(NHI Nanoblog) It’s become a rallying cry for some researchers who are scrutinizing the potential health and environmental effects of super-small particles: Test the products that use nanomaterials, not just the substances themselves.
A new study looking at the exposure risk of nano-enabled cosmetic powders offers a powerful validation of that argument. The researchers conclude that the hazards are different from what might be expected, given the size of the particles involved.
Environmental Health Perspectives
Microscopic images of the cosmetics tested: “Nanopowders” Nano M (A–C), Nano D (D–F), and Nano K (G–I) and “regular” powders Reg F (J–L), Reg G (M–O), and Reg E (P–R).
They also found that even the rudimentary labeling of nano-enabled products isn’t always accurate: Five of the six powders contained nanoparticles, even though only three were marketed that way.
The researchers, from Rutgers University and the Robert Wood Johnson Medical School-University of Medicine and Dentistry of New Jersey, predict that exposure to nanoparticles from cosmetic powders is more likely to be in the upper respiratory system, rather than in the deeper, smaller alveolar area. In other words, these products are mostly coming through — and maybe lodging in — your nose, throat and the bronchial area.
The study was published in Environmental Health Perspectives, an open-access journal put out by the National Institute of Environmental Health Sciences.
Experimental studies using pure versions of nanomaterials suggested that they would migrate to the alveolar region, home of the tiny sacs that form the end of the smallest airways and where the exchange of air and carbon monoxide takes place.
“Our findings on potential nanomaterial inhalation exposure due to the use of actual consumer products emphasize that properties and effects of the pure nanomaterial ingredients cannot be used to predict actual consumer exposures and resulting health effects,” the authors write. “Therefore, experimental techniques for toxicity studies of de facto nanotechnology-based consumer products must be developed. Results of such studies will provide guidance for the developing market of nanotechnology-based consumer products and help clarify the need and feasibility of its regulation.”
Nanotechnology is a broad term that encompasses a wide variety of uses of very small materials. (A nanometer is a billionth of a meter.) These substances can make better batteries or lighter and stronger bike frames, as well as new medical instruments and medicines that can save lives. They’re increasingly common in consumer products, from sunscreens to stain-repellent pants to boat paints that resist algae growth.
Nanomaterials are believed to hold great promise for a wide variety of applications. Their ultra-tiny size often gives them different properties, which is the basis of their appeal; scientists are struggling to figure out whether that can make them dangerous in the process, and how and why it happens.
Scores of researchers are testing everything from super-small silver to carbon nanotubes, looking for clues about safety. But few are testing some of the products already available on store shelves, from nanosilver hunter’s spray to sunscreens using nanoscale titanium dioxide and zinc oxide.
The new study involved a a mannequin and the application of a variety of products, including a powder sunscreen, a powder moisturizer and blush. They contained common ingredients, such as titanium dioxide and silica. (The paper doesn’t give the brand names of the products.) The researchers sampled the particles entering the mannequin’s nose to determine what the exposure might be in an everyday use.
The nanoparticles seem to stick together, or agglomerate, lessening exposure to the very smallest particles, the paper says. But future studies looking at health risks should take that into account, since the exposure that was found could still lead to problems.
The paper’s authors are Yevgen Nazarenko, Huajun Zhen, Taewon Han, Paul J. Lioy, and Gedimina Mainelis.
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