nanoparticles. At the same time, he said the public could use a more sophisticated understanding of the history of nanotechnology and its likely future. The field has been the subject of competing narratives almost from the outset, he said.
On the one hand, scientists speak of understanding matter at the quantum level and creating a new industrial revolution at a scale of matter never previously imagined. The feeling is that "nano's awesome," he said. "You can do anything because we can control matter." Enterprising lab workers can manipulate atoms to spell out their names and researchers create tiny gears and rotors as the first steps to building nanomachines.
On the other hand, there are fears that "we can't control this stuff," Roberts said. "It's going to get out of the manufacturing facilities. It's going to get out of the labs." The conflicting assessments are sometimes referred to as the "wow to yuck" factor, he said. Some of the same people who raised fears about genetically modified organisms (GMOs) running amuck in the environment now ask whether nanoparticles might pose similar dangers.
"All of a sudden, all these bad analogies are drawn up between the two fields," Roberts said. "Part of the story becomes how not to become like GMOs."
The late Michael Crichton, in his novel "Prey," wrote a chilling scenario for environmental disaster in which nano-sized, self-replicating robots consume all matter on Earth while creating more and more copies of themselves. The ultimate result is a gray goo that covers the globe. Scientists worry that the public can be too easily taken in by such tales, which are readily refuted by arguments regarding energy requirements and elemental abundances.
"There's this concern that the only ways in which the public is actually engaged with this topic of nano is through science fiction," Roberts said. "And they don't know that Michael Crichton doesn't know what he is talking about."
Roberts said there are aspects of nanotechnology that could be considered truly scary, including the potential impact on workforce levels if widespread used of robotic surrogates ever did become a reality. He also mentioned potential privacy concerns if nanotechnology is used widely in surveillance applications.
But beyond such concerns, Roberts said, there are more pressing issues on how to deal with the potential environmental, health and safety dangers posed by some nanoscale materials that already are in the marketplace or on the horizon. Scientists are still trying to understand the implications of chronic low-dose exposures to hormone-mimicking chemicals in the environment, he said. The emergence of nanoscale materials just adds to the urgency of learning about the possible cumulative impact of hundreds of industrial chemicals detected in human tissue.
These spaghetti-like structures are carbon nanotubes viewed under an electron microscope. The manufacture of these nanotubes can produce toxic byproducts, researchers report.
[Photo by Anastasios John Hart]
Among one of the more troubling findings, according to Roberts, is the discovery that carbon nanotubes can cross the blood-brain barrier and end up in fish brains. With a reference to the heavily defended U.S. zone in Baghdad, Roberts said: "The blood-brain barrier is the Green Zone of the human body. Nothing gets inside of there, except it turns out carbon nanotubes" probably can. He added: "Nobody is really sure what that's going to mean."
He recounted a conversation he had with the director of a public health program who told him: "We have an awful lot of experience with ultra-fine particles [such as asbestos], and it's usually a bad idea to put them near humans. Once they are in [human tissue], there's really no way of figuring out where they are going to go, how they are going to collect and how to get them back out."
Toxicologists are undertaking new studies to better understand how chemicals can trigger cell death, including the roles played by dose and timing of exposure.
In the meantime, there has been a lively debate on whether nanoscale materials really will require new regulations. Regardless of scale, some ask, aren't carbon atoms just carbon atoms? Not necessarily, Roberts said. Nanoscale materials can have different effects and more reactivity within the body than other materials of similar composition.
Some specialists argue that it still makes sense to fit nanomaterials within the existing Toxic Substances Control Act of 1976 (TSCA). Others say that TSCA has not been working as well as it could for control of existing chemical pollutants, much less the exotic new materials that may be coming as nanotechnology matures.
Congress and federal agencies have been grappling with such questions. The House passed a bill in February, the National Nanotechnology Initiative Amendments Act of 2009, that highlights the growing need to learn more about the possible health and safety dangers of nanoscale materials. The Senate is expected to take up a companion bill later this year, according to the Project on Emerging Nanotechnologies (PEN).
PEN did an evaluation last year of the annual $1.5 billion investment by the government in nanotechnology research. It found just 62 federally-funded projects, with an estimated annual budget of $13 million, were highly relevant to understanding nanotechnology risk. Some experts have been urging that at least 10% of the annual nanotech budget be devoted to risk research.
A House subcommittee also had a hearing in February as part of a reexamination of the Toxic Substances Control Act. According to the Subcommittee on Commerce, Trade, and Consumer Protection, the hearing was aimed at addressing gaps in the law and "how these gaps hinder effective chemical safety policy in the United States." The Environmental Protection Agency released a report recently saying it will consider how best to apply regulatory approaches to nanomaterials under TSCA.
Whatever the regulatory regime, it is clear that new technologies will be needed to help monitor the presence and impact of nanoscale materials in the environment. Roberts noted that the development of the electron capture detector in 1957 opened the door to gas chromatography, a tool for detecting trace amounts of the many industrial chemicals that were starting to make their way into the environment in the 1950s and 1960s. "This required a serious retooling in the ways in which we do monitoring," he said. "We had to change the way we were looking at the world."
Similarly, there are new technologies that allow researchers to "see" nanoparticles in samples, but they are expensive, highly specialized and only exist in certain labs, Roberts said. "If you are going to ask a regulatory agency to monitor water, soil and air for these particles, you have to be able to see them," he said. Cheap and perhaps portable nanoanalyzers must be developed, he said, if regulators are going to have a way of tracking potential problems with manufactured nanoparticles.
10 March 2009