Photograph by Alex Parlini, Project on Emerging Nanotechnologies
Microscopic nanomaterials are used in a variety of children's products. Scientists say too little is known of their toxic properties to allow children or adults to be exposed to them. Studies have suggested they could have similar impacts as asbestos.
Editor's note: The following story originally appeared in the May 1 subscriber-only edition of the political newsletter CounterPunch. It has been updated to reflect additional research on the subject.
The Project on Emerging Nanotechnologies (PEN) waxes futuristic on its Web site when describing nanotechnology, calling it "the next industrial revolution." New cancer therapies, pollution-eating compounds, more durable consumer products, detectors for biohazards like anthrax and "novel foods" are but a few of the nanotech applications PEN cites.
"They promise to change everything from the cars we drive to the clothes we wear, from the medical treatments our doctors can offer to our energy sources and workplaces," PEN, a partnership between the Woodrow Wilson International Center for Scholars and the Pew Charitable Trusts, says. "... Nanotechnologies are changing the way people think about the future."
In an October 2007 talk given at the Museum of Science in Boston, PEN Director David Rejeski said global research and development investments in nanotech totaled $12.6 billion the year before. In 2007, a PEN inventory of "manufacturer-identified nano consumer products" on its Web site totaled 580-plus, he said. The inventory today exceeds 800.
No one would argue with PEN's market assessments, or with Rejeski's concerns about the dearth of knowledge about nanomaterials' health impacts and their use in sunscreens, baby wipes and other products that facilitate their entering the body.
A report published in the November 2007 issue of the journal Environmental Health Perspectives summarized a 2006 workshop held at the Wilson Center that included 26 scientists from government, academia, industry and nonprofits titled "Hazard Assessment for Nanoparticles -- Report from an Interdisciplinary Workshop." Dr. Ellen Silbergeld, an environmental toxicologist from Johns Hopkins University, opened the gathering by suggesting that the evaluation of environmental risks posed by nanoparticles should be focused on "nanoscale interactions that take place in the normal functioning of biological systems."
Paraphrasing her presentation, the report said: "Unique interaction between nanoparticles and biological systems afford great promise for medicinal applications. But the unintended consequences could be harmful."
Nanotechnology uses tools like atomic force microscopes to visualize and manipulate matter and produce materials at the atomic and molecular scales, according to Jennifer Kuzma, an associate professor at the Hubert H. Humphrey Institute of Public Affairs at the University of Minnesota.
"Unique interaction between nanoparticles and biological systems afford great promise for medicinal applications. But the unintended consequences could be harmful."- Environmental Health Perspectives
Kuzma is a former study director at the National Academy of Sciences, where she specialized in genetically engineered plants in the food supply. She said in a phone interview that she was drawn to the parallels between agricultural biotechnology and nanotechnology, specifically as they apply to food and agriculture, and has been researching public policy as it relates to nanotechnology for the past five years.
More precisely defined, nanomaterials measure 100 nanometers or less in at least one dimension, Kuzma said. And they can be produced in two ways. One uses tools to pick up and move atoms. The other breaks molecules apart into nano-sized particles using electricity or light, through processes know as electrospray or photolithography respectively, for example.
"You can assemble these things from the top down by brute force by breaking big things apart," she said, "or you can do it by bottom-up methodology as well."
Size and manipulation, however, are but two of three criteria in the definition of nanotechnology, she said. The third is "novel properties based on size." Specifically, nanomaterials have high-surface-area-to-mass ratio. "It's the scale, it's the manipulation, and it's the novel properties," she said. "Those three parts make it nanotechnology."
The applications for nanotechnology are seemingly endless. The PEN Web site breaks existing nanotech products into eight categories: Appliances, Automotive, Cross Cutting, Electronics and Computers, Food and Beverage, Goods for Children, Health and Fitness, and Home and Garden. Each has multiple subcategories.
Carbon nanotubes, which are lighter and stronger than steel, can be used to produce lighter vehicles, Kuzma said, not to mention stronger bridges and self-cleaning and scratch-resistant eyeglasses. Silver nanotubes have antibacterial properties and are used in a variety of consumer products, including silver-coated food packaging materials. "There's a washing machine on the market that releases silver into the wash cycle in a nano form to keep it suspended and working correctly and get into your clothes and kill the bacteria and keep your clothes fresher longer," she said. "There's also silver-coated nano socks and things that you can buy that will prevent bacterial growth and smelly clothes."
