الفهرس 
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Abstract
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English Summary
Lake Edku is one of the northern Delta lakes, connected with the Mediterranean Sea through El-Boughaz opening. It is an important fishing area in Egypt. It is exposed to different amounts of serious contaminants, especially heavy metals.
The present thesis entitled (Assessment of some heavy metals in water, sediment, plankton and fish samples in Lake Edku, Egypt) comprises four main chapters to illustrate and explain its environmental condition. Result were obtain through chemical and physical analysis of water, particulate matter, sediment and fish (Oreochromis niloticus) selected seasonally from selected stations covering the whole area of the lake during 2016.
First chapter:
Contained the introduction of the thesis, which discussed overall heavy metal pollution, water pollution (type, source and effect), Eutrophication (causes and effect), water quality in addition to Phytoplankton and Zooplankton community which was given from the published paper.
Second chapter:
Includes literature survey on the texture, especially the concentration of heavy metals in water, sediments and fish, in addition to the nutritious salts, water quality, plant and animal habitats in the study area and in different parts of Egypt and the world. The researches were presented and a mechanism of results and comparisons were also reported.
Third chapter:
This chapter describes as experimental the scientific part of the study and describes the analytical methods applied and used to estimate the different variables of the samples collected from the area under study. These methods include laboratory analyzes to estimate the concentrations of some heavy metals in water, plankton, sediments and fish samples, as well as physico-chemical parameters, different types of dissolved salts and relative estimation of plant and animal species. where 10 stations were selected to cover the lake to collect water, sediment, fish and aquatic
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suspended particulate (plankton) samples during 2016. It also includes the methods of statistical analysis that have been used for the work of correlation matrices and the conclusion of factors common to different transactions. It also includes the assessment of the water quality and the extent of the pollution of the sediments and fish of the lake with heavy metals, as well as the assessment of the diversity index phytoplankton and zooplankton.
Fourth chapter:
This chapter was divided into three divisions that illustrated results and their discussions
Water analysis
Physiochemical analysis
The water temperature ranged between 18.80 during autumn and 31.00 during summer. pH values lie slightly on the alkaline side, with a range of (7.47-9.07). Electrical conductivity (EC) showed a wide range from 0.59 mS/cm in spring to 5.13 mS/cm in winter with an average 1.87± 0.52mS/cm. Salinity ranged between 0.29 and 2.92 PSU with an overall average 0.97±0.29. Chlorophyll-a revealed a wide range (17.20–300.20 μg/l) with an average value of 65.13±18.01 μg/l. The values of dissolved oxygen (DO) and Biological oxygen demand (BOD) ranged (1.56 to 18.10 and an overall average10.11±1.58 mgl-1) and (0.91 and 15.90 with an overall average6.02±1.10mgl-1), respectively. Total suspended solid ranged between 16.00 and 122.00 with an average 37.81±9.86 mg/l.
Nutrient Salts:
Dissolved nitrogen salts (ammonium, nitrite, nitrate, total nitrogen), dissolved phosphorus and dissolved silicate. The values of dissolved ammonium in Lake Edku ranged between the lowest value of (1.54 μM) and the highest value (80.04 μM) at the average of the lake (18.65 ± 13.92 μM). Nitrite fluctuated between the lowest value of (0.11 μM) and the highest value of (37.29 μM) with an overall average (10.72 ± 3.66μM). Nitrate values ranged between (1.33 - 108.38 μM) with average lake average (31.63 ± 12.23 μM). Total Nitrogen values varied between the lowest value of (3.56 μM) and the highest value of (160.05 μM) with an overall average (60.99 ±
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34.43 μM). Dissolved phosphorus value in the lake water ranged between the lowest value of (0.22 μM) and the highest (67.30 μM) with an overall average (11.36 ± 7.00 μM). Dissolved silicates: The value of dissolved silicate ranged between 1.36-70.97 μM with an overall average (19.17 ± 10.23 μM.
