In vitro and in vivo studies of lead immobilization by synthetic hydroxyapatite.

Apatite appears a useful compound for removing lead from water, due to its ability to immobilize the metal by precipitation. In dilute solution, dissolved hydroxyapatite [HA, Ca1O(P04)6(OH)2] provided phosphates that were reactive with aqueous lead (molar ratio HA/Pb= 1/10) forming precipitates at around pH 6. These dissolved at a more acidic pH (3).