25^th Nano Congress for Future Advancements

Biography

Biography: Christian Gagnon

Abstract

Silver nanoparticle is largely used for various products and is finally found in discharged wastewaters. Silver was typically detected in all investigated municipal wastewaters. Concentrations of total silver in municipal were measured to assess Ag removal efficiency of treatment plants. Wastewater samples were also analyzed by the technique of single-particle inductively coupled plasma–mass spectrometry (SP-ICP-MS) to identify and determine that they contained silver nanoparticles. Nano-sized forms would account for less than 5% of the total Ag released from municipal effluents. Once released in the receiving environment, Ag NPs can undergo major transformation and their initial properties can be modified under natural conditions. The developed analytical approach was used for tracking silver nanoparticles and their degradation products over a period of 80 days. Particle size distributions changed significantly under different experimental conditions where most material was found in coarse colloidal fractions (<100 kDa). The presence of natural humic substances slowed degradation of nanoparticles, which is characterized by the increase of free/small ion complexes and the detection of colloids with a size less than 80 nm. Haft-live values were generally estimated to be less than 15 days under natural conditions. Future research on nanotoxicity should consider exposure conditions, and then potential transformation, for risk assessment studies.