As it turns out, lead poisoning has been known since Ancient Greeks described the classic signs: colic, constipation, pallor, palsy (1). Lead acetate was used by Romans in wine production, where poisoning known to adult population (1). In the early days of US, lead exposure health problems noted in printers, plumbers, and painters (2). In the industrial world, the explosion in lead exposure was primarily due to leaded gasoline which was regulated in 1980s (1). Children exposed to lead were noted in this time to be particularly at risk due to lead's "significant and persistent impact on brain reorganization associated with language function" (2). Children particularly at risk were those in inner city in pre-1978 housing, and those in pre-1950s housing (due to lead paint), and those who whose parents smoked (higher content of lead in cigarette smoke) (2). Additionally, mother's exposed to lead may have impact on developing fetus (2).
With increasing awareness of lead related problems in children, the tolerable levels in blood have been reduced between 1950 to 1990 from 80 to 10 micrograms/dL in blood (1). The lower limit for dangerous levels of lead in blood is now 5 ug/dL (2), although arguments are made for a zero tolerable blood levels (3).
Source:
(1) Berney, B., 1993. Round and round it goes: the epidemiology of childhood lead poisoning, 1950-1990. Milbank Q 71, 3–39.
https://www.atsdr.cdc.gov/csem/csem.asp?csem=34&po=7
(3) Shefa, S.T., Héroux, P., 2017. Both physiology and epidemiology support zero tolerable blood lead levels. Toxicology Letters 280, 232–237. https://doi.org/10.1016/j.toxlet.2017.08.015
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