It was erosion control after some new road work. I sorta suspect they did bring in new dirt for it as well. I do only use it in small amounts.
Not really gonna make a difference over time in terms of pollution/heavy metals. But it was still a worthwhile project.
I've harvested 25lbs of wheat berries from a boulevard in my city. I then threshed, winnowed it myself. I still have some of the flour and berries left and use it to make bread.
I did my threshing using a lawn mower on a big tarp. This actually worked fairly well. Were I to do it again I would probably want a more repeatable setup. Ive seen some good strategies on youtube.
The winnowing I did with a leaf blower, and worked pretty well, I think I would use this strategy again, but I suspect if you were going to do it more often it would be very easy to build something that would help mechanically.
I have a friend with a little home flour mill which took a while but was perfect for turning it into flour. If you were to do it fresh when you wanted to make bread these little mills are fantastic.
There's a book I highly recommend reading called Small Scale Grain Raising [1] that has a lot of good tips, and ways to do this kinda stuff.
In this book they recommend using a leaf shredder or wood chipper which would be incredibly effective.