Emerging Contaminants -
Nanomaterials
September 2009
FACT SHEET
At a Glance
Introduction
NMs are a diverse class of small-
scale substances that have
structural components smaller than 1
micrometer (1000 nanometers (nm))
in at least one dimension (Luoma
2008). NMs include nanoparticles
(NPs) which are particles with at
least two dimensions between
approximately 1 and 100 nm in the
nanoscale. (EPA2008a).
NMs can be categorized into three
types: natural, incidental, and
engineered.
Engineered NMs are being used in a
wide variety of applications including
environmental remediation, pollution
sensors, photovoltaics, medical
imaging, and drug delivery.
NMs may be released through point
and nonpoint sources, or introduced
directly to the environment when
used for remediation purposes.
NMs may be readily transported
through media usually over much
greater distances than larger
particles of the same composition.
The mobility of NMs depends on
their surface chemistry and particle
size, among other factors, and also
on biological and abiotic processes
in the media
NPs may stay in suspension as
individual particles, aggregate,
dissolve, or react with natural
materials.
Characterization and detection
technologies for NMs include
differential mobility analyzers, mass
spectrometry, and scanning electron
microscopy.
Some possible treatment methods
include air filters and respirators to
remove NMs from air and
flocculation, sedimentation, and
filtration to remove NMs from water.
An "emerging contaminant" is a chemical or material that is characterized by
a perceived, potential, or real threat to human health or the environment or a
lack of published health standards. A contaminant may also be "emerging"
because a new source or a new pathway to humans has been discovered
or a new detection method or treatment technology has been developed
(DoD 2009). This fact sheet, developed by the U.S. Environmental
Protection Agency (EPA) Federal Facilities Restoration and Reuse Office
(FFRRO), provides a brief summary of nanomaterials (NMs) as emerging
contaminants, including their physical and chemical properties; potential
environmental and health impacts; existing federal and state guidelines;
detection and treatment methods; and additional sources of information.
Because of their unique properties, NMs are increasingly being used in a
wide range of scientific, environmental, industrial, and medicinal
applications. However, there is a growing concern about the lack of
environmental health and safety data for nanomaterials. This fact sheet is
intended for use by site managers and other field personnel who may need
to address or use NMs at cleanup sites or in drinking water supplies.
What are nanomaterials?
* NMs are a diverse class of small-scale substances that have
structural components smaller than 1 micrometer (1000 nanometers
(nm)) in at least one dimension (Luoma 2008). NMs include
nanoparticles (NPs) which are particles with at least two dimensions
between approximately 1 and 100 nm in the nanoscale. (EPA
2008a).
»> NMs can be categorized into three types according to their source:
natural, incidental (emissions from engine combustion), and
engineered (manufactured). See Exhibit 1 for examples.
»> Engineered NMs, designed with very specific properties, are
intentionally produced through certain chemical processes, physical
processes, or both, such as self-assembly (from atoms and
molecules) or milling (from their macro-scale counterparts), and may
be released into the environment primarily through industrial and
environmental applications or improper handling of NMs (DHHS
2006; EPA 2007).
»> Due to their novel nanoscale size, NMs may possess unique
chemical, biological, and physical properties as compared to larger
particles of the same material (Keiner2008).
»> The unique properties of NMs allow them to be used for various
applications as shown in Exhibit 1.
»> More than 1000 consumer products that contain NMs are on the
market today (VWVIC 2009).
