الفهرس 
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Abstract
Bahr Yusuf is connecting the Nile River via the Ibrahimia Canal. With about length of 315 km, Bahr Yusuf Canal runs northward to irrigate lands of west Assiut, west El-Menyia, Beni-suef, Fayoum, and Giza governorates. Bahr Yusuf Canal takes a zigzag course of about 276 km until it reaches Fayoum depression through Hawara Gap where Lahoon regulator exists. It was natural cut through the mountain bordering the Libyan desert, with 16 km long and 1.5 km wide and was connecting the Nile to Moreis Lake (now it is known as Qarun Lake) that was used as a reservoir for the Nile water during the flood period. During the 12th dynasty, King Amenemhat III constructed the artificial canal (Old Bahr Yusuf Canal) to restore about 13 BCM each year of flood water in Moreis Lake. The artificial canal, 15km long, 5m depth, and trapezoidal shape with a 600 m width at the bottom, was dug along the natural incline of the valley. At Al-Lahoon barrages, Bahr Yusuf Canal proper branches to many streams including three main canals, the first one is the Giza Canal (or ”Beni-Suef”- Bahr Yusuf segment) that was diverted northeastward in westnorth Beni-Suef and Giza districts. While the other two branches, known as Bahr Yusuf and Bahr Hassan Wasef canals, veer west into Fayoum depression.
In Fayoum province, the section of Bahr Yusuf Canal extends about 24km length, 3-5 m depth and 30-50 m width. Numerous canals take their water from Bahr Yusuf (the major one is Bahr Wahby Canal that transfers water to northern areas) and distribute it over the Fayoum land. In addition, Bahr Yusuf, together with Bahr Hassan WasefCanals, provide the water demand for more than 3.5 million capita for different human activities and served about 454,700 Feddans (1 Feddan = 4200 m2) of the agricultural land in Fayoum province. However, Bahr Yusuf, in Fayoum district, is exposed to many sources of pollution include agricultural runoff and domestic sewage effluents of the neighboring houses along the two banks of the canal.
Twelve subsurface water samples are collected seasonally during (2017). The present work is the first study devoted to evaluate the capability of Bahr Yusuf Canal water for different purposes, and to assess the potential health risk that may be caused by consumption of its water. Therefore, this study was carried out to achieve the following objectives. (a) To evaluate the spatial-temporal variations of physicochemical characteristics and trace element levels in the canal’s water. (b) To indicate the viability of the water for the various utilizations as drinking, irrigation, and aquatic life habitat using different water Quality Indices and heavy metal pollution load. (c)To assess the possible chemical toxicity and the hazard health risk due to the presence of trace elements in the canal water.
The present work includes three chapters a brief description of them is given as follow:
The first chapter is related to introduction and the literature survey for physicochemical characteristics and trace element levels.
The second chapter contains the experimental parts including sampling techniques, description of the selection, investigated sampling stations and describing the methods applied to determine the physico-chemical properties in water and heavy metals in water.
. The third chapter includes the obtained results and their discussion and data analysis as the following during the period of study and discussion of these results obtained which can be summarized as follow: -
Water analysis
1- Physical characteristics
1-1-Temperature:
Temperature ranged from 19.0 oC to 30.5 oC. ANOVA showed a highlytemporal significant difference (p< 0.01).
1-2-Transparency:
Transparency was affected by domestic sewage effluents and flow level, it has fluctuated between 34 and 94 cm. ANOVA results show a high temporal significant difference (p< 0.01) for transparencyvalue.
1-3-Electrical conductivity (EC):
EC varied in the ranges of 406 - 495, 353 - 505, 313 -446 and 518 – 592 μs/cm during winter, spring, summer, and autumn, respectively with a highly temporal significant difference (p< 0.01).
1-4-Total solids (TS):
The total solids (TS) content is a very useful parameter describing the chemical constituents of water. It is affected greatly by discharged effluents and the obtained values were in the range of (204.6-375.8mg/L).
1-5-Total Dissolved Solids (TDS):
TDS values fluctuated between (187.8- 355.2 mg/L). The maximum value was recorded during autumn. On the other side, the minimum value of TDS (187.8mg/L) recorded during summer. The lowest value of TDS may be due to the raising of water level during flood period.
