STUDY ON THE CORRELATION BETWEEN THE CONTENTS OF HEAVY METALS WITH COASTAL SEDIMENT PARTICLE SIZE IN THE MEKONG DELTA

Abstract

      Four heavy metals including As, Cd, Cr, and Pb were determined in 72 marine sediment samples in the Mekong Delta by Atomic Absorption Spectrophotometric method (AAS). Analysis results showed that contents of heavy metals were not exceed permissible limits. Sediment particle size be determined by the Robinson's straw method. Based on the average particle size (Md), the sample of marine sediments can be divided into three groups: clay (Md = 1 - 10μm); silt (Md = 10 - 100μm); sand (Md = 100 - 1000μm).Their correlations with sediment particle size has been studied. The research results indicated that, size of Md and Mean closely correlated with contents of heavy metals. For powder particles, correlation was negative, generally when the particle size increases, the contents of heavy metals decreases. For clay particles, correlation was positive, when the particle size increases, the contents of heavy metal increases.