Lead is famous for having bad developmental effects. People have grown up with damaged neurons not making the right connections. Maybe Restoration works against that; it's worth trying - but Keltham wouldn't bet on it.
The obvious thing to try to get faster info here would be raising mice, rats, or some other mammal with shorter developmental times. Keltham will sketch out some basic experimental techniques for measuring the thinkoomph of mice so that developmental damage can be quickly observed within an experimental versus control group. That can verify the problems with lead and prove them to other countries; and they can also see whether Neutralize Poison or Restoration helps at all there, once a mouse has already grown up damaged.
It's - so bizarre that an element as high on the periodic table as 82 would be the most affordable metal for pipes. Civilization uses complicated synthetic liners for pipes that carry drinking water, but Keltham knows that underneath the liners are Element-29 - what they currently think is 'copper' - and Civilization would use something failover safe underneath the linings, so copper pipes would probably be safe.
Keltham will look into copper mining, see if anything there stands out as obviously improvable. Keltham was thinking about electrorefining / electroplating anyways. Maybe they can line the lead pipes with a thin sheen of copper via electroplating, it wouldn't - wouldn't be a great idea - but it's probably better than exposing the lead outright - though Keltham will need to figure out, some way to check, that the metal-to-metal contacts aren't generating voltages and putting even more lead ions into the water -