So.

We force them to eat each other until their concentrations are high enough to extract the metals for industrial uses.

That's a feature.

We force them to gorge on themselves until there's one, inbred, leaded rich guy left. Then we put it on display as a warning to everyone else

We're halfway there; many of the rich want desperately to strap themselves on top of a million tons of explosives in the shape of a penis. All we have to do now is convince them that there are poor people with money on the sun, and they'll trip over each other to be the first to steal from the poor sun-people.

I didn't know that! Thanks for sharing that info.

I was really into growing culinary mushrooms for awhile was cautioned about my compost choices and to avoid fish based ones because mushrooms absorb mercury(and others like cadmium) particularly well. I didn't know potatoes and herbs did that too

Prions are quite stable, and also they don't need to stay in the soil for long, just enough to get reconsumed. Supposedly that's how CWD (chronic wasting disease, not coarse woody debris), is spread among deer.

Edit: in context with composting, overall temps would be higher in such a pit but not by much. Its anywhere from room temp to 140F/60C. Prion destruction is a lot higher temp wise. As for bacteria in the pile, maybe? It might be more likely to become meaningfully degraded in a compost pile instead of normal soil.

As for cwd prion bio accumulation, it's been hypothesized but not demonstrated (like grass picking it up from the soil itself). It's spread in saliva and indirectly from the environment which is probably why you shouldn't feed deer in areas with cwd and explains a lot of the spread. Also apparently the scrapie prion can endure for 16 years. Wtf.

a quick look at wikipedia will show you are wrong

"In 2015, researchers at The University of Texas Health Science Center at Houston found that plants can be a vector for prions. When researchers fed hamsters grass that grew on ground where a deer that died with chronic wasting disease (CWD) was buried, the hamsters became ill with CWD, suggesting that prions can bind to plants, which then take them up into the leaf and stem structure, where they can be eaten by herbivores, thus completing the cycle. It is thus possible that there is a progressively accumulating number of prions in the environment."

Proteins are also typically denatured by heat, and yet cooking does not remove prions. Prions are hard to get rid of.