Of more interest to Kuzma, however, are nanomaterials' capacities to serve as "delivery agents" for medical and other purposes. She cites cancer therapies and pollution-eating compounds as two of her "favorites."
While chemotherapeutic drugs like methotrexate are effective in killing cancer cells, they are nonspecific and can "kill everything" when used in the body, she said. As cancer cells grow and divide they take up more and more folic acid. And nanoparticles made up of complex organic molecules called dendrimers, attached to folic acid, penetrate tumors and can deliver drugs more directly to the cancer cells. These are being tested in animal and clinical trials. "It would help kill the tumor without the side effects of chemotherapy, or with minimal effects of chemotherapy," she said. "There are people working on that sort of thing with these more active molecules that will target certain tissues and deliver compounds into them."
Another application Kuzma finds encouraging is using iron nanoparticles to remove arsenic from drinking water. "Arsenic is a big problem everywhere, especially in developing countries like Bangladesh," she said. "It's a problem in the U.S., as well. And so these iron nanoparticles are being used to remove arsenic from drinking water."
Among the more eye-catching items the PEN Web site lists are nanotech cosmetics and baby products.
The Zenyaku Kogyo Co., Ltd., for example, touts its Arouge Deep NanoMoisture(TM) Care Set as follows: "Arouge uses advanced technology to create extremely small moisture molecules. Because they are so small, they rapidly penetrate the deep layers of your skin."
"Concerns have been mounting that nano silver poses unacceptable risks to beneficial bacteria in environmental systems and to human health."- Friends of the Earth
A company called Pure Plushy promotes its Benny the Bear Plush Toy: "With the additive of Silver Nanoparticles, our product has been clinically proven to fight against harmful bacteria, molds and mites."
GNS Nanogist sells a product called NANOVER(TM) Wet Wipes, which it says is "safe to use for children's toys" and, "soft like cotton, protects babies' frail skin."
But, as the scientists attending Wilson Center workshop and others have observed, such claims may not be as well-grounded as the companies assert.
Kuzma said she normally does not respond to questions about whether products have received adequate testing before hitting the market. But she's unequivocal about cosmetics. "We haven't done enough testing," she said when asked about nanotech moisturizers. "Just in general, our regulatory system for cosmetics is abysmal."
In 2006, the Friends of the Earth called for Samsung's "Nano Silver" washing machine to be taken off the market. "Concerns have been mounting that nano silver poses unacceptable risks to beneficial bacteria in environmental systems and to human health," it said.
And in an essay titled "Emerging Technologies," which will be published later this year in the American Academy of Pediatrics' third edition of its Handbook on Children's Environmental Health, Dr. Philip Landrigan from the Mount Sinai School of Medicine says flatly that children should not be exposed to nanomaterials under any circumstance.
Knowledge of the potential toxicity of nanomaterials is "scant," the head of Mount Sinai's Children's Environmental Health Center, argues. And what is known about possible toxicity to early human development is "virtually nil." He cites several studies that reinforce Silbergeld's assertion that unintended consequences of nanomaterials in the environment could be significant.
"This information suggests need to exercise considerable caution in adopting nanotechnology and in introducing nanomaterials into children's environments," he writes. "Several expert advisory groups have called for prudent assessment of the potential hazards of nanotechnology prior to further dissemination. ... This sensible advice has not to date been translated into action."
The primary concerns about health threats from nanomaterials stem from their size, which is in the same range as virus particles, DNA and protein molecules, according to Landrigan.
"Nanoparticles may be able to produce toxic effects as a consequence of their ability to enter cells."- Dr. Philip Landrigan, Mount Sinai School of Medicine
"Nanoparticles may be able to produce toxic effects as a consequence of their ability to enter cells," he writes in "Emerging Technologies." "Small size enhances cell entry and appears to be a major determinant of toxicity." Nanotubes, on the other hand, are predominantly fibrous and do not enter cells, he continues. But they remain in the extracellular spaces, where they can induce chronic inflammation.
