Only about a 20dB improvement for something that has a zero safe exposure level.
The problem with heavy metals is that they're cumulative, but it's also impossible to avoid them completely, so minimization is the strategy.
-20db is 1/100th which is a dramatic improvement, at least for that threat source.
This means is damages your neurons in any amount.
Contrast to say, copper, which doesn't start causing damage until levels exceed a certain tolerable threshold.
While lead is toxic at any amount, low amounts of lead cause low amounts of damage. It doesn't change the fact that the ideal exposure is 0 and over 99% of people have about 5 to 10 times the bond lead levels found in remains of our ancestors, and that even relatively low lead exposure levels from breathing lead in the air from just air pollution are linked to dramatically reduced IQ.
99% of people live better lives than all of our ancestors, in every dimension.
if you're telling me it's because of lead, then lead is a good thing.
https://x.com/Noahpinion/status/1825584397363589312
Basically the IQ gap between the lead exposed and non exposed has stayed the same even though the amount of lead in the bloodstream has dropped by orders of magnitude. So either the first part of lead exposure is 100x more damaging then the 100th part of lead exposure (which animal models do not bear out) or a lot of the lead exposure IQ research is confounded.
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
https://www.epa.gov/ground-water-and-drinking-water/basic-in...
It's not trying to be alarmist, it's just different from things like, say, table salt, where small amounts over time are fine but 1 pound will kill.
Many things have no safe value but a low level is less likely to play a major role in a life than another risk.. Cars, guns, opioids, suicide, cancer, maybe the last two have a minor lead influence, mostly outweighed by alcohol.