Date of Award

6-2004

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Esam Abd EI-Gawad

Second Advisor

Dr. Fadhil N.Sadooni

Abstract

The present study aims at quantifying and assessing the organic and inorganic pollutants in the offshore sediments of the Zakum Field, Abu Dhabi, UAE. Twenty-six sampling stations were selected to cover the maximum area of the field. Sediments samples were subjected to a variety of analyses including mechanical analysis, Total Organic Carbon (TOC) analysis, Total Petroleum Hydrocarbon (TPH) analysis, twenty congeners of Poly Chlorinated Biphenyls (PCBs) analysis, sixteen different Polycyclic Aromatic Hydrocarbons (PAHs) analysis and eight heavy metals analysis. For a comparison purpose six old marine seabed core samples which collected from Zakum Filed between 1966 and 1978 were analyzed for TPHs, PCBs & PAH's.

The average TOC % analyzed in the study area is 4.76 % which higher value than other regional studies. The average TPH in Zakum Field is around 22.7 ppm, which is consistent with previous studies in the area. No significant correlation observed between TPH and grain size distribution. The average concentration of PCBs in the study area is 13.5 ppb, which is slightly above the level recorded previously in the region (i.e. below 5 ppb).

The total PAH's concentration in Zakum Field area ranges between 0 and 31.5 ppb. PAHs values increases towards Northwestern area with the minimum concentration in the central part area of the field. The Average Total petroleum hydrocarbon concentration in the old seabed cores is 17.4 ppm. While the average concentration of PCBs is 39.9 ppb and the total poly Aromatic hydrocarbons is 20.9 ppb.

Eight heavy metals elements have been analyzed in this study i.e. Cr, Cu, Fe, Mn, Ni, Pb, V and Hg. The highest detected concentration is Fe with average of 23.6 ppm. The lowest determined concentration is Ni with average of 0.035 ppm. In general, the heavy metals concentrations in the study area are low compared to previous studies in the region.

High concentration of pristane relative to phytane in most of the sediments indicates biological hydrocarbon input from a marine biological source except station no. 11 which indicates petrogenic source.

The site related operations in the Zakum field offshore area found maintaining minim adverse effect to the marine environment.

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