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| Effects of Various Amendments on the Fractions of Cadmium in a Polluted Soil |
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| KeyWord:soil; amendment; cadmium; fractions |
| Author Name | Affiliation | | LIU Li-juan | College of Resources and Environment Sciences, Nanjing Agricultural University | | DONG Yuan-hua | Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences | | LIU Yun | Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences | | GE Ying | College of Resources and Environment Sciences, Nanjing Agricultural University |
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| Abstract: |
| Amendments have been widely applied to remediate heavy metal polluted soils. In this paper, an experiment was conducted in laboratory to study the effects of four different amendments on the fractions of Cd in a polluted soil. The main fraction of Cd was exchangeable and its percentage was 35.2%~44.0% of the total Cd in soil. Addition of amendments increased soil pH to some extent, thereby affecting the distribution of Cd fractions in the soil, with the order of #1>#4>#3>#2. Compared with the control treatment, the four types of amendments remarkably reduced the exchangeable Cd concentrations and increased the residual Cd concentrations after 35-days incubation, at slight pollution of Cd （１ ｍｇ·ｋｇ-1） and high Cd concentration （１０ ｍｇ·ｋｇ－１）, on the contrary, the exchangeable concentrations increased and the residual concentration reduced at Cd contaminated soil of 5 mg·kg-1. During the process of incubation, carbonate-bound Cd and Fe-Mn oxide-bound Cd scarcely transformed. As the experiment carried on, the exchangeable Cd concentration increased at first and reduced afterwards, oppositely, the residual Cd concentration firstly reduced then increased but reduced overall. Carbonate-bound, Fe-Mn oxide-bound and organic-bound Cd did not transform as much as exchangeable and residual Cd. In other words, the transformation of Cd fractions caused by the amendments was mainly between exchangeable Cd and residual Cd, and this led to the decline of Cd bioavailability. |
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