United States
Environmental Protection Agency
Solid Waste and
Emergency Response (5106P)
1
EPA505-F-09-011
September 2009
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Emerging Contaminant - Nanomaterials
Exhibit 1: Properties and Common Uses of NMs
(Occurrence) 1
Carbon-based
(Natural or Engineered)
(EPA 2007; Klaine et al
2008)
Metal Oxides (Natural
or Engineered)
(Klaine et al 2008)
Zero-Valent Metals
(Engineered) (EPA
2008a, Klaine et al
2008)
Quantum Dots
(Engineered)
(Klaine et al 2008)
Dendrimers
(Engineered) (EPA
2007, Watlington 2005)
Composite NMs
(Engineered)
(EPA 2007, Gil & Parak
2008)
Nanosilver
(Engineered)
(Klaine et al 2008;
Luoma 2008)
| Example 1
Fullerenes/Buckyballs
(Carbon 60, Carbon 20,
Carbon 70); carbon
nanotubes;
nanodiamonds;
nanowires.
Titanium dioxide (TiC>2);
zinc oxide (ZnO);
cerium oxide (CeC^).
Nanoscale zero-valent
iron (nZVI), emulsified
zero-valent iron (EZVI),
and bimetallic
nanoscale particles
(BNPs). BNPs include
elemental iron and a
metal catalyst (such as
gold, nickel, palladium,
or platinum)
Quantum dots made
from cadmium selenide
(CdSe), cadmium
telluride (CdTe), and
zinc selenide (ZnSe).
Hyperbranched
polymers, dendrigraft
polymers, and
dendrons.
Made with two different
NMs or NMs combined
with nanosized clay.
They can also include
be made with NMs
combined with
synthetic polymers or
resins.
Forms include colloidal
silver, spun silver,
nanosilver powder, and
polymeric silver.
| Physical Properties 1
They exist as hollow
spheres (buckyballs),
ellipsoids, tubes
(nanotubes); 1nm wires
(nanowires) or
hexagonal structures
(nanodiamonds).
Excellent thermal and
electrical conductivity;
Some have
photocatalytic
properties, and some
have ultraviolet (UV)
blocking ability. When
used in sunscreen,
nano-TiC>2 and nano-
ZnO appear
transparent when
applied on skin.
Generally between
100-200 nm, depending
on the NM-type
containing the zero-
valent metal. Properties
can be controlled by
varying the reductant
type and the reduction
conditions.
Size: 10to50nm.
Reactive core controls
the material's optical
properties. The larger
the dot, the redder
(lower energy) its
fluorescence spectrum.
Size: 2 to 20 nm.
Highly branched
polymers. Common
shapes include cones,
spheres, and disc-like
structures.
Composite NMs have
novel electrical,
magnetic, mechanical,
thermal, or imaging
features.
Size: 10to200nm.
Made up of many
atoms of silver in the
form of silver ions.
| Chemical Properties |
Carbon-based NMs are
stable, have limited
reactivity, are
composed entirely of
carbon, and are strong
antioxidants.
High reactivity;
photolytic properties.
High surface reactivity.
Popular starting
materials used in
production include:
ferric (Fe [III]) or ferrous
(Fe [I I]) salts with
sodium borohydride.
Closely packed
semiconductor whose
excitons (bound
electron-hole pairs) are
confined in all three
spatial dimensions.
Possible metal
structures include:
CdSe, CdTe, CdSeTe,
ZnSe, InAs, or PbSe,
for the core; CdS or
ZnS for the shell.
Highly branched; multi-
functional polymers.
Multifunctional
components; catalytic
features.
High surface reactivity;
strong antimicrobial
properties.
^^K^^^H
Biomedical
applications, super-
capacitors, sensors,
and photovoltaics.
Photocatalysts,
pigments, drug release,
medical diagnostics,
UV blockers in
sunscreen, diesel fuel
additive, and
remediation.
Remediation of waters,
sediments, and soils to
reduce contaminants
such as nitrates,
trichloroethene, and
tetrachloroethene.
Medical imaging,
photovoltaics,
telecommunication, and
sensors.
Drug delivery, chemical
sensors, modified
electrodes, and DNA
transferring agents.
Potential applications in
drug delivery and
cancer detection. Also
used in auto parts and
packaging materials to
enhance mechanical
and flame-retardant
properties.
