From post on Sustainable Cities Collective:
"Urban garden owners can do a few things. First, they should test the soils in a variety of places for the metals and other compounds mentioned. Second, if they discover the site 'exceeds toxic levels,' they should 'cover a site with clay soil, remove localized hot spots, use raised beds with clean soils, or add vertical or hydroponic gardens.' Gardeners can also go up and add a farm on their roof. Any of these solutions can be extremely productive."
"Beyond the food that is consumed from these sites though, the E.P.A. is concerned about the potential health impacts for someone touching, inhaling, and accidentally eating contaminated soils every day. We are creating stringent soil standards to determine acceptable exposure rates. While these standards may end up 'ruling out many potential brownfield sites, at least gardeners will be kept safe."