Determination of Heavy Metals in Two Regions from Kirkuk City Using Sequential Extraction

摘要

Soil is a major reservoir for heavy metals and other contamination as it possesses an ability to absorb these metals on the surface of clay minerals and bind various chemicals. These heavy metals and chemicals can exist in various forms in soil and different forces keep them bound to clay minerals and soil particles. The aim of the present work is to estimate the concentration levels of some heavy metals Zn, Cu, Pb and Cd in two sites of soil Kirkuk city. In this study the first sample was taken from inside the city of four areas around (Northern Oil Company) in Kirkuk city, while the second sample was taken from outside the city of four areas and both were randomly chosen. Sequential extraction procedure was applied to fractionate heavy metals which may help in the prediction of their mobility, bioavailability and fate of the metal contaminant. Results of sequential extraction showed that Cd and Pb were mainly bound to residual fraction, Cu was mainly bound to organic fraction and Zn was bound to Fe-Mn oxide fraction in the two sites of the study. The overall mean values obtained for the metals in the fractions gave the range: inside the city Cu (28.12 ppm), Zn (77.9 ppm), Pb (21.73 ppm) and Cd(4.21 ppm), and outside the city Cu (24.65 ppm), Zn (59.28 ppm), Pb (13.25 ppm) and Cd (2.38 ppm). The extracts were analyzed for heavy metal, using flameless-atomic absorption spectrophotometers (Flameless-AAS).