Not really, infrastructure changes of various sorts are often correlated with socio-economic factors. There's a reason Flint, MI's water system was wantonly destroyed and not that of a wealth Connecticut Suburb.

Anyway, there are still researchers doubting whether lead was the primary cause of the 80s-2000s rise and decline of violence. Just googling, see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829390/

But the main thing is single causes are hard in complex things like human society.