I Would like to Thank the Research and Creative Opportunities for Undergraduates Program at a Novel Fungal Growth Inhibition Bioassay and Effects of Suwannee River Humic Acid on Nanosilver Toxicity

The use of nanoparticles in both industrial and household products is currently undergoing rapid expansion despite the lack of information regarding the behavior and toxicity of nanoparticles in the environment. Estimates suggest multiple thousands of tons of each major nanomaterial are being produced annually. Silver nanoparticles (AgNPs) are currently being used as an anti-microbial additive in consumer products. Additionally, there have been suggestions of using AgNPs as a fungicide applied to plants and as a preservative applied to lumber. Wild fungi may become unintentionally exposed to AgNPs through contact with industrial and residential effluents, fungicide spray drift or leaching of silver nanoparticles from treated lumber. Current literature regarding the toxicity of AgNPs to fungi is limited to a few studies examining only phytopathogenic species. This study was designed to determine what levels of AgNPs are toxic to the common wild oyster mushroom, Pleurotus ostreatus, and effects of Suwannee River humic acid on toxicity. This work may provide insight into the mode by which nanoparticles cause cellular damage and can be used to inform future management decisions on nanoparticle releases into the environment. The toxicity of silver was relatively low considering it is a strong antimicrobial. Silver nanoparticles of different diameters and different coatings displayed no conclusive differences in toxicity. The effects of Suwanee River humic acid on Ag toxicity is not clear. Ag ions in the presence of or released from AgNPs appeared to display higher toxicity than those from Ag2SO4.