> If half of the world’s water supplies had lead levels of X you’d expect evolution to make that specific level a non issue. Obviously lead levels above that ca

> If half of the world’s water supplies had lead levels of X you’d expect evolution to make that specific level a non issue. Obviously lead levels above that can and are still problematic. Not necessarily true if the effect is relatively small compared to other evolutionary pressures. A few points drop in IQ might not be bad for ancient hunter-gatherer tribes but does have a much larger impact in our modern age. Every point increase of average IQ at the population level generally leads to better societal outcomes overall. To your earlier question, filtering flouride might be beneficial then. We can do flouride teeth treatments at dentists or switch more to nano-hydroxyapatite [1]. Though it'd seem nano-hydroxyapatite needs more safety studies as well. 1: https://pmc.ncbi.nlm.nih.gov/articles/PMC6747619/ https://pmc.ncbi.nlm.nih.gov/articles/PMC6747619/