I remember a longtime ago, hearing of how waste
water from olive oil production, which is highly toxic and very damaging to the environment, was being cleaned using a water loving grass of some type. Not sure what the particular grass was and I can't find anything through google about it. Obviously there are plants that will tolerate pollutants and some that may help clear them from the soil. whether they just trap them or actually convert them?
Unleaded fuel is as much a problem as leaded fuel from a pollution point of view and diesel is terrible.
If you are worried about ground pollution, then build raised beds from new
compost. Air pollution will be hard to avoid so close to a road.