The Gray Goo Scenario and Environmental Contamination

While nanotechnology has great promise for a variety of “environmentally friendly” products and processes, it is also possible that these applications will have unintended consequences. Desirable properties of nanomaterials such as high surface reactivity and the ability to cross cell membranes in the human body could potentially have negative consequences if nanoparticles go where they are unwanted.

One of the most popularized fears about nanotechnology involves the notion of molecular manufacturing. Molecular manufacturing has been promoted by Eric Drexler, one of the world’s most outspoken nanotechnologists. He differentiates molecular manufacturing from conventional nanotechnology applications by emphasizing the ability to self-replicate. While molecular manufacturing has great promise, it also has potentially negative consequences, as Drexler has frequently commented.

The so-called ‘gray goo scenario’ is an imagined scenario where self-replicating nanobots spread uncontrollably and create a gigantic mass of gray goo. This dystopian disaster scenario was popularized by Bill Joy in a popular article in Wired magazine in 2000 and in Michael Crichton’s 2003 science fiction novel Prey. In April 2003, even England’s Prince Charles weighed in on the possibility of a gray goo future when he publicly raised concerns about the potential environmental dangers of nanotechnology. However, researchers in the field argue that such a scenario is highly unlikely and these “technology out-of-control” disasters are not possible in the near future.

Beyond the gray goo scenario, there are a number of near term environmental concerns with nanotechnology. One present unknown is the exposure of factory workers and consumers to nanoparticles either during production processes or normal consumer use. For example, when you wear a pair of stain resistant pants created with nanomaterials, is it possible for nanoparticles to travel through the air and eventually get into your lungs? Because of their size, exposure routes for nanoparticles are greatly increased and they can effectively pass through barriers (i.e. human skin) that normal materials cannot and enter the bloodstream more readily. Further, detection of nanomaterials will be impossible until highly sensitive equipment is also developed.

In addition to direct exposure to nanoparticles, it might be possible for nano materials to contaminate soil and water similar to conventional chemicals in the past. The concentration of artificially produced substances in the environment increases in direct proportion to their use in society, and this will undoubtedly be the case as nanomaterials are introduced to the market and widespread use becomes common. With increasing levels of nanomaterials in water and soil come increased exposure opportunities for all living things, whether they use these products or not. To date, only a few nanotechnology products are on the market and thus, the near-term environmental risks are probably not that great. However, as these materials are manufactured more frequently and disseminated into the public, the potential for environmental impacts will increase.

Further Reading:

• Colvin, Vicki L. 2003. The potential environmental impact of engineered nanomaterials, Nature Biotechnology 21(10):1166-70.
• Joy, Bill. 2000. Why the future doesn't need us, Wired 238-62.