Silver nanoparticles, used for their potent antimicrobial properties in hospitals and consumer products, may negatively impact plant growth as they make their way into the environment, according to a new study. Whereas it may not spell the end of all flora as we know it, the findings suggest that the nanomaterial has environmental impacts worthy of further investigation.

The antimicrobial properties of silver in its ionized form have been recognized for centuries. When it is nanosize-between one and 100 nanometers, which is smaller than many viruses (a nanometer is one billionth of a meter)-silver is even more effective at killing microbes. This antimicrobial potency has prompted manufacturers to include silver nanoparticles in a wide variety of consumer products, such as odor-resistant clothing, hand sanitizers, water treatment systems and even microbe-proof teddy bears. (Currently, labels on products for sale in the U.S. are not required to disclose the presence of nanomaterials. Consumers can learn more about which products contain nanoparticles by visiting the Web site for The Project on Emerging Nanotechnologies.)

Although the microbicidal effects of silver nanoparticles are well documented, their impact on the environment is less understood.