Former CEINT PhD student Nina Quadros assessed the potential for children's exposure to bioavailable silver during the realistic use of selected silver nanotechnology-based consumer products (plush toy, fabric products, breast milk storage bags, sippy cups, cleaning products, humidifiers, and humidifier accessory). Silver nanoparticles are known for their broad-spectrum antimicrobial properties, which have led to many applications in consumer products. Along with her collaborators at Virginia Tech, EPA, and CPSC, she measured the release of ionic and particulate silver from products into water, orange juice, milk formula, synthetic saliva, sweat, and urine; into air; and onto dermal wipes. Their results support the more theoretical studies in silver nanoparticle dissolution. They found that the release of silver from products that contain silver nanoparticles depends heavily on how the product is used. The total amount of silver released by a consumer product is likely to be very low and, for the products tested, happened only in the beginning of product life.
Figure reprinted with permission from Quadros, Marina et al. (2013). Release of silver from nanotechnology-based consumer products for children. Environmental Science & Technology. http://dx.doi.org/10.1021/es4015844. Copyright 2013 American Chemical Society.
This research is addressing a knowledge gap between the toxicity of nanomaterials to humans and the popularity of consumer products that contain nanotechnology in the marketplace. Silver (nanoparticles or ions) has not been proved to cause significant health effects at low levels, but contradictory views on the toxicity of silver ions and nanoparticles still exist and their effects on molecular mechanisms is still under study. The possibility for consumers to become chronically exposed to silver from multiple sources will be minimized if all products that use silver advertise their use and the amounts used. By measuring the amount of nanosilver in many different consumer products, we can educate consumers concerning the nanosilver ingredients that are present and their likely exposure due to typical use.
This work as a collaboration between Virginia Tech, EPA, and CPSC (Consumer Product Safety Comission).
Nina Quadros is associate director of VTSuN, http://www.sun.ictas.vt.edu