الفهرس 
Marine pollutionOnly 14 pages are availabe for public view
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Abstract
The estuaries and coastal lakes are the most important land-based sources that contribute to environmental pollution, physically, chemically or biologically to the Mediterranean Sea especially along the African shore. The coastal lakes and rivers receive large quantities of wastewater either agricultural, industrial or sewage partially treated or without treatment. This water may contain compounds of nitrogen and phosphorus which may cause phytoplankton blooms (algae) and cause the so-called red tide, which appears frequently in certain areas of the Mediterranean Sea.
The Mediterranean Sea receives the flowing Nile water directly or indirectly through the terminals of the drainage network effluents. These effluents are continuously pumped to the sea carrying a complex of various wastes. The quantity and the quality of these wastes reflect the variation of human activities. The coastal lakes are considered as transitional zones between land and sea; they are among the most productive natural systems in Egypt. The dramatic deterioration is observed in the resources of the Egyptian coastal Lakes and lagoons indicates that, the impact of pollutant discharges in the upper Nile, as well as those in the Egyptian part are being delivered to the Mediterranean coastal waters through these lagoons, in addition to the River Nile Estuaries, Rosetta and Damietta. In the present time, the regions along the Mediterranean Sea coast, which are subjected to heavy pollution, are found at several points “hot spots”.
The aim of the study is to evaluate sources of pollution and its effects on the marine environment along the Egyptian Coast of the Mediterranean Sea.
Seven of the major land-based sources discharging into the south eastern coast as well as its adjacent sites along the Egyptian coast of the Mediterranean Sea were selected for this investigation, these sites are:
A-Man-made connection (Nobareya Drain) station I
B-Delta coastal lagoons :( El-Mex Outlet, Lake Edku Outlet, Burullus Outlet and El-Gameel Outlet) stations II, III, V and VII, respectively
C- Rosetta and Damietta estuaries (Nile River Estuaries; stations IV and VI):
Samples were collected from these stations bimonthly from June 2001 to April 2002 and analyzed for physicochemical parameters, nutrients, heavy metals, total and faecal coliforms and algae count.
Generally, all the examined parameters at the inland sources are in agreement with the permissible limits of the environmental law 4/ 1994 except for the total coliforms values especially at El-Mex outlet.
1. Physicochemical characteristics:
The inland sources stations had temperatures ranged between 15.3 to 27.6 ºC, while the receiving seawater stations had range of 15.0-26.9 ºC.
Turbidity levels at the inland sources are higher than the receiving seawater and varied from 6.40 to 37.60 NTU at stations VII and II, respectively, while at the receiving sea water ranged between 3.3 and 30.0 NTU at station VI and III respectively.
the pH values of both types of water were slightly alkaline. The pH values of the inland sources varied from 7.14 at station II “El-Mex outlet” to 8.53 at station VI “Rosetta estuary”. On the other hand, sea water pH values fluctuated between 7.28 and 8.40at stations III and station V, respectively.
Receiving seawater samples were more oxygenated than the inland sources. Dissolved oxygen values were higher during winter months. The DO concentrations ranges were (4.20 -10.60) and (6.00-8.40) mg/l for both the inland sources and receiving seawater, respectively. El-Mex area recorded the lowest DO values.
The land based sources reported that the minimum value of BOD (7.20 mg/L) was occurred at stations III during October and the maximum value (39.20 mg/L) was measured at station I during December, while the amounts of oxygen required to oxidize organic matter in seawater biologically were fluctuated between 1.20 and 19.20 mg/L. The lowest BOD value was observed at station III and the highest one was recorded at station II.
The annual mean values of BOD5 recorded at inland sources ranged between 18.67 and 30.0 mg/L at station VII and VI, respectively, while at the receiving seawater the lowest and the highest annual means of 2.80 mg/L and 13.93 mg/L were observed at stations III and II, respectively.
The lowest annual mean value of COD at the inland sources recorded at station II (48.20 mg/L) and the highest recorded (80.53 mg/L) at station VI. On the other hand, at the receiving seawater the lowest annual mean (6.30 mg/L) recorded at station III and the highest one (37.67 mg/L) recorded at station II.
TDS values of the receiving seawater were higher than the sources. At the inland sources stations, Rosetta Eatuary (station VI) recorded the lowest annual mean of TDS (2.00 g/l), while Damietta Estuary (stationVII) recorded the highest annual mean (35.99 g/l), consequently the adjacent seawater TDS ranged between (30.87 g/l) and (38.1 g/l) recorded at stations VI and VII, respectively.
There is no significant difference in TSS annual mean values for both types of water, where the ranges between (29.40 - 52.93 mg/l) and (22.23- 50.90 mg/l) for both inland and receiving seawater, respectively. The lowest values recorded at Nobareya area (station I) and highest values at lake Burullus (station IV)
Total alkalinity values of the receiving seawater were higher than those of inland sources. The annual mean values of total alkalinity ranges were (119.3 - 202.0 mg/l ) and (185.67- 241.0 mg/l) for the inland sources and receiving seawater, respectively.
