Microelement composition of bottom sediments in Mekong River delta, Republic of Vietnam

Mean concentrations of Zn, Cu, Pb, Cd, As, and Hg in water and bottom sediments of Mekong Delta (Socialist Republic of Vietnam) over low-water period of 2013 were evaluated. The space distribution of the chemical composition of bottom sediments shows a tendency toward an increase in the concentrations of the examined microelements toward the sea coastline. The mechanism of those changes was considered and attributed to a release of low-solubility compounds from water and with sorption of microelements on alluvium and sediment particles at the mixing of river and sea water. The value of surface water pH was suggested as an indicator of current and forecasted variations of the concentrations of some microelements in bottom sediments.