Nanoparticles in the Environment

• W. Ball:  Very (!) brief introduction to Engineered Nanoparticles (ENPs) 

• W. Ball presentation of M. Wiesner* slides on“Nanoparticle Behavior in Complex Environments”

* Center for the Environmental Implications of NanoTechnology(CEINT)

Environmental Transport, Transformation, and Fate

Consumer Goods and Technologies Containing Nanomaterials

Woodrow Wilson International Center for Scholars http://www.nanotechproject.org/

Thousands of manufacturer‐identified nanotechnology‐based consumer products currently on the market

Single Walled Carbon Nanotube (SWCNT)

Multi Walled Carbon Nanotubes

(MWCNT)•Mechanical Strength• Electrical Conductivity• High Aspect Ratio

Materials Properties

Carbon NanotubesInorganic ENPsEngineered Nanoparticles

Rational development of “safe‐by‐design” nanomaterials will require knowledge of how intrinsic nanoparticles properties (size, shape, surface chemistry) impact environmentally relevant properties (colloidal stability, sorption properties)

Naphthalene

Zn2+ (aq)

Oxidized Carbon Nanotube

Atomic Percentage of Surface Oxides

Sorp

tion

cap

acit

ySurface Oxygen

Concentration (Atomic %)

Sorp

tion

Cap

acit

y

Cho et al., Langmuir,26:967 (2010)

Cho et al., Env. Sci. Technol.43: 2899 (2008)

E.g. Impact of Surface Chemistryon sorption properties of carbon nanotubes

Surface Oxidation

OH

Surfactant Adsorption Natural Organic Molecules

e.g., surface modificationof  MWCNTs

Probing the Influence of Surface Chemistryon Engineered Nanoparticle Behavior, Fate

and Effects in Aquatic Environments 

after Smith et al.  Environ. Sci. 43: 819(2009).

Amy L. Dale †‡, Gregory V. Lowry ‡, and Elizabeth A. Casman *† 

† Engineering and Public Policy, Carnegie Mellon University‡ Civil and Environmental Engineering, Carnegie Mellon UniversityEnviron. Sci. Technol., Article ASAP (2015)DOI: 10.1021/acs.est.5b01205

Stream Dynamics and Chemical Transformations Control the Environmental Fate of Silver and Zinc Oxide Nanoparticles in a Watershed-Scale Model

A little more bio information…..

Some take home points:(WPB addition, based on summary comments from MRW)

• Nanoparticles (whether engineered [“ENPs”] or natural):can be taken up by plants and animals;

• NPs are subject to trophic transfer‐ in some cases with biomagnification, in some with dilution;

• Attachment efficiencies appear to be a promising way of predicting NP behavior. 

• The toxicity issue is secondary.Most important ‐‐ growing awareness of:• Complexity of nanometric phases in their interactions with living systems; and• Potentially important roles of NPs in uptake of chemicals, nutrient cycling, transport of other species, etc.

Nanomaterial behavior in complex environments

Mark R. Wiesner

Director Center for the Environmental Implications of NanoTechnology

Duke University

RISK

Hazard

Nanoparticle Properties

Exposure

•  Composition •  Bandgap •  Size…

•  Production amounts •  Ambient

Concentrations •  Effective dose…

•  Mortality •  Development •  Population •  Nutrient cycling…

RISK

Hazard

Nanoparticle Properties

System Properties Social Properties

Exposure

•  Product life cycles and value chains

•  Product use behaviors

•  ENM production magnitudes

•  pH, NOM, Ionic strength, …

•  Surfaces (biotic, mineral, organic…)

•  Fluid flow, temperature…

•  Composition •  Bandgap •  Size…

•  Surface affinity •  Surface charge/

potential (ζ-potential) •  Aggregation rate •  Hydrophobicity…

RISK

Hazard

Nanoparticle Properties

System Properties Social Properties

Functional Assays

Exposure

•  Measurement in prescribed system

•  Quantifies a meaningful process for exposure, hazard or both

Functional Assay Focus – Fate & Transport Example

• Precipitation • Bioproduction • Photosensitization

i = speciation

EXPOSURE HAZARD

RISK

• Adsorption • Settling • Aggregation • Deposition

NOM

pH

Proteins

Ionic Strength

• Sulfidation • Complexation

!!!!!" = ±!"!!!! − !!"#!"#$%&"'!! + !!"#$%&'"(!! + !!"#$%!"#$%&'"(!! + !!"#$%&'()!! + !!"#$%&!"#$!! !

