Of course I know that I should clean every bit of shingle debris out of my garden beds - but that is really hard to do. How dangerous is this debris? I'm afraid since there were THREE layers on the roof that the bottom layer was asbestos on top of everything else. The raised vegetable beds (why didn't I think about covering them?) didn't get too much stuff in them but the areas where I grow berries and rhubarb got hit. They cleaned up the big stuff but I have pieces a quarter size and under all over. I'm (really) going to try my shop vac to pick up stuff now that the ground is frozen - but I need to know if I can even use the fruit or plant food crops in the contaminated beds. I would appreciate your input!
The shop vac is a great idea. If I were you, I would get all of that out of there. Some people will not even let runoff from an intact roof with asphalt shingles go to their food gardens. From what I have read, the chemicals in the asphalt are the real danger. If pieces are sitting in your soil, it would seem to me there would be a greater chance of that stuff being released to your plants than if it was just that rainwater ran over them, ya know? I would be more concerned, though, if you were growing leafy greens there than berries. My understanding is that toxic chemicals can be present in leaves but are not usually present in fruits. Something about plant physiology. I remember seeing that about lead and sewage, for instance.
My understanding of the situation: Asbestos is okay as long as it doesn't make dust that you can inhale - you don't need to worry about your plants taking it up. Don't inhale the dust when you empty the shop vac. The concern with the tar-based shingles is that IF they contain heavy metals, it might leach out. I would think that if you have gotten all the visible pieces - scrape off the top of the soil if necessary - that should be good enough.
We had our roof replaced 7 years ago and have gutters. Loose "grit" washed down for a long time and I still see it in small amounts today after heavy rain. The roofers walked on your roof loosening all that grit. I would check what the shingles were made of if you have food gardens under your eves, but I think todays stuff is safe, just annoying. I had a clean-up clause yet they still missed a great deal- I don't think they thought little pieces counted.
A few years after we did our roof I started noticing roofs done with metal sheets. Think that would hold up better than shingles in a big storm. No grit to contend with but you will always have stray nails.
Late to this thread but we had ours redone a few years ago. The contractors were very meticulous but I noticed a lot of grit from the shingles in the beds. That should not present a problem as asbestos is no longer a part of shingle material.
Should the old roofing (if removed) have asbestos, it would have been of more harm to the roofers than the ground that it fell upon.
I did however find roofing nails that had escaped their grasp. I found these by thoroughly scouring the area with one of those magnets of a long handle. OTOH, if we don't drive over them or step of them, nails will add iron to the beds. lol