To hopefully offer some useful context to what 500ppb means here, the lower bound for blood lead levels the CDC monitors is 3.5 ug/dL or 35ppb. Lower blood conc

To hopefully offer some useful context to what 500ppb means here, the lower bound for blood lead levels the CDC monitors is 3.5 ug/dL or 35ppb. Lower blood concentrations than this are not nessecarily safe, and levels as low as 0.5 ug/dL have been found to be correlated with ADHD [1]. Add to this that children's bodies absorb more lead than adults, between 50 and 100% of the amount of lead ingested [2]. So the concentration of lead in drinking water does not have to be very high at all before it can be harmful. Certainly it's lower than the 500 to 11,000+ ppb reported on here. Hopefully current and past students of these schools will be tested for lead and given treatment if nessecary. Edit forgot links 1. https://www.psychiatrictimes.com/view/understanding-link-between-lead-toxicity-and-adhd https://www.psychiatrictimes.com/view/understanding-link-bet... 2. https://www.atsdr.cdc.gov/csem/leadtoxicity/biologic_fate.html https://www.atsdr.cdc.gov/csem/leadtoxicity/biologic_fate.ht...