Estimation of the Total Inorganic Phosphate-Phosphorus in Sediments of the Old Phosphate Port at Jordan’s Gulf of Aqaba

Abstract

Between 1970–2013, huge amounts of phosphate particles were lost to the sea floor during the transport of phosphate to the port and loading it on ships sailing from the Gulf of Aqaba around the world. The dissolution of the lost phosphate was a major concern. Due to the importance of this issue, the amount of the total inorganic phosphate-phosphorus (TIP) was estimated in the sediment cores from different transects around the Old Phosphate Port (OPP). Additionally, some physical and chemical properties of seawater at OPP were measured. Samples for TIP were collected by SCUBA from 27 sites using metal pipes inserted into a certain depth (est.1.5–2 m) of the bottom. In the lab, sediments of the cores were cut into layers as thin as 25 cm to measure TIP in each layer. The phosphate concentration in each layer revealed the highest amount in layers at 75–100 cm, with an obvious gradual increase from layers at 0–25cm and from layers at 75–100 cm (91.4 and 3.0 million kg, respectively). In contrary, TIP tends to decrease from layers at 75–100 cm until layers at 150–175 cm. Obviously, phosphate concentrations decreased significantly in the layers at 150–175 cm. Based on the above estimations and taking into account the various calculations, the total mass of phosphate was around 11.5 × 106 kg. The final recommendation to the decision maker in Aqaba is / that there is no need to remove the existing phosphate.