- Nitrogen to Phosphorus ratio (N / P): The results indicate the predominance of dissolved nitrogen on phosphorus in all stations except station III (VI, VII).
- Water Quality: The results and readings indicate that the water quality index considered to be good water quality, According to NSF-WQI.
Heavy metals:
• Dissolved heavy metals
The concentration of the iron ranged between the lowest value of (0.60 μg / L) and the highest value of (81.37 μg /L) with an overall average (28.00±7.59 μg /L). The concentration of manganese in water ranged between the lowest value of (4.00 μg /L) and the highest value of (24.47 μg /L) with an overall average (9.89±2.21 μg /L). Copper concentration ranged from 0.33 to 4.50 μg /L with an overall average (1.35 ± 0.37 μg / L). Zinc values fluctuated between (2.87-101.40 μg /L) with an overall average 26.59±13/09 μg/L. The chromium content ranged between the lowest value of (10.07 μg /L) and the highest value of (16.87 μg /L) with an overall average (5.53 ± 3.07 μg /L). Concentration of nickel fluctuated between (0.67 - 7.63 μg /L) with an average of 3.24 ± 0.66 μg /L. Dissolved cadmium value ranged between the lowest value of (0.57 μg /L) and the highest of (2.50 μg /L) with an overall average (1,16 ± 0.16 μg /L).
- Concentrations of different elements of heavy metals in water did not exceed the permissible limits from EEAA, EPA, USEPA, FEPA, WHO.
• Suspended heavy metals
The concentration of iron ranged between the lowest value of (0.58 g/kg) and the highest value of (42.89 g/kg) with an overall average (7.97±3.13 g/kg). Concentration of manganese ranged between the minimum value of (0.11 g/kg) and the maximum value of (1.77 g/kg) with an overall average (0.85 ± 0.34 g/kg). Copper concentration ranged from 16.77 to 104.29 mg/kg with an overall average of 49.23± 12.09 mg/kg.
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Zinc concentration ranged between 0.11 to 1.77 mg/kg with an overall average (0.85 ± 0.34 mg/kg). chromium concentration recorded a lowest value 0.01g/kg and highest value 0.10 g/kg with an overall average 0.04± 0.01 g/kg. Nickel concentration ranged between 0.06 to 0.67 mg/kg with an average (0.25± 0.08 mg/kg). Cadmium concentration recorded a highest value (0.06 g/kg) with an overall average (0.02 ± 0.01 g/kg).
• Heavy metals in sediments
The concentration of iron ranged between (39.30 g/kg) and (69.57 g/kg) with an average value (50.25± 7.75 g/kg). Concentration of manganese ranged between the lowest value of (0.46 g/kg) and the highest of (3.11 g/kg) with an average (1.56± 0.76 g/kg). The concentration of copper ranged between (5.40 to 23.20 mg/kg) with an average of (14.09± 6.43 mg/kg). Zinc concentration ranged from 36.80 to 90.00 mg/kg with an average of 65.94± 16.67 mg/kg. The concentration of chromium ranged between the lowest value of (65.30 mg/kg) and the highest value of (136.80 mg/kg) with an overall average (89.08 ± 21.85 mg/kg). Concentration of nickel fluctuated between (13.00 and 53.30 mg/kg and an overall average of 35.35± 12.05 mg/kg. Cadmium concentration ranged between the lowest value (0.40 mg/kg) and the highest of (2.10 mg/kg) and an overall average (0.99 ± 0.59 mg/kg).
- Concentrations of different elements of heavy metals in sediment did not exceed the permissible limits that permitted by the Canadian Environmental Quality (CEQG).
- chromium and nickel exceed the permissible limits according to (FAO, USEPA, WHO 2004, CEQG).
- All stations and element fluctuated between unpolluted to moderate pollution this refers to anthropogenic pollution input.
- Iron, chromium and manganese recorded a highest geoaccumulation index that refers to Increase the rate of input and deposition of these metals in the lake.
