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Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms.
Citation:
Wang, H., K. Ho, K. Scheckel, F. Wu, M. Cantwell, D. Katz, D. Borsay, W. Boothman, AND R. Burgess. Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms. To be Presented at Society of Environmental Toxicology and Chemistry (SETAC) Europe 25th Annual Meeting, Barcelona, SPAIN, May 03 - 07, 2015.
Impact/Purpose:
The widespread popularity of silver nanomaterials (AgNM) in consumer products increases the risk for metal contamination and adverse effects in aquatic environments. Many information gaps exist on the potential toxicity of silver nanomaterials in aquatic ecosystems, particularly in marine environments. We exposed marine worms to silver nanomaterials spiked sediments and determined the uptake and speciation of the different coated silver nanomaterials as well as ionic silver. Results indicate that AgNMs have different pathways depending upon their coating and those pathways are also different from ionic silver. Findings of this investigation indicate AgNMs are processed differently than ionic silver within the worm and more research into the kinetic pathways of AgNPs would be useful in this type of study.
Description:
The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that AgNP-citrate and AgNP-PVP did not exhibit toxicity to the amphipod (Ampelisca abdita) or mysid (Americamysis bahia) at < 75 mg/ kg dry wt. A 28-d bioaccumulation study showed that Ag was significantly accumulated in the marine polychaete (Nereis virens) in the AgNP-citrate, AgNP-PVP and a conventional salt (AgNO3) treatments. Synchrotron X-ray absorption spectroscopy (XAS) results showed the distribution of Ag species in marine sediments amended with AgNP-citrate, AgNP-PVP and AgNO3 was AgCl (50-65%) > Ag2S (32-42%) > Ag metal (Ag0) (3-11%). In N. virens, AgCl (25-59%) and Ag2S (10-31%) were generally decreased and, Ag metal (32-44%) increased, relative to the sediments. The patterns of speciation in the worm were different depending upon the coating of the AgNP and both types of AgNPs were different than the AgNO3 salt. These results show that the AgNP surface capping agents influenced Ag uptake, biotransformation and/or excretion. To our knowledge, this is the first demonstration of the bioaccumulation and speciation of AgNPs in a marine organism (N. virens).