1-6-Total Suspended Solids (TSS):
TSS ranged between7.20– 78.80mg/L. TSS showed an opposite trend to transparency values, where the highestvalues were recorded in autumn, while summer recorded the lowest TSS contents.
2-Chemical characteristics
2-1-The hydrogen ion concentration (pH):
pH values were in the acceptable ranges for the different usages. It was in the alkaline side (7.49–8.38) reflecting the increase in photosynthetic activity of planktonic algae, with a highly temporal significant difference (p< 0.01).
2-2-Dissolved oxygen (DO):
DO values ranged between (6.52- 9.30mg/L). The highest values of DO that were recorded during spring may be attributed to the increase of photosynthesis activity, which liberate a significant amount of oxygen to surrounding water ecosystem.
2-3-Biological oxygen demand (BOD):
BOD is a good indicator of organic pollution in rivers. It ranged between (2.93- 6.32 mg/L). The maximum value of BOD was observed during summer and this may due to the activity of microorganisms and a higher rate of decomposition of organic matter at high temperature.
2-4-Chemical oxygen demand (COD):
COD are of great importance where the BOD values cannot be determined accurately. COD values fluctuated between (5.0- 10.2 mg/L). The highest content of COD was recorded during autumn at low water level.
2-5-Major anions and cations:
2-5-1-Carbonate Alkalinity and bicarbonate Alkalinity:
CO3-2 and HCO3-concentrations were varied in the ranges of2.16-9.60and 114.35-187.29 mg/L, respectively, with significant seasonal variations (p <0.01). Bicarbonates are the most abundant anions, in stream water. It recorded the highest values during the spring season.
2-5-2-Chloride:
Chloride values ranged between (15.22- 27.62mg/L).
2-5-3-Sulphate:
Sulphate values ranged between (9.88- 19.17mg/L).
2-6-1-Calcium:
Calcium concentrations varied between (14.65- 26.03mg/L).
2-6-2-Magnesium:
Magnesium values ranged between (11.4-18.9mg/L).
2-6-3-Sodium:
Sodium values ranged between (17.73- 23.28mg/L).
2-6-7-Potassium:
Potassium values ranged between (4.3-6.55mg/L).
2-7-Basic nutrient salts and chlorophyll a
The nutrient salts include compounds that contain nitrogen (NH3, NO2-, NO3- and TN), phosphorus (ortho-P, TP) or silicate (SiO23-) in different forms either in available or non-available forms. The basic nutrient salts show highly temporal significant differences (p<0.01).
2-7-1-Amonia
The ammonia concentrations changed in the ranges of 111.4-331.0 µg/L. The increase of ammonia levels in autumn may be attributed to the denitrification process.
2-7-2-Nitrate concentrations changed in the ranges of 52.92-707 µg/L.
2-7-3-Nitrite concentrations changed in the ranges of 4.8 – 45.2µg/L.
2-7-4- total nitrogen
The total nitrogen concentrationshave changed in the ranges of 436-1393µg/L. The highest contents of TN was recorded during the cold seasons (autumn and winter) revealing the impact of the different wastes at the low water level (drought period).
2-7-5- orthophosphate
The orthophosphate concentrations changed in the ranges of 7.22-25.33µg/L.
2-7-6- Total phosphate
The total phosphate concentrations changed in the ranges of 45.6 – 167.0µg/L. The orthophosphate and total phosphorus showed a remarkable increase during the drought period.
2-7-7-Silicate The Silicate concentrationschanged in the ranges of2.20 – 7.86mg/L
2-7-8- Chlorophyll-a
Chlorophyll-a can be used as an indicator parameter for the quality and health of the water bodies. The values of chlorophyll a in Bahr Yusuf Canal water varied in the ranges (13.96-44.47) μg/L
3- Boron and Heavy Metals
Boron and most heavy metals concentrations showed highly significant differences (p <0.01) among different seasons, where the lowest values were measured in summer coinciding with high flow level for Bahr Yusuf Canal while the highest values were recorded in autumn.
3-1- Boron
Boron contents in Bahr Yusuf Canal were much lower than the national and international acceptable levels for the different purposes, they have been ranged between 25.38 and 77.22 µg/L with a high significant temporal difference (p < 0.01).
