Lead in Urban Gardens

Today's NY Times has an article about lead in urban gardens.

Soil is likely to contain high levels of lead if it is near any structure built before 1978, when lead-based paint was taken off the market, or if a building of that vintage was ever demolished on the site.

Soil with a pH level above 7 binds with lead, making it less likely to be absorbed by plants and the human body if the dirt is inadvertently inhaled or ingested.

But some experts advise planting greens, specifically Indian mustard and spinach, for a couple of seasons as phytoremediation, or plant-based mitigation, before growing crops intended for food. By growing spinach for three months, researchers at the University of Southern Maine lowered the lead count in one garden by 200 p.p.m. Of course, the lead-leaching crop cannot be eaten or composted and must be disposed of as toxic waste.

For Urban Gardeners, Lead Is a Concern - NYTimes.com