Vol. XX, no. 3
How Nanoparticles Are Changing Everything From Our Sunscreen to
By Carole Bass
It's a beautiful summer day. You pull on your stain-resistant
cargo shorts and odor-resistant hiking socks, gulp down an
energy-boosting supplement, slather yourself with sunscreen and head
out for a ramble in the woods. Are you poisoning yourself? When you
get home, you jump in the shower and toss your clothes in the wash.
Are you poisoning the environment? Maybe.
Your sunscreen, energy drink and high-tech clothing may be among the
800-plus consumer products made with nanomaterials: those manufactured
at the scale of atoms and molecules. Sunscreen that turns clear on the
skin contains titanium dioxide, an ordinary UV-blocker in
extraordinarily small particles. Odor-eating socks are made with atoms
of germ-killing silver. Supplement makers boast of amazing health
effects from swallowing nanosolutions that are completely untested for
effectiveness or safety. And that stain-repellant clothing? The
manufacturer won't even tell you what nanomaterials are in it.
The problem is not just that you, the consumer, don't know what's
in the products you use. The much bigger problem is that at the
nanoscale, common substances behave in uncommon ways. And nobody-not
even the world's leading nanoscientists-knows what nanoparticles
do inside the body or in the environment.
Nanotechnology, a fast-growing global industry, is essentially
unregulated. Advocates and independent scientists agree that we need
to get ahead of the risks before it's too late. Some call for a
moratorium on the riskiest nanoproducts. Some say we just need more
research, and more protection for workers in the meantime. All are
worried about unleashing a powerful new technology that could have
vast unintended consquences. Nanomaterials are in food, cosmetics,
clothing, toys and scores of other everyday products. Yet when it
comes to trying to get a handle on them, we can't answer the most
basic questions. What companies are using nanomaterials, and where?
What kinds, and in what amounts? How much of the potentially hazardous
stuff is escaping into the air, water and soil? Into our food and
drinks? Nobody knows.
At a February workshop on what research is needed to better understand
nanorisks, speaker after speaker presented questions without answers.
Rutgers University environmental scientist Paul Lioy, assigned to talk
about human exposures to nanomaterials, was especially blunt.
"This is basically virgin territory," he said. "The fact that
it's virgin territory is not good for the field, and it should be
fixed really quick."
Big Benefits, Big Risks?
Nanomaterials are not new. Some exist naturally, and others result
from combustion-like the ultrafine particles in diesel exhaust that
have been linked to respiratory and heart diseases.
What's new is nanotechnology, the ability to manufacture and
manipulate minuscule materials into forms such as quantum dots,
spherical buckyballs, and cylindrical carbon nanotubes. These
engineered nanomaterials take on unusual properties: changing color,
for example, or becoming electrically conductive, or penetrating cell
walls. And they have many uses. Carbon nanotubes, or CNTs-made by
rolling up sheets of graphite just one atom thick-are extremely
light and strong; they show up in high-end tennis rackets and bicycle
frames. Nanosilver is used as an antimicrobial agent in everything
from paint to toothpaste to teddy bears. Nanometal oxides are blended
into ceramics and coatings, making them more durable.
While there's no universal definition, the "nano" moniker
generally covers materials between one and 100 nanometers. A nanometer
is one billionth of a meter, or between 50,000 and 100,000 times
thinner than a human hair.
Nanotech offers enormous potential benefits. Medical researchers are
investigating ways to use nanomaterials to target tumors and then
deliver tiny amounts of drugs directly inside the cancer cells,
sparing the healthy cells. Possible green tech applications include
cheaper, more efficient solar panels and water-filtration systems,
energy-saving batteries and lighter vehicles that use less fuel.
That's the upside. But exciting new wonder materials often reveal a
dark side, too. Asbestos-now synonymous with bankrutpcy-inducing
lawsuits and slow, painful death-was once seen as a miraculous
fireproofing agent that would save millions of lives. Much of its
damage could have been avoided if industry and government had heeded
the ample danger signs. Now, early research on the potential hazards
of nanotech is producing danger signs of its own. Workers handling
nanomaterials face the biggest risks. But there are concerns for
consumers, too, especially with products-like cosmetics, food and
supplements-that go directly on or in the body. And with potentially
toxic nanomaterials washing down the drain and into the water and
soil, there's reason to worry about environmental damage as
Yet studies on nanotech's downside are a mere nanospeck compared to
the research that's being done on how this technology can benefit
humanity-and corporate profits. Of $1.5 billion in federal nano
spending each year, only between 1% and 2.5% goes toward studying
environmental, health and safety risks. Worse, there's no national
strategy for deciding what questions need to be answered, or what to
do with those answers as they arrive.