3-2-Iorn
Fe concentrations were in the ranges of (169.55-568.4)µg/L with high significant temporal variations (p < 0.01). The present results in several cases exceed the permissible national and international limits (300 μg/L of Fe), which is a bad indication for the water criteria of Bahr Yusuf Canal.
3-2-manganese
Mn concentrations were in the ranges of (34.27-69.35) µg/L. with high significant temporal variations (p < 0.01). The present results in several cases exceed the permissible international (0.05 of Mn) for drinking and aquatic life utilizations, which is a bad indication for the water criteria of Bahr Yusuf Canal.
3-4- Aluminum
Aluminum level in general, was within the allowable national and international standard levels for drinking and irrigation water (200 and 5000 µg/L, respectively). While it showed exception override for aquatic life (100µg/L) during autumn and winter seasons affected with the impact of wastes during the drought period. It ranged between 49.27 and 145.77 µg/L with highly significant differences among the sites (p < 0.01).
3-5- Nickel
Nickel -in many sites-has exceeded the acceptable limits for drinking water (20μg/L) and aquatic life (25 μg/L), it was in the range of 16.07-47.56 μg/L, with a highly significant temporal difference (p <0.01).
3-6-Copper
The concentrations of Cu were below the guidelines for drinking and irrigation water, while Cu exceeded the allowable limits for the aquatic life. Cu were in the ranges of 3.04-13.94 μg/L with highly significant temporal variations (p < 0.01).
3-7-Zinc
The concentrations were in the ranges of 16.03-42.18 μg/L with highly significant temporal variations (p < 0.01).
3-8-Chromium
The concentrations of Cr were in the range 8.62-21.44 μg/L with highly significant temporal variations (p < 0.01).
3-9-Cadmium
Cd fluctuated between 1.86 -8.25 µg/L that exceed the guidelines of drinking and aquatic life water, for some samples especially during the drought period.
3-10-Lead
Pb concentrations fluctuated between 17.62 – 49.62 µg/L that exceed the guidelines of drinking and aquatic life water, for most samples.
4- Water Quality Index (WQI):
Several indices were used to assess the water quality of Bahr Yusuf Canal, include Aquatic Toxicity index (ATI), Canadian Water Quality index (CWQI), Oregon Water Quality Index (OWQI) and Weighted Arithmetic Water Quality index (WAWQI). The OWQI score ranged between 58.82 and 64.77 with a mean value of 61.6 for the whole canal. On the contrary, the results of the ATI give an idea about the suitability of water quality for all fish species, where ATI ranged between 87.77 and 90.26. Based on CWQI results, the canal water was classified as fair (WQI=73), good (WQI=92) and marginal (WQI=64) for drinking water, irrigation and aquatic life employments, respectively. CWQI indicated that Bahr Yusuf Canal may be somewhat suitable for drinking water and irrigation usages, but it is an inconvenient habitat for the aquatic life.
According to WAWQI, Bahr Yusuf Canal water is classified as excellent, from good to poor, and from good to excellent for irrigation, drinking and aquatic life utilizations, respectively. where the corresponding values of WAWQI were in the ranges 0.87 - 2.02, 36.09 – 65.36 and 17.16-39.03, respectively.
5- Heavy Pollution index (HPI)
The Heavy pollution index for Bahr Yusuf Canal water has changed from 104.44 to 206.32, 16.81 to 38.48 and 219.07 to 472.24 for drinking, irrigation, and aquatic life usages, respectively. These results have demonstrated that all the studied metals did not cause a polluted effect for irrigation utilization, but Bahr Yusuf Canal suffers from different contamination grades with the studied metals concerning aquatic life and drinking uses.
6-Human Health Risk
The obtained results showed that HQoral were much higher than HQdermal, they ranged from 2.98 x 10-3 to 3.22 x 10-1 and 3.3 x 10-2 to 9.16 x 10-6 for respectively, where Cd and Zn have recorded the highest and lowest HQoral and HQdermal values, respectively. Generally, the HQ and HI values were < 1 that indicates that the entire study area hasn’t non-carcinogenic risk due to consumption and using of the water of Bahr Yusuf Canal water.