Transcript NanoRelease: Developing Methods to Measure Release of

NanoRelease
Developing Methods to Measure Release
of Nanomaterials from Solid Matrices
A multinational public private partnership with
administrative support by the ILSI Research Foundation
[email protected]
www.riskscience.org
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NanoRelease “Consumer Products”
Project Overview
Goals
• Identify best practices for measuring release at critical points of
the life cycle of current products
• Use inter-laboratory testing to advance the state of science for
release measurement
• Develop/refine methodologies and demonstrate transportability
• Work with Standard Development Organizations to develop
standard methodologies for release
• Come to the point of “cross stakeholder agreed-to” methods on
release detection and characterization for nanoparticles
NanoRelease
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NanoRelease Consumer Products
Steering Committee
Co-Chair: Darrell Boverhof
Co-Chair: Yasir Sultan
Richard Canady
Bill Kojola
JoAnne Shatkin
Carolyn Cairns
Michael Hansen
Bernd Nowack
Shaun Clancy
Andrew Atkinson
Lie Chen
Myriam Hill
Christopher Kingston
Dow
Environment Canada
ILSI RF
AFL-CIO
CLF
Consumers Union
Consumers Union
EMPA
Evonik Degussa
Health Canada
Health Canada
Health Canada
NRC-Canada
[email protected]
John Monica
Dick Brouwer
Treye Thomas
Cathy Fehrenbacher
Phil Sayre
Richard Zepp
Aleksandr Stefaniak
Charles Geraci
Vladimir Murashov
Barbara Karn
Debra Kaiser
Janet Carter
www.riskscience.org
Porter Wright
TNO Research Group
US CPSC
US EPA
US EPA
US EPA
US NIOSH
US NIOSH
US NIOSH and WHO
US NSF
US NIST
US OSHA
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Where are we looking for risk information
on nanomaterials now?
Exposure
21%
Release
1%
Hazard
78%
- based on NCBI citations 2011
Within the 1%, there are very few of what is actually released
from real-world uses
Data/Graphic Source: Shaun Clancy
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Initial literature review on “nanorelease”
measurement methods
• www.ilsi.org/ResearchFoundation/Documents/NanoRelease%20Bac
kground%20Doc.pdf
• Many qualitative methods available to detect, characterize
or measure nanomaterials under controlled conditions
• Quantification difficult and not routine
• Differentiation of engineered nanomaterial particles from
nanoparticles of the composite generally not addressed
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A nanomaterial is NOT the chemistry and
electron micrograph of a particle.
It is a set of continuous distributions.
Composition
Size
Aspect ratio
%Coating
Pb
[email protected]
As
Hg
Se
Fe
Sb
Surface adherents
yy
xx
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Transformations Alter the Distributions
The “Neat” nanomaterial in hazard studies is not what is
released or what is in exposure media from uses
In composite
“Neat” nanomaterial
In product
Released material
In exposure medium
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Multiple Paths Make Multiple Outcomes
Where is the toxic part?
What do we relate to the tox studies?
Receptor population A
Soil
Receptor population B
Released nanomaterial
Air
Receptor population C
[email protected]
Water
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Release is the defining condition
Risk depends on what is released at specific points
along the life cycle
Release conditions and pathways to receptor cause
different and unpredictable exposures
Without labeling, we may never know how to measure
the real exposure at the receptor
How do we measure release to assess the risk of the
product?
To make progress we must focus on the release as the
control point for understanding risk. Not the pristine
material in a controlled suspension.
