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https://medicalxpress.com/news/2018-06-iq-scores-1970s.html. Actually, IQ scores have been falling by 7 pts per generation since 1970. During that time, thanks to the elimination of Pb from gasoline & paint, airborne levels of Pb have fallen to virtually undetectable levels. ....Not to change the subject, but since the Draconian regulations concerning auto exhaust emissions went into effect, despite measurably "cleaner" air in our cities, rates of asthma & COPD have also skyrocketed....Have they done us a favor with their over-reaching regs? Our regulations concerning acceptable Pb levels/exposures are purely arbitrary, there being no systematicallly acquired body of data upon which to make an educated estimate. The only large-scale experience is based on one episode of chemical warfare committed in Iraq about 30 y/a. Pts with very high Pb levels remained asymptomatic. Symptoms only developed in those with levels several hundred (IIRC) times over levels considered "safe." In the famous case of Flint, MI several y/a, they never told us the levels of Pb found in the water. Doing an orders of magnitude estimation, if the levels were 1000x higher than the regulatory acceptable levels, a 30 kg kid (who never got any bigger nor excreted any of the ingested Pb) would have had to drink 5 gal of water a day for 100 yrs to attain blood levels above the levels considered safe....Always do the arithmetic before panicking. Environmental Pb levels probably vary with geographic location. Before becoming known as Cheeseheads, Wisconsinites were known as Badgers because lead miners in the SW corner of the state used to provide shelter for themselves by burrowing caves, like badgers, into the banks of the Miss. R. where Pb veins are very close to the surface. How does this apply to ancient Romans??? Pb pipes do not cause contamination of the water because a biofilm quickly forms inside the pipes so the flowing water does not actually contact the pipes ...Pb cooking utensils? Doubtful, because most Romans were poor, so they didn't have metal vessels, and besides, most plebs in insulae and ate at the many tabernae & popinae, doing little cooking at home.