A long 2-page MUST READ article if you garden in an urban area or you have kids:
America's Real Criminal Element: Lead
While the article revolves around the astounding relationship between the rise and drop of crime corresponding to the use of leaded gasoline and paint, this is important to gardeners and people with young kids because the lead does NOT go away.
I have not heard anything at all about lead abatement programs and that's shocking considering these numbers:

… Mielke has studied this in New Orleans, and it turns out that the numbers go up very fast even at low levels. Children who live in neighborhoods with a soil level of 100 ppm have average blood lead concentrations of 3.8 ?g/dL—a level that's only barely tolerable. At 500 ppm, blood levels go up to 5.9 ?g/dL, and at 1,000 ppm they go up to 7.5 ?g/dL. These levels are high enough to do serious damage.

“I know people who have moved into gentrified neighborhoods and immediately renovate everything. They create huge hazards for their kids.”

Mielke's partner, Sammy Zahran, walked me through a lengthy—and hair-raising—presentation about the effect that all that old gasoline lead continues to have in New Orleans. The very first slide describes the basic problem: Lead in soil doesn't stay in the soil. Every summer, like clockwork, as the weather dries up, all that lead gets kicked back into the atmosphere in a process called resuspension. The zombie lead is back to haunt us.
Mark Laidlaw, a doctoral student who has worked with Mielke, explains how this works: People and pets track lead dust from soil into houses, where it's ingested by small children via hand-to-mouth contact. Ditto for lead dust generated by old paint inside houses. This dust cocktail is where most lead exposure today comes from. …

Fortunately we garden on virgin land way out in the desert and we don't have to worry about lead.  However, I've been looking for an inexpensive way to test plants for metals and toxins just to be on the safe side and I'd really like to test some of the supermarket and farmers market food.
Please let me know of a lab doing affordable plant / veggie testing!