Environmental Implications of Nanotechnology

Christine Ogilvie Hendren, PhDCEINT Executive Director

Association of Public Health Laboratories Annual Conference6413

Nanotechnology: The Sleeping Giant of Public Health?

Breaking the Cycle of Unintended ConsequencesMercury amalgamation for precious metals mining

Chloroflurocarbons (CFCs)

Pesticides for control of disease

Outline• Context: What is new or unique about nano?

• New ability to observe and control matter at the nanoscale• Extreme broad scope requires interdisciplinary collaboration

• Approach: How to assess the environmental risks of nanomaterials?• Integrate broad expertise in pursuit of targeted research questions• Measure the right things to answer those questions• Iterative feedback between disciplines, experimental scales, and models• Continuous focus on enabling decisions

• Environmental forethought: We have the opportunity to get nano right!

Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications*.

Encompasses nanoscale science, engineering, and technology, and involves imaging, measuring, modeling, and manipulating matter at this length scale.

* National Nanotechnology Initiative, http://www.nano.gov/index.html

Nanotechnology

0.45m filter

450 nm

10 kDafilter

1 nm

Nanoparticles

Viruses

Dissolved organic matter

Bacteria

Colloids

Dissolved metal complexes

Meters 10-10 10-9 10-8 10-7 10-6 10-5 10-4

Polynuclear cluster

Dissolved Colloidal Particulate

Nano Scale

• Hemoglobin• Smoke from fire• Volcanic ash• Sea spray• Automobile exhaust

Unique Properties at the NanoscaleMaterials manufactured to ~1-100 nm in size exhibit unique properties due to their small size (relative to larger materials).

Auffan et al., Nature Nano, 2009

Unique Properties at the NanoscaleMaterials manufactured to ~1-100 nm in size exhibit unique properties due to their small size (relative to larger materials).

www.nano.gov

Engineered Nanomaterials Timeline

F U T U R E

• Electronics

• Sustainable energy

• Clean water

• Targeted drug delivery

• Disease detection

• Sensors

• Sustainable transportation

• Everyday materials

1 8 5 7 Michael Faraday discovered colloidal “ruby”gold, demonstrating that nanostructured gold under certain lighting conditions produces different-colored solutions.

1 9 8 5 Rice University researchers Kroto, O’Brien, Curl, and Smalley discovered the Buckminsterfullerene (C60), or buckyball, a previously unknown form of pure carbon. The team was awarded the 1996 Nobel Prize in Chemistry.

1 9 9 9 - E a r l y 2 0 0 0 s

Consumer products making use of nanotechnology began appearing in the marketplace.

1 9 8 9 Don Eigler and colleagues spelled the IBM logo in atoms by literally moving 35 xenon atoms on a background of copper atoms to spell out the letters.

1 9 4 7 The semiconductor transistor is discovered at Bell Labs, laying the foundation for electronic devices and the Information Age.

2 0 0 0 ~ 2 0 0 3

NNI: National Nanotechnology InitiativeNEHI: Nanotechnology Environmental

and Health Implications

THE NOVEL PROPERTIES OF ENGINEERED NANOMATERIALS THAT INSPIRE NEW PRODUCTS WILL OFTEN BE THE SAME

PROPERTIES THAT POSE RISKS

Responsible Nanotechnology

“Peptide coatings can help nanoparticles slip into cells, a process that may prove useful for in vivo imaging or drug delivery if scientists can clear up how it works.”

Clathrin-Mediated Endocytosis of Quantum Dot−Peptide Conjugates in Living Cells, Anas et al., ACS Nano, 2009, 3 (8), pp 2419–2429 – via C&EN News

Applications & Implications

Impacts

Electronics

Energy and Environmental Applications

http://www.nanotechproject.org/inventories/map/

Impacts

TiO2 in China

TiO2 in Korea

Impacts

Dumping Grounds in Accra, Ghana

EXPOSUREHAZARD = RISKx

Research to inform Risk-Based Decisions

No Risk

Hazard, No Exposure

No Hazard, ExposureNo Risk

RISKHazard AND Exposure

If nanomaterials pose risk, what are the options for managing it?

EXPOSUREHAZARD = RISKx

Material substitution

Material modification Green-chemistry

• Reduce bioavailability• Reduce/ engineer mobility• Persistence

Handling practices

Out-right ban

Treatment/ remediation

Comprehensive Environmental Assessment Framework

How does it change?

Where does it go?

How much gets into the

environment?

How much of a material is there?

Is it bioavailable?

How much gets into plants, animals, ecosystems?

How much does it take to make something bad happen?