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NanoRelease General Work Plan
• Phase 1: Nanomaterial/Scope Selection
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The Consumer Products Steering Committee chose multiwalled carbon nanotubes in polymer for the first evaluation
• Phase 2: Methods Evaluation
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Expert Task Groups
• Compile & catalogue database of data/info
• White Papers
• State of the Science Document
• Workplan for Inter-laboratory Studies
• Phase 3: Inter-laboratory Studies
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Project Outputs
• Separate evaluations of methods, materials, life cycle
release scenarios for potential uses of MWCNT in
polymers
• State of the Science evaluation of release of MWCNT
from polymers, including methods-needs
• Measurement methods development plan for release of
MWCNT from polymer for key life cycle release
scenarios
• Agreed-to methods to measure MWCNT release from
current commercial uses in polymer composites
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The project will translate developing science of
measurement of release of nanomaterials into
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best practice
infrastructure
experience, and
risk assessment confidence
This will aid
– development of guidance for risk assessment and
management,
– safe development of products, and
– public confidence in the safe uses of the technology
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Phase 2 Methods Evaluation:
MWCNTs in Polymer
• 3 Task Groups
– Compile & catalogue database of data/info
– White Papers (for publication & informing SOS)
• TG1: Measurement Methods
• TG2: Materials
• TG3: Exposure/Release Scenarios
• June 21/22 2012 Workshop at CPSC in Bethesda, MD, US
– White paper presentations
– Draft State of Science and Methods Workplan sections
• State of the Science Team (SOST)
– An independent integrative document
• Inter-Laboratory Testing Group
– Begin to design and coordinate inter-laboratory testing
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Task Group 1: Measurement Methods
How can MWCNT release from polymers be measured?
• Co-chairs:
Debra Kaiser (US NIST),
Aleksandr Stefaniak (US NIOSH)
• 13 Experts from: NIOSH, NIST, US EPA, U. Mass, U.
Vienna, CSIRO, U. Iowa, Lockheed Martin
[email protected]
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The Meaning of Release Measurement
Release measurement has multiple components
1) Choosing and modeling the release
– Life cycle: fabrication, use/wear, destruction, environmental
degradation, incineration, recycling
– Air, water, dust
– How to mimic the real world condition?
2) Sampling the release
– Dispersion, statistics, etc
3) Analyzing the sample
4) Reporting the necessary information
– Detection <==> Characterization (recursive: you need to define
the nano-characteristic of interest in order to know if you have
detected it)
– Integration of release measurement to pathway modeling,
exposure assessment, and toxicity data…
– Informatics! (and interface to in silico modeling?!)
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Findings/Challenges
• Complexity of considering measurement for multiple
forms of released material, the media into which it is
released, and the time frame of interest (consider
immediate exposure or further transformation in
transport?).
• It is critical to tackle “problem formulation” first in order
to select between detection, characterization, and
quantitative vs. qualitative methods. What do you need to
decide, and what data are possible to generate that can
support the decision.
• Many possible methods to specifically detect and
characterize released MWCNT/polymer material;
however, except for simple mass and particle counts,
none appear to be sufficiently selective and quantitative
for specific MWCNT related exposure assessment now.
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The materials released to a pathway can vary
Source:
Wendel Wohlleben
The release scenarios affect what is released
Source:
Wendel Wohlleben
Task Group 2: Materials
How do MWCNTs in polymer behave/interact with
regard to measurement of release?
• Co-chairs:
Christopher Kingston (NRC Canada),
Richard Zepp (US EPA)
• 16 Experts from: NRC, US EPA, NC State,
Applied Nanotech, Nano-C, Dow, BASF,
Environment Canada, Lockheed Martin, Arkema
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Initial focus on 5 polymer types
To limit scope to the most commercially relevant
applications of MWCNT, using expert opinion and
review of market surveys the project initially focused
review on MWCNT applications in:
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Epoxy
Polycarbonate
Polyamide
Polyurethane
Polyethylene
Even with this limitation the scope of variation is
tremendous.
However, the purpose of the review is to identify ranges of
material characteristics that should be captured within
the methods we develop, not be exhaustive in review. 20
Findings/Challenges
• There is tremendous variety in materials and uses, but
very little data on actual or anticipated uses
• Factors considered in materials evaluation include UV
exposure, changes in temperature, exposure to acids/
bases, mechanical stresses
• UV stabilizers, coatings, and MWCNT functionalization
and load can have a large effect on MWCNT release
• “Pristine” polymer abrasion and/or degradation
characteristics are informative but not necessarily
indicative of MWCNT release from commercial articles
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Task Group 3: Exposure/Release Scenarios
What are the most likely MWCNTs-polymer release scenarios?
