Interaction between dissolved phosphorus and suspended sediments in a tropical estuary

Abstract

Nutrients from the Fitzroy River (Queensland, Australia) may impact on the Great Barrier Reef, a marine area of world significance. In this study, experiments were carried out to determine the equilibrium distribution of phosphorus between Fitzroy River sediments and estuarine water under a range of conditions. The kinetics of sorption processes were also studied. Sorption reactions reached a steady state after about 2 days. The sorption of P was weaker at higher pH values, but did not decrease with an increase in ionic strength. The amount of P bound by sediment particles was limited by the surface site density of the solid phase (about 140 ^mol/g). The Fe content of suspended particles increased moving down the estuary, due to the precipitation of amorphous Fe- oxides. Adsorption of P on freshly. Open Access