Dear Dr. James:

My chemistry prof at UBC almost 30 years ago was a Dr. James ...

A friend (yes, really) recently purchased a 5-acre country property which had been used for decades by a man who was in the roofing business. The man had evidently disposed of his surplus asphalt shingles and other roofing waste, both new and removed from clients houses, by dumping it on the property. Another method was by burning it (on the property).

My friend has removed a dozen truckloads of garbage, but has encountered stacks of old asphalt shingles among which large (6 metre) trees have grown up. He's thinking that the lesser evil at this point may be simply to leave them alone, or to cover them over with some clay (he could pile it on up to a metre in depth).

My friend asked me to investigate what further site consequences there might be. I've spend several hours on the internet, searching for such combinations as:
+PAH +asphalt
+"asphalt shingle" +groundwater

and have not found a single reference that says he can't just bury these shingles. I found some concern about PAHs and asphalt. I found no studies that said PAHs would leach out. I found two studies (I did look at the source, one was the Florida Department of Transport and the other was the Asphalt Institute, so I'm taking them with a huge chunk of salt) that said there was no PAH leaching from granulated road debris or new asphalt road-making material.

Are there any directions you can lead me, or any advice you want to give?

Thank you.
Sincerely yours,
Jonathan Berry
Nanaimo, BC