Removal efficiencies of Cd, Cr, Pb and Zn in different soil particle-size fractions after washinga.
| Washing agent | Removal efficiency (%) | ||||
|---|---|---|---|---|---|
| Cd | Cr | Pb | Zn | ||
| FeCl3 | Original | 95.57 ± 1.06a | 23.68 ± 0.32b | 96.96 ± 1.26b | 89.87 ± 0.89b |
| Coarse sand | 99.21 ± 2.31a | 19.62 ± 0.15c | 70.39 ± 3.05c | 96.17 ± 2.54a | |
| Fine sand | 93.75 ± 0.36a | 16.75 ± 0.38d | 63.76 ± 0.83d | 90.06 ± 0.27b | |
| Silty clay | 97.09 ± 0.71a | 27.13 ± 0.56a | 99.64 ± 0.07a | 87.19 ± 0.31b | |
| CA | Original | 94.23 ± 2.98a | 68.24 ± 0.94a | 42.32 ± 0.62a | 95.44 ± 0.73bc |
| Coarse sand | 96.23 ± 2.62a | 57.29 ± 2.74b | 44.69 ± 1.95a | 98.98 ± 2.66a | |
| Fine sand | 92.65 ± 1.06a | 46.66 ± 0.67c | 24.87 ± 0.41b | 98.10 ± 0.53ab | |
| Silty clay | 95.79 ± 0.83a | 68.73 ± 0.89a | 42.22 ± 0.28a | 93.93 ± 0.39c | |
| CA+ | Original | 94.85 ± 3.08a | 75.48 ± 4.20a | 91.23 ± 0.84a | 94.74 ± 0.76a |
| FeCl3 | Coarse sand | 93.11 ± 1.58a | 74.39 ± 3.80ab | 77.71 ± 1.33b | 95.16 ± 2.60a |
| Fine sand | 93.30 ± 1.53a | 65.37 ± 2.90b | 68.28 ± 1.12c | 92.50 ± 0.46a | |
| Silty clay | 85.87 ± 1.87a | 79.86 ± 0.72a | 94.83 ± 0.70a | 95.02 ± 0.73a | |
a
Different letters (a–d) behind the data indicate a significant difference among different soil particle size fractions (one-way ANOVA, P < 0.05).