OH-

OH-

OH-

OH-

Human & Eco Toxicology

Dosiemetry

Exposure

Life Cycle Assessment

ENM Characterization

ENM Detection & Measurement

Market Analysis

Fate and Transport

Bio-Geo-Chemistry

Economics

Mandatory Interdisciplinary Approach

• Headquartered at Duke University, 7 US Universities• Funded by NSF and EPA in 2008, renewed in 2013• CEINT’s Vision:

Elucidate principles that determine nanomaterial behavior in the environment

Translate this knowledge into language of risk assessment Provide guidance to assess existing & future concerns surrounding

environmental implications of nanomaterials Educate next generation of scientists and engineers

Center for the Environmental Implications of NanoTechnology (CEINT)

Outline• Nearly infinite possible materials and interactions

• Persistent uncertainty

• Concurrent research and need for near term decisions

• Integrate broad expertise in pursuit of targeted research questions

• Measure the right things to answer those questions

• Iterative feedback between disciplines, experimental scales, and models

• Continuous focus on enabling decisions

In light of

The CEINT approach is:

CEINT Research Focus

Exposure, transport and transformation

Effects in complex, real-world systems

Risk Forecasting to inform decision-making

CEINT organizes a comprehensive effort looking at the environmental implications of nanotechnology with a focus on:

NanomaterialProperties

SystemProperties

NanomaterialDescriptors

What is it?

What can happen because of it?

NanoparticleImpacts

The old way of nano risk thinking…

Intrinsic Properties

• Fundamental to identity

• Do not change

Extrinsic Properties

• Still describe the person in question

• Change as a function of system properties

Describe a man…

Male

5’10’’

Grey eyes

Hungry

Laughing

Standing

Male

Hungry

5’10’’

Laughing

Blue eyes

Standing

How do we answer: What is it?

Male

5’10’’

Blue eyes

Hungry

Laughing

Standing

How do we answer: What is it?

Male5’10”Blue eyes

Male5’10”Blue eyes

Male5’10”Blue eyes

HungryFrowningSeated

FullLaughingStanding

StarvingYellingJumping

State 1

State 2

State 3

Static Changing

Male5’10”Blue eyes

Male5’10”Blue eyes

Male5’10”Blue eyes

HungryFrowningSeated

FullLaughingStanding

StarvingYellingJumping

State 1

State 2

State 3

System 1

On an airplane on a 6 hour flight that doesn’t serve snacks.

System 2

At tonight’s poster reception and cocktail hour.

System 3

Apocalypse.

Quite possibly important

Definitely important

Not a good use of

resources

All systems are NOT

created equal…

How do we answer: What is it?

Core compositionBand gapParticulate diameter

Core compositionBand gapParticulate diameter

Core compositionBand gapParticulate diameter

Surface composition 1Surface charge 1Aggregation state 1

Surface composition 2Surface charge 2Aggregation state 2

Surface composition 3Surface charge 3Aggregation state 3

State 1

State 2

State 3

System 1

In a WWTP secondary clarifier

System 2

In surface water

System 3

In stomach acid

How do we answer: What is it?

NanomaterialProperties

SystemProperties

NanomaterialDescriptors

Mat

eria

l & S

yste

m P

rope

rties

Mat

eria

l Im

pact

s

What is it?

What can happen because of it?

NanoparticleImpacts

Separating Nanomaterial and System Properties…

Intermediate Descriptors of Interactions between

Material and System Properties

…still doesn’t get us there.

Snapshots of Nanomaterial and System Properties…

Time-of-flight mass spectra of carbon clusters prepared by laser vaporization of graphite and cooled in a supersonic beam.

H. W. Kroto·, J. R. Heath, S.C. O'Brien, R. F. Curl, and R. E. Smalley (1985) C60: Buckminsterfullerene, Nature, 318.

Scanning electron micrograph (SEM) of SWNT material.

A. Thess et al. (1996) Crystalline Ropes of Metallic Carbon Nanotubes, Science, 273.

Snapshots of Nanomaterial and System Properties…

Snapshots Outcomes

Various materials in various systems and states

Hazardous outcome

Snapshots Measurable Functional Indicators Outcomes

Various materials in various systems and states

Hazardous outcome

Need: Functional Intermediate Indicators• Have to be measurable• Have to tell us something about

what is happening in the system

Snapshots Measurable Functional Indicators Outcomes

Various materials in various systems and states

Hazardous outcome

Need: Functional Intermediate Indicators• Have to be measurable• Have to tell us something about

what is happening in the system

Snapshots Measurable Functional Indicators Outcomes

Hazardous outcome

Various materials in various systems and states

Need: Functional Intermediate Indicators• Have to be measurable• Have to tell us something about

what is happening in the system

Snapshots Measurable Functional Indicators Outcomes

NanomaterialProperties

SystemProperties

NanomaterialDescriptors

What is it?

What can happen because of it?

