Soil lead and blood

There's always a little lead in the soil, but sometimes there's way too much--and it gets into the kids. The soil is much harder to deal with than walls or floors, and the safety limit for soil is "37 times higher" (or 151 for the new interior standard) than for floors. That's probably not unreasonable. But.

"In August 2005, Hurricane Katrina flooded 80% of New Orleans, thereby creating a unique natural experimental condition not ethically possible by any scientific standard.. Ten years after Katrina, the same research team was reinstated to remap New Orleans"

Yep. Lead levels dropped in the soil, and in the kids--a factor of 2.63! (They used the same census tracts to compare apples and apples.) But, of course, it wasn't just the soil. The population wasn't quite the same, and the cleanup sometimes involved repainting. And the stuff that gets picked up may be superficial, so if you can clean up the first few inches you probably cut down on the dust and subsequent transfer by a lot.

Before you ask: phytoremediation is hard. "despite some promising preliminary studies of sunflowers’ phytoextraction of lead, more extensive research has been disappointing. Since the 1990s, plants, including sunflowers, have been shown to increase accumulation of lead when a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), is added to the soil. Although the additive raises lead's solubility in the soil, EDTA is extremely expensive. Moreover, EDTA works in combination with other soil practices, such as adding compost, which are proven, cost-effective responses on their own."

"That said, another type of phytoremediation, called phytostabilization, does work. With phytostabilization, soil amendments are added, and the contaminant is sequestered, diluted, and prevented from becoming bioavailable. “The ability to phytostabilize lead is very strong and well demonstrated,” Chaney says. “Most lead problems can be solved by treating the soil with phosphate, limestone, and organic matter.”