Originally Posted by Botnst

Warning, aluminum foil zone! Conjecture follows.

I don't know what the combustion products of tetra-ethyl lead are, but I imagine that it's Co2, water, and lead oxide. How long does lead oxide stay aloft? I dunno. Probably not too long and probably gets quickly washed from the atmosphere with rain. Lead oxide, IRRC has a pretty high dissociation constant so it probably doesn't go readily into a neutral aqueous sol'n. Probably goes into sol'n more readily with a lower pH, like from acid rain. So I'll bet that [Pb] is greater in and around roadways southwestern cities than around southern or northeastern cities. Lower rainfalls in the desert southwest result in higher accumulation of metal ores in the soil than in the areas of higher rainfall. But who licks dust off roadways? Well, maybe dust in the wind would be a source?

Lead in surface water out east is more measurable. I recall that it is present in the mud in every body of water in the east.

Drink up!

B