Sedimentary and Environmental Geochemistry of metals in the surface Sediments of the North-west of Persian Gulf (Boushehr Province Area)

Abstract

Sediments are generally regarded as the sink for dissolved elements carried out to the sea by rivers. In order to study the source and mechanism of metal transport in sea water, 123 surface sediment samples were taken by using grab sampler in the northwest part of the Persian Gulf in summer. Grain size analysis and geochemical analysis by ICP-OES were carried out on samples after sample preparation. The geochemical results reveal that the mean (and standard deviation) values for trace elements are as follows: V:52 (20.83), Ti:1738 (574.67), Sr:1170 (638.15), Ni:64 (27.68), Mn:366 (104.12), Mo:0.506 (0.27), Fe:21454 (7340.8), Cu:14 (6.19), Cr:80 (26.90), Cd:0.19 (0.07), As:4 (3.35), Al:31876 (11390.6) ppm. Factor analysis and other multivariate statistical methods were used for discrimination of source of the elements. Al, Fe, Cr, Cu, Mn, Ni, Ti and V show strong correlation coefficients and they could be related to a detrital origin out of the sedimentary basin. However, As and Mo are placed in another factor which could be related to agricultural and industrial sources. Ca and Sr fall also in the third component indicating a close relationship and biogenic origin. Based on grain size analysis, fine-grained fraction are also correlated with Al, Cr, Cu, Fe, Ni, Ti, V, As, Mo, Mn, Cd and again Ca and Sr show strong correlation with coarse-grained fraction, i.e. sandy sediments of biogenic origin. The element association indicates the adsorption processes for fine-grained fractions as one of main factor for enrichment of the elements.