Nanotechnology is pretty amazing. Soon we might have molecule-sized vehicle that can travel through the bloodstream, and deliver medicine right to diseased cells.

Amazing, but also kind of troubling.

Think about it this way. In our history, we tend to rush into new technologies without considering the possible consequences. People started using coal without thinking about how it might pollute the air. Industries used new chemicals and dyes without thinking about how they could pollute groundwater. Now we're getting all excited about things like carbon nanotubes. Do we have any idea how nano- materials could affect the environment?

In some ways we have learned from past mistakes. For instance, environmental engineers at the Georgia Institute of Technology have been testing how carbon nanotubes behave in river water, and what they found was pretty surprising. We know that, typically, nanotubes don't like water. IIf you were to put a bunch in a test tube and they tend to clump together and sink to the bottom. However, when the researchers put them in river water, that didn't happen.

Organic material in the water caused them to float around and spread out. Now, this doesn't necessarily mean that carbon nanotubes would pollute natural waters like rivers and oceans. In any case, nanotubes aren't yet in wide enough use to make this a real concern at the moment.