Heavy metal speciation and their accumulation in sediments of Lake Burullus, Egypt

Abstract

Several sediment samples in Lake Burullus have been affected by the discharges of heavy metals through different drains. The study aimed to analyze the chemical speciation of these metals. In particular, the chemical forms of Cd, Cu, Fe, Mn, Pb and Zn in sediments collected in spring season were studied using a sequential chemical extraction method. In general, all the elements recorded highest concentrations in the area near the discharge point. The data indicated that, the sediments were under a wide variety of environmental conditions ranging from oxic to fully anoxic conditions. Owing a wide variety of grain sizes and organic matter, these metals showed the order of abundance: Fe > Mn > Zn > Cu > Cd > Pb. Significant correlations between iron with clay, organic carbon and manganese concentrations were calculated as (r=0.685, 0.581 and 0.610, P= 0.05), respectively. This gives an idea about association of iron and manganese as main compositions of clays. In the mean time, it showed insignificant relation with total carbonate and all phosphorus forms. The metal speciation characterizes the degree to which they are potentially labile or bioavailability. It gives different fraction ratios depending on binding and sediment origin. Key words: Heavy metals, chemical speciation, sediments, Burullus, Lake.