Numbers . . .
From my iPhone, Tom, so it'll be a bit sloppy, but here goes:
http://www.dartmouth.edu/~toxmetal/arsenic/food.html
Just one good source, but there are others out there. Please note that the initial story simply states it might be a good idea to cut back on certain foods thought to be good for us, but there was no call for completely stopping. Some foreign elements are cumulative in living tissue, while others dissipate, sometimes quickly.
Cheers.