HOUSTON, Oct. 4, 2005 ‹ Using a method for assessing the premiums that companies pay for insurance, a team of scientists and insurance experts have concluded that the manufacturing processes for five, near-market nanomaterials ‹ including quantum dots, carbon nanotubes and buckyballs ‹ present fewer risks to the environment than some common industrial processes like oil refining. For two of the nanomaterials ­ nanotubes and alumoxane nanoparticles ‹ manufacturing risks were comparable with those of making wine or aspirin.

The study is available online and slated for publication in the Nov. 15 issue of Environmental Science and Technology. It compares the environmental and health risks associated with the production of five nanomaterials ‹ single-walled carbon nanotubes, buckyballs, zinc selenide quantum dots, alumoxane nanoparticles and titantium dioxide nanoparticles ‹ with the risks of making six commonplace products ‹ silicon wafers, wine, high-density plastic, lead-acid car batteries, refined petroleum and aspirin.

³There are many unknowns about the impacts of nanomaterials on living organisms and ecosystems, but a great deal is known about the properties of the materials that are used to create nanomaterials,² said study co-author Mark Wiesner, professor of civil and environmental engineering at Rice University. ³Our goal was to produce an early estimate of the environmental Œfootprint¹ for nanomaterials fabrication.

³The jury is still out on whether some nanomaterials pose a risk, but it is not too early to consider how we might avoid environmental and health risks associated with making these new materials,² Wiesner said. ³We have a narrow window of opportunity to guide the emerging nanomaterial industry towards a green future. With this study, we hope to establish a baseline for the safe, responsible development of the nanomaterials manufacturing industry.²

In developing their risk assessments, the research team developed a detailed account of the input materials, output materials and waste streams for each process. Risk was qualitatively assessed for each process, based on factors including toxicity, flammability and persistence in the environment.

Using an actuarial protocol developed by the Zurich-based insurance company, XL Insurance, the researchers developed three risk scores for each of the 11
processes: incident risk, which refers to in-process accidents; normal operations risk, which refers to waste streams and airborne emissions; and latent contamination, which refers to the potential for long-term contamination.

Wiesner said the incident risks for most of the nanomaterials were comparable or lower than those of non-nanoprocesses.

³That doesn¹t imply that the non-nano processes present an acceptable level of risk, or that there is no room for improvement across the board, but the study does suggest that the risks of making these new materials will not be drastically different from those we encounter in current industries,² he said.

For example, the incident risks associated with alumoxane and nanotube production fell near or below the scores for wine production. Buckyballs had the highest incident risk rating among nanomaterials and scored near the risks associated with producing polyolefins, a broad class of polymers like polyethylene that are used in making plastics.

The normal operations risk scores for nanotubes and alumoxanes were comparable to those of wine and aspirin making, while the scores for buckyballs, quantum dots and titanium dioxide were comparable to the operations risks of making silicon wafers and car batteries. The normal operations risks associated with plastics and petroleum refining were greater than those for any nanomaterial.

For all of the nanomaterials except buckyballs, latent risk scores were comparable to those of silicon wafers, wine and aspirin production.
Buckyballs had a latent score comparable to car battery and plastics production and considerably lower than the score for petroleum refining.

³We can¹t anticipate all of the details of how nanomaterials fabrication will evolve, but based on what we do know, the fabrication of the nanomaterials we considered appears to present lower risks than current industrial activities like petrochemical refining, polyethylene production and synthetic pharmaceutical production,² said Wiesner.

Co-authors on the study include Rice doctoral student Christine Robichaud; sustainability researcher Dicksen Tanzil of Bridges to Sustainability; and Ulrich Weilenmann of XL Insurance.

The research was funded in part by the National Science Foundation, and by the Environmental Protection Agency.



Rice University is consistently ranked one of America¹s best teaching and research universities. It is distinguished by its: size‹2,850 undergraduates and 1,950 graduate students; selectivity‹10 applicants for each place in the freshman class; resources‹an undergraduate student-to-faculty ratio of 6-to-1, and the fifth largest endowment per student among American universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work. Rice¹s wooded campus is located in the nation¹s fourth largest city and on America¹s South Coast.

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