Chemical fractionation of heavy metals in urban soils of Guangzhou, China.
Knowledge of the total concentration of heavy metals is not enough to fully assess the environmental impact of urban soils. For this reason, the determination of metal speciation is important to evaluate their environment and the mobilization capacity. Sequential extraction technique proposed by the former European Community Bureau of Reference (BCR) was used to speciate Cd, Cu, Fe, Mn, Ni, Pb, and Zn in urban soils from Guangzhou into four operationally defined fractions: HOAc extractable, reducible, oxidizable, and residual. The Cu, Fe, Ni, and Zn were predominantly located in the residual fraction, Pb in the reducible fraction, and Cd and Mn within the HOAc extractable fraction. The order of Cd in each fraction was generally HOAc extractable > reducible > residual > oxidizable; Cu and Fe were residual > reducible > oxidizable > HOAc extractable; Mn was HOAc extractable > residual > reducible > oxidizable; Ni and Zn were residual > reducible > HOAc extractable > oxidizable; and Pb was reducible > residual > oxidizable > HOAc extractable. Cadmium was identified as being the most mobile of the elements, followed by Mn, Zn, Ni, Cu, Pb and Fe. Iron-Mn oxides can play an important role in binding Cd, Cu, Ni, Pb, and Zn and in decreasing their proportion associated with the residual fraction in the soils. With total concentrations of Cd, Cu, Ni, Pb, Zn, and Mn increase, these metals more easily release and may produce more negative effects on the urban environment.
Lu
Ying
Y
State Key Laboratory of Soil and Sustainable Agriculture (Institute of Soil Science), Chinese Academy of Sciences, Nanjing 210008, People's Republic of China. luying@scau.edu.cn
Zhu
Feng
F
Chen
Jie
J
Gan
Haihua
H
Guo
Yanbiao
Y
D005591:Chemical Fractionation; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
D019216:Metals, Heavy; D012989:Soil Pollutants