September 14, 2012

Nanotech In Sunscreen: What’s The Harm?

Summer is over, but I still have sunscreen on my mind. This summer I’ve been enjoying more of my Lake Michigan coastline and taking my children for frequent dips. Like any parent, I make sure they’re coated nose to toes with sunscreen. But if I were to listen to the anti-nanotech alarmists, I’d have to check to see if there were any nanosized ingredients in the product.

For more than a decade now, anti-technology organizations such as the ETC Group and Friends of the Earth have been warning against the possible hazards of nanoscale titanium dioxide and zinc oxide in sunscreen. This warning has come with absolutely no scientific proof. They made it up.


Zinc oxide (ZnO) nanoparticle distribution in excised human skin. The black line represents the surface of the skin (top), blue represents ZnO nanoparticle distribution in the skin (stratum corneum), and pink represents skin. Credit: Timothy Kelf, Macquarie University.

 However, like I said in a previous post, if enough bad information is repeated often enough, it simply becomes “true” in the world of viral online information. Often, you’ll see something like “scientists question” the safety of nanoscale ingredients in sunscreen in news stories about nanotechnology. The “scientists,” however, are simply agenda groups that repeat the same lie over and over again.

In fact, real scientists have already answered the question. No study has proven there is any danger from nanoscale particles in sunscreen. Here’s one of the latest examples, from late last year, in the journal Biomedical Optics Express:

Ultra-tiny zinc oxide (ZnO) particles with dimensions less than one-ten-millionth of a meter are among the ingredients list of some commercially available sunscreen products, raising concerns about whether the particles may be absorbed beneath the outer layer of skin. To help answer these safety questions, an international team of scientists from Australia and Switzerland have developed a way to optically test the concentration of ZnO nanoparticles at different skin depths. They found that the nanoparticles did not penetrate beneath the outermost layer of cells when applied to patches of excised skin. More here 

Yet, the Chicago Tribune, for example, chose the lazy way of simply reprinting the doubts invented by anti-nanotech activists, rather than checking the actual studies. The Tribune “reported” in July:

Improved sunscreens are just one of the many innovative uses of nanotechnology, which involves drastically shrinking and fundamentally changing the structure of chemical compounds. But products made with nanomaterials also raise largely unanswered safety questions — such as whether the particles that make them effective can be absorbed into the bloodstream and are toxic to living cells. More here

The NanoBusiness Commercialization Association (admittedly an advocacy group itself) has a well-thought-out response to the Chicago Tribune article here.

And, in Australia, where they take their sunscreen seriously, a government study reached much the same conclusion:

To date, the current weight of evidence suggests that titanium dioxide and zinc oxide nanoparticles do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer of the skin that is composed of non-viable cells. More here

These studies are rarely ever cited. Most journalists covering nanotech, unfortunately, take the word of agenda groups — and not actual scientists — on the nano sunscreen issue. Unfortunately, as newspapers close and science sections are gutted, it’s up to readers to try to decode some of this for themselves.

As I wrote last year: “Find out who’s behind the fear-mongering, what actual studies have been done and what is simply fantasy.”

Image Credit: mangostock / Shutterstock

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