• Heavy metals in the different tissues (muscles, bone, gills and skin) of tilapia
The concentration of iron in the different tissues of the tilapia fish that collected from the lake ranged between the lowest value of (15.95 mg/kg) and the highest value of (23.38 mg/kg) and the overall average of the lake (18.83±3.27 mg/kg) for the muscle,
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ranging from 5.62 to 37.22 with an average 18.81±13.99 mg/kg for bone, ranging from 102.70 to 150.40 mg/kg, with an average 115.55 ± 32.00 mg/Kg for gills and fluctuated between 5.62 and 18.81 with an average 13.99 mg/kg in skin. Concentration of manganese ranged from 1.19 to 6.24 mg/kg with an average 2.61±2.43 in muscle tissue, fluctuated between 2.00 to 15.76 mg/kg, and an average 8.36± 7.19 mg/kg, ranged between 1.23 to 11.36 with an average 7.23±4.82 in the bone, ranged between (1.65-42.50 with an average of 26.81±18.77 for gills, the concentration of manganese can arranged in different organs and tissues, as gills>skin>bone>muscles. Copper concentrations at different tissues fluctuated between (0.13 to 0.78 with an average of 0.52±0.29 mg/kg, 0.45 to 3.94 with an average of 1.46±1.67 mg/kg, 0.17 to 0.59 and an average 0.43 ±0.18 mg/kg and 0.21 to 1.4.14 and an average 1.64 ± 1.91 mg/kg) for muscle, skin, bone and gills. Zinc concentrations ranged from 8.10 to 34.80 with an average of 17.68±12.42 mg/kg, 13.00 to 111.40 with an average of 48.80±43.27 mg/kg, 0.36 to 43.42 and an average18. 48± 19.47 and between 6.28 to 124.97 and mean 48.34±54.34) for muscle>skin> bone>gill respectively. The concentration of chromium ranged between 0.97 to 3.26 mg/kg with an average (3.26±3.12 mg/kg) in muscle (0.69 to 2.93 mg / kg with an average 1.46±1.05 mg/kg) for skin, 0.06 to 1.37 With an average of 0.49±0.60mg/kg) for bone and fluctuated between (0.07 to 1.99 with an average of 0.92 ± 0.96 mg/kg) in the gills. chromium concentration can be arranged in different organs and tissues as muscle > skin> gills> skin. The concentrations of nickel fluctuated from 0.03 to 0.05 with an average of 0.04±0.01, ranged from 0.03 to 0.10 and with an average of 0.07±0.03, ranged from 0.02 to 0.10, with an average of 0.05±0.04, and ranged between 0.01 to 0.08 and an average of 0.06± 0.03 mg/kg for muscles, skin, bone and gills respectively. The concentrations of cadmium ranged from 0.02 to 0.67 with an average 0.23±0.30, ranged from 0.06 to 1.42, and with an average 0.42±0.67, ranged from 0.04 to 0.30, with an average of 0.16±0.11, and ranged from 0.03 to 076 with an average 0.37 ± 0.38 mg/kg for Muscles, skin, bone and gills respectively.
• Previous results of concentrations of heavy metals in different tissues in the present study were evaluated for risk (THQ). The results showed that the concentration of cadmium is higher for the rest of the other elements and the concentration of metals within the safe concentrations of the internationally permissible limits.
