Environmental effects of nanoparticles on aquatic organisms: toxicity, behavior, gene expression

Rebecca KlaperGreat Lakes WATER Institute, University of Wisconsin-Milwaukee; 600 East Greenfield Ave. Milwaukee WI 53204; 414-382-1713; rklaper@uwm.edu

Collaborators: Sarah Lovern, Caroline Hagerman, Dimitar Iliev, Rick Goetz, Rudi Strickler

GREAT LAKESWATERINSTITUTE

Nanotech means more than miniaturisation

Potential Uses of Nanoparticles

http://news.bbc.co.uk/2/hi/science/nature/3930179.stm

Nanoparticles as environmental cleanup tools

• Fullerene tubes absorb dioxins• Iron nanoparticles catalyze breakdown of

solvents • Currently testing for environmental

remediation of groundwater

Nanoparticles as pollutants-not necessarily a new phenomenon-bringing in a new class of compounds

Impact of Particles in the Environment

• Toxicity of manufactured nanoparticles• Mechanism of action• Nanoparticles of natural products versus

macroparticles• Will the organisms interact differently with

nanoparticles than larger particles?• Ecosystem impact?

– Bioaccumulation– Fate – Changes in species interactions-behavior

Manufactured nanoparticles: Traditional Toxicity Tests

• Toxicity tests– Exposure to particles

for 48 hours– Determination of

mortality rate

• Daphnia spp.• Abundant in freshwater • Filter feeders• Crucial to food web

Nanoparticles

• Titanium Dioxide– 10-20nm particles– Conduct charge

efficiently– Photocatalyst for

cancerous tumors

• Fullerenes– ~1nm particles– High electrically affinity– Environmental clean-up– Drug delivery

Mortality after Exposure to Titanium Dioxide or Fullerenes

Lovern, SB & R Klaper. 2006. Daphnia magna mortality when exposed to titanium dioxide and fullerene (C60) nanoparticles, ET&C, Volume 25,

Filtered vs.

SonicatedSize Matters

Lovern, SB & R Klaper. 2006. Daphnia magna mortality when exposed to titanium dioxide and fullerene (C60) nanoparticles, ET&C, Volume 25,

Effects of Exposure on Behavior

• Video ImagingDaphnia placed in vessel, allowed to acclimate, and then exposed

Why Behavior

• Energetics• More obvious to predator, problems

with mating/feeding etc.• Easy first indicator of response

Behavior Before Nanoparticles

Exposed to Nanoparticles

Hi-Speed

Before exposure

After exposure

Average Deviation from Pre-exposure

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Time (minutes)Ave

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Heart Rate Feeding Appendages Hopping Tail Curl

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Time (minutes)

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FullereneExposed

From Lovern and Klaper, 2005, SETAC Baltimore

Control

Average Frequency of Behaviors

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Heart Rate Appendages Hopping Tail Curling

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Lovern and Klaper 2005, SETAC Baltimore

Control C60

Other projects:--Effects of Natural nanoparticles--Impacts of nanoparticles on immune response

(not publicly available yetsee R. Klaper for more information)

Environmental Impact of Nanoparticles?

• Depends on type of particle– Mortality differs with particle type and any

changes in side chains (Colvin et al.: Variations in C60 nanocrystal can alter toxic response. )

– Gene expression differs with particle type• Interference with filter feeders

– Future studies behavior and feeding• Ecosystem effects?

Increasing Investment in Nanotechnology

Environmental Risk Assessment for Nanoparticles

• Identify potential risks• Exposure – different than macroparticles?

– Routes of exposure– Fate in the environment– Measuring exposure

• Effects – different than macroparticles?– Toxicity testing – different methods?– Ecosystem – bioaccumulation? Changes in

interactions?• Risk management

– Limiting use of certain products– Waste reduction

Acknowledgements

GREAT LAKESWATERINSTITUTE