Medicine applications,
water purification, and
antimicrobial uses.
They are used for a
wide variety of
commercial products.
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Emerging Contaminant - Nanomaterials
How can nanomaterials impact the environment?
NMs in solid wastes, wastewater effluents, direct
discharges, or accidental spillages may be
transported to aquatic systems by wind or
rainwater runoff (Klaine et al. 2008).
NPs fate and transport in the environment are
largely dependent on material properties such as
surface chemistry, particle size, and biological and
abiotic processes in environmental media.
Depending on these properties, NPs may stay in
suspension as individual particles, aggregate
forming larger sized NMs, dissolve, or react with
natural materials (Luoma 2008).
Because of their small size and slower rate of
gravitational settling, some NMs may remain
suspended in air and water for longer periods and
may be readily transported over much greater
distances than larger particles of the same
material (EPA 2007; 2009b).
The mobility of NMs in porous media is influenced
by their ability to attach to mineral surfaces to form
aggregates. For example, NMs that readily attach
to mineral surfaces may be less mobile in ground
water aquifers (Wiesner et al. 2006); smaller NMs
that can fit into the interlayer spaces between soil
particles may travel longer distances before
becoming trapped in the soil matrix (EPA 2007);
and soils with high clay content tend to stabilize
NMs and allow greater dispersal (EPA 2008a).
The surface chemistry and therefore the mobility
of NMs in porous media may be affected through
the addition of surface coatings. For example,
TiO2 can be harmless in soil, but could be
problematic in water once a surface coating is
added (Lubick 2008).
Some NMs are reported to be photoactive, but
their susceptibility to photodegradation in the
atmosphere has not been studied (EPA 2007).
The potential mechanisms of biodegradation of
NMs are the subject of current investigation.
Some fullerenes such as C60 and C70 have been
found to biodegrade after several months. Many
NMs containing inherently non-biodegradable
inorganic chemicals like metals and metal oxides
may not biodegrade as readily (EPA 2007).
Research is still being conducted on the effects of
NMs on wildlife species. Some studies have
reported oxidative stress and pathological
changes in aquatic species, specifically trout, after
exposure to nano-TiO2 (Federici et al. 2007).
Although nanoscale zero-valent iron (nZVI) is
widely used in site remediation, information is
limited on its fate and transport in the environment.
While increased mobility due to the smaller size
may allow for efficient remediation, there are
insufficient data regarding whether such NMs
could migrate beyond the contaminated plume
area and persist in drinking water aquifers or
surface water (EPA 2008a).
What are the methods of exposure to nanomaterials?
Human exposure to NMs may occur through
ingestion, inhalation, injection, and dermal
exposure depending on the source and activities
of the person. In the workplace, inhalation is a
widely recognized route of human exposure (EPA
2007; Watlington 2005).
The small size, solubility, and large surface area of
NMs may enable them to translocate from their
deposition site (typically in the lungs) and interact
with biological systems. Circulation time increases
drastically when the NMs are water-soluble. With
smaller NM sizes, the tendency for pulmonary
toxicity may be greater (DHHS 2006; SCENIHR
2009).
Studies have shown that NMs, due to their small
size, have the potential to pass through both the
blood-brain barrier (BBB) and the placenta. For
example, a recent study showed that nano-
anatase TiO2 may pass the BBB of mice when
injected with high doses (Liu et al. 2009).
Some types of NMs that translocate into
systematic circulation may reach the liver and
spleen, the two major organs for detoxification and
further circulatory distribution. Various
cardiovascular and other extra pulmonary effects
may occur (Nel et al. 2006). In humans, although
most inhaled carbon NMs remain in the lung, less
than 1 percent of the inhaled dose may reach the
circulatory system (SCENIHR, 2009).
