The very first L-SETAC Ottawa Pub Night of 2015 was held on January 28 at the Clocktower Brew Pub. Dr. Dina Schwertfeger & Jessica Velicogna, researchers in the Biological Assessment & Standardization Section at Environment Canada, discussed the effects of silver nanoparticles in soil systems. Their presentation was titled:
"Effects of Silver Nanoparticles in Soil: Challenges and Perspectives." The talk was well attended by a mixture of students, government researchers, and regulators alike. Silver nanoparticles are of particular importance given their widespread use in household and personal care products and the potential for the particles to wash out of these products, be sent to waste water treatment plants, and eventually end up in biosolids applied to agricultural soils. Jessica provided insight into the challenges faced when working with nanoparticles in ecotoxicity tests. From particle dissolution and ionization to water solubility issues, identifying the toxicological effects of silver nanoparticles in soil is no easy feat. Nevertheless, Jessica was able to discover that silver nanoparticles demonstrate less toxicity than ionic silver in two plant species. A different story emerged in earthworms, where silver nanoparticles bioconcentrated to a greater extent than ionic silver, thereby likely causing the greater toxicity observed. Dina vividly discussed her results on the quantification and bioavailability of silver nanoparticles in soils, using useful analytical techniques such as inductively coupled plasma mass spectrometry (ICP-MS) for differentiating silver nanoparticles in their aggregate, agglomerate, or pristine state. In addition, Dina was able to visually detect silver nanoparticles by scanning and transmission electron microscopy in laboratory soil samples. These techniques help researchers better understand silver nanoparticle transformations and their fate and behaviour in soils, which in turn leads to a robust exposure characterization. The presenters wrapped up their talks with a description of their ongoing and future research in the field of silver nanoparticle toxicity in terrestrial environments. On behalf of all attendees, I believe it’s safe to say that we all look forward to hearing more about their upcoming results. Submitted by Cristina Inglis