Abstract

Assessment of Seawater Quality of El-Dekhaila Harbor, Alexandria, Egypt

Author(s): N. A. Shaltout and D. E. Abd-El-Khalek*

Water quality of El-Dekhaila harbor was monitored seasonally at nine samples covered the harbor surface water during 2011-2012. The chemical parameters of surface water reveal that pH, dissolved oxygen, oxidizable organic matter, chlorophyll and total alkalinity were in the range 7.70- 9.16, 1.07-7.54 mgO2/l, 0.16- 9.92 mgO2/l, 0.002-0.23µg/l and 2540.3-4668.8μmol/l respectively. Nutrients salts showed large variations 1.7-51.15, 0.17-12.5, 0.4-14.9, 0.09-17.1 and 10.3-77.3 (μ M) for ammonia, nitrite, nitrate, reactive phosphate and reactive silicate respectively. Depending on DIN/P ratio of seawater samples, phosphorus was the limiting factor for the Harbour water productivity. Principle component analysis (PCA) which was used to develop water quality index (WQI) revealed that, stations 1, 2 and 3 is highly polluted by water discharged from EI-Umum drain through EI-Mex pumping station. The ecological evaluation of El-Dekhaila Harbour water quality parameters after 20 years of the constructions of the harbor indicates that, the construction of the harbor decreases surface water circulation pattern out of the harbor leading to increase in polluted water residence time and hence increase the flushing time and decrease harbor water self purification. Moreover increasing shipping activity and waste water directly dumped too the harbor dramatically affect the harbor water quality. This is reflected in large increase in nutrient salt concentration after 20 years from the harbor construction. This is also accompanied by increasing intensity of microbial activity and decrease dissolved oxygen content.

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