Use of sunscreen products may lead to dermal
exposure of NMs (TiO2 and ZnO) depending on
the properties of the sunscreen and the condition
of the skin. In healthy skin, the epidermis may
prevent NM migration to the dermis. However,
damaged skin may allow NMs to penetrate the
dermis and access regional lymph nodes, as
suggested by quantum dots and nanosilver (Nel et
al. 2006; Mortensen et al. 2008).
Ingestion exposure may occur from consuming
NMs contained in drinking water or food (for
example, fish) (Wiesner 2006).
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Emerging Contaminant - Nanomaterials
What are the health effects to nanomaterials?
There are insufficient scientific data to determine
whether NMs, under realistic exposure scenarios,
may present adverse health effects to humans.
The health effects of NMs are variable depending
on their characteristics. Depending on their
charge and particle size, NMs can induce different
levels of cell injury and oxidative stress. In
addition, particle coatings, size, charge, surface
treatments, and surface excitation by UV radiation
can modify surface properties and thus the
aggregation and biological effects of NMs (Nel et
al. 2006; Stone & Donaldson 2006).
Some NPs may generate reactive oxygen species
(ROS), which can lead to membrane damage,
including increases in membrane permeability and
fluidity. Cells may become more susceptible to
osmotic stress or impaired nutrient uptake (Klaine
et al. 2008).
When cultured cells are exposed to NMs of
various metals (such as NMs containing titanium
and iron), NMs may be absorbed and gain access
to tissues that the metals alone cannot normally
reach. The uptake-and-damage mechanism is
frequently called the "Trojan Horse effect," where
the NPs appear to "trick" the cells to let them in,
and once inside, the toxic metals can significantly
increase the damaging action of such materials
(Limbach et al. 2007).
Metal-containing NMs may cause toxicity to cells
by releasing harmful trace elements or chemical
ions. For example, silver NMs may release silver
ions that can interact with proteins and inactivate
vital enzymes. The lead and cadmium used in
quantum dots are known reproductive and
developmental toxins (Powell & Kanarek 2006).
However, estimates of releases of these metals
from NMs are very crude because of varying
factors such as the concentration of metal in the
source (Klaine et al. 2008; Luoma 2008).
Research has shown that NMs may stimulate or
suppress immune responses (or both) by binding
to proteins in the blood (Dobrovolskaia & McNeil
2007).
Are there any federal and state guidelines or health standards for
nanomaterials?
Currently there are no specific federal standards
that regulate NMs based solely on their size.
However, depending on the specific media of
application or release certain federal statutes
apply to NMs. These are presented below:
• Many currently available nano-products fall
under the Food and Drug Administration's (FDA)
regulation, such as cosmetics, drugs, and
sunscreen products. FDA regulates these
products based on a safety assessment of the
bulk material ingredients or product (Kimbrell
2006).
• The presence of an NP in a pesticide may affect
EPA's assessment under the Federal
Insecticide, Fungicide, and Rodenticide Act to
determine whether the product causes
unreasonable adverse effects on the
environment (EPA 2009b).
• Many nanomaterials are regarded as "chemical
substances" under the Toxic Substances Control
Act (TSCA) and therefore subject to the
requirements of the act. EPA has already
determined that carbon nanotubes are subject to
reporting under section 5 of TSCA. Under
TSCA, EPA may also regulate nanomaterials
considered to be existing chemicals. (EPA
2008b; 2009).
If NMs enter drinking water or are injected into a
well, they may be subject to the Safe Drinking
Water Act (EPA 2009b). However, currently no
Maximum Contaminant Level Goals (MCLGs)
and Maximum Contaminant Levels (MCLs) have
been established for NMs based solely on their
size. MCLGs and MCLs are established for the
macro-sized forms of NMs.
Risks from NMs in waste sites may be evaluated
and addressed under the Comprehensive
Environmental Response, Compensation, and
Liability Act and Resource Conservation and
Recovery Act (EPA 2009b).
