Effect of pollution on the Western Harbour of Alexandria. I: Environmental characteristics

The Western Harbour of Alexandria has an area of about 1862 acres and a water depth ranging from 6-14 m. This harbour is protected by two water breaks and is divided into two areas; the inner and outer ports. The water quality of the harbour has deteriorated due to the effects of various pollutants discharged from ships at anchor and sewage waste outfalls. Variations of some of the environmental conditions in the harbour were studied. Temperature measurements generally decreased with depth. The highest average water temperatures were recorded in July and August, whereas the lowest were in January and February. The Secchi disc readings showed remarkable variations: the minimum and maximum regional average Secchi values were accompanied by the highest and lowest regional averages of suspended matter (SM). The irregularity in the vertical distribution of SM possibly coincided with turbulence of the water column from navigation and the effect of pollution. Salinity values generally increased with depth. The discharge of sewage wastes from numerous ships and land-based sources decreased the surface salinity. The highest regional average salinity values were found at locations far from the direct effect of sewage pollution. The pH values generally decreased with depth: low pH values were found at locations directly affected by sewage wastes.