Nanoparticles: Small Packages, case study on the health risks

The potential dangers of nanotechnology have been capturing imaginations for some years now-and for good reason. The technology is getting researchers closer to designing and engineering materials atom by atom. And it’s allowing them to tap into material properties that, until recently, were either unknown, or mere intellectual curiosities. Chances are that the device you’re reading this on does what it does because of nanotechnology. Batteries, computer chips, digital memory, display screens, all perform better now because they use engineered nanoscale materials. And this is just the beginning. The sometimes-unusual properties of materials engineered at this exquisitely fine scale can now be found in new drugs, medical implants, super-lightweight materials, cheap and efficient solar cells, cars, clothing, cosmetics, food packaging-almost everywhere you look, someone is either using nanotechnology or thinking about how they can use it to make the products you use and rely on cheaper, more efficient, and more effective. But the unusual properties that are making all this possible are raising alarm bells with people who worry about what can go wrong with new technologies. What happens, they ask, when these nanomaterials and products get into the environment, or into our bodies? Can the cool things they are designed to do also be harmful if they end up in the wrong place? It’s a compelling question: History is littered with great technologies that also had an unexpected downside-just look at some of the health and environmental challenges that plastics are creating, for instance. It’s also especially pertinent to the nanoscale, where particles too small to see with the naked eye can potentially throw a nanowrench into the nanoworld of biology. This is not idle speculation-there’s a growing body of research that shows some nanoscopically small particles can cause harm in unexpected ways if they get into your body or out into the environment. A few days ago, these concerns were brought to the fore with the publication of a case report in the American Journal of Industrial Medicine. The report describes a chemist who developed symptoms that included throat irritation, nasal congestion, facial ﬂushing, and skin reactions to jewelry containing nickel, after starting to work with a powder consisting of nanometer-sized nickel particles. According to the report’s lead author, this is “case one in our modern economy” of exposure to a product of nanotechnology leading to an individual becoming ill. Although there have been other instances where engineered nanoparticles have been suspected of causing ill health, this is the first where the link seems credible. But beyond indicating that working with a fine nickel powder without any form of protection probably isn’t a good idea, does this case help better understand the risks of nanotechnology? In the grand scheme of things, probably not-although as an indicator of what not to do, it is important. For more than a decade now, there has been a massive global investment in research into the health and environmental impacts of engineered nanomaterials. Between 2004 and 2013 more than 6,000 academic papers were published on how these materials possibly cause harm, and how it might be averted. And for decades before this, researchers were studying the health impacts of nanoscale particles arising from natural processes, and as by-products of industrial processes. As a result, we now know quite a lot about how nanoscale materials behave in the human body and how to reduce the chances of harm occurring. We know, for instance, that inhaled or injected nanoparticles can get to places in the body that larger particles cannot go; that the surface of nanoparticles is important in determining how harmful they are; and that nanoparticles are sometimes less harmful than the chemicals they’re made of. We also know that our bodies have evolved over millennia to handle nanoparticles, and that fine particles are integral to many biological and environmental systems. These studies have also indicated how much we don’t know, which is why research in this area remains a priority. And one area we know less about than many would like is: How dangerous is the stuff people are actually exposed to, as opposed to the pure materials that researchers often use in their studies? Over a couple of days in London last summer, I found myself mulling over a very similar question with a small group of colleagues. We were a pretty eclectic group-engineers, designers, toxicologists, business leaders, academics, policy wonks-but we had one thing in common: We wanted get a better handle on how dangerous realistic products of nanotechnology might be, and how these dangers might be avoided. Unfortunately, the pristine engineered nano materials that toxicologists like to work with don’t reveal much about what happens in the real world-for instance, after those materials have been put into your smartphone and you’ve handled it with greasy fingers, held it to your face, dropped it, had the shattered screen mended, and eventually disposed of it. Our approach was to imagine products based on engineered nano materials that were technologically feasible and would also have a reasonable chance of surviving a cut-throat economy-products like active food packaging labels that indicated the presence of contaminants; helium-filled balloons with solar cell skins; and materials templated from viruses to generate hydrogen and oxygen from water. We then tried to imagine how these plausible products could potentially release dangerous materials into the environment. To our surprise, we struggled to come up with scenarios that scared us. What we discovered was that placing technological and economic constraints on the products we imagined reduced the chances of exposure to especially harmful materials. In part, this was due to the knowledge we already have on the safe use of engineered nanomaterials. But it was also because, technologically wonderful as engineered nanomaterials are, many of them don’t seem as worrisome as imagined when seen in the cold light of commercial reality. We also found that, for many new materials, good production and use practices go a long way to reducing the chances of harmful exposures. And this is why the case of the nickel nanoparticles above needs to be approached with some caution. Many people have an allergic skin reaction to nickel, and research has shown that inhaling nickel particles can cause people to become sensitized to the metal. It’s also well known that fine powders will become airborne more easily than coarse ones when they’re handled, and that the finer the powder you inhale, the more potent it is in your lungs. So it shouldn’t come as a surprise that handling nickel nanopowder in an open lab without exposure controls is not a great idea. In other words, the reported incident was more a case of bad exposure management than nanoparticle risk. That said, the case does highlight the level of respect with which any new or unusual material should be treated. This was also one of the conclusions from those two days in London. Just because the risks of many nanotechnology products seem relatively small, doesn’t mean that we can afford to be complacent. There’s still the possibility that someone will create a particularly dangerous new material, or will use a material that seems safe in a dangerous way. As a society we need to be vigilant when it comes to advanced materials, whether they are branded with the nano insignia or not. We need to continue investing in the science that will inform the safe development and use of new materials, and to apply every ounce of understanding we currently have to preventing them from causing harm. So far though, with one or two notable exceptions (I wouldn’t advocate inhaling carbon nanotubes for instance), there are surprisingly few in-your-face risk red flags when engineered nanomaterials are developed and used responsibly. That’s good news for nanotechnology safety. But it will only stay good as long as the state of the science on potential risks of new materials keeps pace with materials themselves. This article is part of Future Tense, a collaboration among Arizona State University, the New America Foundation, and Slate. Future Tense explores the ways emerging technologies affect society, policy, and culture. To read more, visit the Future Tense blog and the Future Tense home page. You can also follow us on Twitter.