Lead tends to stabilize in-situ in most installations over time to be fairly safe and non-reactive.
Messing with it or changing the environmental equilibrium is often what what increases risk / makes it a non-negligible risk.
See also:
EPA's embarrassing DC screw-up where replacing chlorine with a "safer" alternative caused lead chemical pathways to reverse and lead levels to spike: years of deposits into non-lead infrastructure -from (previously removed) lead pipes- suddenly became unstable and began leaching back into water due to the chemistry change. The leadfree water system suddenly had a lead problem, because some one at the EPA decided that the chlorine system was a bigger problem than it really was.
Especially when it comes to these types of (potential) remediation projects, never assume that the unknown unknowns will be harmless, or even less risky than the no-build alternative.
Messing with it or changing the environmental equilibrium is often what what increases risk / makes it a non-negligible risk.
See also:
EPA's embarrassing DC screw-up where replacing chlorine with a "safer" alternative caused lead chemical pathways to reverse and lead levels to spike: years of deposits into non-lead infrastructure -from (previously removed) lead pipes- suddenly became unstable and began leaching back into water due to the chemistry change. The leadfree water system suddenly had a lead problem, because some one at the EPA decided that the chlorine system was a bigger problem than it really was.
Especially when it comes to these types of (potential) remediation projects, never assume that the unknown unknowns will be harmless, or even less risky than the no-build alternative.