There's no way this is promoted enough. Yahoo! News reports on a University of Washington study that poplar trees pull contaminants out of groundwater. Kudos to Sharon Doty, an assistant professor of forest resources at the University of Washington. Her study on the trees appears in the Proceedings of the National Academy of Sciences, and it's made it to the mainstream media.
This article targets "genetically modified plants" as toxin busters. What about all the great advantages of any old plant? Who's talking about that?