Mechanism and equilibrium relationships for the uptake of Cd2+, Cu2+ and Pb2+ by coral sand from their nitrate aqueous solutions were studied. The maximum amounts of Pb2+ and Cd2+ uptaken by coral sand dried at 4013 K were about 1.3 and 0.9 mol-kg-1, respectively. That of Cu2+ was only about 1/100 that of Pb2+ at pH = 6.1-5.5. Equilibrium relationships between the concentrations of those ionic species and the amounts uptaken were expressed by either the Langmuir or the Freundlich isotherm. The amounts of those ions uptaken and the physical properties of the coral sand varied with the maximum temperature during treatment. For example, the B.E.T. specific surface area decreased with increasing heat-treatment temperature. This is due to the change in the crystallographic structure of calcium carbonate, which is the main component of the coral sand, from aragonite to calcite.