Table 3.
Heavy metal levels in PPWW-irrigated soil extracts in comparison with control soil and ordinary soil (Bowen 1979) and in function of incubation time
| Heavy metals | Soil control (SD) | PPWW-irrigated soil | Ordinary soil | |||
|---|---|---|---|---|---|---|
| S30 (SD) | S60 (SD) | S90 (SD) | S120 (SD) | Bowen (1979) | ||
| Cu (mg l−1) | 2.08(0.1)a | 82.00 (2)b | 108.30 (3)c | 135.00(3)d | 142.00 (3)d | 30.00e |
| Zn (mg l−1) | 4.15(0.5)a | 105.35 (3)b | 158.45 (4)c | 173.00(5)d | 175.00 (5)d | 90.00b |
| Fe (mg l−1) | 11.35(1)a | 185.45 (5)b | 255.16 (5)c | 282.00 (5)d | 288.00 (5)d | 100.00e |
| Cd (mg l−1) | 0.37(0.05)a | 37.50 (2)b | 54.12 (2)c | 67.50 (2)d | 73.00 (2)e | 2.00f |
| Pb (mg l−1) | 2.33(0.1)a | 73.15(2)b | 125.25 (3)c | 152.00 (3)d | 163.00 (3)e | 35.00f |
Means followed within the same row by the same small letter are not statistically different
SD standard deviation (P ≤ 0.05)