Particle Size and Agglomeration Affect the Toxicity Levels of Silver Nanoparticle Types in Aquatic Environment

In order to understand the importance of particle size and agglomeration for nano-eco-toxicological studies in aquatic environments, the acute toxicity of two different types (suspended powder and colloidal) of silver nanoparticles (AgNPs) were studied in alevin and juvenilerainbow trout. Fish were exposed to each type of AgNPs at nominal concentrations of ۰.۰۳۲, ۰.۱, ۰.۳۲, ۱, ۳.۲, ۱۰, ۳۲, and ۱۰۰ mg/L. Lethal concentrations (LC) were calculated using a Probit analysis. Some physical and chemical characteristics of silver nanoparticles were determined. In the case of colloidal form, particles were well dispersed in the water column and retained their size; but in the case of suspended powder, particles were agglomerated to large clumps and precipitated on the bottom. In alevins, the calculated ۹۶ h LC۵۰ values were ۰.۲۵ and ۲۸.۲۵mg/L for colloidal and suspended powder AgNPs respectively. In the case of juveniles, the ۹۶h LC۵۰ of colloidal form was ۲.۱۶mg/L, but suspended powder did not caused mortality in fish even after ۲۱ days. The results showed that both in alevin and juvenile stages, colloidal form is much toxic than suspended powder; this shows increase of nanoparticles size due to agglomeration, will reduce the toxicity. Silver nanoparticles are toxic materials and their release into the water environment should be avoided.

کلیدواژه ها:

Aquatic nanotoxicology ، Agglomeration ، Silver nanoparticle ، Size-dependent toxicity Rainbow trout