Thursday, April 10, 2008

"NANOTECH: Silver nanoparticles leaching into environment"

Scientists are raising alarms about toxic nanoparticles being woven into fabrics as "odor neutralizers" in socks and as antibacterial agents in bandages. Silver nanoparticles used in fabrics were found by researchers to leach out after just a few washings, releasing harmful toxins shown to harm aquatic life. While the effects of silver nanoparticles on humans have yet to be established, the researchers recommended that the Environmental Protection Agency (EPA) require manufacturers to bind silver nanoparticles to fabrics to prevent leaching during washing. They also recommended labeling products as containing potentially harmful nanoparticles. The researchers purchased socks and bandages from six different manufacturers to test whether the silver nanoparticles leached out during washing. Testing consisted of soaking socks in distilled water, shaking the contents for one hour, then testing the water for the presence of toxic ionic silver as well as for silver nanoparticles. The toxicity of silver nanoparticles has yet to be established by EPA. The results showed a wide spectrum of toxicity, with some socks releasing both toxic ionic silver and silver nanoparticles, and some retaining silver. The worst brands released all their silver after just a few washings; others gradually released it while some brands retained silver nanoparticles through repeated washings. The scientists concluded that it should be possible to require fabric makers to use processes that retain silver nanoparticles. They added that is it up to the EPA to specify a requirement.