Nature Healing Itself
Air Date: Week of January 12, 1996
Commentator Ruth Page has words on the wisdom of plants to restore themselves from damage.
CURWOOD: As we all learned in science class, to every action there is an equal and opposite reaction. Nowhere is that more evident than in what we like to think of as technological progress. New technology often leads to unanticipated ecological damage, which leads to a seemingly endless effort to repair that damage. But as Living on Earth commentator Ruth Page notes, in their search for solutions scientists are learning that nature may already have the answers.
PAGE: Ever thought of saying to a batch of plants, okay you guys, get the lead out? Me either, but in fact many plants can absorb heavy metals from soil, slurping them up into their stems and leaves which can be harvested and destroyed. Fitotech Company of New Jersey is using plants, especially Indian mustard, to pull chromium out of the state's soil. Around Chernobyl, mustard plants are cleaning up radioactive strontium and cesium left over from the nuclear plant's near-meltdown.
Various plants, even corn and tobacco, can absorb heavy metals. But Indian mustard will ingest lead, cadmium, chromium, nickel, zinc, and copper. So it's widely usable in contaminated areas. Where 3 plantings in 1 year are possible, mustard can soak up 6 metric tons of lead from a 2-and-a-half acre area. To dig up and haul away 1 acre of contaminated soil costs about $400,000, and you still have the dirty soil. Indian mustard treatment costs only a fourth as much.
Sunflowers can absorb heavy metals into their roots but can't raise them up into their stems, so they're used to leach metals out of contaminated water. In Ashtabula, Ohio, sunflowers are drinking the uranium out of water at an atomic bomb plant. Some of the filthiest soil on earth lies in Kuwait, where the 1991 Gulf War left pools of oil, which is toxic to plants, hither and yon in the desert. To scientists' surprise, plants are reappearing in oil-soaked areas. How come? These particular plants, because they lie in oily soil, attract bacteria that love oil. When researchers pull up a plant, its roots are clean, though there may be an oily color on it above ground. Tests show that a family of bacteria called arthrobacter provides the best clean-up crew.
Corn, barley, wheat, tomatoes, and at least one legume thrive in the oily soil, though they are shorter than normal. With their bacterial partners they work rapidly and cheaply. Once they've slurped at the oily goo up into their stems and leaves, the plants can be gathered and disposed of. While it's the oil alone that attracts petroleum-eating microbes, sugars, vitamins, and oxygen from the plants make them much more efficient. And because they grow in desert, we know this system can work in extreme conditions. There may be only one thing cheaper in the long run than using bacteria and plants to clean up the filth we spew into the earth. That is to dump a lot less in the first place.
CURWOOD: Living on Earth commentator Ruth Page lives and writes in Burlington, Vermont. She comes to us from Vermont Public Radio.
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