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• Phytoplankton:
Phytoplankton community in the investigated area recorded a total of 30 phytoplankton taxa were identified belonging to four genera represented by nine groups. Chlorophceae comprised the highest abundance 55.66 % with total count 1578 x 105 cells l−1 represented by common 13 species, while Bacillariophyceae 32.20 % with total count 913 x 105 cells l−1 comprised six species. Euglenozoa represented with an abundance 10.86% with total count 308 x 105 cells l−1. Cyanobacteria, were rarely recorded, contributing about 1.27 % with a total count 36 x 105 cells l−1. Summer recorded a highest value of Phytoplankton, which recorded 1498 x 105 cells l−1 with percentage 52.84%while autumn recorded a lowest value which recorded 416 x 105 cells l−1 with a percentage 14.67% (5.18%, 2.42% and 17.09%) respectively, During the fall by 48.08% followed by green algae by 46.63% and then iodine by 4.33%. The dominant species during the four seasons were Thalassiosira (17.55%) followed by Melosira (8.10%), Chlorella (17.55), Oocystis (8.10%), and Chlorella (60.89%) followed by Closterium 9.27, which belong to Chlorophyceae. Closterium recorded 10.28%, Scenedesmus 9.48% and Euglenaceae 17.09%. In the autumn, Ankistrodesmus recorded 9.62%, which belongs to Chlorophyceae, followed by Thalassiosira 9.13% which belongs to diatoms.
- The diversity index for phytoplankton varied between the lowest value of 1.36 in station ST5 during the spring season and the highest value of 2.85 for the same station during the summer. The number of individuals recorded the lowest value of 46 in Station No. ST4 during the spring season, when the highest value of 414 was recorded in station ST5 during the summer with a general average of Lake 141. The abundance of diversity recorded the lowest value of 6 at station ST3 during the spring, with the highest value of 22 in Station ST5 during the summer. Species Evenness ranged between 0.57 during the spring season in Station ST5 and recorded the highest value in Station ST5 during the autumn.
- Shannon-weaver diversity Indices refers to that water fluctuated between moderate to light pollution, Diversity index refer to a high evenness and richness.
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Zooplankton
The common Zooplankton community in Lake Edku contains six common species belonged to three groups and tow phylum. Crustacean and Rotifers Phylum formed the majority of total distribution in lake with annual percentage 55% and 45 % and total a count 933 ×103/L and 776 ×103/L respectively. Brachionus, Cyclopoida, , Calanoida, Asplanchna, Daphniidae, Nauplius recorded most abundance of Zooplankton were present all year with a percentage 32% , 21% , 15% , 13 % 10% and 9% ; and total a count 548×103/L, 367×103/L , 251×103/L, 228 ×103/L, 167×103/L , 148×103 /L respectively .Seasonal distribution of common Zooplankton at Edku lake Cyclopoida, Brachionus, Calanoida recorded most dominated species at the winter with a percentage 42% , 30%, 15% and count 130× 103/L, 94×103/L, 45×103/L respectively. 38% of Brachionuswith count 346×103, Cyclopoida with percentage 15% with count 143× 103/L, Calanoida with a percentage 13.5% and count 125×103 was most dominated species at spring. In the summer and autumn Brachionus was the most dominated species in the lake with a percentage 22% and 26% and count 89× 103and 19× 103, followed by Cyclopoida with a percentage 18% and 26% and count 75×103 /L and 19 ×103/L. Calanoida recorded the third position with a percentage 16% and 22% and count 65×103/L and 16×103/L respectively. Daphniidae recorded a percentage 4% with a count 12 ×103 /L at winter, 6% with a count 52×103 /L at spring, 25% with a count 101 ×103/L at summer and 3% with count 2×103 /L at autumn. The diversity index for Zooplankton ranged between 0.85 at station ST5 in winter and 1.7 at station ST4 in spring. Number of individuals ranged between the lowest value of 6 at Station ST5 in autumn and the highest value of 529 at station ST3 in spring with an average 85 individuals. Species evenness between different species fluctuated between 0.32 in winter at Station ST5, and the highest value of 1.17 at station ST4 in summer.
Statistical analysis
The correlation analysis between the studied elements, component analysis and the main factor analysis was used to assess the extent of the lake pollution in the presence of the different variables, which showed that there are three main factors that control the concentrations in the lake. This was done using SPSS.23.
This result proves the importance of performing measurements of contaminants in various compartments of Lake Ecosystem, including sediment, biota, and suspended particulate matter for proper management.