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Behavioral response of Daphnia magna to silver salt and nanoparticle exposure
Citation:
ALLEN, H. J. AND D. MACKE. Behavioral response of Daphnia magna to silver salt and nanoparticle exposure . Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Boston, MA, November 13 - 17, 2011.
Impact/Purpose:
To inform the public.
Description:
Endpoints in the investigation of the toxicity of metallic nanoparticles have varied from genetic and molecular through whole organism responses such as death and reproduction. The work presented here is an effort to quantify behavioral responses of Daphnia magna to exposure to silver nanopartic1es. Experiments were performed using the Daphtox biomonitoring system developed by BBE Moldaenke. In this flow-through system, swimming behavior of eight <72 hour old D. magna are recorded and plotted using a video capture system. The organisms were observed for 24 hours, exposed for 2 hours, and observed for 24 hours. Test solutions of silver nitrate, laboratory synthesized citrate coated silver nanoparticles, and commercially available coated silver nanoparticles were used. Stock suspensions were sonicated and filtered through 100nm filters. Stock suspension were digested via microwave digester (EPA Method 3015) and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnace-atomic absorption spectroscopy. A stock suspension was diluted (with stirring) to create working suspensions and transferred to digestion vessels/organism exposure vessel. The lowest observed effect concentration (LOEC) for silver nitrate was observed to be 1.25ppb (all concentrations nominal), the citrate coated panicles was 10ppb, and the commercially available coated nanoparticles was 6.25ppb. A complete review of the response elements of the algorithm will be presented. The observed behavioral effect value for silver nitrate is similar to D. magna LC50 values found in the literature. The nanoparticle behavioral toxicity values were within an order of magnitude of the silver nitrate. These results suggest that toxicity of organically-coated silver nanoparticles is in the same range as their metallic ions.