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Seyed Ali Johari

Seyed Ali Johari

Academic rank: Associate Professor
ORCID:
Education: PhD.
ScopusId: 35092663900
Faculty: Faculty of Natural Resources
Address: Fisheries Department, Faculty of Natural Resources, University of Kurdistan, ZIP Code: 66177-15175, P.O. Box 416, Sanandaj, Kurdistan, Iran.
Phone: 08733627721-5 (int. 4303)

Research

Title
Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna (Highly accessed paper)
Type
JournalPaper
Keywords
Daphnia magna; Silver; Nanoparticle; Colloid; Ion; Acute toxicity
Year
2012
Journal Journal of Nanobiotechnology
DOI
Researchers Saba Asghari ، Seyed Ali Johari ، Ji H Lee ، Yong S Kim ، Yong B Jeon ، Hyun J Choi ، Min C Moon ، Il Je Yu

Abstract

Background To better understand the potential ecotoxicological impacts of silver nanoparticles released into freshwater environments, the Daphnia magna 48-hour immobilization test was used. Methods The toxicities of silver nitrate, two types of colloidal silver nanoparticles, and a suspension of silver nanoparticles were assessed and compared using standard OECD guidelines. Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared. The particle suspension and colloids used in the toxicity tests were well-characterized. Results The results obtained from the exposure studies showed that the toxicity of all the silver species tested was dose and composition dependent. Plus, the silver nanoparticle powders subsequently suspended in the exposure water were much less toxic than the previously prepared silver nanoparticle colloids, whereas the colloidal silver nanoparticles and AgNO3 were almost similar in terms of mortality. The silver nanoparticles were ingested by the Daphnia and accumulated under the carapace, on the external body surface, and connected to the appendages. All the silver species in this study caused abnormal swimming by the D. magna. Conclusion According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered.