الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
5. SUMMARY
The Nile Delta of Egypt represents one of the best agricultural soil in the world. On the other hand, urban encroachment on this agricultural soil consider one of the most serious problems that facing the Egypt, especially in recent years, not only because the danger of losing this fertile soil that formed over many years but also the negative impact of this urban expansion on the remaining agricultural soil that leads to degradation in quality standards of this soils. The main objectives of the current study are to track informal land use changes in a study area, represents the two soil orders Entisols and Vertisols, as well as the impact of these changes on some soil quality indicators that are related to pollution.
To achieve these goals the study included two main parts: first, the use of remote sensing data and geographic information systems with the aid of maps and land classification in tracking the rates of land use change in in the study area. Second, evaluating the impact of these informal land use changes on some of the soil quality indices associated with agricultural soils pollution in the study area.
After studying the soil map of Egypt that was produced by the Academy of Scientific Research and Technology (ASRT, 1982) El-Khanka destrict in Qalubiyah Governorate - Egypt was selected to monitore the land-use changes and calculate the rates of these changes using remote sensing and GIS techniques.
Two types of remote sensing data were used to track urban sprawl in El-Khanka district during the periods of 2000-2007, 2007-2014.
The used data were the U.S. satellite Landsat 7 (ETM+) images in 2000 and 2007, and Landsat 8 image in 2014. A series of image processing and pre-processing steps were applied on the data to reach the highest possible accuracy in tracking and calculation of different land use classes.
The obtained results showed that the total area of the El-Khanka is 66245.24 feddans; Entisols soils represent 58262.6 feddans equivalent to about 88 percent of the total area of the district, while, Vertisols represented 7882.55 feddans (12%). It was found that the informal urban expansions in El-Khanka district reached 7166.700, 9579.060 and 11930.95 feddens during the years 2000, 2007 and 2014 respectively. The results also showed that the rate of loss of agricultural land was 49.2 feddans/ year during the period from 2000 to 2007, while it was 61.5 feddans/ year during the period from 2007 to 2014 .
On the other hand, to track the impact of this informal urban sprawl on some pollution-related soil quality indices, three study sites located in El-Khanka district, two sites in El-Gabal El-Asfar area (representing the Entisols) and irrigated with sewage treated water, and one site in Mostorod area (representing Vertisols) irrigated with water containing both industrial wastes and wastes resulted from urban activates adjacent to agricultural areas.
One soil profile was dug in each location of the three study sites and morphologically descried. Represented soil samples were collected and analyzed. The analyses included soil size distribution, calcium carbonate, soil pH, organic matter content, Soil EC, exchangable sodium percent and anions and cations content.
Also, 33 soil samples collected from the surface layer (0- 30 cm) in the three sites (15 samples collected from Mostorod and 18 samples collected from El-Gabal El-Asfar - 9 from each site). Eight irrigation water samples, five plant samples as well as 8 sediment samples from the bottom of the irrigation canals.
The conducted laboratory analyses were soil pH, Soil EC, ESP, anions and cations content and nitrate content. In addition to the total and available content of some studies heavy metals (lead, nickel, cadmium, chromium, and cobalt) in both soil and sediment samples.
Water samples were analyzed to determine its content of heavy metals and nitrate. Biological analyses were applied to determine COD, BOD, total and fecal coliform, salmonella and shigella bacteria.
Some indices were calculated to assess the degree of contamination and the extent of its association with human factor (Representative of the informal urban sprawl) such as contamination factor (CF), modified degree of contamination (mCd), enrichment factor (EF) and hazard index (HI).
The most important results could be concluded as follow:-
Analyses of soil samples showed that the clay content in Mostorod ranging between 55.8 to 61.8 percent, while the it was ranging between 2.7 to 33 % in El-Gabal El-Asfar. in Mostorod area the pH was high 7.98 - 8.68 compared with El-Gabal El-Asfar 6.86 - 7.85. The electrical conductivity (EC) ranged between 0.84 - 4.27 in Mostorod, while ranged between 1.24 - 5.42 in El-Gabal El-Asfar, which indicate the validity of the soils in both locations to grow most crops and vegetables without adverse impact of salinity.
The results of heavy metals content in the studied soil samples the lead, nickel, cadmium, and cobalt overall content was much higher in Mostorod (Vertisols) compared to El-Gabal El-Asfar soils (Entisols).
The degree of contamination with total cadmium content in Mostorod 4.8 - 7.9 mgkg-1 was higher than the allowed limits mentioned in the reference.
Moreover, the content of the available heavy metals (chemically extracted by DTPA) in soil samples differently behaved compared with the total content behavior of the same element; Pb, Ni. The available heavy metals were higher in El-Gabal El-Asfar soils (Entisols) in comparison with Mostorod (Vertisols) which have a higher proportion of clay content.
The calculated contamination factor for the soil samples (CF) in Mostorod area were greater than 3 in the case of each of lead and cadmium, which indicates that the soil of this area is medium contaminated for lead but high for cadmium.
Sediment analysis, showed that it has high content of heavy metals, where the average content of these elements 561.3, 18.10, 26.63, 52.50, 16.63 mgkg-1 of each of the lead , nickel, cadmium, chromium and cobalt, respectively in Mostorod area. While the averages were 65.54, 0.610, 2.930, 4.650 and 0.990 mgkg-1, respectively, for the same elements in the El-Gabal El-Asfar area. The results of contamination indices indicated that the high content of heavy metals especially for lead and cadmium in sediment in the study areas is due mainly human activities in these areas and not as a result of the presence of these elements in the original parent materials.
The biological analysis of showed that the COD and BOD concentration in the samples of both study areas were higher than the permissible limits where the COD values ranged between 670 - 1606 and 85 - 210 mgL-1 in Mostorod and El-Gabal El-Asfar, respectively. The BOD values ranged between 500 - 700 and 50 - 150 mgL-1 in Mostorod and El-Gabal El-Asfar, respectively. The results also showed that the samples were high contaminated with bacteria (Total coliform and Fecal coliform) and (Salmonella and Shigella) in both study locations.
The chemical analysis of the irrigation water samples in both locations refer to that the heavy metals content was located in the permissible limits of irrigation water recommended by (FAO, 1985). This in accordance with the existence of high content of these metals (either total or available) in the sediment, which refers to the possibility of accumulation of these elements in the sequence of irrigation.
Also the enrichment factor (EF) values in the sediment indicates that Mostorod area (Vertisol and closest to the areas of urban sprawl) is more contaminated compared with El-Gabal El-Asfar area (Entisol).
In general the degree of heavy metal pollution in El-Gabal El-Asfar (Entisols with low content of clay) was less than in the area of Mostorod (Vertisols with rich content of clay). With reference to the agricultural soil in Mostorod area adjacent to the areas of informal urban sprawl and, which causes pollution of irrigation canals, both wastes of factories or car exhaust means adjacent agricultural soils or random residues.
An assessment of the impact of exposure to these heavy elements on human health in the two study areas through the hazard index (HI) indicated that the chromium hazard is high for children in both areas.