| Heavy metals in environment caused by the base metal smelting activity have led to public concerns in considerable soil contamination. This study focused on heavy metal contents and pollution sources in topsoil and typical profile soil around the historical Pb-Zn smelter and the degree of pollution based on evaluation factor of background value and Environmental quality standard for soil. Chemical fractions of heavy metal and main influencing factors were also analyzed by BCR sequential extraction procedure, and the correlation between chemical fractions distribution and soil physical-chemical properties were investigated, then. The results showed that the mean concentrations in topsoil near the smelter were Cd 117．9 mg·kg-1 , Cu 259．0 mg·kg-1 , Pb 776．7 mg·kg-1 , Zn 5393．4 mg·kg-1 ,respectively, and heavy metal contents decreased with soil depth in profile soil. It decreased significantly in the layers of 0-40 cm, while changed smoothly under 40 cm soil layers. It seemed that Cd, Zn, Pb and Cu pollution in the whole area were severely, while As and Hg pollution were locally, and the Cr and Ni were close to background value in all soils. It was also found that contamination was remarked closed the smelter in the profile soil in depth of 100 cm but there was not obvious pollution far from the smelter except Cd, Pb and Hg that above background values. Analysis on pollution source seemed that the pollution associated with waste gas emission from the smelter. Chemical fractions analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb and Cu were mostly associated with the residual fraction and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution patterns of Cd, Pb and Zn were obviously affected by soil pH and their contents in acid soluble fraction decreased with increasing soil pH values. Fractions pattern of Cd was also affected by Organic matter.
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