NanoparticleImpacts

The old way of nano risk thinking…

LEV

EL

2P

roce

sses

Pre

cedi

ng

Bio

upta

keLE

VE

L 4

Out

com

esLE

VE

L 1

Mat

eria

l and

Sys

tem

Pro

perti

es

LEV

EL

3P

roce

sses

Fol

low

ing

Bio

upta

ke

Ecosystem Hazard

Cellular and Cellular and Organismal

Hazards

Biodegredation

ROS

Aggregation

NanoparticleProperties

SystemProperties

NOM/Macromol

IonicComposition

pH

Surfaces(bacteria,

clay…)

Size

Composition

CoatingFluid Flow

Shape

Light

EnvironmentalStressors

CollisionRate

Deposition

Distribution in the

System

Settling

Transport

Nutrient Cycling

CommunityComposition

Attachment

ProductProperties

Release Fraction

Milieu (solid matrix, suspension…)

Amount

Dissolution

Bio-Geo-Chemical Transformations

Geochemical Transformations

Biodistribution

Maternal TransferTrophic Transfer

LEG

EN

D

Parameter or Process

Mechanism

Example of Mechanism Discovered Via Integrated Research

Biouptake /System Transfer

Speciation/Exposure Potential

Availability

Biotransformation

Redox

CEINT Structure

Currently working with over 50 nanomaterials

CNTs SWCNTs DWCNTs MWCNTs

Caged fullerenesC60C60(OH)x

Quantum dotsCdSeZnS

Metal oxides TiO2 CeO2 ZnOFeOx

- maghemite- magnetite- hematite

Metal sulfides MetalsAgFe Au

surface treatment PVP gum arabic PSSCitrateBSAPAAPEGNOM

size1 to 100 nm

shaperodsphere

potential:-33,0 mV

Citrate-coated Ag nanoparticle

Mesocosms: Exposure and Effects in Complex Real-world Systems

30 mesocosms constructed Probes, data acquisition, and web-based

data monitoring Weather, redox conditions, water levels,

temp measured continuously

Mesocosm Results

NSF EF-0830093

0%

20%

40%

60%

80%

100%

Mortality (+/‐SEM)

Mesocosm Toxicity ‐ 24 h post dosing Fundulus Larval Mortality

LaboratorySpiked ‐ 48 hMesocosm ‐ 48 h

mesocosms

Microcosms in iCEINTINE wastewater treatment plant

labs

Iterative Feedback Between Field and Lab Scale Experiments

Integration Between: People, Disciplines, & Experimental Scales

• Ag NPs with different coatings had different effects on DOM release from plants

• Plant exudates, stimulated by Ag ions, in turn had different effects on Ag NP aggregation and dissolution

• Via complex interactions, coating type does in fact affect dissolution and therefore toxicity of Ag NPs

Bone AJ, Colman BP, Gondikas AP, Newton K, Harrold KH, Unrine JM, et al. Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles: Part 2 –Toxicity and chemical speciation. Environmental Science and Technology 2012; 46: 6925-6933.

Unrine JM, Colman BP, Bone AJ, Gondikas AP, Matson CW. Biotic and Abiotic Interactions in Aquatic Microcosms Determine Fate and Toxicity of Ag Nanoparticles. Part 1. Aggregation and Dissolution. Environmental Science & Technology 2012; 46: 6915-6924.

WaterWater

Water Water

SedimentPlantsPlants

Sediment

Integration Between: People, Disciplines, & Experimental Scales

• To investigate environmentally relevant systems, studied effects of rate and extent of Ag NP sulfidation on oxidative dissolution to release Ag ions

• Showed dramatic decrease in available Ag ions even at low levels of sulfidation

• Sulfidation (and interaction with chloride) are more important than size in the dissolution behavior of Ag

Levard C, Reinsch BC, Michel FM, Oumahi C, Lowry GV, Brown GE. Sulfidation Processes of PVP-Coated Silver Nanoparticles in Aqueous Solution: Impact on Dissolution Rate. Environmental Science & Technology 2011; 45: 5260-5266.

DionizedWater

Surface Water Discharge

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Wastewater disposal

Atmospheric deposition

Water Column/Sediment Exchange

Biosolids

Atmospheric Deposition

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Trophic Transfer Rates

Aggregation Rates Particle

Settling Rates

Nano-Ag Sulfidation

Rates

Partitioning Behavior

Highlights of Progress to Date

Clear Evidence of nanoparticle-specific effects

Identification of key parameters controlling spatial and temporal distribution of nanomaterials in the environment

Transformations

Elaboration of sources and processes generating nanoparticles in natural systems

Risk Forecasting

How do we Move from this “Approach”to Making Real Decisions?

What decisions must be made? What to regulate What to research next How much information is needed to inform a given

decision How much uncertainty we can live with

What Should Regulation Address/Prioritize?

• Hazard or exposure or both?

• Which material or materials? Greatest use Most potential for release Highest toxicity potential

• How do we prioritize research to best reduce uncertainty to these questions? Value of information

TĪNĒ

Acknowledgements

Mark R. Wiesner, CEINT DirectorGregory V. Lowry, CEINT Deputy Director

This material is based upon work supported by the National Science Foundation (NSF)and the Environmental Protection Agency (EPA) under NSF Cooperative Agreement EF‐0830093, Center for the Environmental Implications of NanoTechnology (CEINT). Any opinions, findings, conclusions or 

recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF or the EPA. This work has not been subjected 

to EPA review and no official endorsement should be inferred.

Thank You