Critics of nanotechnology have fastened onto speculation by Sun Microsystems co-founder Bill Joy about runaway nanobots turning the planet into "gray goo," tainting the technology in all its forms. Now, cooperating engineering teams at the Georgia Institute of Technology and Rice University are angling to find out if that's so. Their preliminary results in measuring the behavior of nanomaterials in the environment show that the threats are real, but so is the hope of preventive solutions. A detailed study by the Georgia Tech and Rice researchers reveals that fullerene, one of the first nanomaterials, could threaten water supplies if not handled properly. In particular, nanoscale fullerenes were found to clump together in groundwater to form larger, micrometer-scale particles that could accumulate, gray-goo style. The researchers also found that saltwater broke up the clumps as well as various preparation steps that could be mandated by government regulators. "To look at a material's potential as a pollutant, how to minimize its environmental impact and make the industry sustainable is really the right thing to do," said John Fortner, a Georgia Tech research scientist and a Rice University doctoral candidate. Fortner performed the work with Joe Hughes, chairman of the Georgia Tech School of Civil and Environmental Engineering, under the auspices of the Rice University Center for Biological and Environmental Nanotechnology.