title: Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna.
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 AgNO(3) 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Saba
authors.initials: S
authors.lastname: Asghari
authors.forename: Seyed Ali
authors.initials: SA
authors.lastname: Johari
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Yong Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Yong Bae
authors.initials: YB
authors.lastname: Jeon
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Choi
authors.forename: Min Chaul
authors.initials: MC
authors.lastname: Moon
authors.forename: Il Je
authors.initials: IJ
authors.lastname: Yu
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003621:Daphnia / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D012834:Silver / Q000737:chemistry*; D012835:Silver Nitrate / Q000633:toxicity*; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D012834:Silver; D012835:Silver Nitrate