• Co-chairs:
Bernd Nowack (EMPA Switzerland),
Charles Geraci (NIOSH),
Dick Brouwer (TNO Research Group Q&S)
• 17 Experts from: EMPA, NIOSH, TNO, SafeWork
Australia, Northeastern U., CLF Ventures, USEPA,
Lockheed Martin, Bayer, Tech. U. of Dresden,
BASF, CPSC, U. Duisburg-Essen
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Scope limiting decisions for Life
Cycle Assessment evaluations
• Release scenarios were selected to represent a
range of situations
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injection molding
mechanical stress during manufacturing,
sports equipment
electronics
non-abrasive outdoor use
small parts in automobiles
tires
end of life treatment (incineration/landfills)
• Life cycle evaluations beginning at master batch
– We are not considering free MWCNT prior to polymer
compositing
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• Focus is release scenarios, but will discuss
how findings relate to “risk relevant” exposure
• It is possible in some scenarios there is
essentially zero release
• Polymer and scenario selections interact and
will be considered in the evaluations (but the
combinations are difficult to bound)
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There are many potential sources for
initiation of an exposure pathway
Source:
Bernd Nowack
Source:
Bernd Nowack
The likelihood of release for a given
stage of life cycle varies by use
• Low release potential for electronic component or
car component uses in consumers hands
• Higher release during industrial fabrication (but
controlled conditions, so exposure can be
managed)
• Relatively low release potential in landfill due to
binding
• Potentially higher release under recycling
scenarios (but again, conditions can be controlled
if the materials are known)
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Findings/Challenges
• Knowledge of actual uses is limited, the material choice
will matter, and theoretical combinations of materials
with uses/scenarios are quite varied.
• Nonetheless, some general observations can be made
based on the types of uses and the polymers
• For most uses evaluated, MWCNT release likelihood
during “consumer” life cycle phase seems very low
based on inaccessibility of the product (e.g., encased as
a component in a car), so detection methods may be all
that are needed (rather than spending resources on full
characterization and quantification methods).
• Release during fabrication and recycling would be
higher and may be worthy of release quantification
methods development, for conditions where control of
release and exposure is uncertain.
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State of the Science Team (SOST)
• Integrate release measurement knowledge and the needs for
methods development
– Andrew Maynard (University of Michigan, USA)
– Bernd Nowack (EMPA Swiss Federal Laboratories for
Materials Science and Technology)
– Maria Doa (US Environmental Protection Agency)
– Richard Canady (ILSI Research Foundation)
– Shaun Clancy (Evonik Degussa)
– Stacey Harper (Oregon State University, USA)
– Wendel Wohlleben (BASF Chemical Company)
7/16/2015
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Phase 3: Interlaboratory Testing
(pilot phase beginning 2013)
• To enable improvements, standardization, and
widespread use of methods
• Interlaboratory Testing Group (ITG)
– Co-chairs: Janet Carter (US OSHA), Carolyn Cairns
(Consumers Union)
– ~20 Experts: OSHA, Consumers Union, CSIRO, NRC
Canada, U. Iowa, NIST, US Army, U. Mass, Bayer,
NERL, BASF, US EPA
– Build from TG & SOS reports to create testing workplan
• Phase 3 Testing:
― Multi-lab participation to test methods with highest potential
― Use “round-robin” approach
7/16/2015
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Plan for Phase 3 Inter-laboratory Methods Development
(beginning 2013)
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International Public Private Partnership
• The NanoRelease platform
– Established for over 2 years,
– Methods for measuring release of carbon nanotubes in polymer matrices,
now starting on food additives.
– Over 80 experts active from industry, NGO, government, academia in US,
Canada, Europe, Australia, and more
• Funding is ~50/50 private/public
– Pew Charitable Trusts, Health Canada, Environment Canada, US EPA,
US FDA, American Chemistry Council, ILSI North America,
Nanotechnology Industries Association, Institute for Food Safety and
Health, and more.
[email protected]
www.riskscience.org
Thank you
Sponsors
• US Environmental Protection Agency, Office of
Research and Development
• Environment Canada, Emerging Priorities Division
• Health Canada, New Substances Assessment and
Control Bureau
• American Chemistry Council, Nanotechnology Panel
• Society of Chemical Manufacturers & Affiliates
• National Institute of Standards and Technology
• The Adhesive and Sealant Council
• American Cleaning Institute
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