The line from the CDC page reads almost like a call for help:

"Some studies suggest that the current OSHA PEL and NIOSH REL may be too high to protect against certain health effects"

This was an interesting bit from that link:

> Some studies suggest that the current OSHA PEL and NIOSH REL may be too high to protect against certain health effects.

The medical limit for lead is zero (you can find that statement in various forms on all the major - official, main stream, government, education - sites that have something to say about the subject).

The reason we have non-zero "official" threshold values is for practical reasons: In our times and on this earth right now it simply is not possible. The values are set so that medical people are kind of okay with it - any damages are too subtle and not too obvious (e.g. less IQ as well as most small issues nicely also correlate with age so it can always be attributed to aging, and proving for an individual (and not just statistically for a lot of people without being able to say anything about each individual) that some issue was caused by or was contributed to by e.g. lead is impossible (we can't tag all the atoms and follow them around and see what they do, and even if we could do the first part perfectly, the following those atoms, we still would not know what they actually do just from knowing where they've been, even less so how the local bio-chemistry deals with consequences longer term than we can observe). So we need to have a limit that is low enough to not cause medical alarm bells to go off, but high enough to not bankrupt government and industry if they were told they had to clean it all up. Which, quite frankly, they can't at this point.

Last time I heard about China they have an already huge and increasing problem with heavy metals on large parts of their agricultural lands... (Example, two links of many randomly chosen: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6239058/ or https://www.chinawaterrisk.org/resources/analysis-reviews/he...) and the West had a lot of time where nobody cared about pollution one bit, during and after industrial revolution. The "superfund sites" (https://en.wikipedia.org/wiki/List_of_Superfund_sites) are just the biggest concentrations. Oh and then there's coal - burning it also has been releasing heavy metals such as mercury for a long time, and it's still going on.

Oh and by the way, please nobody blame "capitalism". I grew up in East Germany, near ash mountains and a river clearly unsuitable to even be touched by a human, everything was dirty and gray. I did not even live in one of the known polluted places (e.g. Bitterfeld). After reunification everything was cleaned up with Western money and methods - ash mountains gone, the river is clear and has nice water plants showing it's really healthy, etc. East Germany under capitalism is A LOT cleaner than under socialism. I say this because in sooo many discussions about the environment always somebody blames capitalism, but it's deeper and orthogonal to whatever system is used I think. People do or don't care about their environment, if it was just about economic pressure, you have them in all systems, because all systems need to produce something.

Thank you for that last paragraph. It is so tiresome to read other people saying that "capitalism" is to blame for everything. You make an excellent point that it's neither socialism nor capitalism per se that's to blame.