exceeded at a loading of around 650 μm of Zn per gram of mussel shell. The second flow-through experiment decreased the solution-solid contact time to 30 mins, extended the shell particle size range and increased the amount of shell being used, each column containing 150 g of shell in contrast to 20 g initially used. The results of the second flow-through experiment demonstrated the near-equivalent relationship between zinc loading and calcium release and found that the column absorption efficiency was not