الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Land degradation is considered one of the most serious environmental issues. Land use changes from agriculture to other uses and the use of low-quality water are the main issues causing soil degradation in the Nile Delta areas. One of the major drains in the Nile Delta area was the Kitchener drain started from south to north till it reaches the Mediterranean Sea with an average annual discharge of 1.8 billion cubic meters. Currently, most of irrigation water in the irrigation canals are mixed with drainage water and used for irrigation. Also, drainage water from Kitchener drain was used directly for irrigation in many places in the northern part. The current study aims to track and measure the changes of land use in the study area; analyze the physical and chemical indicators of soil quality and the Kitchener drain’s water quality; and assess the impacts of land-use changes on agricultural soil and water qualities in the study area.
To achieve the study objectives a study area was outlined using ArcGIS software by creating a 10 km buffering zone along the banks of A 60-km-long of the Kitchener drain. Landsat satellite data images for 2000, 2010 and 2020 were selected as remote sensing data source to monitor land-use changes for 20 years period. Digital land use maps have been produced, using the IDW approach. A field campaign was performed for collecting water, sediments and soil samples and information on existing land use types. During the fieldwork, twenty-six soil profiles were dug in 26 sites distributed in El-Gharbia (seven sites) and Kafr El-Sheikh (19 sites) Governorates. Soil samples were collected from various depths, air dried and then sieved through 2 mm sieve before laboratory analysis. Twenty-six samples of irrigation water and 26 sediment samples were collected. The collected water, sediment and soil samples were analyzed in laboratory. The water samples were analyzed to determine pH, ECw, Cations and anions, NO3-, NH4+, PO43-, heavy metals content (Pb, Cd and Co). The collected soil samples were examined to determine pH, ECe, cations and anions, available N, K, and P, as well as texture, bulk density, calcium carbonate %, and organic matter content. Some biological parameters also determined in both water and sediments samples including Total coliforms, Feacal coliforms and salmonella & shigella. Moreover, total heavy metals (Pb, Cd and Co) were analyzed in both soil and sediment samples. Some equations were employed to calculate indices that evaluate the degree of contamination including “contamination factor” (CF), “modified degree of contamination” (mCd) and “enrichment factor” (EF). Finally, the soil quality in the study area was assessed by calculating the soil quality index (SQI) and mapping its distribution.
The assessment of Land-use changes was covering about 600 Km2. Results illustrated that the urban class occupied 49.40, 75.74 and 80.98 Km2 of the total studied area in the years 2000, 2010 and 2020, respectively. During this period, urban expansion showed two different patterns of land- use change to urban expansion: a considerable rate phase during 2000 – 2010 and a low rate during 2010 – 2020. Furthermore, the rate of loss of cultivated area was 24.93 Km2 (2.49 Km2/year) and 6.11 Km2 (0.61 Km2/year) within the periods from 2000 to 2010 and from 2010 to 2020, respectively.
The results of water samples analyses revealed that nitrate (NO3-) concentrations were above the permissible limit in sites 2 and 6. phosphate (PO43-) concentrations were above permissible limit in site 3 and 4 in El-Gharbia sites. On the other hand, in Kafr El-Sheikh, nitrate concentrations were above the permissible limit in site 10, 11, 12, 14, 18, 24, 25, 26. While, phosphate (PO43-) concentrations were above permissible limit in site 8 and 24. Whereas, all ammonium (NH4+) concentrations were within permissible limit of 5 mgL-1 in all studied sites. All water samples have Cd concentrations above the permissible limit in both El-Gharbia and Kafr El-Sheikh sites. Furthermore, analyses of water samples indicated that total and faecal coliform counts were above permissible limit in most sites.
The results of sediments analyses showed that the total Pb ranged between 3.90 (site 7) to 108.8 (site 3) mgkg-1 while, total Cd ranged between 1.10 (site 7) to 3.82 (site 2) mgkg-1. Total Co ranged between 34.5 (site 5) to 46.9 (site 7) mgkg-1 in El-Gharbia. On the other hand, in Kafr El-Sheikh sites, total lead ranged between 13.1 (site 8) to 65.1 (site 26) mgkg-1 while, total Cd ranged between 3.33 (site 8) to 14.6 (site 26) mgkg-1. Total Co ranged between 19.8 (site 20) to 49.0 (site 25) mgkg-1. This high level of heavy metals, especially Cd, in sediments of Kitchener drain may be attributed to increased rate of non-treatment industrial waste discharge in the drain or the sub-drains and the application of excusive phosphatic fertilizers. The enrichment factor (EF) showed a significant level in all sites in Kafr El-Sheikh except sites 8 and 9 which indicated moderate level with Pb. Whereas, Cd showed extremely high in all sites while Co revealed significant level in all sampling sites except site 20 which showed moderate EF. The counts of bacterial indicator in the sediment samples were higher compared with water samples for each of the sampling sites.
