GEOCHEMISTRY OF COASTAL MARINE SEDIMENTS AND
THEIR CONTAMINANT METALS, RED SEA, EGYPT:
A LEGACY FOR THE FUTURE AND A TRACER TO
MODERN SEDIMENT DYNAMICS
ABBAS M, MANSOUR, AHMED H. NAWAR1, AND AHMED W.
MOHAMED1
Geology Dept. Fac. Sciences, South Valley Univ., 83511 Qena. Egypt;
1National Inst. Oceanography and Fisheries, Red Sea Branch, Hurghada, Egypt
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Mineral and chemical compositions of the coastal sediments, Red Sea, Egypt, show terrigenous fine-grained sediments to be abundant to ab. 200m from shoreline, and carbonates dominate the seaward bottom sediments. The correlation of elements analyzed to the sediment type, carbonates, total organic matter, organic carbon and water depth indicates that sediments could be grouped into; 1) Carbonate association including Ca, Mg and Sr, and 2) terrigenous association comprising Fe, Mn, P, Zn, Cu, Co, Ni, V and Pb. Metals concentration in the sediments vary between sites within a wide range for Cu, Zn, Pb. V, Ni and Cd. Concentrations of metals in surface nearshore sediments highly exceed the background values in some areas. Tile highest cone. of P and V in Quseir, Pb, Zn in S Safaga, Cd, Ni in S Hurghada may be attributed to anthropogenic inputs from the surrounding areas and nearby harbors. Contamination with fine grained terrigenous material is recorded in Quseir, S Safaga and in front of marine station at Hurghada. Landfill and resuspended sediments are carried out southward to them by currents. Contamination with organic matter is recorded in Quseir, S safaga, Sharm AbuMakhadeg, and N Hurghada. The increase in their contaminants is probably due to nearby phosphate deposits, sewage sludge discharge to the sea and Pb in gasoline of motor boats. Harbors in these areas are mainly the source of contaminated sediment to offshore areas. Pollution and sediment fill threaten their nearby coral reefs.
Contaminants in sediments of some areas are associated with natural variations in sediment sources, deposition and transport processes. Concentrations of metals and physical properties measured in surface samples are a legacy for the future and a tracer to modern sediment dynamics, and will help managers identify anthropogenic impacts, and better assessing the needs for remediation by detecting any changes, from the existing level expected with operation of future activity.
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