Soil Contamination

Okay, I watched a Youtube video the other day that has me all freaked out about the prospect of soil contamination.  (It’s a fun watch about an urban farmer; the lead issue was just a side note.  Check out http://www.youtube.com/watch?v=8yYO4L2vegE.)  My husband had just agreed to help with the sod cutter to help me skip the extra work of the raised beds, too!  Ugh.  How much due diligence do I need to give this issue since I’m gardening among old houses that were built during the days of widespread lead and asbestos usage?  We had a lead poisoning scare with one of my little ones early on by a false read on a blood test.  They found nothing of major concern in our home and admitted that most kids with high lead levels in their blood have something obvious, like a fan blowing an inch of lead filled dust over their sleeping area.  So, even if there is a little lead in my soil, is it anywhere close to the level that would leech into the plants and cause poisoning through leafy vegetables?  My gut reaction is no way, but I’m a bit cautious on such things (some might call me a worrier), so I’m definitely rethinking the plan and leaning toward raised beds again.