title: Influence of Suwannee River humic acid on particle properties and toxicity of silver nanoparticles.
abstract: Adsorption of natural organic matter (NOM) on nanoparticles can have dramatic impacts on particle dispersion resulting in altered fate and transport as well as bioavailability and toxicity. In this study, the adsorption of Suwannee River humic acid (SRHA) on silver nanoparticles (nano-Ag) was determined and showed a Langmuir adsorption at pH 7 with an adsorption maximum of 28.6 mg g(-1) nano-Ag. It was also revealed that addition of <10 mg L(-1) total organic carbon (TOC) increased the total Ag content suspended in the aquatic system, likely due to increased dispersion. Total silver content decreased with concentrations of NOM greater than 10mg TOCL(-1) indicating an increase in nanoparticle agglomeration and settling above this concentration. However, SRHA did not have any significant effect on the equilibrium concentration of ionic Ag dissolved in solution. Exposure of Daphnia to nano-Ag particles (50 μg L(-1) and pH 7) produced a linear decrease in toxicity with increasing NOM. These results clearly indicate the importance of water chemistry on the fate and toxicity of nanoparticulates.
authors.affiliation: Particle Engineering Research Center, University of Florida, Gainesville, FL 32611, USA. dencyl@ufl.edu
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Kevin
authors.initials: K
authors.lastname: Powers
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Haoyan
authors.initials: H
authors.lastname: Zhou
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Roberts
authors.forename: Brij M
authors.initials: BM
authors.lastname: Moudgil
authors.forename: Ben
authors.initials: B
authors.lastname: Koopman
authors.forename: David S
authors.initials: DS
authors.lastname: Barber
mesh_terms: D000327:Adsorption; D000818:Animals; D003621:Daphnia / Q000187:drug effects; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D045483:Rivers / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical; D012834:Silver