الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The last decade has brought a significant increase in research on the
environmental problems, especially, the contamination of earth’s ecosystem
by potentially toxic heavy metals. Due to the health impacts of pollution from
the ingestion of heavy metals via respiration, food and drink water. The WHO
estimates that about a quarter of the diseases facing mankind today occur due
to prolonged exposure to environmental pollution.
The present study is a continuation to the aforementioned efforts. It
deals with mineralogy, geochemistry and environmental geochemistry of the
Egyptian phosphorites, phosphatic fertilizers, agricultural soils and mudbrick
samples, to evaluate their content of environment-toxic elements and discuss
the environmental impact of application of phosphorites and their fertilizers in
accumulation of toxic metals in agricultural soil. The results of the study
conclude in the following sentences.
1- Petrographically, the Upper Cretaceous phosphorite, at the main
productive localities (Red Sea, Nile Valley and Abu Tartur),
composed: phosphatic grains, non-phosphatic grains, and cements.
There are two basic types of phosphatic grains observed in the
studied samples; skeletal and diagenetic grains. The non-phosphatic
grains contain quartz, organic matter, ferruginous material and
calcareous biogenic debris such as foraminifera and pelecypod shell
fragments. The intergranular pore-spaces of the Duwi Formation
phosphorites are mostly cemented by silica and carbonate materials.
2- The mineralogical analysis of the phosphorites indicates that francolite
is the main phosphatic minerals. The major non-phosphatic minerals
are quartz, calcite, pyrite and dolomite. Traces of glauconite,
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gypsum, pyrite and some clay are also recorded as secondary
constituent. The CO2 content of the apatite in all studied
phosphorite samples was determined semi quantitatively from their
x-ray diffractograms according to the equation of Gulbrandsen
(1970) and the new equation that has suggested by Schuffert et al.
(1990).
3- The mineralogical composition of the agricultural soil indicated that
montmorillonite is the dominant clay mineral, followed in
abundance by kaolinite, vermiculite and little amount of illite. While
the non-clay minerals composed of quartz and feldspars minerals.
4- The results of the grain size distribution reveal that the investigated soil
samples are mainly silt loam with lesser samples of silt, sandy loam
and loam texture.
5- The studied agricultural soil and mudbrick samples are slightly to
moderately alkaline soils with pH ranging from 7.75 to 8.32. The
agricultural soil salinity optimum to grow any plants and it classified
under category non-saline (EC < 2 dS/m). The continuous
evaporation and lime paint salts that cause increasing in mudbrick
salinity. The soil samples are enriched in its total organic matter
content.
6- The geochemical data indicate that the Egyptian phosphorite classified as
medium-grade ore depending on their P2O5 content. The total average of
P2O5 content is 25% in Red Sea samples, 21 Nile Valley and 20 in Abu
Tartur. The P2O5 content enriched through the fertilizer manufacturing to
reach 28% in mono-super phosphate and 34% in tri-super phosphate. The
Egyptian phosphorites composed CaO, SrO, Fe2O3, MnO, Na2O, MgO,
SiO2, Al2O3, K2O and SO3 similar to the world phosphorites. Silicon,
aluminum and iron oxides are the highest major oxides in soil samples.
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7- The phosphorites and phosphatic fertilizers composed a significant amount
of environment-sensitive metals as As, Se, Cd, U, Cu, Co, Pb and Ni. Abu
Tartur phosphorites are depleted in U content in compare to the
phosphorite of Nile Valley and Red Sea. Such metals are transfer to the
fertilizers. The total toxic metals in Egyptian phosphorites are lower than.