Microscopic particles are increasingly found in cleaning products, clotehs and children's toys to kill germs and make things smell fresher. Photo: David Hawxhurst at the Woodrow Wilson International Center for Scholars
Consumer products are laden with nanoparticles, but scientists are uncertain of their risks
By Yang Zhang
Spring 2010
There’s more to your cosmetics, food containers and anti-odor socks than meets the eye.
These products contain microscopic particles that kill germs and make things cleaner and smell fresher.
But scientists are uncertain about the risks of these engineered particles, called nanomaterials, and current regulations on the technology are lax. Neither the manufacturers nor government regulators are required to tell consumers of their presence in a growing number of consumer products.
Nanoparticles are currently found in more than a thousand products, from cleaning products to clothes and children’s toys, according to a consumer nanoproducts inventory developed by the Project on Emerging Nanotechnologies, a national nanotechnology think tank.
“It’s an exciting technology…But some nanoparticles under certain conditions may harm humans and the environment,” says Karen Chou, an associate professor of environmental toxicology at Michigan State University.
That’s because nanoparticles are small: “nano” means one billionth.
A nanometer is one billionth of a meter. A sheet of paper is about 100,000 nanometers thick; human hair is 80,000 nanometers wide.
Materials that small have different chemical and physical properties, Chou says.
Studies show nano-sized particles are more reactive and some are more toxic than their bulk counterparts.
But downsizing enables novel applications. By manipulating nanomaterials, scientists have created new medical treatments, found more effective ways to prevent pollution and made things stronger and lighter.
Take silver — it’s toxic to fungi and algae and makes for a potent anti-bacterial agent.
But only in recent years has nanosilver been widely used as a germ killer in consumer products, according to a 2009 nanosilver report from the Friends of the Earth, an international federation of environmental groups comprising 77 countries.
“It has been used as (an) anti-microbial in…many products,” says Ian Illuminato, the health and environment campaigner at the U.S. Friends of the Earth and a co-author of the report.
NANOSILVERS
Silver nanoparticles at 60,000x magnification. Photo courtesy of nanoComposix, Inc. San Deigo, Calif.
More than 260 nanosilver products, such as water filters, kitchen appliances and bedding materials, are on the market, according to a 2008 nanosilver legal petition by the International Center for Technology Assessment, a non-profit organization that estimates technological impacts.
That accounts for a quarter of the market share. But the potential environmental and health impacts of nanosilver trouble some scientists.
Silver nanoparticles from textiles, cleaning products and cosmetics have the potential to enter the water system as common household wastewater. Some particles may remain in surface water and accumulate and deposit into soils, according to Beyond Pesticides, a national environmental organization.
“We know where nanoparticles go,” Chou says. “Those we use probably go to rivers and soils.”
Nearly one third of nanosilver products on the market in September 2007 had the potential to disperse silver nanoparticles into the environment, according to research by Samuel Luoma with the John Muir Institute of the Environment at the University of California, Davis.
Once in the environment, these particles can be harmful to aquatic invertebrates at low concentrations.
“Based on the lab experiments, small fish, if exposed to certain nanoparticles, may die or become sterile,” Chou says.
Studies indicate nanosilver is also toxic to mammalian liver, stem and brain cells.
Silver nanoparticles can easily enter human cells and cause health problems, according to the Friends of the Earth report.
Issued last June, the report highlights the potential risks of nanosilver to human health, especially to children.
A 2006 study found that silver nanoparticles in burn dressings can be toxic. After doctors treated a severely burned 17-year-old boy with nanosilver-coated wound dressings the nanoparticles seeped into his body and damaged his liver, according to the study.
When the dressings were removed, the boy returned to normal.
“It’s definitely coming into contact with humans,” says Ian Illuminato, a health and environment campaigner for the Friends of the Earth. “And it is especially concerning for children who have much more delicate systems they are working with.”
Scientists are also concerned about nanosilver killing good bacteria.
The majority of bacteria are harmless and some are even beneficial.
Bacteria are found on the skin, nose, mouth and in the gut. They help humans digest food, produce vitamins and prevent pathogens from gaining a foothold in the body.
