photo: Richard Masoner via flickr
DCL
The unintended (and largely unregulated) consequences of use of silver nanoparticles in a wide range of products, from sunscreens and cosmetics to antibacterial socks and underwear, is receiving some more attention. Researchers from Duke University have looked at what might be the environmental impact of these nanoparticles in a more realistic setting than the laboratory.
New Scientist describes the experiment:
[The scientists] added a high dose of silver nanoparticles - 1.25 milligrams per gram of water - to microbes in a sample of stream water and soil kept within their laboratory. They also set up two outdoor tubs of plants. Treated sludge known to be free of nanoparticles was added to the soil in both tubs, while one tub was also dosed with 55 micrograms of silver nanoparticles per gram of sludge, a concentration similar to levels often found in waste water.
What they found was that after two months the microbial population containing the silver nanoparticles dropped compared to the lab samples, and the enzymes produced from these microbes in the nanoparticle tub were 34% lower than the nanoparticle-free tub.
Here's the greenhouse gas emissions part: The researchers found that the nitrous oxide (more potent than CO2, if shorter lived—as well as damaging to the ozone layer) levels coming off the nanoparticle tub were four times higher than from the tub without nanoparticles.
Further research is being conducted to examine what effect silver nanoparticles might have at the ecosystem level.
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