A F k t S t D i i M kiA Framework to Support Decision-Making: Tools for Classification, Release, and
E A t f N t h lExposure Assessment of Nanotechnology
Jeffery Steevens, Al Kennedy, Jessica Coleman, Aimee Poda, Zack Collier, Robert Moser, Chuck Weiss,
Mark Chappell, Anthony Bednar
U.S. Army Engineer Research and Development Center, y g p ,Vicksburg, MS
Overview
Life cycle approach to problem► Metallofullerene, self-decontaminating surfaces,
printed electronics, explosivesR l f lif l t Role of life cycle assessment
Framework and use of material categorization Case studies: paint, concrete, and electronics Conclusions
Army Technologies
Deployable force protection Self cleaning concrete
Nanosilver ink for printed electronics Nanotechnology will impact ALL Army platforms; will
enable dramatic improvements in: force protection, ease overburdened Soldiers, reduce logistics burden, create operational overmatch, operate in C
Runway Mats
CBRNE environment, improve operational energy, and reduce life-cycle costs
Composite food pouches
NanocelluloseRobert McElroy, Army Times
3
p
(Publicly available: www.erdc.usace.army.mil/missions/militaryengineering )
Thermites
Problem: Do Nanomaterials Pose Unacceptable Risk?
Are they safe? Engineered nanomaterials have potential to behave differently from traditional contaminants in the environment and cause biological effects
Unacceptable Risk?
biological effects Uncertainty of environmental regulations and liability are affecting the ability
for industry to manufacture and DoD to use
Mouse lung with alveolar bronchiolar Electron micrograph of self-decontaminating surface carcinoma (Sargent, 2013)releasing nanoparticles (Army ERDC, 2012)
Life Cycle ApproachTechnology Life Cycle
R M t i l P d ti M f t U Disposal /
Waste
Raw Materials Production Manufacture Use pRecycling
Releases to Environment
Nano Enabled Technologies
Conceptual Model, Characterization, Risk Analysis
Decision MakingNano Enabled Technologies• Dispersions• Coatings• Energetics• Textiles
Decision-Making• Research and Development• Management• Regulatory Compliance
• Textiles• Composites
Kennedy et al., 2013; Poda et al., 2013
Metallofullerene By-Product Streams
Soot> 90% Waste
Electric Arc Process
Graphite Rods
Gd and Cu metal recovered in processed soot
200
250
100%
120%
50
100
150
Met
als
conc
entr
atio
n (m
g/kg
)
Gd Cu
40%
60%
80%
Perc
ent S
urvi
val
MHRW
0250 1000
Soot sample (kg)
0%
20%
Control 0.001% 0.010% 0.100% 1% 10% 100%
MHRWMHRW (EDTA)
Metal Content in Processed Soot Toxicity of Leachate
Hull, M., Kennedy, A., Bednar, A., Weiss, C., and J. Steevens. 2009. NanomanufacturingEcotoxicology. Environmental Science and Technology.
Carbon Nanotube Electronics
Single-walled CNTs used in the manufacture of sensors, computer memory and flexible printed electronicscomputer memory, and flexible printed electronics.
Application requires manufacture of a stable aqueous suspension of SWCNTs.
Stable suspension is also produced for other electronics manufacturers.
CNT-Based Printed Flexible and Stretchable Circuit Board on Silicone
CNT-Based Printed Flexible and Stretchable Antenna
Carbon Nanotube Electronics
“Life Cycle Assessment” is a “cradle-to-grave” approach for comprehensively accounting the total cost of a product or technology.
1 Product or technology is considered in terms of life cycle1. Product or technology is considered in terms of life cycle phases representing points where resources are expended and emissions are created.
2 Valuable for technology developer/manufacture; Identifies2. Valuable for technology developer/manufacture; Identifies “leakages” or wasted energy in the system.