Discharges containing NMs to waters of the
United States may require authorization under a
Clean Water Act (CWA) permit pursuant to
Section 402 of the CWA. EPA can establish
compound-specific effluent limits in permits
under the CWA (EPA 2009b).
NMs may also be regulated under the Clean Air
Act if it is determined that their presence in the
air would endanger public health and welfare
(EPA 2009b).
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Emerging Contaminant - Nanomaterials
Are there any federal and state guidelines or health standards for
nanomaterials? (continued)
• The Occupational Health and Safety
Administration (OSHA) has approved plans for
21 states that enable them to adopt federal
safety standards for workers in private industry.
This allows states to adopt guidelines to manage
the risks of NMs in the workplace (Keiner 2008).
• The National Institute for Occupational Safety
and Health has developed interim guidance on
the occupational safety and health implications
and applications of NMs, including the use of
effective control technologies, work practices,
and personal protective equipment (NIOSH
2009).
State and local standards and guidelines:
• In 2006, Berkeley, California, adopted the first
local regulation specifically for NMs requiring all
facilities manufacturing or using manufactured
NMs to disclose current toxicology information,
as available (Keiner 2008).
In January 2009, the California Department of
Toxic Substances Control (CA DTSC) requested
information regarding analytical test methods,
fate and transport in the environment, and other
relevant information from manufacturers of
nanomaterials (CA DTSC 2009).
Several other states may have community right-
to-know laws that authorize reporting or
disclosures broader than the federal law; this
may provide authority to require reporting when
facilities use or produce NMs (Keiner 2008).
What detection and characterization methods are available for
nanomaterials?
The detection, extraction, and analysis of NMs are
challenging due to their small size, unique
structure, physical and chemical characteristics,
surface coatings and interactions in the
environment, including agglomeration and
sequestration (EPA 2007). The analysis of NMs in
environmental samples often requires the use of
multiple technologies in tandem. This can include
the use of size separation technologies combined
with particle counting systems, morphological
analysis and /or chemical analysis technologies
Aerosol fractionation technologies (differential
mobility analyzers and scanning mobility particle
sizers) use the mobility properties of charged NMs
in an electrical field to obtain size fractions for
subsequent analysis. Multi-stage impactor
samplers separate NM fractions based upon the
aerodynamic mobility properties of the NMs
(Grassian et al. 2007; EPA 2007).
Aerosol mass spectrometer provides chemical
analysis of NMs suspended in gases and liquids
by vaporizing them and analyzing the resulting
ions in a mass spectrometer (SCENIHR 2009).
Expansion Condensation Nucleus Counters
measure and derive NM density in gas suspension
through adiabatic expansion followed by optical
measurement. Currently available instruments
can detect NPs as small as 3 nm (Saghafifar et al.
2007).
Size-exclusion chromatography, ultrafiltration, and
field flow fractionation can be used for size
fractionation and collection of NM fractions in
liquid media. NM fractions may be further
analyzed using dynamic light scattering for size
analysis and mass spectrometry for chemical
characterization (EPA 2007).
One of the main methods of analyzing NM
characteristics is electron microscopy. Scanning
Electron Microscopy and Transmission Electron
Microscopy can be used to determine the size,
shape, and aggregation state of NMs below 10 nm
(SCENIHR 2006). Atomic Force Microscopy, a
more recently developed technology, has the
ability to provide single particle size and
morphological information at the nanometer level
in air and liquid media (Colton, 2004).
Other analytical techniques include X-ray
diffraction to measure the crystalline phase and X-
ray photoelectron spectroscopy to determine the
surface chemical composition and functionality of
NMs (Grassian et al. 2007).
Additional research is needed to determine
methods to detect and quantify engineered NMs in
environmental media.
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Emerging Contaminant - Nanomaterials
What technologies are being used to control nanomaterials?
Limited information is available about
technologies that can be used to control NMs in
water and wastewater streams.
Air filters and respirators are used to filter and
remove NMs from air (Wiesner et al. 2006).
