الفهرس 
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Abstract
1.1 Pollution of Coastal Areas and Sediments Importance
Marine pollution is a direct and/or indirect introduction of substances or energy to the
marine environment, resulting in deleterious effects as hazards to human health, hindrance of
marine activities, impairment of the quality for the use of seawater, and reduction of amenities
(Clark, 2001). Among the marine environments, marginal and inner-shelf settings (i.e., coastal
waters) are ecologically and economically important zones in all countries in terms of
agriculture, fisheries, recreation, industries, shipping and nature conservation. About two-third
of the world’s population is living within these coastal areas. The growing of the human
population in these areas has resulted in dramatic increases in water, sediment, sewage, and
chemical pollution discharges into coastal marine settings. These have produced substantial
impacts on the character of the sediment and biota of many coastal areas (All, 1997; Murray,
2006; Bader El-Din, 2007), including the more sheltered and enclosed coastal environments
such as harbors (Matthews et al., 2005). .
In general, the effects of chemicals on the component of the marine environment (e.g.,
waters, fauna, flora and sediments) depend on the toxicity, amount, administrated dose and
concentration of chemicals and the length of exposure. Accordingly, to determine the effects
of chemicals on a particular environment, two factors have to be investigated; toxicity and
length of exposure (Zitko, 2000).
Aquatic sediments can be regarded as reliable indices for the quality of the environment
and they are as important in environmental studies as water and biota (Ahmed, 1996).
Sediments occupy a special position in this respect, reflecting the current quality of
environment as well as providing a history of chemical parameters of the area (Forstner et al.,
1982; Thornton and Abraham, 1984). Aquatic sediments are mixture of inorganic and organic
materials that reach the site of deposition as solid particles (i.e., detrital) or have been
incorporated into the sediment from solution by various ways (i.e., non-detrital) (Al-Alimi,
2008). Sediments can be divided into two distinctly different groups that differ in
mineralogical and morphological characteristics (Raudkivi, 1976). Fine sediments composed
of particles smaller than 50 urn and subdivided into silts and clays. Coarse sediments, with
grains exceeding 50 um, include sands and gravels.
Marine sediments are contaminated by chemicals that tend to sorbs to fine grained
particles (Islam and Tanaka, 2004), which offer a greater combined surface area for
contaminant sorption than coarser particles (Rubio et al., 2000; Fukue et al., 2006). The
contaminants include trace metals and hydrophobic organics, such as dioxins, polychlorinated
biphenyls (PCBs), and poly aromatic hydrocarbons (PARs). Metals bind to mineral surfaces or
are present as sulfide precipitates. Because of the physiochemical state of the hydrophobic
organics, they tend either to sorbs to natural organic matter and fine clays or to be partitioned
into a separate liquid phase, such as oil or coal tar (Mil-Homens et al., 2009 a) As a result,.