Nanoparticles used in sunscreens and cosmetics may be harmful to the environment, according to U.S. scientists who have been studying the effects of nanos on living organisms.
Two separate studies, by researchers at the University of Toledo and at Utah State University and the University of Utah, found that the nanoparticles had powerful harmful effects on bacteria and a certain type of beneficial soil microbes.
The findings, released this week, were reported at the national meeting of the American Chemical Society in Salt Lake City. They are likely to fuel debate over the safe use of nanoparticles and concerns that consumers lack important information about the nano-engineering behind hundreds of personal care products already on the market.
"We have no assurance that they're effective and we have no assurance that they're safe either," said Ian Illuminato, an advocate with Friends of the Earth, which wants the U.S. to require disclosure on products using nanoparticles.
While nanotechnology is a "very exciting field" certain to catapult many scientific advancements, there are still problems with using nanoparticles for consumables at this early juncture, Illuminato said.
"More and more studies are raising red flags," showing that nanoparticles used in personal products can cross into body tissues, where their effects are largely unexplored. Once study with pregnant lab mice showed that exposure to nano titanium dioxide crossed the placental barrier, producing brain damage in the offspring, he said.
This week, the European Union voted to tighten safety testing requirements for personal products made with nanoparticles and to require labeling of consumer goods with nanoparticles. The new rules go into effect in 2012.
One of the two studies released in Salt Lake City this week looked at nano-titanium dioxide - used in regular and nano-versions in sunscreens and skin products that advertise sunscreen protection because it can block UV rays. In the study, Dr. Cyndee Gruden, of the University of Toledo, and colleague Olga Mileyeva-Biebesheimer , found that nano-titanium dioxide (nano-TiO2) quickly killed Escherichia coli (E.coli) in lab cultures.
"How fast the impact was surprised me," she said in a news release. Gruden's concern: What happens when nano-particles from personal products are rinsed away and end up in water supplies. "When they enter a lake, what happens? Would they enter an organism or bind to it? Maybe they kill it - or have nothing to do with it at all Right now, we're not really sure of the answers."
In the other study of nanotoxicity, Utah scientists Anne Anderson and colleagues inserted a newly developed nano-detecting "biosensor" into the Pseudomonas putida (P. putida) soil microbe.
They found that the microbe, which is considered a beneficial soil organism, could not "tolerate" the intrusion of silver, copper oxide or zinc oxide nanoparticles. The biosensor provided the evidence, showing that the microbes exposed to the nanoparticles dimmed compared with the unexposed microbes, which glowed brightly when healthy.
Anderson said the results were worrisome because the levels of nanoparticles that produced damage were very small relative to the size of the microbe - akin to two or three drops of water in an Olympic-sized swimming pool. She reported that this could be dangerous for aquatic life because even very small amounts of copper contamination, for instance, can be harmful to fish and other organisms.
As for possible harm to other organisms, like the human ones in the swimming pool, groups like Friends of the Earth and others want more studies on human exposures. The effect of nanoparticles has not been well researched in the U.S. because of assumptions that manufacturers will do the appropriate testing and that nanoparticles are probably too small to pass through the skin in topical applications, Illuminato said.
As for environmental damage, some scientists assume that nanos will clump together and bind to organic matter, making them less toxic. But Anderson questioned that hypothesis. "We don't know if that's true or not," she says in the news release.
Gruden adds that scientists are responsible for determining the hazards and "to date, it's unclear whether the benefits of nontech outweigh the risks associated with environmental release and exposure to nanoparticles."
While nanoparticles hold great promise for the treatment of diseases and the development of pollution-fighting products (scientists are developing potential ways to cleanse wastewater using nanos), there is a growing consensus that more research is needed.
Even a 2007 EPA white paper on nanoparticles concluded that "not enough is known to enable meaningful predictions on the biodegradation of nanomaterials in the environment and much further testing and research are needed."
For more information on nano research see:
* The Woodrow Wilson Center Project on Emerging Nanotechnologies
* National NanoTechnology Inititiave
Studies Show Nanoparticles Used in Sunscreens and Makeup can Harm the Environment
KABC-TV, March 26, 2009
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