NMs in ground water, surface water, and
drinking water may be removed using
flocculation, sedimentation, and sand or
membrane filtration (Wiesner et al. 2006).
Where can I find more information about nanomaterials?
California Department of Toxic Substances
Control (CA DISC). 2009. Web site accessed on
September 1
httpV/www.dtsc.ca.gov/TechnologvDevelopment/N
anotechnology/index.cfm T
Colton, Richard. 2004. "Nanoscale Measurements
and Manipulation." Journal of Vacuum Science
Technology. Volume B. Pages 1609-1635.
Dobrovolskaia, M.A. S.E McNeil. 2007.
"Immunological properties of engineered
nanomaterials." Nature Nanotechnology. Volume
2. Pages 469 to 478.
Federici, G., B.J. Shaw, R.R. Handy. 2007.
"Toxicity of Titanium Dioxide Nanoparticles to
Rainbow Trout: Gill Injury, Oxidative Stress, and
Other Physiological Effects." Aquativ Toxicology.
Volume 84. Pages 415 to 430.
Gil, P.R. and W.J Parak. 2008. "Composite
Nanoparticles Take Aim at Cancer." ACS Nano.
Volume 2 (11). Pages 2200 to 2205.
Keiner, S. 2008. "Room at the Bottom?:
Potential State and Local Strategies for Managing
the Risks and Benefits of Nanotechnology."
Woodrow Wilson International Center for Scholars.
http://emerginglitigation.shb.com/Portals/f81bfc4f-
Cc59-46fe-9ed5-7795e6eea5b5/pen11 keiner.pdf
Kimbrell, G.A. 2006. "Nanotechnology and
Nanomaterials in Consumer Products: Regulatory
Challenges and Necessary Amendments. Food
and Drug Administration (FDA) Public Meeting on
Nanotechnology. October 10, 2006.
Klaine, S.J., P.J.J. Alvarez, G.E. Batley, T.E.
Fernandes, R.D. Handy, D.Y. Lyon, S. Mahendra,
M.J. McLaughlin, and J.R. Lead. 2008.
"Nanoparticles in the Environment: Behavior,
Fate, Bioavailability and Effects." Environmental
Toxicology and Chemistry. Volume 27 (9). Pages
1825 to 1851.
Limbach, K. L., P. Wick, P. Manser, R. N. Grass,
A. Bruinink, and W.J. Stark. 2007. "Exposure of
Engineered Nanoparticles to Human Lung
Epithelial Cells: Influence of Chemical
Composition and Catalytic Activity on Oxidative
Stress." Environmental Science & Technology.
Volume41 (11). Pages 4158 to 4163.
Liu, H., L.Ma, J. Zhao, J. Liu, J. Yan, J. Ruan, and
F. Hong. 2009. "Biochemical Toxicity of Nano-
anatase TiO2 Particles in Mice." Biological Trace
Element Research. Volume 126 (1-3). Pages 170
to 180.
Lubick, N. 2008. "Risks of Nanotechnology
Remain Uncertain." Environmental Science &
Technology. Volume 42 (6). Pages 1821 to 1824.
Luoma, S.N. 2008. "Silver Nanotechnologies and
the Environment: Old Problems or New
Challenges?" Woodrow Wilson International
Center for Scholars.
Mortensen L.J, G. Oberdorster; A.P. Pentland;
L.A. Delouise. 2008. "In Vivo Skin Penetration of
Quantum Dot Nanoparticles in the Murine Model:
The effect of UVR. Nano Letters. Volume 8 (9).
Pages 2779 to 2787.
National Institute for Occupational Safety and
Health (NIOSH). 2009. Nanotechnology at
NIOSH. Web site accessed on January 31.
http://www.cdc.gov/niosh/topics/nanotech/
Nel, A., T. Xia, L. Madler, N. Li. 2006. "Toxic
Potential of Materials at the Nanolevel." Science.
