Grapes do not absorb much
The interesting tests are cucumber peel and mushrooms.
My family has a couple of friends who pinched a Geiger counter post Chernobyl and measured everything they could get their hands on (which was going to end up on the table).
There were only two things which drove it off the scale. Cucumbers (specifically the peel) and forest mushrooms.
Biting the hand that feeds IT
