Originally Posted by
RatherBeFlying
Before unleaded gas came into use in the mid 70s, cars were broadcasting lead on every road. That lead has mostly remained where it came down.
Neighborhoods adjacent to expressways have been found to have elevated soil lead levels, I suspect considerably more than adjacent to airports.
At one point, the big push to get lead out of gasoline was due to lead poisoning concerns. However, when they actually started looking at it, they determined the contribution of lead of automotive gas was quite small - most of the exposure came from things like paint and lead plumbing (remember, years ago the standard solder to connect pipes was ~50% lead, and some houses actually had lead pipes).
They did get lead out of the gasoline, but the primary driver was the lead poisoned the catalytic converter - not to reduce lead poisoning.