News that Michelle Obama's much touted White House vegetable garden is contaminated with lead comes as no surprise to me. A few years ago we were developing a London brownfield site adjacent to a large council allotment with scores of plots. To the west of the site a number of light industries had flourished until the 1950s. When we got the results of the ground investigation, we found the soil heavily contaminated with Cadmium, Arsenic, Mercury and Lead - heavy metals that fell out of the factories' smoke plumes most rapidly - and that the contamination was a long teardrop shape stretching eastwards, driven by a prevailing westerly wind. Straight across the allotments.
This is also why I'm also pretty sure that whatever comes out of the new Buckingham Palace 'allotment' will end up in the tourist cafe or in staff meals rather than on the royal plate. For the upper classes who maintained both a country estate and a town house, it was the job of the country house kitchen garden and hothouses to produce healthy fare for the table; town houses rarely had their own kitchen gardens.
While I'm quite happy to use the fruit and herbs from my small London garden, I wouldn't want to eat spuds or carrots or other root veg from it in any great quantity. Fresh horseradish root is the exception - the first of the big Autumn roasts wouldn't be the same without the nose-streaming torture of grating fresh horseradish sauce.
The only reason I'd take a local allotment plot would be to grow tobacco on. In fact, for the sake of putting two fingers up to the council, I think I'll put my name down ...