Monona, et al.,

The "Boston EPA" results almost certainly came from the EPA Region 1 lab in Bedford, and I'll bet were done by Dr. Tom Spittler.  I did a sabbatical with him in the 1990s, and learned a lot.  Some community agency planning a garden on some of its property had brought a soil sample to him for a "routine check."  He found astronomically high levels of Pb, and communicated his serious concerns re a garden there.   He went on to document excess lead in countless other places, but alas I don't have a specific reference to a publication.  Hopefully the name, and the affiliation as Jim said  will be helpful.  

One irony of all that work was that the safety officer at the site pointed out that of course, no part of any of the samples he had received over the yearsÑand there were drums of them by the time I arrivedÑcould be disposed of as trash since they were of course hazardous waste.  [We won't think about 90-day limits because of course they might be used for something. ..].  Then came NIST [National Institute of Standards and Technology] to the rescue: would he please send them all the lead-contaminated soil he could muster, so they could use it to prepare an SRM [Standard Reference Material]  for sale to meet the burgeoning demand?  

As another list member has pointed out, lead contamination is ubiquitous.  I painted houses for a living for several years, and can attest that not only chips, but dust, as from when we used electric sanders, traveled far.  In fact, on a windy day and with a taller building, we had to ask people to move their cars from our side of the street, because the Pb-contaminated spatters had sometimes been so visible that litigation ensued.  Dr. Spittler once told me that the half life of Pb in soil is 2000 yr.   My students quantified it many years after it was banned in gas and paint.

Re the original post:

1.  I would think that your workers exposure would be minimal, and 

2. Since most cars still use lead batteries, those sheets should be a marketable commodity on the scrap market. 

Good luck.

Steve Stepenuck

And eating veggies from urban home gardens.  do you have a year or other identifier for that article.  Like to get a copy.