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EPA Examining Use of Nanoscale Silver In Washing Machines as Possible Pesticide
The Environmental Protection Agency is working to determine whether nanoscale silver used in a new type of washing machine to kill bacteria should be regulated as a pesticide, according to agency officials.
The agency is examining the question but does not know when it will make a decision, EPA spokeswoman Enesta Jones told BNA May 9.
The issue has generated attention recently because of a washing
machine marketed by Samsung that injects silver ions--silver atoms stripped of
an electron--into the wash and rinse cycle to penetrate fabric and kill bacteria
without the need for hot water and bleach.
The agency declined to comment further on its assessment of the washing machine.
Jones said EPA was examining two nano-engineered products on the market that may
be using claims that they kill pests, although it was unclear if those products
were in addition to the washing machine.
"EPA is currently reviewing the product ingredients, the label, the marketing
material, and consulting with the Office of Enforcement Compliance and
Assistance to determine if and what steps EPA needs to take," Jones said.
Samsung said it has worked with EPA regarding the agency's regulation of the
washing machine to be fully compliant with all applicable laws and regulations
and will continue to do so.
Utilities Ask EPA to Register Silver
Two wastewater utility associations, the National Association of Clean Water
Agencies and Tri-TAC, which advises California publicly owned treatment works,
wrote EPA earlier this year asking it to regulate the use of nanoscale silver in
washing machines as a pesticide. Colorado regulators also are pressing EPA to
act (34 DEN A-8, 02/21/06 ).
If the product is a pesticide it would have to be registered, meaning EPA would
require extensive data to ensure that the pesticide, when used according to
label directions, could be used with a reasonable certainty of no harm to human
health and without posing unreasonable risks to the environment. To make such
determinations, EPA can require more than 100 different scientific studies and
tests from applicants.
Tri-TAC recommended EPA require the registration of Samsung's SilverCare(TM)
washing machines and similar products that use silver ions as disinfectants. As
part of the registration process, EPA should obtain data on the silver ion
concentrations and wash cycle volumes used by such machines to ensure that water
quality standards are not exceeded and the existing bioaccumulation of silver in
aquatic environments is not exacerbated, Tri-TAC said in a Jan. 27 letter to
EPA.
"Our main concern is that a certain percentage of the ions will go through the
sewage and get discharged to the [San Francisco] Bay where they will kill the
plankton, which form the base of the food chain," Phil Bobel, who works with
Tri-Tac and manages environmental compliance for Palo Alto, Calif., told BNA May
10.
Norman LeBlanc, who chairs NACWA's water quality committee, agreed the
bottom-of-the-food-chain effects of the nanoscale silver should be evaluated
before the washing machines are widely used.
Product Said to Kill Bacteria
In information posted on its website, Samsung says its SilverCare(TM) washing
machine injects "over 100 quadrillion silver ions" into the wash and rinse
cycle. The ions then penetrate fabrics and kill bacteria without the need for
hot water or bleach, Samsung said, adding the process helps meet the consumer
demand for energy-saving products.
If a load of laundry is sanitized with the silver ions rather than hot water,
the machine uses about 92 percent less energy, Samsung said.
In its statement to BNA, Samsung said the quantity of silver that would be
released from its washing machine is very low compared with the quantity of
silver already in wastewater.
Samsung acknowledged that free silver ions are very toxic to microorganisms, but
in waste they quickly bind to organic matter and become inactive, it said.
Samsung has conducted at least five toxicity studies on species, including water
fleas, fish and earthworms, and the resulting data showed "minimal risk to the
environment," the firm said.
According to Samsung's estimates, a household that used the silver ions to wash
100 loads of laundry a year would release about 0.001 part per million silver in
the wastewater. Loss in the wastewater collection systems, wastewater treatment,
and other factors would reduce the concentration of silver in wastewater-plant
effluent to be less than 0.00001 ppm, the firm said.
Responding to the requests from NACWA and Tri-TAC, James J. Jones, director of
EPA's Office of Pesticide Programs, told both organizations in separate letters
in February and March: "We want to assure you that we are carefully considering
your recommendations and the issue of registration of products that use silver
ion electrodes as disinfectants."
