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Abstract The present work aimed to follow up the effect of using different sources of pollutd waters for irrigation on the chemical composition of the irrigated soils for irrigation and to throw light on contents of non-nutrient heavy metals (Ni, Cd, Pb) and micronutrient heavy ones (Fe, CU,Mn and Zn). Three different sources of polluted waters were used, namely sewage water supplied by EI. Gabal EI- Asfar Sludge Station, sewage water supplied by Arab Abou- Saeid SlUdge Station at Helwan and drainage water supplied by EI- Wadi main drain at EI- Fayoum, Governorate. The wastewaters were chemically analysed for their Ee, pH, soluble cations and anions and the micronutrient heavy metals (Fe, Cu, Mn, and Zn) and the non-nutrient heavy metals (Ni, Cd and Pb). Samples of the soils irrigated with the above mentioned wastewaters for periods of less or more than 10 years were collectd and chemically analysed. Also, samples representing the investigated soils in their original states as well as the adjacent soils irrigated with the Nile water were analysed for comparison with the wastewaters irrigated ones. The corn plants grown on the soils under study were analysed for the heavy nutritive and non-nutritive metals since the accumulation of phytotoxic levefs of microelements in the soil from the repeated applications of metal rich wastes is a serious concern of ultimate disposal wastewaters on agricultural land. The results obtained from this study could be summarized in the followina: 1- (A) The water samples of EI~ Gabal E~Asfar were classified as C~1 (modrate salinity hazard and low alkalinity hazard) or C3S1 (medium high salinity hazard and low alkalinity hazard). (B) The water samples of Arab Abou 8aeid Sludge Station, Helwan were classified as C3S1(medium high salinity hazard and low alkalinity hazard) or C4S1 (high salinity hazard and low alkalinity hazard): (C) The water samples of EI~ Fayoum were classified as C4S1 (high salinity hazard and low alkalinity hazard). 2- Concentration of B in all wastewater samples did not exceed the normal limit (0.3 ppm). 3- The concentration of different heavy metals ranged from 0..2 to 0.92, 0.01 to 0.05, 0.02 to 0.16, O.11to 0.35, 0.02 to 0.31, 0.01 to 0.05 and 0.02 to 0.08 for Fe, Cu, In, Ni,Cd and Pb, respectively. 4- Generally, soli organic matter was highest in the sudace layer (0.15 em) and tended to decrease with depth. Prolonging the period of irrigation with wastewaters Increased markedly the organic matter content specially In the surface soli layer. 5- Values of ECin the virgin soils decreased upon cocntinuous irrigation of these soils with wastewaters which was more pronounced in the surface layers. This result is considered a good indicator for the possibility of using such wastewater for leaching salts out of the salt affected soils and consequently saving the Nile water for the other purposes. 6- Most values of pH in the studied soil samples were neutral or slightly alkaline except for that representing fl- Gabal fl- Asfar irrigated with sewage water for a period more than 10 years which was slightly acidic. 7.. In the water extracts of the investigated soils, concentration of soluble Na+ was the highest followed by soluble ca+2 then soluble Mg+2 and finnaly soluble K+’ 8- Soluble CI- ions dominated the anionic composition of the soil-water extracts while the soluble C03-2 Ions were completely absent The soluble HC03- anions fluctuated within a relatively narrow range (1.5 to 6.0 meiO where as soluble 5°4-2 anions fluctuated widely between 1.1 to’ 32 men 9- Values of total and available Fe, Cu. Mn, Zn, N~ Cd and Pb were highest in the surface of the soils (0.15 em) and tended to decrease with depth. Considering soil contents of heavy metals, Fe was found in relatively higher concentration than the other ones. Moreover, soils contents of total as well as available heavy elements increased, in general, upon irrigating them with wastewaters. The increases were more obvious in the surface layers and became more pronunced by prolonging period of irrigation. The results showed the possibility of reusing the investigated polluted waters for irrigation purposes, however, special management for salinity control and sodicity hazards should be followed. Application of wastewatrs enriched soil content in some undesirable heavy metals e.g. Pb was largely increased specially in the surface layers and hence their accumulation presents a long term potential for phytotoxicity. It is worthy to indicate that the presence of CaC03 In soils as well as their relatlve high pH values are factors reducing or delaying the phytotoxicity hazards. It seems that these factors reduce the uptake of micro elements by plants and strongly influence the movement of micro elements to the edible plant parts. 10- Plant samples which were collected from the different studied locations shoWedhigh accumulation of Fe, CU, Mn, Zn, N~ Cd, and Pb in the different organs of corn plants, specially the roots. However, in most cases, concentrations of these elements were below the phytotoxic levels. |