2-Nutrient Salts
Generally, nutrient salts at the inland sources are much higher than those of the receiving seawater. The concentrations of all forms of nutrients are far below the limits of the Environmental law 4/1994. The highest levels of nutrients concentrations recorded during autumn and winter monthes.
The maximum annual mean value of phosphate at the inland sources (80.4 µg/l) recorded at Burullus outlet (station IV) and the minimum (57.8 µg/l) at Nobareya drain outlet (station I), while at the receiving sea water the annual mean values ranged between 5.7 and 22.8 µg/l at stations I and III, respectively.
TP annual mean values ranged between 75.86 µg/L at station I (Nobareya drain) and 107.64 µg /L at station IV (Lake Burullus outlet). While at the receiving seawater TP ranged between 13.07 μg/l and 77.57 μg/L; recorded at stations I (Nobareya coastal area) and V (Lake Manzala coastal area) respectively.
The lowest annual mean value of nitrate at the inland sources recorded at station V (92.28 µg/l) and the highest recorded (122.49 µg/l) at station II. On the other hand, at the receiving seawater the lowest annual mean (29.37µg/l) recorded at station III and the highest one (110.53 µg/l) recorded at station II.
Station II represented the maximum annual mean value of ammonia (61.1g/l) while station IV had the lowest value of 22.5 g/l. However, at the coastal stations the regional distribution of ammonia revealed that the annual means variations fluctuated between 8.9 to 40.6 g/l. Also the lowest average value noticed at station IV and the highest observed at station II.
The regional distribution of nitrite content revealed that the highest annual mean of nitrite observed at station II (EL-Mex outfall) of 85.31µg/l which represented 7% of total nitrogen, while at the receiving seawater the nitrite annual means ranged between 1.8µg/l at station VI (Rosetta Nile Branch) and 11.92µg/l at El-Mex Bay (station II).
The highest annual mean concentration of total nitrogen (1297.35 μg/l) reported at El-Mex outlet Station II and the lowest annual mean of 438.14 μg/l observed at station IV (Lake Burullus outlet). while at the adjacent seawater the annual mean values revealed that station II also had the highest value (802.1μg/L) and station VI has the lowest one (328μg/L).
3- Heavy metals
The concentrations of the dissolved heavy metals measured at both the inland sources as well as the receiving seawater were far below the maximum permissible limits of the environmental law 4/1994. Lead and zinc recorded the highest concentrations at both types of water while cobalt and nickel recorded the lowest concentrations and not detected in most samples.
El-Mex area recorded the highest level in heavy metals concentrations.
4- Bacteriological measurements
The total coliforms results showed that the inland sources samples recorded higher geometric mean than the receiving seawater. El-Mex outlet and consequently the adjacent seawater recorded the highest annual geometric means for total and faecal coliform bacteria. While, Damietta Estuary and adjacent seawater reported the lowest annual geometric means for total and faecal coliform bacteria.
5-Algal Count
The highest geometrical annual mean count of the phytoplankton at the inland sources (1.20E+05 units/L) recorded at station IV (Burullus outlet) while the lowest (6.26E+04 units/L) recorded at station I (Nobareya outlet).
At the receiving seawater the lowest geometric annual mean (3.92E+03 units/L) recorded at station I and the highest (8.94E+04 units/L) recorded at station V.
The most dominant species found in the study area during the present work are Nitzschia sp , Asterionella sp, Navicula sp, Ankistrodesmus sp, Cyclotella sp, Anabaena sp, Synedra sp and Oscillatoria sp.
6- Statistical analysis
For the bacterial indicators the correlation coefficient matrix revealed that at the inland sources, the most probable numbers significantly negative correlated with COD and DO, but positively correlated with total alkalinity, turbidity, ammonia, nitrite and total nitrogen, while at the receiving seawater, they positively correlated with BOD, COD, PO4, NH4, NO2, TN and TP whereas negatively correlated with DO and TSS.
At the inland sources, the correlation coefficient matrix showed that the number of algal cells is significantly positive correlated with TSS, whereas negatively correlated with both of nitrate, lead and zinc; while at the receiving seawater it was positively correlated with TSS and ammonia.
So the study recommended the following:
1. 1-Applying the environmental laws for the point sources of pollution discharges to the sea.
2. Control of faecal pollution by biological treatment of sewage before discharging to the sea.
3. Control of fertilizers and pesticides to prevent heavy growth of algae due to excess of phosphorus and nitrogenous compounds and consequently eutrophication.
4. Paying special attention for El-Mex area to reduce the pollution load.
5. Environmental laws must specify characterization of marine water quality after receiving discharges.
6. Environmental laws must specify limits for fecal pollution in the surface water.
7. Due to the shortage of the fresh water, in the future we will depend on the desalination of sea water for drinking, so we must give more attention to the sea water sources to prevent its pollution.