3. For risk assessment, it can be used to determine significance of NP releasesof NP releases
Eco-LCA Methodology
Dispersion, Derivatization
PrintingDerivatization
Boundaries (scope): Gate to Gate► Receipt of CNT powders (CNT synthesis not included in the calculations)
Environmental impacts overwhelmingly driven by waste incineration Ecotoxicity studies with these materials suggest little hazard; human
health? Waste volume mitigation is key to reducing environmental footprint
Self- Decontaminating Surfaces• Nano titanium dioxide based coating used for photocatalytic disinfection a o t ta u d o de based coat g used o p otocata yt c d s ect o
process in air-handling systems or coatings Address uncertainties to support technology development
► Release from substrate particle characteristics► Release from substrate, particle characteristics► Toxicity screening using mixed alveolar cell culture
Research Production Use Disposal and R li
Life-cycle Stage
and Development
Recycling
Sol-Gel process for
manufacturer of NP on site
Normal use
Stability in landfill
Scraping and Sanding
Aging
Coatings and Paints
HVAC Recycle in new materials
50
100
150
200
250
300
350
400
450
500
550
Frequency
50
Ri k b d C t l d l t id tif d t
Particulate releaseWaste from processing
Containment of NP
through Best Management
Practices
Inhalation Ingestion Dermal Contact
0
0.25
0.75
1.25
1.75
2.25
2.75
3.25
3.75
4.25
4.75
5.25
5.75
6.25
6.75
7.25
7.75
8.25
8.75
9.25
9.75
10.25
10.75
11.25
11.75
12.25
Mean Diameter (micron)
50mm
Coupon
• Exposure: Mean particle size = 1.9 µm 0.42% id d lt fi ( 100 )Risk based Conceptual model to identify data
gaps, releases, and routes of exposureare considered ultrafine (< 100 nm)
• Toxicity: No cytotoxicity or inflammation to milled surface using A549 pneumocytes and alveolar macrophages
(a) Backscattered SEM micrograph of SDS (b) EDS mapping of Si, Fe, Ag, and Ti
p g• Risk: Low level of risk; compared to existing
NIOSH guidance(Steevens et al., Army ERDC, 2012)
Environmental Life Cycle of Nanothermites Aluminum + reducing agent (Fe2O3 , Bi2O3, or CuO) Releases and risks evaluated over life-cycle Focus on release during use: transformation, fate, exposure, toxicityg p y Enables informed decisions regarding safety and informs/proactively
addresses regulations
Research / Production Use
4000 x
Tekna plasma system for nanoscale Al (above); SEM of nanoscale aluminum (below),
Robert McElroy, Army Times
Scanning electron microscope image of Al/Fe2O3 energetic residue showing wide range
10 µm
Chris Haines, ARDEC 2 3 g g gof particle size; many greater than 1 µm
Nanotechnology Life Cycle
Study of “raw material” NP informs risk analysis
Transformation of NP in environment makes predictions of fate,
d h dexposure, and hazard challenging
From Lowry et al., 2012
Releases During Life Cycle
Carbon Soot CNT Ink Byproduct
SDS Particles Thermite Residue
Transformation of NP during processing, manufacture, use, and end of life are poorly understood.
Processes: intentional chemical and physical modification Processes: intentional chemical and physical modification, weathering and wear, and degradation
Poses a significant challenge in developing an exposure-effect relationshiprelationship
Next Steps: Development of a Framework
Safety of advanced materials goes beyond individual t i l ( b t b ) d h ld id fi lmaterial (e.g., carbon nanotube) and should consider final
technology or product (e.g., composite) Develop a framework for communicating material safety; is the p g y
material nanostructured or nanofeatured? Address regulatory requirements through development of
protocols/standard methods for assessmentp Reduce uncertainty for product liability raised by manufacturers’
insurance – supports technology transition and Army sustainability goalsg
Development of a Framework
Response to Army Problem• Regulatory guidance lags
technology development► No consistency► Uncertain sustainability
Free particle worse case Stated Army needs:
► Establish nanoEHS procedure► In context with technology;
Category (free vs. structured), Task 4Use & release scenarios
► Develop industry standards
Solution: Develop Adaptive GuidanceNano Guidance for Risk Informed Deployment (NanoGRID)
Tiered process (testing exclusions) tied to regulatory Product: Executable web tool step-wiseProduct: Executable web tool step wise
EHS process and methods
Collier et al, 2015, J. Nanoparticle Researchhttps://nanodev.erdc.dren.mil/NanoGrid/User.html
A Proposed Framework
TIER 1Screening CriteriaBased on material amount, size, properties, technology categories, and use
Screening Steps
TIER 2 Proceed through
Release PotentialConservatively assume 100% release, determine actual amount released
Increasing information
& costTIER 3
process until an informed decision is possible
Environmental PersistenceDetermine free particle persistence and dissolved fraction
TIER 4Sustainability TestingBiological testing for acute and chronic toxicity
Adequate Information f D i i
TIER 5In Depth Product InvestigationMaterial specific and site specific
for Decision
Nanotechnology Categories
Nanomaterial taxonomy adapted from Hansen et al. 2007;
CATEGORY I: “BULK”A grain orientation map for single phase
B DC
A. grain orientation map for single-phase austenitic steel (category IA);
B. Silicon carbine nanocomposite including porosity and nano-scale carbon impurities (category IB);
CATEGORY II: “SURFACE” E F G
D. silicon bio-inspired hydrophobic surface (category IIA) from Vasudevan et al 2014;
E. graphene thin film on a metallic surface (category IIB);
F. nanobismuth metal over an iron oxide surface (category IIC);(category IIC);
CATEGORY III: “PARTICLES”G. Al2O3 nanoparticles adsorbed onto the surface
of Bi spheres (category IIIA); H. nanocomposite film with layered nanoclay
structures suspended in an polymeric matrix
H JI
p p y(category IIIB);
