Nanosilver risks and benefits studied

WASHINGTON, Sept. 10 (UPI) -- U.S. researchers say widespread use of nanoscale silver will challenge regulators to balance potential benefits against substantial environmental risks.

A report by the Project on Emerging Nanotechnologies notes there currently are more than 200 manufacturer-identified nanosilver products on the market, including baby carriages, air filters, athletic socks and coin-operated washing machines.

Silver itself is classified as an environmental hazard because it's more toxic to aquatic plants and animals than any metal except mercury, scientists said, noting even if a nanoparticle itself is not especially toxic, silver nanoparticles increase the effectiveness of delivering toxic silver ions to locations where they can cause toxicity.

"We need not assume that because nano is new, we have no scientific basis for managing risks," said Samuel Luoma, the author of the PEN report. "The silver that went into wastewaters when millions of people had their photographs developed taught us that small additions of silver to the environment make a big difference.

"Perhaps more significant," he added, "we have no means of detecting nanosilver in the environment once it is released, even if concentrations rise to levels that are toxic to aquatic ecosystems."

The 72-page report is available in PDF format at http://www.nanotechproject.org/process/assets/files/7036/nano_pen_15_final.pdf.