The unique properties of silver nanoparticles (AgNPs) allow for their use in a wide spectrum of applications and consumer products. As a result, there is an increasing risk for their release into various environmental systems, potentially affecting the functionality of waste treatment systems which rely on bacterial processes (e.g., landfills and wastewater treatment facilities). Previous research concentrated on the fate, transport and toxicity of pristine, lab-synthesized AgNPs. However, AgNPs are mainly integrated into or embedded onto the surface of commercial products and are seldom used or available as pure materials. The physicochemical characteristics of AgNPs are known to vary significantly through exposure to environmental factors (e.g., air and direct sunlight), as well as, aging over time. Consequently, it is important to study the physicochemical characteristics and potential transformations of AgNPs under realistic conditions as present in commercially available products. We investigated a variety of AgNPs containing consumer products applied under different scenarios (e.g., disinfectants, pesticides and bio-protectants). For example, we evaluated the fate, transport and transformations of a common nanosilver suspension (ASAP-AGX-32, 0.0032% Ag) used as a disinfectant for the reduction of biofilm and bacterial buildup in dental unit water lines. The interactions between the AgNPs and biofilm were assessed in the process, concentrating on the physicochemical characteristics of the AgNPs and the morphology of the biofilm development. The results obtained indicated the polymeric stabilizing agent encapsulating the pristine AgNPs was no longer present after the disinfection process, potentially being adsorbed onto the biofilm surface. Subsequently, the diminishing of the polymeric stabilizing agent may have initiated AgNPs aggregation. We identified surface transformations before and after the disinfection process, as well as, AgNPs adsorption onto the biofilms surface.

Environmentally relevant physicochemical transformations of silver nanoparticles used in consumer products

253rd National Meeting (2017)

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