Release Rate

Mass Available

Social & Engineered Properties

System Properties

• Mutagenicity • Carcinogenicity • Mortality

• Concentration • Speciation

Material Properties (Intrinsic)

Band Gap

Core Size

Composition

DLVO

Hydro- phobicity

Steric Effects

System Derived Material Phenomena

Translocation of Au NPs in Nicotiana xanthi

30 nm Au-citrate NPs

Judy et al., ES&T 46:8647 2012

Effect of Particle Size and Shape on Reactivity

Figure 1. A) SEM and B) AFM images of unsulfidized AgNP arrays produced by NSL. C) AFM image of an AgNP array after a 2-d exposure to 10 µM Na2S. D) AgNP height distributions before (black) and after (red) the exposure.

 

 

Time (h)

0 2 4 6 8 10 12 14M

ed

ian

Heig

ht

(nm

)0

10

20

30

40

50

60

70

pH 6.5

Figure 3. AgNP dissolution in 1 mg/L NaOCl at pH 6.5. Error bars are standard deviations of triplicate samples.

Kent and Vikesland, Environ. Sci. Technol., 2012, 46 (13), pp 6977–6984

Sulfidation of Ag, ZnO, and CuO NPs

Ag

ZnO +HS-

+HS-

Ag2S

ZnS

CuO +HS-

CuxSy

Ma et al., 2013 ES&T 47 (6), pp 2527–2534; Levard et al., ES&T 2011 45 (12), 5260.

Ma et al., 2014 ES Nano

Mode of Uptake of Ag by Duckweed

Duckweed Landoltia punctata

AgNO3 AgNPs Ag2S-NPs

18 h

~60 h Dead

Stegemeier et al., ES&T (in preparation)

Sulfidation Decreases Toxicity

Zebrafish Killifish C. Elegans Duckweed

Levard, Hotze, et al., ES&T 2013, 47, 13440−13448

“Real World” Transformations Wastewater Treatment Plant

Freshwater Wetland

ZnO Fate in the Wastewater System? Primary clarifier

(180 L)

Anaerobic digester (150 L)

\Secondary clarifier (150 L)

Zn2+

Control

ZnO NP

Mesocosms: Controlled Release Field Sites

!  30 mesocosms

!  year-long experiments

!  pulse & chronic inputs !  Nano- Ag, CeO2, Cu, Au, TiO2, SWCNTs

!  NPs+conventional contaminants

! Release form commercial productions

Mesocosm  Results  

NSF EF-0830093

0%  

20%  

40%  

60%  

80%  

100%  

Mortality  (+/-­‐  SEM

)  

Mesocosm  Toxicity  -­‐  24  h  post  dosing  Fundulus  Larval  Mortality  

Laboratory  Spiked  -­‐  48  h  

Mesocosm  -­‐  48  h  

YES1,2

YES1,2,3 YES2,3

YES2

YES1,2,3

YES

1Joel Meyer 2Paul Bertsch and Jason Unrine 3Bernhardt, Richardson & Gunsch 4Hunt

YES2

Bioaccumulation & Trophic Transfer of NPs

Judy  et  al.,  2011  ES&T  

Au IV Au foil

Hot spot

Au Lα XANES

~100 mg kg-1

Trophic transfer & dilution of Au NPs

Rana catesbeiana

Eisenia fetida

~10 mg kg-1

Unrine et al. ES&T 2012

<1 mg kg-1

What parameters are needed to predict transport and fate of

nanoparticles/

Affinity of nanoparticles for various surfaces

deposition & heteroäggregation

homoäggregation

Aggregation, Transport and Surface affinity

Aggregation: Dissolution Reactivity Photo-catalysis Molecular Adsorption transport

Deposition: Environmental dispersal Biouptake Translocation in organisms

€

dnk

dt=

1

2α β i, j( )nin j

i+ j→k

∑ −αnk β i,k( )i

∑ ni

+/- breakup –settling – dissolution…

Hotze et al., Langmuir 2010, 26(13), 11170–11175 Jassby et al., Environ. Sci. Technol. 2012, 46, 6934−6941

Nanosilver concentration in water column of mesocosm following pulse input

Simulations of heteroaggregation

!

