Influence of Suwannee River humic acid on particle properties and toxicity of silver nanoparticles

• Published in: Chemosphere (Oxford) Vol. 89; no. 1; pp. 96 - 101
• Main Authors: Gao, Jie, Powers, Kevin, Wang, Yu, Zhou, Haoyan, Roberts, Stephen M., Moudgil, Brij M., Koopman, Ben, Barber, David S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2012; Elsevier
• Subjects: Adsorption; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Daphnia - drug effects; Dissolution; Ecotoxicology, biological effects of pollution; Fresh water ecosystems; Fundamental and applied biological sciences. Psychology; General aspects; Humic Substances - analysis; Hydrogen-Ion Concentration; Metal Nanoparticles - chemistry; Metal Nanoparticles - toxicity; Nanoparticles; Nanotoxicity; Organic matter; Rivers - chemistry; Silver - chemistry; Synecology; Water; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Nanoparticles; Water; Nanotoxicity; Organic matter; Dissolution; Nanoparticle; Toxicity; Rivers; Heavy metal; Freshwater environment; Trace element; Silver; Stream; Humic acid
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2012.04.024

► Adsorption of humic acid on silver nanoparticles had a Langmuir adsorption isotherm at neutral pH. ► Dispersion of nano-Ag particles increased with SRHA amount and started decreasing at TOC>10mgL−1. ► Equilibrium concentration of ionic Ag remained constant at all SRHA concentrations. ► There was a linear decrease in toxicity within a certain nano-Ag concentration range. 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 28.6mgg−1 nano-Ag. It was also revealed that addition of <10mgL−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 (50μgL−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.