How many heavy metals are actually in the body? And wouldn't the dirt absorb them just as well as the mushrooms? Wouldn't the mushrooms eventually degrade and t

How many heavy metals are actually in the body? And wouldn't the dirt absorb them just as well as the mushrooms? Wouldn't the mushrooms eventually degrade and turn into dirt? Aren't coffins commonly made out of metal anyways? And who exactly is trying to plant shit on top of graves anyways?