[notjulianjaynes]

I believe when in life you are exposed makes a difference too. Children are at a higher risk for being harmed by lead for a number of reasons including having less blood than an adult, and being more likely to eat paint chips off the ground than (most) adults. I'd imagine that lead replacing calcium in the brain during critical developmental periods also matters a lot.

Effects of calcium supplementation on blood lead levels and short term memory of chronically exposed children https://oamjms.eu/index.php/mjms/article/view/3285