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Effects from Filtration, Capping Agents, and Presence/Absence of Food on the Toxicity of Silver Nanoparticles to Daphnia Magna
Citation:
ALLEN, H. J., CHRISTOPHER IMPELLITTERI, D. MACKE, D. ROOSE, J. M. LAZORCHAK, H. POYNTON, L. HECKMAN, S. GOVINDASWAMY, AND M. Nadagouda. Effects from Filtration, Capping Agents, and Presence/Absence of Food on the Toxicity of Silver Nanoparticles to Daphnia Magna. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 29(12):2742-2750, (2010).
Impact/Purpose:
To inform the public.
Description:
Relatively little is known regarding the behavior and toxicity of nanoparticles in the environment. The objectives of the work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvandages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a solution of silver nitrate and suspensions of AgNPs including commercially available AgNPs (uncoated and coated), and lab synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were characterized for concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicity of filtered (100 nm) versus unfiltered suspensions were compared using standard EPA test methodologies. In addition, effects from the addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water. The stock suspensions were diluted and used straight or after filtration with 100 nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnace-atomic absorption spectroscopy. Dose response curves were calculated for the AgNP exposures and LC50 values calculated. The LC50 values were (in g/L): 0.7±0.1-AgNO3; 1.1-coffee and citrate coated (unfiltered); 1.4±0.1-Sigma Aldrich Ag-nanoparticles (SA)-uncoated, filtered; 4.4±1.4 SA-coated, filtered; 16.7±2.4 SA uncoated, unfiltered; 31.5±8.1 SA coated, unfiltered; 176.4±25.5 SA unfiltered, uncoated with addition of food. Recommendations presented in this work include AgNP handling methods, effects from sample preparation and advantages/disadvantages of different nanoparticle characterization techniques.
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EFFECTS FROM FILTRATION, CAPPING AGENTS, AND PRESENCE/ABSENCE OF FOOD ON THE TOXICITY OF SILVER NANOPARTICLES TO DAPHNIA MAGNA
Abstract
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