Geochemistry of Trace Elements in Iraqi Marine Environment

Abstract

Geochemistry of trace and some major element components were studied in Iraqi marine sediments. Two cores at profile depths of 10, 20, 30, and 40 cm (from profile A, B, C, to D respectively) of major elements (SiO2, Al2O3, K2O, MgO, CaO, MnO and Fe2O3 ) and trace elements ( Cr, Mo, Ba, Pb, Th, Ga, Sr, Ni, Cu, Br, Zn, Zr ,V, Nb, As, and Rb) are investigated in 2018. The spatial distributions of element components showed the range of Al2O3 between 5.258-5.8%, when compared this result with alumina content in crustal content gave us data to mixed sediments between quartz and clay minerals. Mn and Fe consider as redox elements in marine sediments , and the spatial distribution for these elements showed high concentration within the uppermost part of the profiles, but with increase the depth it have undergoing some degree of depletion. Most of trace elements except Pb and As showed the same pattern of redox elements within the high concentration in upper surface and decrease steadily with increase the depth. It is clearly observable that the surface sediments are enriched with most of trace elements. These results may be considerable to adsorption the ions or ionic complex onto particle surfaces, such as clay minerals and organic matters. The negative relationship between organic matter with Pb and As elements may be attributed to liberate Pb and As during decomposition of organic matter. There is obvious positive relationship between CaCO3 minerals with Pb and As. This relationship formed by the fact that calcite minerals supply regions of higher pH as well as nucleates centers of trace elements on the surface of carbonate. The relations between trace elements and Al are confirm these results. Enrichment factors in both cores for Cr, Sr, Ni, Br, and Ga elements often exhibited constantly high enrichment except at depth of 40 cm (profile D) for Sr , and at depth of 20 , 30 and 40 cm ( profiles B, C and D) for Ga element. While  enrichment factors for Mo, Pb, Zn, Zr, and Cu are commonly oscillate around more than 1 except the depleted elements at depth 40 cm (profile D) for Zr and depleted elements at depths of 20, 30, and 40 cm ( profiles B, C, and D) for Cu . As is constantly enriched with the profiles C and D (30 cm and 40 cm).High concentrations of EF for some of trace elements in marine sediments are often attributed to anthropogenic sources.