Changing Brown to Green

ECOTRENDS

Shuttered industrial operations often leave behind land poisoned with toxic substances, particularly lead and mercury. These "brownfields" are now being rehabilitated using nature's own cleaning crew: plants and microbes. Phytoremediation and bioremediation, as these processes are called, not only make the sites safer; they are reclaiming the land for ecologically vital open spaces and even urban farms.

In the past, most brownfield sites simply deteriorated into eyesores. A few were "capped and covered"; that is, turned into parking lots and the like. At best, the contaminated soil was excavated and replaced with clean fill.

Now, carefully selected plants and microbes are used to extract, filter, or bind up toxins in the soil. In Hartford, Connecticut, for instance, at the site of a former paint store, students from Trinity College used mustard plants to extract lead from the soil. A garden and a soup kitchen turned the space back into a valuable community asset, says Diane Kelley, the EPA's brownfields coordinator for New England.

Mustard is one of the most commonly used plants in brownfields, as are poplar and willow trees. The trees are effective because they "grow rapidly, have many and deep roots, and take up large quantities of water," report Lynne M. Westphal and J. G. Isebrands (now retired) of the USDA Forest Service.

Cleaning up brownfields can be a valuable mechanism for slowing urban sprawl and preserving farmland, says Julie Bargmann, associate professor of landscape architecture at the University of Virginia. "These sites can be regenerated into ecologically productive landscapes," she says. "Brownfields are our new frontier."

For information on the EPA's community grant program, go to epa.gov/brownfields.

PHOTO (COLOR): Tired site: Abandoned factories are being turned back into safe even productive land.

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By Zizel Lovén

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