Pore water Chemistry of Alexandria Eastern Harbour (2004-05)

Alexandria Eastern Harbour is one of the most important areas for tourism, Fisheries and several recreational and developmental purposes. Till the year 2003, the basin received a huge amount of unprocessed sewage. Large quantities of metals and paints are still dampened the harbour by local boatyard. Accumulation of nutrients, organics and other elements on the bottom as well as their diffusion from the sediment pore water to overlying water are expected. The study aimed to know the level and distribution of the nutritive salts in the harbour pore water. 77 Surfacial sediment samples collected during ten cruises among the year (Oct.2004-Oct.2005) at eight sites cover the basin in addition to four samples outside the harbour. Their pore waters were analyzed for measuring dissolved inorganic phosphorus, nitrogen and silicon ions content in addition to other hydrographical variables such as pH-value, total alkalinity, calcium, magnesium and oxidizable organic matter. For sediment itself, water and organic contents were also determined. The results reveal accumulation of ammonia, silicates, phosphates, nitrates and nitrites. High organic matter content is also accumulated and high alkalinity levels were also detected. Most of the harbour sediment is not homogeneous and poorly sorted and consequently no general trend of variation could be detected. The western edge of the basin where yachting and fishing processes carried out reflect their pore water relative higher levels of nutrients and organic matter content.