Volume 311. Pages 622 to 627.
Powell, M.C. and M.S Kanarek. 2006.
"Nanomaterial Health Effects - Part 2:
Uncertainties and Recommendations for the
Future." Wisconsin Medical Journal. Volume 105
(3). Pages 18 to 23.
http://www.wisconsinmedicalsociety.org/ WMS/pu
blications/wmi/issues/wmj v105n3/Powell.pdf
Saghafifar, H., A. Kiirten, J. Curtius, and S.
Borrmann. 2007. "Modification and
Characterization of an Expansion Condensation
Nucleus Counter for Nanometer-sized Particles."
European Aerosol Conference 2007.
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Emerging Contaminant - Nanomaterials
Where can I find more information about nanomaterials? (continued)
Scientific Committee on Emerging and Newly
Identified Health Risks (SCENIHR). 2006. "The
Appropriateness of Existing Methodologies to
Assess the Potential Risks Associated with
Engineered and Adventitious Products of
Nanotechnologies." European Commission:
Directorate-General for Health and Consumers.
Available at
http://ec.europa.eu/health/ph risk/documents/synt
h report.pdf
SCENIHR. 2009. "Risk Assessment of Products
of Nanotechnologies." European Commission:
Directorate-General for Health and Consumers.
Stone, V. and K. Donaldson. 2006.
"Nanotoxiocology: Signs of Stress." Nature U.S.
Department of Defense (DoD). 2009. Emerging
Contaminants. Web site accessed on January 29.
https://www.denix.osd.mil/portal/page/portal/denix/
environment/MERIT
U.S. Department of Health and Human Services
(DHHS). Centers for Disease Control and
Prevention. 2006. Approaches to Safe
Nanotechnology: An Information Exchange with
NIOSH.
http://www.cdc.gov/niosh/topics/nanotech/safenan
o/
EPA. 2007. Senior Policy Council.
Nanotechnology White Paper.
http://www.epa.gov/osa/pdfs/nanotecli/epa-
nanotechnology-whitepaper-0207.pdf
EPA. 2008a. Nanotechnology for Site
Remediation Fact Sheet. Solid Waste and
Emergency Response. EPA 542-F-08-009.
http://www.clu-in.org/download/remed/542-f-08-
009.pdf
EPA. 2008b. "Toxic Substances Control Act
Inventory Status of Carbon Nanotubes." Federal
Register. Volume 73. Pages 64946 to 64947.
http://frwebgate6.access.gpo.gov/cgi-
bin/TEXTgate.cgi?WAISdoclD=05381360432+2+1
+0&WAISaction=retrieve
EPA. 2009a. "Nanotechnology under the Toxic
Substances Control Act."
http://epa.gov/oppt/nano/index.htm
EPA. 2009b. Office of Research and
Development. Final Nanomaterial Research
Strategy (NRS).
http://www.epa.gov/ord/lrp/guickfinder/
nanotech.htm
Nanotechnology. Volume 1. Pages 23 to 24.
Watlington, K. 2005. "Emerging
Nanotechnologies for Site Remediation and
Wastewater Treatment." http://www.clu-
in.org/download/studentpapers/K Watlington Nan
otech.pdf
Wiesner, M.R., G.V. Lowry, P. Alvarez, D.
Dionysiou, and P. Biswas. 2006. "Assessing the
Risks of Manufactured Nanoparticles."
Environmental Science & Technology. Volume 40
(14). Pages 4336 to 4365.
Woodrow Wilson International Center of Scholars
(WWIC). 2009. "Consumer Products." The
Project on Emerging Nanotechnologies.
http://www.nanotechproiect.org/inventories/consu
mer/
Contact Information
If you have any questions or comments on this fact sheet, please contact: Mary Cooke, FFRRO, by phone at
(703) 603-8712 or by e-mail at cooke.maryt@epa.gov.
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