Trace Metals Distribution and Their Sources in Soil from a Sulfuric Acid Plant,Guangdong Province, China

This study dealed with the distribution and the origin of trace elements (Co, Cd, Mn, Ni, Zn, Tl and Pb) in two soil profiles from a site near a plant roasting pyrite for sulfuric acid production. Chemical partitioning of the trace elements showed that Tl and Pb in each individual extractable fraction(i.e. weak acid exchangeable, reducible and oxidizable)presented increasing trend upward through the depth in both profiles. Meanwhile, Co, Cd, Mn, Ni and Zn in all the above fractions revealed no general consistent trend across the depth. Results of the profile distribution of heavy metals in the chemical fractions combined with the principle component analysis indicated that the contamination of Tl and Pb is mainly from the percolation of pyrite slag particles in the studied soils, while the contamination of Co, Cd, Mn, Ni and Zn is predominantly due to the leaching of wastewaters in the soils.