Journal
ENVIRONMENTAL SCIENCE & TECHNOLOGY
Volume 48, Issue 1, Pages 761-769Publisher
AMER CHEMICAL SOC
DOI: 10.1021/es403969x
Keywords
-
Categories
Funding
- National Science Foundation [CBET 0846719]
- Directorate For Engineering
- Div Of Chem, Bioeng, Env, & Transp Sys [0846719] Funding Source: National Science Foundation
Ask authors/readers for more resources
In this study, we comprehensively evaluate chloride- and ionic-strength-mediated changes in the physical morphology, dissolution, and bacterial toxicity of silver nanoparticles (AgNPs), which are one of the most-used nanomaterials. The findings isolate the impact of ionic strength from that of chloride concentration. As ionic strength increases, AgNP aggregation likewise increases (such that the hydrodynamic radius [HR] increases), fractal dimension (D-f) strongly decreases (providing increased available surface relative to suspensions with higher D-f), and the release of Ag-(aq) increases. With increased Ag+ in solution, Escherichia coli demonstrates reduced tolerance to AgNP exposure (i.e., toxicity increases) under higher ionic strength conditions. As chloride concentration increases, aggregates are formed (HR increases) but are dominated by AgCl(s)0 bridging of AgNPs; relatedly, D-f increases. Furthermore, AgNP dissolution strongly increases under increased chloride conditions, but the dominant, theoretical, equilibrium aqueous silver species shift to negatively charged AgClx(x-1)- species, which appear to be less toxic to E. coli. Thus, E. coli demonstrates increased tolerance to AgNP exposure under higher chloride conditions (i.e., toxicity decreases). Expression measurements of katE, a gene involved in catalase production to alleviate oxidative stress, support oxidative stress in E. coli as a result of Ag+ exposure. Overall, our work indicates that the environmental impacts of AgNPs must be evaluated under relevant water chemistry conditions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available