Date of Award

12-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Ahmed Murad,

Second Advisor

Warren W. Wood,

Third Advisor

Mohamed El -Tokhi,

Abstract

Assessment of availability and mobility is required to predict the behavior of heavy metals in dam's sediments, which hold up rainwater and make use of them. Therefore, a total number of ninety-three of sediments samples collected from the major dams AI-Shuweib, AI-Bih, AI-Tawiyeen and Ham dam were analyzed by several sedimentological and geochemical analyses procedures for Cu, Cd, Cr, Pb, Zn, AI, and Fe. The samples were investigated for mineralogy using X-ray diffraction analyses for non-clay and clay fractions. ICP-OES and Atomic Absorption Spectrophotometer (AAS) were used to measure the concentration of heavy metals. The statistical treatments and graphical presentations of the obtained data are conducted by means of Excel (Microsoft office 2003, windows xp). The correlation matrixes of the obtained data of the chemical and controlling parameters prepared using JUMPlN and SPSS version software. Google Earth software was used to percent the location of the studied areas and GIS used to distribute the histogram of element on the maps.

Sequential extraction procedures were used to predict the percentages of the Cu, Cd, Cr, Pb, and Zn presences in each of the sediments geochemical phases. The non-clay minerals of the sand size fraction are composed mainly of quartz, calcite, dolomite, serpentine, plagioclase, amphibole, and pyroxene. The clay mineral assemblage encountered in the analyzed samples is composed of quartz as major mineral, Illite as subordinate mineral and chlorite as minor mineral. These mineral phases are not likely to contribute to the metal load or act as source of toxic heavy metals. The studied sediments samples from the dams were not enriched with Cu, Cd, Cr, Pb, Zn, AI, as evident from the calculations of the enrichment factor; however, the sediment were slightly enriched with Fe.

According to the index of geoaccumulation, the sediments of the investigated area can be described as uncontaminated with respect to Cu, Cd, Cr, Pb, Zn, and uncontaminated to moderately contaminate with respect to AI and Fe. The measured metals correlated positively with the determined physiochemical factor such as pH, TDS, CaCO3, TOM, P2O5, and CEC differentiated depend on the nature and grain size of each dam; indicating that these physicochemical conditions could control the geochemical behavior of the analyses heavy metals. The concentration of Cu, Cd, Cr, Pb, Zn, AI, and Fe contents are nearly reflected the background values. The sequential extraction procedure and geochemical fractionation indicate that most of analyzed elements are associated mainly with the residual phases and are relatively immobile.

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