Clean Water Advocacy - Newsroom - NACWA in the News
Companies Promote Silver as Germ Fighter
Jun 12, 2006 Arkansas Democrat Gazette
RHONDA L. RUNDLE THE WALL STREET JOURNAL
Since ancient times, people have known of the germ-fighting
qualities of silver. Dead bodies were wrapped in silver cloth to ward off bad
odors. Milk stored in silver vessels didn’t spoil as quickly. Now, silver is
showing up as a bacteria- and odor-fighting material in a range of contemporary
consumer products, from sports socks to washing machines.
Specialty retailer Sharper Image recently introduced a line of plastic food
containers infused with silver nanoparticles that are intended to keep food
fresher. The boxes, priced at $69. 95 for a set of 12, have drawn positive
reviews at Amazon. com. , which sells Sharper Image products - including one
owner raving about strawberries staying fresh for 14 days.
In March, South Korea’s Samsung Electronics introduced a new washer in the
United States that uses silver ions to sanitize laundry. Plank, a small Boston
company that sells yoga accessories, recently introduced Cor, a soap with silver
as the main active ingredient. The company says its supplier is also developing
silver-imbued shampoo and toothpaste.
About three years ago, consumer products incorporating silver as an
antimicrobial ingredient - some made using nanotechnology to bond materials at a
molecular level - took off in Asia. Now some observers believe they are poised
to become big in the United States.
“Silver nanoparticles may very well become the next ‘it’ product, much like
antibacterial soaps that took the consumer sector by storm a decade ago,” said
Marlene Bourne, president of Scottsdale, Ariz. -based Bourne Research, which
specializes in emerging technologies.
The products are typically expensive. Cor soap, for example, costs $115 per bar.
But because they use only tiny amounts of the precious metal, the surge in the
price of silver over the past year hasn’t had much impact on the products.
But the proliferation of silvercontaining products is raising some concerns
among state and federal environmental regulators because silver is highly toxic
to aquatic life. It isn’t toxic to humans except in large quantities that aren’t
at issue when it comes to these consumer products.
“The whole contaminant issue is starting to explode in our face and we need to
look and study it further,” said a spokesman for the National Association of
Clean Water Agencies, a nonprofit association of wastewater and drinking water
plants in Washington.
In a February letter, the organization asked the Environmental Protection Agency
to review consumer products containing silver ions and to consider registering
them as pesticides. The group’s letter to the agency cited the silver ions that
will be discharged into sewer systems when clothing is washed in Samsung’s new
machine.
The EPA’s office of pesticide programs says it is studying the matter. A Samsung
manager in the United States referred questions to the electronics giant’s
headquarters in Seoul. Officials there couldn’t be reached.
Another broad question is whether resistant strains of bacteria could emerge if
the market were flooded with silver nanoparticles.
Silver, in the form of a metal or as dissolved ions, fights microorganisms by
interfering with processes such as how they breathe and reproduce. Tests show
that silver ions kill microorganisms ranging from harmful strains of E. coli
that cause food-borne diseases to the staphylococcus bacteria responsible for
serious infections.
The metal becomes more active against microbes when it’s made into small
particles because they can cover more surface area when they come into direct
contact with bacteria, said Andrew Maynard, a physicist and chief scientific
adviser to the Project on Emerging Nanotechnologies at the Woodrow Wilson
International Center for Scholars in Washington.
In the new Samsung washer, a grapefruit-size device alongside the drum uses
electrical currents to nano-shave two silver plates each time the washer is
turned on (the silver should last 10 years or 3,000 cycles before needing
replacement ). The resulting silver ions are injected during the wash cycle. The
company says this process removes or kills 99. 9 percent of odor-causing
bacteria. It also touts the SilverCare Technology machines, priced about $1,200
at Lowe’s and Best Buy stores, as energy-efficient because they sanitize
clothing without using hot water.
Samsung is also developing refrigerators using similar technology, a spokesman
said. In Asia and Europe, South Korea’s LG Electronics and the German unit of
Daewoo already offer silverlined refrigerators and vacuum cleaners.
Antimicrobial silver is also increasingly popular in athletic and outdoor
clothing. Many apparel makers, including Adidas and Polartec, have licensed a
silver-coated nylon fiber known as X-Static from Noble Biomaterials Inc. Brooks
Sports introduced a line last fall touting the silver fibers’ ability to promote
thermal regulation as well as odor protection. The line of shirts, caps and
socks, called HVAC, short for heating, ventilation and air conditioning, is
supposed to keep athletes comfortable in different temperatures by taking
advantage of silver’s natural energy conduction qualities.
As more clothing companies are using silver yarns, threads and fibers,
competition is brewing among manufacturers that make them. NanoHorizons Inc. ,
founded four years ago by two graduate students and their faculty adviser at
Penn State University in State College, Pa. , uses a proprietary engineering
process to disperse silver nanoparticles uniformly through pellets, powders and
liquids it makes for textile applications. This helps prevent silver from
leeching away in repeated washings, said Dan Hayes, co-founder and director of
operations.
Performance apparel maker ARC Outdoors Inc. has incorporated NanoHorizons’
SmartSilver in a brand of odor-eliminating underwear, gloves, stocking caps and
other items. The company also says it is selling SmartSilver antimicrobial socks
to soldiers in U. S. military stores around the world. ARC’s E47 brand is
available at Wal-Mart stores as well as outdoor specialty retailers Bass Pro
Shops and Cabela’s, which both cater to hunters and fishermen. (E47 is a
reference to silver - No. 47 on the periodic table of elements. )
ARC said it is also exploring embedding silver nanoparticles in hospital products from surgical scrubs to bed sheets.