EPA Reviewing Product
"Once a determination is made as to whether the product requires registration,
we will be able to evaluate potential environmental issues and assess what
efficacy data would be required to support any claims," Jones said, adding the
agency anticipated making that decision "within the next few weeks."
According to Laura Quakenbush, Colorado's pesticide registration coordinator,
EPA already has classified the machine as a "pesticide device," and Colorado has
concerns about that decision. Quakenbush told BNA she has asked EPA to classify
the Samsung machine as a "co-pack," meaning it would be considered both a
pesticide device and a pesticide.
Pesticide devices are subject to certain labeling, recordkeeping, and other
requirements, but unlike pesticides, the devices are not required by EPA to be
registered, said E. Donald Elliott, who served as EPA's general council under
President George H.W. Bush, and now is an attorney with Willkie Farr and
Gallagher.
Elliott agreed with Quakenbush that EPA should register Samsung's washing
machine as a device and its infusion of silver ions as a pesticide.
It is not clear from Samsung's description whether the silver ions used in the
machine are intentionally engineered nanoparticles that have special properties
because of their tiny size or whether they are simply very small charged silver
atoms, said Andrew Maynard, chief science adviser to the Project on Emerging
Nanotechnologies at the Woodrow Wilson International Center for Scholars.
According to Maynard there are two questions: Are the ions a pesticide
regardless of whether they are "nano" or not, and if they are engineered
nanoparticles do they behave differently from larger forms of silver -- for
example, do they persist longer or move differently within the environment?
Growing Use of Nanosilver Cited
The concerns of Bobel and LeBlanc go beyond washing machines.
They said the growing use of nanosilver particles in some clothing was a concern
because some of the particles would come off as clothes are laundered and enter
the wastewater system. Both questioned the necessity of the use of nanoscale
silver on clothing or in a washing machine.
For centuries people kept their clothes clean with detergent and hot water, they
said. "It seems like we're addressing a nonproblem," Bobel said.
Silver is persistent and toxic and it bioaccumulates, he continued.
Depending on the plant design, sewage treatment plants would remove 50 percent
to 90 percent of the silver, he said, adding the rest would remain in sludge.
That means these clothing-related uses of silver could potentially build up in
soil because sludge is commonly placed on farm land and in landfills, Bobel
said.
There may be times when the risk of disease warrants the use of a toxic
substance, such as the continuing use of DDT in some countries to kill
malaria-carrying mosquitoes, Bobel said. "But are these [nanosilver-coated
clothes and nanosilver washing machines] necessary?" he asked.
Glenn Brank, communications director for California's Department of Pesticide
Regulation, said the wastewater utilities were raising pertinent questions that
should be addressed. The department "looks to EPA to address those questions
because this is a national issue," Brank said.
Review Said to Be Necessary
Elliott, the former general counsel at EPA, said the agency should review the
silver ions used in the washing machine as a pesticide, and EPA along with other
federal agencies should be regulating other uses of nanomaterials.
Without such reviews, the public will have many "what if" questions, Elliott
said, adding people are creative and can envision all sorts of problems
resulting from a new technology.
"Samsung's product is probably perfectly safe," Elliott said, adding regulatory
review would provide a public process to assess that safety.
The washing machine illustrates a trend in which manufacturers are increasingly
using nanoscale silver in consumer and medical products because of silver's
well-known antimicrobial properties, according to Marlene Bourne, principal
analyst with Bourne Research, a market analysis company. Bourne released a
report in April describing this trend.
Bourne told BNA nanoscale silver increasingly is used in products such as
brooms, food storage containers, drywall, and paint for surfaces where mold
tends to grow. Medical uses of nanosilver include coating curtains used in
hospitals, wound treatments, and coatings for surgical tools, she said. Another
growing use of nanoscale silver is in sports clothes as a disinfectant, Bourne
said.
J. Clarence "Terry" Davies, who served as EPA assistant administrator for
policy, planning, and evaluation from 1989 to 1991, said "the washing machine
case is just one more example of why we need a careful review of the adequacy of
existing law to deal with nano products."
"Until the public can be assured that the mechanisms for adequate oversight are
in place, so that any adverse effects can be identified and managed," he
continued, "there is no reason for the public to trust that health and the
environment will be protected."
By Pat Phibbs and Tripp Baltz (Denver)