Narrator: This is Science Today. The element selenium is a toxic pollutant all over the world, wherever there's heavy industry or agricultural runoff containing pesticides. Biologist Norman Terry of the University of California, Berkeley is looking at ways to make selenium harmless by planting artificial wetlands, or swamps.

Terry: In a wetlands situation there are both microbes and plants which are capable of taking up inorganic selenium and converting it into a relatively non-toxic gas. And if we can speed up that process and make it more efficient, it may be possible to completely remove selenium from the ecosystem so it moves up into the atmosphere and completely from the site. Without going into the food chain.

Narrator: The process of turning selenium into a gas is called volatilization. In one series of experiments, scientists in Terry's lab genetically engineered the Indian mustard plant, which volatilizes selenium naturally.

Terry: And we hope that these genetically engineered plants may be able to volatilize selenium more efficiently.

Narrator: For Science Today, I'm Steve Tokar.