Major and Trace Element Distribution in Suspended Particulate Matter and Sediments of the Tropical River Estuary (South Vietnam)

Abstract

Al, Fe, Ti, Li, Zn, Pb, U, Sc, Sn, Bi, Zr, Ba, As, Sr, W, V, Co, Cu, Ni, Mo, Cr, Mn, Ba, Sn, Sb, Ag, organic (TOC) and carbonate (TIC) carbon contents in suspended particulate matter (SPM) and sediments were measured along the salinity gradient in the Cay River–Nha Trang Bay estuarine system in dry season. Most trace element contents were at natural levels. Particulate metals were characterized by the most significant loss in the frontal zone of the estuary with the highest horizontal gradients within the salinity interval of 0–8–20‰. Sedimentary metals were largely controlled by the accumulation of their most fine-grained host minerals in the sea floor depression. The calculation of the enrichment coefficient (KSPM/Sed ) revealed associations of elements with a similar geochemical behaviour. Ti, Ca, Zr, Sb and W (KSPM/Sed . 1) are primarily accumulated in estuarine sediments. Co, Cu, Ni, and Mo (KSPM/Sed > 1) are removed out of the estuarine zone with surface water layer SPM. Al, Fe, Mn, Li, V, Zn, Sr, Sn, Cs, Bi, Pb and U (KSPM/Sed ≅ 1) are most likely controlled by their clay host minerals abundant in both sediments and SPM.