Since the 17th century, when Italian physician Bernardino Ramazzini
pioneered the field of occupational medicine, researchers have looked
to the workplace for advance warning of new illnesses. From janitors
blinded by ammonia fumes to chimney sweeps who absorbed cancer-causing
soot through their skin, workers get sick first and most acutely
because of their intense, daily toxic exposures. That's why much of
the still-sparse nano health and safety research has focused on the
possible hazards of working with nanomaterials. Scientists can't
expose workers to potential toxins and watch to see if they keel over.
But if employers cooperate, researchers can find out what materials
workers are using, in what amounts and forms, and under what
conditions. Then they can simulate those exposures with lab
Some studies find little or no risk. Others are alarming. Last year,
British researchers reported that when long, straight carbon
nanotubes-shaped like asbestos fibers-were injected into mice,
they caused the same kind of damage as asbestos. Of course, workers
wouldn't ordinarily stick themselves with a needleful of CNTs. But a
follow-up study this year, by the National Institute for Occupational
Safety and Health (NIOSH), found that when mice inhaled CNTs, the tiny
tubes migrated from their lungs to the surrounding tissue-the very
spot where asbestos causes the rare cancer known as
mesothelioma. One reason nanomaterials can cause trouble
is that they are small enough to evade the body's defenses. In a
University of Rochester study of the accidental nanoparticles known as
ultrafine pollution, they bypassed the protective blood-brain barrier
and slipped directly into the brain's olfactory bulb. Other research
demonstrates that nanomaterials can penetrate the deepest part of the
lungs. From there, they cross into the bloodstream and various
Based on evidence like this, the European Union's occupational
health and safety agency issued an expert report in March, citing
nanoparticles as the number-one emerging risk to workers. In the U.S.,
NIOSH has issued a guidance document urging employers to avoid
exposing workers to nanomaterials-for example, by enclosing
equipment and using ventilation to reduce dust and fumes. But NIOSH
has no regulatory power; it can only suggest.
The Pig-Pen Effect
"You're producing a personal cloud of exposure," Paul Lioy
warned. "Every time you breathe. Every time you move. If the
materials you're wearing have [nano]materials that can be released,
they will be released. It's basically the Pig-Pen effect.
Lioy, the Rutgers environmental scientist, was speaking theoretically.
His audience was fellow scientists, gathered in Bethesda, Maryland,
for a workshop sponsored by the federal government. The workshop's
title: "Human & Environmental Exposure Assessment of
Nanomaterials." Lioy's assignment: Talk about the need for
research to "characterize exposure to the general population from
industrial processes and industrial and consumer products containing
nanomaterials." His message: There is no research on whether and how
the general population is exposed to nanomaterials. Searching the
scholarly literature, Lioy's associates "spent hours looking for
data ... and found nothing," he said.
While workers are on the front lines of nanoexposure, Lioy cautioned
against ignoring consumer exposures. "We are all in contact with
it-300 million of us, if we use products that have nanoparticles,"
he declared. And while nanomaterials that are embedded in a hard
surface like a computer keyboard are probably not a big worry,
clothing and cosmetics might be a different story, he said. That's
where his comparison to Pig-Pen, the Peanuts character forever
surrounded by a cloud of dirt, comes in: the idea that every time we
move, nanoparticles might come loose from our moisturizer or our
Noting that "a lot of nanoparticle uses are terrific," Lioy said
he doesn't want society to do without. As scientists do the
necessary studies, "I think a lot of issues will go away," he
said. "I just don't want unintended consequences."
Down the Drain
Cyndee Gruden is getting the poop on nano-pollution-literally.
One of the main environmental concerns about nanomaterials is what
happens when they wash out of clothing, hair or skin and go down the
drain. Do they harm aquatic life? Do they interfere with wastewater
Gruden, a civil engineering professor at the University of Toledo in
Ohio, is tackling part of that last question by looking at the effects
of two nanometals-titanium dioxide and zinc oxide, used in
sunscreens, paint and other products-on bacteria.
Metals "can be toxic to microorganisms," she notes. "In fact,
that's specifically what they're for" in consumer products: to
inhibit mold, mildew and other nastiness. But when nanometals make
their way to a sewage treatment plant, Gruden worries that they might
harm the beneficial bacteria that break down what's delicately known
in the business as "biosolids."
Her preliminary findings, which she presented at a meeting of the
American Chemical Society (an academic group, not an industry
organization) in March, are mixed. Nano-titanium dioxide damaged
bacteria, causing cell walls to break at "relatively low
concentrations," similar to what you might see at a sewage treatment
plant, Gruden says in an interview. But "in terms of function, what
does that mean? Are the bugs able to do what they're supposed to
To answer that question, she added some biosolids to her test tubes
and measured how much methane the bacteria produced as they digested
for five days. The titanium dioxide didn't seem to slow the bugs
down; in fact, methane production actually increased. But when Gruden
added nano-zinc oxide, gas production slowed down. She's running
more experiments this summer to see what happens when the bacteria are
exposed to the bugs for a full 30 days.
