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Abstract - 88 - 5- Summary This study was conducted to investigate the effect of polluted Nile water, industrial waste water and sewage water on soil pollution with some heavy metals. The studied area is extending from Helwan in the north to EI-Saff in the south. It is involving three sites, the first of them is irrigated with sewage water disposed of Helwan Sludge Station at Arab Abou Saeid, the second site is located to the east of EI-Hager irrigation canal and is irrigated with the industrial waste water obtained directly from outlet pipes of the Irom and Steel factory and the third site is located east of El-Khashab canal from which it is irrigated with polluted Nile water. Samples of the soils representing the three investigated sites were physically and chemically analyzed. Measurements of macro nutrients elements as well as the micronutrient ones were conducted. ALso total and DTPA extractable nonnutrient heavy elements were determined. Samples were taken from the waters used for irrigation and analyzed for EC, PH, soluble cations and anions besides of the heavy elements. The results obtained could be summarized in the following: (1) Soil texture at all depths of the investigated soil profiles was shifted slightly forwards the heavier ones and the change was more obvious in the surface layers. (2) Organic matter content increased but was still low, therefore values of the bulk density decreased slightly specially in the surface layer and on the other hand, values of CEC increased and were highest in the surface layers and lowest in the - 89 - deepest ones. (3) Calcium carbonate content, soluble cations i.e. Ca, Mg, Na and K and solub Le anions i.e . HC03, Cl and 804 decreased at all depths of the soil profiles regardless of the quality of water used for irrigation. (4) All water samples were calssified as C3-S1 (of high salinity, hazard and low alkalinity hazard). Also, heavy matals concentrations of the waste waters were within the permissible limits, however, the suspended material in the sewage water II SWT’ and the industrial waste water (IWW) could be considered dangerous in enriching the soil with such heavy elements which might effect negatively crop production. (5) Values of total and available N, P and K, generally, increased and were highest in the surface layers and lowest in the deepest ones. Significant positive correlations were achieved between the total and available values of each of the three fertilizer elements. Also, significant correlation coefficients were found between the organic matter content and total and available N, P and K. (6) Soils contents of total and available Fe, Mn, Zn and Cu increased and also the avilable from of each of these elements as a percent of the corresponding total content increased and in all cases the increase was more pronounced in the surface layers which are characterized by their relatively higher content of the organic matter. Such enrichment of soils with Fe, Mn.Zn and Cu could be attributed beside of the contents the irrigation waters of these heavy elements to the dust fall - 90 - and over flow of liquids wastes loaded by suspended materials rich in these elements onto the soils specially those adjacent to the factories. (7) The polluted waters could not be considered as the factor mainly responsible for polluting soil with lead and Ni since their contents of these elements are very low. Dust fall and pesticides are probably the most important factors in this regard. (8) Significant and positive correlations were achieved between some soil properties (i.e. the organic matter content and clay + silt content) and both total and available contents of Fe,Mn, Zn, Cu, pb and Ni. On the other hand no significant relation was obtained between values of soils pH and their content of total Fe, Mn, zn, Cu, Pb and Ni. However, significant but negatively correlations were achieved between the pH values and the available contents of the abovementioned elements. (9) Soils content of the studies heavy metals are somewhat lower than the permissible limits that might lead to toxisity except of Fe in all the investigated soils and eu and zinc in the surface layers of the SW and IWW irrigated soils, where their contents exceeded the upper values of the permissible levels. However, comparing concentrations of the heavy elements with the permissible limits, it was evident that the investigated soils are undergoing to contain concentrations of these elements toxic to plants. |