Chemical fractionation and distribution of metals in contaminated urban soil in Zhuzhou City, South Central China
| Main Authors: | Uday Sankar Banerjee, Zhao-hui Guo, Kang-gen Zhou, Li-yuan Chai |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 2016
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/5639358 |
Daftar Isi:
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China E-mail : banerjeesme@csu.edu.cn Manuscript received online 20 April 2016, revised 23 August 2016, accepted 24 August 2016 The present study was conducted to determine the chemical fractions of heavy metals, to assess the current and potential environmental risks and to evaluate the mobility and bioavailability of metals in contaminated urban soils. Sequential extraction procedure was applied to fractionate the metal content into exchangeable fraction, carbonate fraction, fraction bound to Fe-Mn oxides, fraction bound to organic matter and residual fraction. Chemical speciation (Tessier, 1979) study revealed that Cd in soil prevails mostly in exchangeable fractions (26.383%). The overall percentage of metal content in different sequential fractions is in the sequence of Residual > Organic > Fe-Mn Oxides > Carbonate ≈ Exchangeable and the order of metals in each fractions are as follows – Exchangeable : Cd > Cu > Pb > As, Carbonate : Cd > Pb > Cu > As, FeMn Oxides : Pb > Cd > Cu > As, Organic : As > Cu > Pb > Cd and Residual : As > Pb > Cu > Cd. Elemental concentrations from each sequential extraction step were measured using inductively coupled plasma optical emission spectrometer (ICP-OES, IRIS Intrepid II XSP, USA). The pH value of the soils in the study area ranged from 6.44 to 7.05 (mean 6.67), indicating an acidic to neutral type of surface soils. The eco-toxicological assessment of the studied soil using the mobility factor indices revealed the following sequence : Cd (40.627) > Pb (14.941) ≥ Cu (14.399) > As (5.377). Mobility factor indices for soil metals revealed a high environmental contamination risk for Cd, which indicates a serious environmental threat.