"The take-home message for me is, the behavior of these particles is
very complex," Gruden says. "When you take a nanoparticle and put
it into the environment, you have to know how it's going to behave.
And we don't."
One metal Gruden didn't look at is nanosilver, widely used as a
microbe-killer. The Project on Emerging Nanotechnologies, a nonprofit
research and advocacy organization funded by the Pew Charitable Trusts
in Washington, D.C., maintains an inventory of more than 800 consumer
products advertised as using nanotechnology. Silver is by far the most
frequently identified material.
In an experiment publicized last year, Arizona State University
graduate student Troy Benn bought nanosilver-containing socks off the
Internet and simulated washing them in jars of water. He found that,
for several brands, most or all of the silver disappeared in just a
few washings. Silver has been used to kill bacteria since ancient
times, when the Greeks found that wine stayed fresh longer in vessels
lined with the precious metal. It's potent enough that the U.S.
Environmental Protection Agency (EPA) regulates silver as a pesticide.
Which raises the question: What does nanosilver do to the "good
bugs" downstream, at the sewage treatment plant and elsewhere?
In 2006, a trade organization of wastewater treatment operators was
concerned enough about a new silver-ion-emitting Samsung washing
machine to pressure the EPA to include such equipment under its
pesticide rules. The EPA responded by cracking down, not only on the
washer but also on manufacturers of products advertised to contain
nanosilver, including a line of supposedly sanitary computer
peripherals. Separately, a coalition of consumer, health, and
environmental groups filed a petition last year asking the EPA to
impose a moratorium on nanosilver products until more safety research
is done. In addition, the EPA has awarded a grant to Arizona State
researchers to investigate interactions between various kinds of
nanomaterials and wastewater biosolids.
Oversight or Overlooked?
In the U.S., the EPA has emerged as the lead agency on nano oversight.
But that's not saying much. It is wrestling with the possible risks
of nanomaterials, but so far has taken almost no action to regulate
In a voluntary Nanoscale Materials Stewardship Program, the EPA asked
companies to submit information about what nanomaterials they're
using. Very few did, and even the companies that participated withheld
large amounts of data as business secrets. This March, the EPA began
requiring manufacturers of carbon nanotubes to file pre-manufacturing
notices under the Toxic Substances Control Act. California is
requiring carbon nanotube makers to share their environmental, health
and safety test data with the state, and is considering imposing the
same mandate on makers of nanometal oxides, like the ones Gruden is
But the EPA is not the only federal agency with responsibility for
nanomaterials. Cosmetics, sunscreen, and food and beverages-which
fall under the jurisdiction of the Food and Drug Administration
(FDA)-make up roughly 30% of PEN's consumer products inventory. Yet
the FDA is poorly equipped to ensure the safety of nano-containing
dietary supplements, according to a 2008 report by two former agency
officials. (Friends of the Earth has urged mandatory labeling of
nanofoods and a moratorium on nano-containing cosmetics until
they're shown to be safe.) The Occupational Safety and Health
Administration, which is responsible for protecting workers, has not
even begun to work on nano rules.
A former EPA official, J. Clarence Davies, proposes merging all these
agencies and more into a new Department of Environmental and Consumer
Protection. A "scientific agency with a strong oversight component,"
it would cover products, pollution, workplace health and safety,
climate change and health effects of nanotechnology as well as other
technologies, Davies writes in his April 2009 report, "Oversight of
Next Generation Nanotechnology."
Outside the U. S., regulators are taking a somewhat more precautionary
approach. Still, governments have adopted very few nano-specific rules
to protect people or the environment. But there are bright spots. At
Rice University in Houston, Texas, for example, Vicki Colvin and her
colleagues are trying to engineer nanomaterials that are safe from the
get-go, rather than looking for ways to minimize harm from
But fears abound that the teeny genie is escaping from its bottle. The
asbestos parallel causes particular concern-prompting the Australian
Council of Trade Unions, for example, to call for that country to
adopt nano regulations by year's end. At the Bethesda workshop in
February, Harvard industrial hygienist Robert Herrick advocated an
all-out effort to gather information about nano exposures and possible
related illnesses. The asbestos industry could have undertaken a
similar effort in the 1930s, he noted. Instead, industry execs decided
to keep the subject quiet. If they had gone the other way, Herrick
wondered, "how different would history be?"
CAROLE BASS, a journalist, writes about the environment,
workplace health, legal affairs and other subjects