In the July 3, 2008, issue of the journal Nature, two researchers from Brown University explored the most common comparison to nanomaterials' health threats in a paper titled "The asbestos analogy revisited."
"Two recent studies provide important new insight into the possibility that carbon nanotubes may induce mesothelioma -- a disease that is rare in unexposed populations and is thus a sensitive marker for asbestos exposure," wrote Agnes B. Kane and Robert H. Hurt.
One of the studies, from the Medical Research Council at the University of Edinburgh in the United Kingdom, reported that multi-walled carbon nanotubes (MWNT) injected into the abdominal cavities of mice created inflammation, lesions and scarring on the mesothelial lining. The distribution and severity of these reactions are similar to those induced by the long fibers of brown asbestos, which have caused toxicity and carcinogenicity in longer-term animal studies, Kane and Hurt said.
In another study at the Institute of Health Sciences of Japan and the Tokyo Metropolitan Institute of Public Health, researchers injected the same type of MWNTs used in the Edinburgh study into the abdominal cavities of mice genetically engineered for sensitivity to asbestos. They reported lesions and scarring in the mesothelial lining, as well as tumors, in 88 percent of mice after 25 weeks, compared with 79 percent in mice injected with a particularly potent form of asbestos.
Kane and Hurt say these studies identify key physical properties of carbon nanotubes that may be relevant for potential toxicity and carcinogenicity: fiber length and biopersistence. "Taken together, these two pioneering studies provide scientific evidence for an asbestos-like pathologic response to carbon nanotubes, at least in certain cases," they concluded.
The researchers cautioned, however, that it would be premature to declare carbon nanotubes a major risk factor for mesothelioma in humans, as it is unclear whether nanotubes would reach the lining in sufficient numbers to cause the disease.
Kuzma, whose specialty is public policy, said the explosion of nanotech products on the market in the past few years has been accompanied by increased attention to regulatory activity in North America and Europe. The U.S. Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) have both issued white papers and guidance on how they intend to address health threats from nanotechnology.
"Two recent studies provide important new insight into the possibility that carbon nanotubes may induce mesothelioma."- Agnes B. Kane and Robert H. Hurt, Brown University
EPA has implemented a voluntary nanoscale materials framework through which companies can submit safety information on a voluntary basis. "The EPA envisioned that would help them figure out what to do about nanotechnology as they saw more and more data come in from this voluntary mechanism," she said. The FDA has said it will regulate nanoproducts under existing laws. "In other words, no special regulation for nanomaterials that come under their jurisdiction through the federal Drug and Cosmetic Act," she said.
E the Environmental Magazine reports in its July-August edition that Canada earlier this year became "one of the first countries to require companies to disclose information about nano ingredients in products." And the Europeans are adopting a precautionary tone. E reports that the European Union is poised to require increased testing and reporting for nano-containing cosmetics.
"These things are evolving right now on an international scale and on a supranational scale in the case of the EU," Kuzma said.
The U.S. and EU approaches to nanotechnology illustrate longstanding differences in the manner in which the two address environmental health threats, Kuzma said. The United States has always taken a "science-based approach," focusing on risk, safety, cost-benefit and economic-benefit. The EU has added to those parameters social values, such as consumer right to know and choose, product labeling, transparency, public participation and independent expert evaluation of safety studies.
"There's also silver-coated nano socks and things that you can buy that will prevent bacterial growth and smelly clothes."- Jennifer Kuzma, University of Minnesota
She noted that the Obama administration has issued notice in the Federal Register that it is considering revisions in federal regulatory review that would incorporate many of these social values into U.S. policymaking. "It's really going to be an interesting time because that could change," she said. "Our ability to focus on some of these not strictly science-based parameters might change, finally."
Meanwhile, rigorous study of the potential health impacts from nanomaterials should be accelerated, the scientists attending the Wilson Center workshop concluded. "Even though opinion diverged on the most relevant tests," the Environmental Health Perspectives report said, "there was consensus that, for adequate risk management, nanoparticles nearing commercialization should be subjected to a battery of short-term in vitro and in vivo tests to determine broadly the effects on key target organs and possible molecular mechanisms of toxicity."
Steven Higgs can be reached at .