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Sludge Tested As Lead-Poisoning Fix
"There are potential pathogens and chemicals that are not in the realm of safe," Burke told the AP. "What's needed are more studies on what's going on with the pathogens in sludge _ are we actually removing them? The commitment to connecting the dots hasn't been there."
That's not what the subjects of the Baltimore and East St. Louis research were told.
Rufus Chaney, an Agriculture Department research agronomist who co-wrote the Baltimore study, said the researchers provided the families with brochures about lead hazards, tested the soil in their yards and gave assurances that the Orgro fertilizer was store-bought and perfectly safe.
"They were told that their lawn, as it stood, before it was treated, was a lead danger to their children," said Chaney. "So that even if they ate some of the soil, there would not be as much of a risk as there was before. And that's what the science shows."
Chaney said the Baltimore neighborhoods were chosen because they were within an economically depressed area qualifying for tax incentives. He acknowledged the families were not told there have been some safety disputes and health complaints over sludge.
"They were told that it was composted biosolids that are available for sale commercially in the state of Maryland. I don't think there's any other further disclosure required," Chaney said. "There was danger before. There wasn't danger because of the biosolids compost. Composting, of course, kills pathogens."
The Baltimore study concluded that phosphate and iron in sludge can increase the ability of soil to trap more harmful metals including lead, cadmium and zinc. If a child eats the soil, this trapping can let all the material pass safely through a child's system.
It called the fertilizer "a simple low-cost" technology for parents and communities "to reduce risk to their children" who are in danger of lead contamination. The results were published in Science of the Total Environment, an international research journal, in 2005.
Another study investigating whether sludge might inhibit the "bioavailability" of lead _ the rate it enters the bloodstream and circulates to organs and tissues _ was conducted on a vacant lot in East St. Louis next to an elementary school, all of whose 300 students were black and almost entirely from low-income families.
In a newsletter, the EPA-funded Community Environmental Resource Program assured local residents it was all safe.
"Though the lot will be closed off to the public, if people _ particularly children _ get some of the lead contaminated dirt in their mouths, the lead will just pass through their bodies and not be absorbed," the newsletter said. "Without this iron-phosphorus mix, lead poisoning would occur."
Soil chemist Murray McBride, director of the Cornell Waste Management Institute, said he doesn't doubt that sludge can bind lead in soil.