Web edition: September 29, 2009
The Environmental Protection Agency issued a news release this afternoon saying that it had “today outlined a new research strategy to better understand how manufactured nanomaterials may harm human health and the environment.” Interesting as that strategy document is, it was hardly hot off the presses.
The 49 page report is dated two months ago. It underwent its initial peer review more than two years ago and the last of four such reviews some 10 months ago. The agency issued a white paper on nanomaterials about four months before that first peer review of its developing “strategy.” So this topic and how to investigate the health and environmental implications of nanoscale pollutants has been percolating for quite some time. Against this backdrop, why did it take the agency so long to make this strategy public?
I put that question to agency spokesman Dale Kemery, this afternoon. “The agency approved this [report] for publication in June.” But when the final PDF came back in early August, it contained embarrassing typos. They were fixed and sent to the printer. A shipment of the final hard copies arrived in late August, but that was still at least three weeks before EPA’s new nanomaterials website — where a virtual copy of the new strategy resides — went live. It took another week (i.e. until yesterday) for the final language of a press release describing the report to win approval. The result: today’s somewhat tardy unveiling.
Of course, the real value of the report is not its time stamp but what’s between its covers. And the strategy blueprint describes the goal of new, coordinated research programs to fill the many gaps in the science of nanoland.
“It takes about 3 to10 atoms to span the length of a nanometer,” EPA notes. By contrast, a smoke particle is about 1,000 nm wide and the diameter of a human hair roughly 20 times bigger still. Nano ingredients have already found their way into a wide variety of consumer products, from high-SPF sunscreens to medicines, appliances, clothing and more.
Indeed, many companies advertise their use of such billionth-of-a-meter-scale constituents as a measure of a product's state-of-the-art status, implying that ultra-small ingredients are an inherently good thing. They aren’t. Nor does size necessarily make these materials worse than others. At this point it's just maddeningly unpredictable what nano things will do.
What worries risk analysts is what might happen if nano stuff gets loose, either in the workplace or the environment. Research has already demonstrated that nanoparticles can be inhaled deeply into the lungs. There, some have a propensity to penetrate cells or move into the bloodstream. These tiny particles can also engage in interactions that inappropriately provoke changes that might alter immunity.
Nearly all of these studies have taken place in test tubes, of course, although some labs have begun evaluating effects in animals.
What research has demonstrated, thus far, is that the ultra-diminutive stature of nano stuff can alter the way a material will behave — in the air, in the bodies of living things or in products. So cataloging just how the activity of nano things departs from that of larger pollutants is a worthy research endeavor. One that EPA is funding plenty of scientists to study. Links to their projects can be found on the agency’s nano-science website.
EPA's research program will focus on seven manufactured (as opposed to natural) nano things: single-walled carbon nanotubes, multi-walled carbon nanotubes, fullerenes, cerium oxide, silver, titanium dioxide and zero-valent iron. “There is no question that the types of, and variations on, nanomaterials is large and growing, and goes beyond the materials [that EPA’s Office of Research and Development] program has chosen for near-term study,” the new strategy document says. But these materials provide a point of departure for this program, “which will evolve together with state [sic] of nanoscience and as environmental decision-support needs change.” (Sounds like a government document, doesn’t it?)
One big challenge, the report says, will be identifying the presence of manufactured nanomaterials in the environment or tissues and then following not only their movements but also any chemical or physical interactions. Technologies to make this stalking behavior possible are only just emerging.
Indeed, the pivotal importance of finding yardsticks to measure these materials and their activities explains a pair of upcoming research conferences — one taking place next week and another five weeks later, both in Arlington, Va. The first: Nanomaterials and the Environment & Instrumentation, Metrology, and Analytical Methods. The second has virtually the same title — you just swap out “the environment” for “human health.”
People who are more interested in what these teensy pollutants seem capable of doing, based on the best-available technology, might want to check out the 116 scheduled nanotox presentations in New Orleans at the Society of Environmental Toxicology and Chemistry annual meeting in mid-November.
McEuen, P.L. 2000. Single-Wall Carbon Nanotubes: Nanotubes are ideal systems for studying the transport of electrons in one dimension, and have commercial potential as nanoscale wires, transistors and sensors. Physics World (June):31. [Go to]
NIOSH Science Blog. 2009 Nanotechnology: Human and Environmental Exposure Assessment of Nanomaterials Workshop. Centers for Disease Control and Prevention (March 30). [Go to]
Morris, J., R. Wentsel, et al. 2009. Nanomaterial Research Strategy. Environmental Protection Agency report: 620/K-09/011 [Go to]