There have been quite a few article of late about the White House lawn having elevated levels of lead that could adversely affect Michelle Obama’s garden. On one hand, we have the Huffington Post coming down here on the side of caution, taking up Mother Jones’  message that that the land was contaminated by sewage sludge (and from the days of leaded gasoline) and ought not be used for gardening.  On the other, the weblog Obama Foodorama presents counter-arguments by scientists who point out that the lead level in the White House lawn is far below that of many urban soils, and that the crops grown in the White House garden have a low propensity for incorporating lead into edible plant parts, such as peas.

That leaded gasoline from years ago may have contributed to lead in White House soil is a reasonable assertion.  (Getting the lead out of our gasoline is an interesting story–it wasn’t easy to get the gasoline companies to remove it, despite the rather miniscule cost of doing so.)  But Mother Jones is all wet when they say, in terms of helping learn whether sewage sludge or leaded  gasoline was the “culprit”:

Of course, it won’t be possible to know the background lead level on the South Lawn unless someone sampled it before sludge was applied

That’s not true.  Lead levels could be checked in soils near the White House, such as at Lafayette Square, across the street, for example.  Such results would give a handle on whether sludge products purposefully incorporated into White House soil led to the lead in the lawn’s soil.

We also should learn, and teach about, what sort of sampling was done to test the White  House soil.  Was it a single, grab sample, a number of grab samples, or was it a composite sample (produced by mixing a bunch of grab samples) that was analyzed?  And what of retesting, to be certain of the data?

The other teachable moment here, besides looking more carefully at sampling methods and other, nearby soils, is to analyze the edible portions of the vegetables the Obamas are growing.  It would easy to have a lab analyze some peas and lettuce from the garden for lead, to learn what the actual exposure would be from eating vegetables from this garden.

I would be happy to go and have a beer at the White House to discuss these approaches over a picnic lunch.


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