Human Exposure and Atmospheric Sciences
Research in Action
Nanosilver and Consumer Products
Due to their anti-microbial activities, silver nanoparticles have been incorporated into many consumer products. These products include dietary supplements, laundry detergents, body soap, toothbrushes, toothpaste, disinfectant sprays, kitchen utensils, clothing and children’s toys. The increased manufacture, marketing and use of silver nanoparticle-containing household and personal care products is prompting concerns about potential human and ecological exposures.
Current knowledge regarding release of silver nanoparticles from sources such as consumer products; their fate and transport in the environment; and their potential for human and ecosystem exposure is limited. Further research is needed to understand the physico-chemical properties of nanoscale silver that influence transport, transformation, exposure, and bioavailability of this element.
In collaboration with the U.S. Consumer Product Safety Commission (CPSC), EPA scientists have been conducting studies to determine whether consumer products containing nano-silver are releasing nanoparticles in unintended ways. In these studies they are evaluating consumer products to determine the amount of silver leached from products. In particular, researchers are examining children’s potential exposures to nanosilver from child-specific consumer products such as toys.
EPA scientists are also conducting studies to examine chemical and physical changes that might occur in silver nanoparticles that are ingested with food or water. In these studies, silver nanoparticles are exposed to synthetic human stomach fluid to see how ingested nanoparticles might be altered by the stomach’s very acidic environment. A variety of analytical methods showed that nanoparticles formed large aggregates and produced silver chloride when exposed to stomach fluid. Changes in nanoparticle physical form and surface chemistry that occur in the stomach may affect how much silver will be absorbed across the gastrointestinal barrier.
Results and Impact
This research provides the science tools and data to inform EPA decision-making for emerging chemicals and materials, such as nanomaterials. To be protective of human health and the environment, EPA scientists and regulators must understand how nanoscale silver — used in a variety of consumer products — moves through the environment and transforms under different product use scenarios. This research provides information that is crucial for understanding the potential for exposure to nanoscale silver particles and risks to health.
Kim Rogers, Ph.D.