Assessment of Metals Pollution in Sediments of the Coastal Area, U.A.E

The present study aims at the quantifying and assessment of heavy metals concentrations and pollution in the offshore sediments, off Abu Dhabi, Dubai and Sharjah. Thirty three samples were collected and subjected to grain size analysis, organic carbon and total carbonate determinations, mineralogical analysis and heavy metals (leachable and residual phasis) determination. The contents of organic carbon of the study areas vary within a wide range. The maximum was recorded at Abu Dhabi and the minimum at Dubai. There is a trend of increasing organic carbon with the decrease of grain size. In contrast to organic carbon, carbonate contents in the sediments vary within a narrow range. XRD analysis revealed that carbonate minerals represents about 75% of the total minerals in the sediments of the three sectors. Generally, the spatial variations in the mineralogy of the sediments could be attributed to differences in their sources and the prevailing hydrodynamic conditions. The characterization of leachable phases of some metals in the studied sediments shows that Fe has the lowest, whereas Ca has the highest percentages of leachable species. Ni, Sr, Mg and Mn (in descending order have intermediate concentrations. In the present study, Fe is used primarily as a normalizing elements and its relationships with other metals (total concentrations) has been investigated. The calculated index of geoaccumulation (Igeo) indicates that Igeo values for different sites are low as they fall into the lowest grades of Igeo. The recorded low values of Igeo for various metals indicate that sediments of the offshore areas as well as those of the creak have a minimum metal pollution accumulation except for those of Ni