Chemical partitioning of cadmium, zinc, lead, and copper in soils near smelter

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Abstract
Four soil samples which had been polluted with exhaust gas and dust froi smelter were sequentially extracted so that Cd,Zn,Pb, and Cu could be partitioned into five operationally defined geochemical fractions: exchangeable, bound to carbonates, bound to Fe‐Mn oxides, bound to organic natter and residual. Metal recoveries were within ±6% of the independently measured total Cd,Zn,Pb, and Cu concentrations. Amount of the metals which were distributed into various fractions were remarkably different from metal species. The highest amount of Cd (ca. 45% ) was found in the exchangeable fraction, and only 8% in the organic fraction. The highest amount of Cu (ca.52%) was found in the organic fraction, but in the exchangeable and carbonates fraction only 1% and 3%. The Fe‐Mn oxide fraction contained 20,29,27 and 22%, and residual fraction 16,40,25 and 22% of the Cd,Zn,Pb, and Cu, respectively. Assuming that mobitity and biogical availability are related to the solubility of the geochemical form of the metals and decreases in the order of extraction, the apparent mobility and potential metal bioavailability for these polluted soils were Cd > Zn > Pb > Cu.