Analyses of soil samples revealed that the clay percent ranged from 48.72 up to 67.60 % in El-Gharbia and 39.95 up to 75.85 % in Kafr El-Sheikh. soil bulk density increases with depth in both El-Gharbia and Kafr El-Sheikh with some exceptions. Generally, Sodium cation Na+ represented the dominant cation followed by Ca2+ and Mg2+ whereas K+ was the lowest one. The sulfate (SO42-) was the dominant anion followed by Cl- and HCO3- . Also, sodium adsorption ratio (SAR) ranged between 1.16 and 8.44 in El-Gharbia, and between 1.99 and 12.12 in Kafr El-Sheikh.
Analyses of the surface soil samples indicated that all total cadmium concentrations were above the permissible limit in both El-Gharbia and Kafr El-Sheikh with the exception of site (3) in El-Gharbia. Moreover, total cobalt concentrations were above permissible limit in some sites in both El Gharbia and Kafr El Sheikh Governorates. The Contamination Factor (CF) and Modified degree of contamination (mCd) values showed that, the highest (CF) values of Pb (1.80) categorized the soils as moderate contamination, Cd (22.22) classified as very high contamination and Co (5.46) graded as considerable contamination. The highest mCd (9.33) was observed in site (6) in El-Gharbia while, in Kafr El-Sheikh the highest (CF) values of Pb (7.67) categorized as very high contamination, Cd (30.59) classified as very high contamination and Co (5.36) graded as considerable contamination. The highest mCd (14.17) was observed in site (22). These high values may be attributed to the quantity of industrial and municipal wastewater discharged into drain. The spatial distribution of Contamination factor for Pb in the studied area showed that about 5.041, 38.66, 36.10 and 20.21 % of the total studied area are in “low”, “moderate”, “considerable” and “very high”, respectively. Regarding the CF of Cd, the whole studied area was represented by “very high” class. While Contamination factor for Co showed that 99.89 % of the total studied area classified as “considerable” but only 0.112 % was “moderate”. The results of Enrichment factor in both El-Gharbia and Kafr El-Sheikh sites indicated that the soil of these areas was enriched with Pb, Cd and Co due to human activities. Finally, the soil quality index (SQI) was calculated as a quantitative tool to establish linkage between soil quality including physical, chemical, and biological properties of soil and the management. The study area was sited in 4 classes: Very high, High, Moderate and Low classes. The “Moderate” soil quality class occupied about 80.9 % of the total study area while, “Low” soil quality occupied only 3.0 % of the total area. Most low soil quality areas were nearby urban and industrial areas. Those urban and industrial sites play as pollution sources affecting water and soil in the area. Soils in the study area is irrigated from kitchener drain that receives pollutants from various effluents such as agricultural drainage water domestic water, and industrial water.
from the obtained results and discussions, it was found that urbanization is one of the major sources of contamination of agriculture soil and irrigation water. The Contamination Factor (CF) values showed the highest (CF) values of Pb categorized the soils as moderate contamination and classified as very high contamination while, Co graded as considerable contamination. Moreover, pollution was found higher in Kafr El-Sheikh sites than El-Gharbia sites. Increasing concentration of nitrate and cadmium in water and rising pathogenic bacteria counts reflecting that Kitchener drain is considered inappropriate for agricultural purposes. Soil quality evaluation in the study area indicated moderate soil quality represented the predominate grade in study area. Furthermore, most low soil quality areas are adjacent to land use change areas from agriculture to urban land use.
Therefore, the obtained data and discussions suggests that more serious attention should be given to reduce urban sprawl on arable lands, especially in the Nile Delta areas, as it was from the most fertile land. Urgent attention should be given to increase sanitary sewage services since some villages in the study area dump the sewage water directly into the drains. Overall, this study emphasizes the need to avoid the use of low-quality water for irrigation. Continuous use of low-quality water can cause significant effect on soil quality degradation. Therefore, the use of Kitchener drain water for irrigation is not recommended. Use of wastewater treatment plants regularly so that wastewater is not discharged before it is treated.