Effect of long-term irrigation with sewage effluents on some heavy metals content in plants in El-Gabal El-Asfar farm, Egypt [electronic resource].

Includes references.

Surface soil samples (0-20 cm) were taken from five sites located at Elgabal-Elasfar farm to determine the forms of Zn, Cu, Co, Cd, Ni and Pb in sites. Soil samples were selected to represent irrigated with sewage effluent for 0, 19, 28, 47 and 75 years. The selected soil samples were analyzed for bio-available heavy metals content. These metals were sequentially extracted into operationally defined geochemical fractions (exchangeable, bound to carbonate, bound to Fe-Mn oxides, bound to organic matter and residual forms). The concentration of the studied heavy metals in some vegetable plants (Cauli flower, Spinach and Cucurbit) which grown in the studied sites were determined. The soil irrigated at 75 years with sewage effluent showed increment in the total content of the tested heavy metals as compared with the control (316.9,276.4,19.72,9.31,43.81 and 213.3 ug/g soil for Zn, Cu, Co, Cd, Ni and Pb, respectively. On an average basis, the highest amount of the studied heavy metals associated with organic fraction: 52.7, 49.4, 71.1, 46.1,38.8 and 44.4% for Zn, Cu, Co, Cd, Ni and Pb, respectively. While, the Fe-Mn oxide bound fraction was the dominated form of Zn (27%), Cu (32.7%), Ni (34.4%) and Pb (27.5%). Also, for all the studied heavy metals recoveries from the sequential extraction procedure were within 86.7 to 92.9% for their total concentration. Vegetable plants (Cauli flower, Spinach and Cucurbit ) which grown in soil irrigated at 75 years with sewage effluent showed increment in the concentration of the tested heavy metals as compared with the plants which grown in the control site (268, 43, 2.97,1.26, 41.4 and 9.8 ug/g dry matter for Zn, Cu, Co, Cd, Ni and Pb, respectively).

Summary in Arabic.

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