FIFRA Scientific Advisory Panel Considers Nanosilver

• Date: 01 December 2009

12-2009 NEWS & ANALYSIS 39 ELR 11143

C O L U MN S

FIFRA Scientif‌ic Advisory

Panel Considers Nanosilver

by Lynn L. Bergeson

Lynn L. Bergeson is Managing Director of Bergeson & Campbell, P.C., a

Washington, D.C., law rm focusing on conventional and engineered nanoscale

chemical, pesticide, and other specialty chemical product approval and regulation,

environmental health and safety law, chemical product litigation, and associated

business issues. She is also President of e Acta Group, L.L.C., and e Acta

Group EU, Ltd, with oces in Washington, D.C., and Manchester, UK.

On November 3-5, 2009, the

Federal Insecticide, Fungicide,

and Rodenticide Act (FIFRA)

Scientic Advisory Panel (SAP) met

“to consider and review a set of scien-

tic issues related to the assessment of

hazard a nd exposure associated with

nanosilver and other nanometal pes-

ticide products.” e decision to con-

vene an SAP was nomina lly motivated

by the U.S. Environmental Protection

Agency’s (EPA’s) need to consider four

applications pending at the Oce

of Pesticide Programs (OPP) seeking

registration of productscontaining

nanosilver-based active ingredients.

e nanosilver products, which

would take the form of textile addi-

tives, polymers, coatings, and/or

plastics, would be used to protect a

treated product from microorganisms

or to impart antimicrobial activity to

a treated materia l. Accordingly, they

would be used in the same manner as

some of the currently registered sil-

ver products, includingthose used as

materials preservative s and antimicro-

bial pesticides. Notably, many of the

110 currently registered silver-based

products actually contain nanosilver.1

1. As noted in the SAP Background Paper, EPA “has

information suggesting that there are other pes-

ticide products currently in the marketplace that

contain nanosilver.” e Silver Nanotechnology

Working Group (SNWG), an industry group

formed to promote the benecial uses of silver

nanoparticles that testied before and submit-

ted comment to the SAP, went so far as to claim

that “all EPA registered silver products through

to 1994 were nanoscale” (emphasis added) and

“the majority of existing registered silver products

Unmentioned in either the Septem-

ber 16, 2009, Federal Registernotice

announcing the public meeting or the

SAP Background Document EPA pre-

pared in connection with the meeting

is a May 2008 petition submitted by

the International Center for Technol-

ogy Assessment (ICTA) and others

requesting, among other actions, that

EPA classify nanosilver as a pesticide,

require the registration under FIFRA

of nanosilver products, and determine

that nanosilver is a new pesticide that

requires a new FIFRA pesticide registra-

tion (available at http://www.icta.org/

nanoaction/doc/CTA_nano-silver%20

petition_nal_5_1_08.pdf).

Core Issue

EPA states in its Background Paper that

“the current state of the science does not

contain sucient information to deter-

mine denitively whether (and, if so, to

what extent) various forms of nanosilver

particles may cause toxic eects beyond

those attributable to the release of silver

ions.” In light of this, the threshold ques-

tion before the SAP relates to whether

EPA can make its safety nding under

FIFRA that a pesticide product will not

cause “unreasonable adverse eects on

the environment” with respect to the

four pending applications.

According to EPA, the registration

applicants claim that “the mode of

action for nanosilveris the same as for

are nanosilver, including the algaecides and water

lters that have been used for decades.”

silver in that the release of silver ions

is the source of antimicrobial activ-

ity.” Because the pesticidal mode of

action of nanosilver is the same as for

conventionally sized silver, the poten-

tial hazards to human health and the

environment resulting from the use of

nanosilver as a pesticide will therefore

be the same as from the use of silver.

EPA likened the registrants’ argument

to that of the so-called 0-hypothesis put

forward by S. Wijnhoven et al.(2009).

e 0-hypothesis states that the toxic

eects of nanosilver are proportional to

the activity of free silver ions released by

the nanoparticles. e question, then,

for FIFRA regulatory purposes becomes

whether sucient data and information

exist to validate the hypothesis. is

requires a two-step process: (1) deter-

mine whether nanosilver particles enter

the body; and (2) determine whether

nanosilver releases silver ions and to

what extent the ions will be absorbed.

EPA further states that registration

applicants posit that there will be no

or only trivial levels of human expo-

sure to nanosilver particles since these

particles will not leach from nished

products. As a result, any toxic eect to

humans would be the result of exposure

Lynn L. Bergeson

Copyright © 2009 Environmental Law Institute®, Washington, DC. reprinted with permission from ELR®, http://www.eli.org, 1-800-433-5120.