Assessment of heavy metal pollution in water and sediments in the red river delta (Vietnam)

Abstract

The paper studied the features of distribution of main heavy metals in the water-bottom sediments system in the Red River Delta (Vietnam). The tasks were to determine the flow of heavy metals, to study the adsorption processes of heavy metals in suspended matter and burial in bottom sediments. The studies were carried out during the main hydrological seasons of 2014 – 2016 years at 6 stations of main branches of the river for 8 basic heavy metals (Cu, Pb, Zn, Hg, Cd, As, Cr and Fe). Each year, the total flow of heavy metals entering the top of the delta was 98.8 thousand tons. The total flow of all heavy metals differed by hydrological seasons and by watercourses. In general, 1.76% - 16.25% of the flow of heavy metals accumulated throughout the year, the highest accumulation rates are for lead, iron and zinc. In the branches Ba Lat, Tra Ly, Ninh Co, due to the decrease in flow rates, an intensive process of the accumulation of suspended substances and sorbed heavy metals was observed.