Organic and inorganic remediations of contaminated soils with heavy metals resulted from some anthropogenic avtivities [electronic resource].

Includes reference.

Soils can naturally reduce mobility and bioavailability of heavy metals as they are retained in soil by sorption, precipitation and complexation reactions. These natural processes can be accelerated by addition of some soil amendments, which converting the soluble forms to more geochemical stable solid phases. Hence, the current study represents a trial towards ameliorating soils polluted with heavy metals resulted from some anthropogenic activity. To achieve this target, in situ an incubation experiment was executed on two soil samples taken from EI-Gabal El-Asfar farm (Qalubia Governorate) and EI-Saff (Giza Governorate), subjected to heavy metals pollution due to irrigating with sewage effluent and industrial wastes, respectively. The studied two soils were mixed thoroughly in pots of 200 g soil capacity with some soil amendments, Le., poultry manure, organic Gompost and bentonite at a rate of2 %, then the pots were daily wetted wit distilled water to reach a constant moisture content (field capacity) and incubated under room temperature at different periods of0, 25,50 and 75 days. Soil samples were taken to identify the effective role of the applied soil amendments throughout the different incubation periods; however, the values of EDTA-extractable Ni, Co and Cd were determined. The most important obtained results could be .summarized in the following: 1. EDTA-extractable amounts of Ni, Co and Cd showed a progressively decreased in both amended soils with poultry manure, with a more effective role by increasing time of incubation period. The removed amounts of the studied metals for both investigated soils followed •the descending order: Ni > Co > Cd. Also, the removal capacity of poultry manure seemed a highest figure with Ni, lowest with Co and intermediate with Cd. 2. Application of organic compost led to minimize the value of EDTA-extractable Ni, Co and Cd in both soils under study. The adsorbed amounts of these metals in EI-Gabal EI-Asfar soil exceeded obviously the corresponding ones in EI-Saffsoil. This trend was emphasized by the removal capacity of the compost for Ni, Co and Cd, which was recorded higher values in EI-Gabal EIAsfar soil than in EI-Saff one. 3. Values of EDTA-extractable Ni, Co and Cd from both the bentonite amended soils also showed progressively decreased with increasing the incubation period. The absolute adsorbed amounts of Ni were the highest, whereas those of Co and Cd were the lowest and intermediate, respectively, in the bentonite amended soils. In general, the removal capacity of bentonite for Ni was higher than Co and Cd over the studied incubation periods. It is noticed that the removal capacity of bentonite for Co was almost similar over all the incubation periods.

Summary in Arabic.

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