Actually, contaminated soil must go either to an incinerator or more likely any of a number of licensed hazardous waste disposal facilities, all of which are closely monitored for leachate while the petroleum components degrade anaerobically.Like the soil remediation stupidity when then clean contaminated soil at decommissioned gasoline stations. They just haul it.somewhere, toss it like.compost and let the fuel vent into the atmosphere faster than it would have in it's original location. Then haul it back and dump it in the hole it came from.
Shuffling deck chairs.
As for copper loading, the rate can affect acute toxicity.