By: Michael Heintz, Senior Specialist, Environmental Laboratories, APHL
This is the first of a two-part post addressing nanotechnology and the potential implications on public health. First things first… what is nanotechnology?
If you’ve read Michael Crichton’s Prey, or you just like to keep up with the newest technology, you’ve probably heard about nanotechnology. If you’ve not gotten that far down your reading list, or don’t look for the newest gadgets, then maybe this is a new term. But not for long.
While there is no one agreed upon definition for “nanotechnology,” the National Nanotechnology Initiative, a collaborative of 25 federal agencies, defines it as “science, engineering, and technology conducted at the nanoscale, which is about 1 to 100 nanometers.” When simplified, the common definition is purposefully-created materials with at least one dimension between 1 and 100 nanometers.
To put the scale in perspective, human DNA measures 2.5 nanometers in diameter while a gold atom is 1/3 of a nanometer in diameter. Or, put another way, a single-walled carbon nanotube, which is 1 nanometer in diameter, is 100,000 times smaller than the diameter of a human hair (see Figure 1 for a description of the scale).
Nanomaterials fall into three major groups. There are naturally occurring examples, like Halloysite clay and volcanic ash. Metalworking operations (like welding) and even cooking form nanoparticles. However, this conversation focuses on the third category: those engineered or purposefully manufactured.
What makes nanomaterials special is that we can control how materials interact at the atomic and subatomic levels, or quantum realms (stick with me here… I promise this won’t turn into a physics lecture). Essentially, we can control materials at the electron level.( If you want to learn more about the physics, there are many resources.) Scientists manufacture nanomaterials in a variety of ways, including etching from larger forms and “self-organizing” where particles conglomerate to form the sought-after material.
At these small scales, materials behave differently from macro-sized counterparts. Carbon, for example, becomes very lightweight and strong—making it useful for items like baseball bats and boat hulls. Gold does not appear yellow, but rather red or purple making it a useful biological marker. Sunblock contains nanoscale zinc and titanium dioxide, which applies clear, not white. While silver, one of the longest used nanomaterials is a highly-effective antibacterial coating.
Nanomaterials already appear in over 1,000 consumer products (yes, I have one of the bats) and the National Academy of Sciences estimates as of 2009, nanomaterials were a $225 billion industry for product sales alone. Despite this increased availability, there is a significant concern about the potential health and environmental impacts related to their use.
Part 2 of this series will address implications of nanomaterials on various parts of public and environmental health.