Exposure to nanotubes may affect the outer lining of the lungs, according to a study by a collaboration of scientists studying the potential health effects of nanotubes on human health.

Researchers at North Carolina State University, the Hamner Institute for Health Sciences and the National Institute of Environmental Health Sciences decided to take a look at what happens when mice inhale nanotubes.

Nanotubes in the lung

What they found was that multi-walled nanotubes could reach the pleura lining of the lungs, which is the area aggravated by asbestos fibers in the development of the cancer mesothelioma.

In the studies, the researchers determined that the inhaled nanotubes travel through the lungs, where they cause a “unique pathologic reaction on the surface of the pleura.”

The infiltration caused a fibrosis that cleared up over three months. So far, the researchers are unable to say what might happen if subjects – mice or humans – were repeatedly exposed to nanotubes.

The mice used in the experiment were exposed to a single inhalation of nanotubes over six hours. The effects on the pleura were only apparent at the highest dose used by the researchers of 30 milligrams per cubic meter (mg/m3). No ill effects were noticed at lower dose levels.

The local reaction in the affected mice began within one day of the inhalation and the fibrosis or scarring began two weeks later, according to Dr. James Bonner, associate professor of environmental and molecular toxicology at NC State and senior author of the study.

While the study could not project any long-term effects, it argues for more knowledge about how nanotubes, which are used in an array of products, from sports equipment to computer and auto components. Carbon nanotubes are extremely strong and also are being studied for use in medical treatments that would enable small sensors or implants to reach otherwise unreachable areas of the body.

But nanotubes have been suspected of doing biological damage because of their thin fibrous structure, similar to the asbestos fibers that cause mesolethioma.

“The major conclusion from this study is that multiwalled carbon nanotubes, once inhaled into the lungs of mice, travel to the pleural lining surrounding the lungs and remain there for weeks,” Dr. Bonner said.

“They also cause some tissue scarring (i.e., fibrosis) at the pleural lining of the lungs. This finding has the most important implications for occupational exposures, where workers might be exposed to carbon nanotube dust. In this case I advise safe handling and for workers to avoid breathing dust containing nanotubes.”

The scientist said he was not immediately concerned about specific consumer products because those that use carbon nanotubes such as carbon tennis rackets and bike frames are likely not a threat because they are “solid packed composites.”

As for the potential of nanotubes incursions into the body to trigger cancer, the study was not definitive.

“It remains unclear whether the pleura could recover from chronic, or repeated, exposures,” Bonner said in a statement. “More work needs to be done in that area and it is completely unknown at this point whether inhaled carbon nanotubes will prove to be carcinogenic in the lungs or in the pleural lining.”

“Inhaled Carbon Nanotubes Reach the Sub-Pleural Tissue in Mice,” was co-authored by Bonner, Dr. Jessica Ryman-Rasmussen, Dr. Arnold Brody, and Dr. Jeanette Shipley-Phillips of NC State, and Dr. Jeffrey Everitt who is an adjunct faculty at NC State; Dr. Mark Cesta of the National Institute of Environmental Health Sciences (NIEHS), Earl Tewksbury, Dr. Owen Moss, Dr. Brian Wong, Dr. Darol Dodd and Dr. Melvin Andersen of The Hamner Institutes for Health Sciences. The study is published in the Oct. 25 issue of Nature Nanotechnology and was funded by The Hamner Institutes for Health Sciences, NIEHS and NC State’s College of Agriculture and Life Sciences.

Deb Lovig’s official title at Cree, the lighting and semiconductor company, is “LED Programs Evangelist.” The description fits. Ask her to pick a favorite project and she’ll name five before you get her stopped. She’ll skip from North Carolina State’s dorm lighting project (see picture, right) to the University of California-Davis’ smart parking garage to Notre Dame’s beautiful acorn-shaped fixtures without taking a breath.

The projects are all part of Cree’s “LED University,” a program that combines the company’s expertise with university situations and helps campuses figure out how to begin evaluating LED lighting projects for themselves. While many organizations know that LED lighting is less expensive and lasts longer than conventional lighting, they aren’t sure where to take it from there. Interior projects? Exterior security? A total campus makeover?

“The biggest issue I see besides price is just not knowing how to start,” Lovig said. “That’s what we’re trying to do, is just get people to get started.”

The motivation is there, certainly. As LED (light-emitting diode) technology continues to develop in brightness and color, it is becoming a darling in the green market. LED devices reduce carbon emissions and energy consumption, and contain no mercury. And they can make a big difference in an electric bill, partly because they consume less energy and partly because they can last for as many as 20-25 years.

Take the South Entry Parking Structure at UC-Davis, for example. You might not think it’s a very exciting project, but Prof. Michael Siminovitch, the director of the university’s Lighting Technology Center, would disagree.

“Parking garages are kind of unique,” Siminovitch said. “Parking garages are pretty intensive energy users because it’s 24/7, and they’ve got some real safety and security issues. LEDs are really suited to smart applications. You can have controls that respond to occupancy.”

The lights in the garage can be set at half-power, increasing to full power when sensors detect people or movement within.

“It’s a real opportunity to demonstrate effectiveness of new technology,” Siminovitch said.

And an opportunity to illustrate cost efficiency as well, considering that lighting accounts for 20 percent of the overall energy use in a building, according to U.S. Department of Energy statistics.

“The numbers that we’ve presented to the vice chancellor, we’re talking statewide about 50 percent savings. And while we usually associate (cost savings) with having to do without, this is not the case. Here it’s not how much lighting, it’s more the quality of the lighting. Lighting that improves safety, essentially.”

From Green Right Now Reports

South Carolina is the latest state to target the harvesting of offshore winds for future energy needs. A partnership of Santee Cooper, the state-owned electric and water utility, along with Coastal Carolina University and the South Carolina Energy Office plans to launch weather buoys that will measure wind off the coast of Georgetown and Little River, S.C. as a first step in what could become an offshore wind farm.

The buoy deployment, which could begin later this month, will be followed by Santee Cooper’s installation of an offshore platform in about six months, project officials said. Coastal Carolina researchers, working closely with counterparts at North Carolina State University, will evaluate the buoy data to help pinpoint the best location for the platform. The offshore wind platform is expected to gather data for at least a year.

Currently there are no offshore wind installations anywhere in the United States, and there are many challenges still to resolve. The two projects announced today will gather data for at least the next 18 months.

“Santee Cooper believes that all reasonable renewable energy initiatives must be explored, and wind energy is a promising opportunity for South Carolina,” Lonnie Carter, Santee Cooper president and chief executive officer, said in a stement. “As a public power company, Santee Cooper is committed to providing South Carolinians with affordable, reliable energy that is protective of our environment. We have been testing wind viability onshore for several years, and the experience has encouraged us to take this next important step.

State officials must still determine how to permit offshore wind turbines, and a separate group will be considering transmission needs. Federal permitting is also under development.

Costs associated with the buoy project are being paid by Santee Cooper and by a U.S. Department of Energy grant administered by the South Carolina Energy Office. Grant money is helping fund Coastal Carolina’s role in the buoy research. Santee Cooper said it will pay for the platform.

“No power company in America is generating offshore wind energy, and very few are exploring its viability,” Carter said. “Santee Cooper is the only public power company, in fact, that is working alongside leading state scientists to prove the viability of offshore wind as a source of electrical generation. And this project falls squarely in line with Santee Cooper’s goal to provide 40 percent of our energy by 2020 through non-greenhouse gas emitting resources, biomass fuels, conservation and energy efficiency.”