“Those nanosilver particles don’t distinguish between good and bad bacteria,” Illuminato says. “They are powerful bacteria killers.”
OTHER HARMFUL NANOMATERIALS
Carbon nanotubes, found in tennis rackets or golf clubs, and titanium dioxide nanoparticles in sunscreens also threaten the environment and human health.
A 2008 study by a team of international scientists showed carbon nanotubes have needle-like fiber shapes similar to asbestos and could potentially cause asbestos-like diseases, such as lung cancer.
Titanium dioxide nanoparticles in sunscreens can also damage biological molecules by degrading sunscreen under illumination, according to research by Vicki L. Colvin, a professor in the department of chemistry and chemical and biomolecular engineering at Rice University.
Studies suggest nanomaterials can even take lives.
After long–term exposure to nanoparticles used in polyacrylic ester paste, seven Chinese workers in a print plant suffered unusual and progressive lung disease. Two of the workers died from their illness, according to a study by China’s Capital University of Medical Science.
LAX REGULATIONS
Despite the potential threats, the government doesn’t require companies to disclose the presences of nanomaterials in products. And there aren’t any regulations on the books.
“The government has been really struggling to work hard to regulate products of nanotechnology,” says Andrew Maynard, chief science advisor for the Project on Emerging Nanotechnologies at Woodrow Wilson International Center for Scholars.
The U.S. Environmental Protection Agency launched the Nanoscale Materials Stewardship Program in January 2008 to study nanotechnology. But it has no regulatory power.
The regulations are strict for new drugs containing nanomaterials, Maynard says. But that’s not the case for personal products, like cosmetics.
Manufactures are required to report and register personal products that contain nanosilver, but there is no labeling requirement.
“The bare minimum should be that products are labeled to contain nanoparticles so that consumers can be aware and make educated choices when they buy them,” Illuminato says.
The Friends of the Earth claims the EPA and the U.S. Food and Drug Administration has taken a “no data, no problem” attitude, which means the product is safe if no evidence shows its harm, even if little research has been done to examine its safety.
“They are not taking the health of consumers as the first priority,” Illuminato says. “It’s more like if nobody dies from it yet, then it’s OK, it’s fine.”
He recommends a “no data, no market” approach adopted by some European countries.
If it cannot be proven that something will not affect human health and the environment, it shouldn’t be on the market, Illuminato says.
“The main hurdles, some of the big ones we’ve identified, are uncertainties of the health and safety risks associated with nanotechnology,” Maynard says.
But determining potential dangers isn’t easy.
Nanoparticles change fast because of their instability and reactivity, Chou says. When conditions vary, the size of a nanoparticle and its properties are altered.
“You have to know the toxicity of each nanoparticle as precisely as possible to regulate it,” she says.
And determining toxicity is expensive. Each test costs tens of thousands of dollars, which makes it harder to get data.
The Friends of the Earth and some other environmental groups are calling for an immediate moratorium on the commercial nanoproducts, especially those containing nanosilvers, until the technology is proven safe or specific regulation is introduced.
“A company wants to invest in nanotechnology, but they don’t know how to make it safe,” Maynard says. “That makes it very hard to develop it.”
Still, the industry is growing.
Federal funding for nanotechnology has increased from approximately $464 million in 2001 to nearly $1.8 billion in 2009, according to the National Nanotechnology Initiative, a program to coordinate federal nanotechnology research and development.
The initiative estimates that private industry is investing at least as much as the government.
“If you look at the development of technology like this,” Maynard says. “It is very hard to see how it can be successful if we don’t indentify any possible way that can harm and manage them at early stages.”
Both Maynard and Chou see nanotechnology as a promising industry. But they hope comprehensive risk assessments and sound regulations will ensure the safety of the field and its future.
“A well-characterized toxicology study on nanomaterials will help us assess the risks and make effective regulations,” Chou says. “It is very hard, but not impossible.”
Yang Zhang is a second-year graduate student studying environmental journalism at MSU. Contact her at zhangy49@msu.edu.