Measuring surface affinity (alpha) in model systems

detector

data acquisition

gear pump

feed solution

syringe pump

flow measurement

porous medium

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

C/Co

Pore Volumes

Breakthrough curves GB

0.001

0.005

0.01

0.02

0.03

0.05

Tracer

Measuring surface affinity in complex systems

dnk

dt=

1

2α β i, j( )ninj

i+ j→k

∑ −αnk β i, k( )i

∑ ni − breakup

ln γB+1( ) =αβ n, B( )Bt

Barton et al., ENVIRONMENTAL ENGINEERING SCIENCE Volume 31, Number 7, 2014

Transformed distribution coefficient aggregation time

ln γB+1( ) =αβ n, B( )Bt

Barton et al., ENVIRONMENTAL ENGINEERING SCIENCE Volume 31, Number 7, 2014

Conceptual model for nanoparticle reactivity

transport attachment reaction / effect

β α k

1 2 3

Importance of surface affinity for transformtion: CeO2

CeO2

CeO2-citrate stabilized

Barton et al. 2014 (in review)

Ag  NP  Embryotoxicity  across  a  Salinity  Gradient  –  The  Role  of  CoaJngs  and  Dissolved  Silver  

Atlan?c  killifish  Fundulus  heteroclitus  

1  

10  

100  

1000  

10000  

0   0.1   0.5   1   5   10  

Hydrod

ynam

ic  Diameter  (n

m)  

Salinity  (‰)  

Colloidal  Stability  

Ag-­‐PVP  100  mg/L  Ag-­‐citrate  50  mg/L  Ag-­‐GA  5  mg/L  

• Ag  NP  coa?ngs  significantly  affect  par?cle  behavior  • Stability/Aggrega?on  (Ag-­‐gum  arabic  most  stable)  • Toxicity  (Ag-­‐gum  arabic  most  toxic)  

• Dissolved  silver  and  silver  specia?on  play  a  significant  role  in  toxicity  

• Toxicity  curve  shape  related  to  silver  specia?on  (total  dissolved  Ag,  not  Ag+)  

0%  

20%  

40%  

60%  

80%  

100%  

0   0.1   0.5   1   5   10  

Mortality  (+/-­‐  SE)  

Salinity  ‰  

Toxicity  

CHESS  Model  Dissolved  Ag  

AgNO3  4  µM  

Ag-­‐PVP  50  mg/L  

Ag-­‐citrate  50  mg/L  

Ag-­‐GA  5  mg/L  

Auffan et al., Nanotoxicology, 2013, Bone et al, ES&T 2012

GA PVP

CIT

GA

CIT PVP

Examples of nanoparticle reactivity

Effect Underlying reaction

Toxicity to plants and fish by nano Ag Nano silver dissolution

Viral inactivation by fullerol Singlet oxygen generation

Bacterial inactivation by CeO2 Ce reduction

n

B

n-B n*

P

B*

1!! =

1!!"# +

1!!"!"#!

!! =!!"#!!"!"#!!"# + !!"!"#!

heteroäggregation reaction

Importance of surface affinity for transformtion: CeO2

Alpha = 0.16

Alpha = 0.07

Barton et al. 2014 (in review)

Particle deposition and translocation in organisms

Summary

1.  Need for functional assays (like surface affinity) for key processes (Transport, transformation, bioüptake…)

2.  Many interactions between nano-scale materials, organisms and ecosystems- RICH SCIENTIFIC TERRAIN

Some take home points:(WPB addition, based on summary comments from MRW)

• Nanoparticles (whether engineered [“ENPs”] or natural):can be taken up by plants and animals;

• NPs are subject to trophic transfer‐ in some cases with biomagnification, in some with dilution;

• Attachment efficiencies appear to be a promising way of predicting NP behavior. 

• The toxicity issue is secondary.Most important ‐‐ growing awareness of:• Complexity of nanometric phases in their interactions with living systems; and• Potentially important roles of NPs in uptake of chemicals, nutrient cycling, transport of other species, etc.

Thank You

Greg Mélanie Jason Lowry Auffan Unrine Jean-Yves Christine Bottero Hendren

Paul Bertsch Mike Hochella Rich Di Giulio Cole Matson Emily Bernhardt Liz Casman Joel Meyer Peter Vikesland Clement Levard Gordon Brown Paul Westerhoff Olga Tsyusko

Raju Badireddy Shihong Lin Yao Xiao Fabienne Schwab Lauren Barton Mathieu Terezien Jeff Farner David Jassby Benjamin Espinasse Charles De Lannoy Alexis Carpenter Amalia Turner