CMU to study the hazards of nanoparticles

Akanksha Vaidya Sep 29, 2008

The advancement of technology has always affected the environment, often adversely. Techniques to counteract those negative effects and to promote sustainable development are usually employed only after it is too late. In order to prevent this from happening again, the Center for the Environmental Implications of NanoTechnology (CEINT) was established as a collaboration between four universities, including Carnegie Mellon University.

Since the field of nanotechnology is still new, sustainable development of the nanotechnology industry right now will prevent mankind from regretting this new technology in the future.

Headquartered at Duke University, the center consists of four core universities including Duke, Carnegie Mellon, Howard University, and Virginia Tech. Faculty from the University of Kentucky and Stanford University are also involved.

The center aims to understand the impacts of nanoparticles on the environment. As reported in the Pittsburgh Tribune-Review last week, the center plans to develop 32 controlled ecosystems called “mesocosms” in the Duke Forest in Durham, N.C. The report further stated that the ecosystems will serve as “laboratories” where the researchers can study the effects of nanoparticles on different ecosystems.

Testing nanoparticles on different ecosystems is just one aspect of what the center aims to do.

The center will also explore the transport and transformations of nanoparticles in the environment and also the effects that microorganisms have on the nanoparticles. This is where Carnegie Mellon comes into the picture.
Gregory Lowry, an associate professor of civil and environmental engineering and also the deputy director of the center, explained Carnegie Mellon’s role; “Carnegie Mellon’s part of this is [studying the] fate, transport and transformation of nanomaterials in the environment.”

Studying how nanoparticles are transformed and transported in the environment is important, as nanoparticles do not follow the same rules that bulk materials do.

“The whole reason that we’re using nanomaterials is because their properties are different from the bulk properties,” Lowry explained.

“If I make [a bulk material] small enough, the surface properties are going to change, there are changes in crystal structure, there are changes in surface energy, [and there are also] changes in the number of reactive sites on the particles.”

Since such nanomaterials are used very often in commercial products now, it is important to know what happens after these are exposed to the environment. Lowry mentioned the use of silver nanoparticles in items of daily usage like socks, washing machines, and water filters. When items such as socks get washed, the nanoparticles get washed down the drain and eventually enter the environment. In the course of this transport, the nanoparticles undergo a variety of transformations.

The particles can undergo chemical transformations due to oxidation-reduction reactions, they can be transformed by microorganisms, and they can also undergo physical transformations by attracting other nanoparticles and forming a larger particle.
All these transformations can drastically change the properties of the nanomaterials and could perhaps increase their toxicity. “We have to understand how chemical, biological, and physical transformations occur and then how those impact transport in the environment,” Lowry said.

He added that these studies would help interpret the observed effects of the nanoparticles on the artificially created ecosystems.
“There is no way for us to interpret that data unless we have the fundamental understanding of fate, transport, and transformations of the nanomaterials. We will conduct [such experiments] largely at Carnegie Mellon University,” Lowry said.

Carnegie Mellon has a couple of projects focusing on the theme of fate, transport, and transformation of nanoparticles.
Assistant professor of civil and environmental engineering Kelvin Gregory leads one such projects, which will focus on the biological transformations of nanoparticles.

Specifically, the group plans to study how microorganisms affect nanoparticles in the environment.

Since such studies have not been conducted until now, the researchers have no idea what results to expect.

“[Microorganisms] aren’t necessarily going to be intensifying any hazards. They could be ameliorating them as well. But there is no doubt that the interactions of nanomaterials and microorganisms are going to affect the fate, transport and toxicity of nanomaterials,” Gregory said. Gregory explained that the transformations due to microorganisms could enhance or lessen the toxicity of the nanoparticle and could prevent or ease the transport of nanomaterials into the environment. The team currently has no answers to these questions, but hopes to find them very soon.

This research that Carnegie Mellon is doing is part of the bigger picture of developing the nanotechnology industry in an environmentally friendly way.

“We’re going to develop some design rules for nanomaterials to make them environmentally benign. [We aim to] maximize benefits and minimize risks,” Lowry said.

The center aims at developing sustainable techniques before the field gains momentum, so that the new technology does not run amok. “We’re trying to avoid the pitfalls of very rapid growth of new technology, such as the burning of fossil fuels, now years and years later causing an effect in the accumulation of greenhouse gases,” Gregory said.

As reported in the Pittsburgh Tribune-Review, the center was awarded a $14.4 million grant by the National Science Foundation and the United States Environmental Protection Agency. The official opening ceremony of the Center for the Environmental Implications of NanoTechnology was held on Sept. 26.