I. TiO2 nanoparticles suspended in a viscous (sunscreen) gel matrix (category IIIC);
J. freely dispersed multi-walled carbon nanotubes (category IIID).
Collier et al., 2015, J. Nanoparticle Research
Categorization Within Tiered Structure
Ecotoxicologist’s perspective: fate categories in EHS Cascading effect: categories will influence exposure and toxicity
testing
Tier I
g
Categorization of nanotechnologies / products► By physical structure Tier I
Screening
y y► By intended use
Fate categorization of nanoparticles► By composition
Tier II-ReleaseTier III-Fate
► By size► By release potential (Nano in nano out)► By dispersibility & stability (coating, charge, media)► By dissolution kinetics (and completeness)
Tier IV/V-Hazard► By dissolution kinetics (and completeness)► Toxicity► By interactions (ligands, transformations)
Solution: Develop Scientific Methods Standard Operating Procedures linked to
NanoGRID Methods: functional tests
► Preparation methods, characterization, release, fate, toxicology
Products:► Written SOPs (web)► Written SOPs (web)► Video demos (Youtube)
https://www.youtube.com/channel/UCe3wh_zmg3FATtbs5bcwnew/feed
R l t di hift
Army Nanotechnology Testing
Airfield Landing
Regulatory paradigm shift► Ingredients vs. technology
Testing by NanoGRID► Relevant categories Electric TESLA Airfield Landing
Mat -ERDC-
► Relevant categories► Relevant use► Release & transformation
Products: EHS Reports, improved EHS process
PRISTINE-GRL/CRREL-
Electric Switches-ARDEC-
Nanothermite-Air Force,
DTRA-
TESLA Primer-CERL-
Self Cleaning Concrete
-GSL-
NanocelluloseComposite
-ARL-improved EHS processDecreasing potential for release
UV& R i f ll& Rainfall
Kennedy et al 2014. Nanotechnology Environmental Health and Safety: Risks, Regulation and Management , Elsevier, 2014.
Abrasion testingHansen et al. (2007)
Nanotoxicology 1(3): 243-250
Printable Nanosilver CircuitsFl id di d t h l 2 D Surface bound technologyFluid-dispersed technology 2-D Surface-bound technology
ReleaseRelease
Size < 20 nm
LC50 = 3 g/L(C i d h i d bi )(Ceriodaphnia dubia)
AJK7
Slide 22
AJK7 Dave Martin - please update, revise as neededAl Kennedy, 3/11/2015
Self Cleaning Concrete
3D porous nano-solidtechnology
TiO2 and Pure TiO2cement phases
u e O2nanoparticles
Released concentration range: 58-120 ppb
Anticorrosive Paint
•Paint starts suspended in liquid (IIIb)
Originally developed and demonstrated in DoDCorrosion Prevention and Control ProgramDr. Susan Drozdz, ERDC-CERL
Test CouponsRaw materialsZn CNTs
•Paint starts suspended in liquid (IIIb)•Aerosolized during application (IIId)•Applied to a surface (IIIa)•Dried into a solid matrix (IIIc)
Primer & Primer
e &Topcoat
Zn particles> 1000 nm
MWCNTs
Coated fuel Tank: Fort Bragg
Identification of CNTs in raw form and onin raw form and on coated surface
Incorporating NanoGrid into DoD Decision Makingg
• DUSD (Installations & Environment), Chemical and Materials Risk Management
Developing guidance for the acquisition– Developing guidance for the acquisition community to better characterize chemicals as they are brought into DoD technologies
• Guidance Manual for the Collection of Chemical, Physical, and Toxicological Data (CPT) to Support DoD SystemsData (CPT) to Support DoD Systems Acquisition
• Coordinated by Tricia Underwood and the DoD Nanotechnology Working Group
January 2015 Collection of Chemical, Physical and Toxicological Data to y y gSupport DoD Systems Acquisition, DRAFT
Conclusions
Conclusions Understanding the form of NP released during manufacture, use,
and end of life for technolog is criticaland end of life for technology is critical Need to incorporate “life cycle approach” to the risk assessment of
nanotechnologies Categorization of materials based on range of properties will guide a
“technology based” assessment
Still questions remain:q At what point in the technology life cycle are NP being released? What is being released? Transformation? How do we improve the relationship between exposure assessment How do we improve the relationship between exposure assessment
and ecological hazard?
Acknowledgments
Collaborators at Brewer Science, Inc. Rolla, MO; Dan Janzen,Inc. Rolla, MO; Dan Janzen, Stephen Gibbons, Doyle Edwards, and Wu-Sheng Shih
U.S. Army Environmental Quality and Installations Research Program, Elizabeth Ferguson,Program, Elizabeth Ferguson, Technical Director
http://el.erdc.usace.army.mil/nano/[email protected]
Top Related