Spherulitic Lead Calcium Apatite Minerals in Lead Water Pipes Exposed to Phosphate-Dosed Tap Water.

Phosphate dosing is the principle strategy used in the United Kingdom to reduce the concentration of lead in tap waters supplied by lead water pipes. The mechanisms of phosphate-mediated lead control are not fully understood, but solid solutions of lead calcium apatite are thought to play an important role. This study investigated the microstructure of a lead pipe, supplied with high-alkalinity tap water, in which the lead calcium apatite crystals were spherulitic having rounded and dumb-bell-shaped morphologies.