الفهرس 
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Abstract
This study aimed to use sediments as an indicators for metal pollutions. where heavy metals in sediments may exist in different chemical forms or ways of binding. In unpolluted sediments trace metals are mainly bound to silicates and primary minerals forming relatively immobile species, whereas in polluted ones trace metals are generally more mobile and bound to other sediments phases. In environmental studies the determination of the different ways of binding gives more information on trace metal mobility, as well as on their availability, in comparison with the total element content. As far as heavy metals are concerned sediments are usually sink and may also become source under certain conditions, especially in heavily contaminated areas or in drastically changing environments. Therefore, In that way sediments act only as a temporary reservoir. The results concluded that at Kanater and Cairo area, all heavy metals are relatively stable under normal conditions. This means that there is a low source of pollution arriving to these areas. While at different sites of Helwan area, all heavy metals are relatively stable under normal conditions except for Pb in H2 site (in front of Iron and Steel Factory) which is related to the sources of pollution from iron and steel factory. Also, All heavy metals at the different locations of Talkha and Rahawy drains are relatively stable under normal conditions except for Cd (Talkha), Zn and Mn in both of them which are distributed mainly in the unstable form of exchangeable, carbonate and Fe/Mnoxide. But, In all sludge samples from the different wastewater treatment plants (WWTPs), the speciation pattern of Mn, Ni and Zn were mostly abundant in the exchangeable, carbonate and Fe/Mnoxide forms which are the easily assimilable fractions and showed the greatest degree of their mobility. Cd, Cu, Cr, Fe and Pb were the major in the organic and sulphide which exhibit some degree of mobility and residual form which is named an ?inert phase?, corresponds to the part of the metals which cannot be mobilized. Results showed that EDTA can extracts weakly held heavy metals from a variety of phases in the sediment and effectively dissolves exchangeable, carbonate, Fe/Mnoxide and organic and sulfide fractions. Finally, cement kiln dust is uniquely suited for use as stabilizer material for heavy metal contaminants in sediments and sludges. Therefore it reduces the mobility of heavy metals by increasing the percentages of metal forms in the Fe/Mn oxide and residual fractions. The stabilized sediment or sludge can be used in construction.