MAP Technical Reports Series No. 106 UNEP

5.2.11 Egypt: South-eastern Mediterranean
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Cases of acute eutrophication in the Egyptian waters are reported above all from the
ports and coastal waters off Alexandria, and from the lagoons in the Nile delta. Overall,
eutrophication and the worsening of water quality (abnormal water colours, anoxia in bottom
waters and production of hydrogen sulphide) in Egyptian coastal and brackish waters are
caused by the combination of: (a) large inputs of fertilizing substances from urban, agricultural
and industrial sources; (b) the long water residence times in the lagoons, partly due to physical
barriers; (c) salinity stratification of the waters; (d) generally high water temperatures.
Coastal waters and ports. Along the coast, high trophic levels have been observed in
the area off Alexandria and in a number of sites close to the outflows of the main arms of the Nile
(Rosetta and Damietta). The city of Alexandria discharges some 183,000,000 m 3 /year of sewage
(Aboul Kassim et al., 1992) and industrial waste into the nearby Bay of El-Mex (El-Sherif, 1990).
These waters are transported by the geostrophic currents eastward off and along shore causing
not only a seriously trophic state but also a general deterioration in the coastal ecosystem.
However, dilution prevents the most catastrophic manifestations of eutrophication along the
most important Egyptian bathing beach areas.
Eutrophication is more serious in the two rather closed port areas, the East Harbour
and the West Harbour. Conditions in these harbours have recently been extensively studied by
members of the Alexandria University (Aboul-Kassim et al., 1992; Emara et al., 1992; Saad and
Hemeda, 1992a, 1992b; Zaghloul and Halim, 1992).
Western Harbour (7.54 km 2 ). Beside Port Said east of the delta, this is the most
important Egyptian harbour. Heavy shipping traffic and the discharge of effluent from the urban
sector create recurrent algal blooms associated with anoxic conditions in the bottom waters
(GESAMP, 1988; Saad and Hemeda, 1992a). Zaghoul (1992) states that this area is markedly
eutrophic; conditions of low transparency values and high concentrations of nutrients and
chlorophyll-a occur frequently.
Eastern Harbour (2.53 km 2 ). Heavy algal blooms in this area are caused as a result of
the excessive input of nutrients from the city of Alexandria, combined with the marked vertical
stability of the basin. In June 1985 Dowidar and Aboul-Kassim (1986) estimated mean
chlorophyll-a at 23 mg/m 3 . Zaghloul and Halim (1992) record red tides caused by the toxic
dinoflagellate Alexandrium minutum, and anoxia in the bottom waters. Dowidar et al. (1990)
estimated the total amount of dissolved inorganic phosphorus discharged into the Eastern
Harbour at 1,094 kg/year.
Lagoons in the Nile delta. With the exception of L. Burullus these extended lagoons of
mean depth around 1 m (Mariout, Edku, Burullus, Menzalah) and their fisheries have been
extensively studied in a combined FAO/UNESCO programme in the late 1950' prior to the
construction of the High Dam (Elster and Vollenweider, 1961). The lagoons are in part enclosed
by reed belts (Phragmites), and in part covered by macrophytes (Potamogeton species; floating
Eichhornia). They are important habitats for commercially valued fish. All lagoons receive the
drainage waters from the extended irrigation systems that provide water to the highly developed
agricultural areas of the Nile delta. These waters are then discharged into the Mediterranean.
The interplay between nutrient rich fresh water supply from the South and seawater intrusion via
the connections to the sea in the North creates strong salinity gradients, both horizontally and
vertically.