Scientists are interested in using metal hyper-accumulating plants as a means to clean up contaminated brownfield sites. Researchers believe that soil polluted with heavy metal or radioactive materials could be cleaned up by using crop plants that could absorb the material. This process is called bioremediation, or more specifically when using plants, phytoremediation.
"Imagine if you have a site contaminated with cadmium. Right now your options are to put a fence around it and put a sign up telling people to stay out, build a parking lot over it, or dig up all of the soil and truck it to a landfill, which is very expensive," Salt said. "The idea would be that you could take plants that accumulate metalyou could essentially farm the metal out of the ground. Over five or ten years, by growing crop rotations there, you could remove the metal from the site. The nice thing is that it's cheap, and you're left with a soil at the end of it which could be used for other things."
Salt says the metal hyper-accumulating plants found in nature would not be used for phytoremediation because they are all small and slow growing. Instead, scientists could move the genes Salt and his colleagues have identified into fast growing, large plants, such as grasses.
Another benefit of Salt's work could be functional foodsfoods that contain micronutrients missing from diets in certain areas. Metals are essential nutrients in small doses, but some regions of the world lack foods that contain sufficient levels of these micronutrients, which causes severe health problems. Using the genetic tools Salt and his colleagues have identified, scientists could begin to bioengineer foods that contain these essential micronutrients.
A third application of the research would be for improved crop nutrition. "Instead of adding zinc to the soil because you live in a zinc-deficient region, why not have the wheat plant itself be more zinc-efficient so that you can reduce agricultural inputs?" Salt asks.
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