Evaluation of heavy metal content in Qaroun Lake, El-Fayoum, Egypt. Part I: Bottom sediments

This paper was undertaken in order to assess the extent of contamination in bottom sediments of Qaroun Lake, El-Fayoum, Egypt. Sediment samples were analyzed for grain size distribution and heavy metals concentration. Ten heavy metals were determined (in ppm) by X-Ray Fluorescence Spectrometry. The average concentration values in sediments are 2.99 (As), 124.89 (Cr), 38.91(Cu), 14.21 (Pb), 54.74 (Ni), 58.76 (Zn), 3.27 (Sn), 6.77 (Mo), 162.77 (V) and 11.70 (Co). Most of these metals are found with high concentrations in the eastern part of the lake, comparing with them in sediments of the central and western parts. The impact of drains effluents on the lake sediment-metals content is revealed. The dependence of concentrations on the sediment grain size is examined and high correlations between silt and clay-sized grains and the concentrations of Cr, Cu, Ni and Mo are deduced (R ranges from 0.61 to 0.73). Potential contamination of the lake is assessed using the contamination indicators, the geo-accumulation index, Igeo and contamination factor, Cf and the degree of contamination, Cd. Based on the obtained results, it is concluded that the lake sediments are found in contamination conditions. They are moderately contaminated with Cr, Mo, V and Co metals.