Table 4.
Concentrations of heavy metals in topsoils from the vicinity of industrial areas and related soil quality standards.
| Places | Depth | Hg | As | Pb | Cu | Zn | Ni | Cr | Cd | |
|---|---|---|---|---|---|---|---|---|---|---|
| Dongguan | This study | 0–20 cm | 0.7 | 7.1 | 61.8 | 48.3 | 92.0 | 42.8 | 40.8 | 0.13 |
| Yan’an | reference [37] | 0–20 cm | - | - | 23.97 | 27.31 | 82.15 | 38.01 | 73.88 | 0.11 |
| Weinan | reference [38] | 0–15 cm | - | 8.49 | 46.71 | 20.88 | 71.56 | 25.43 | 96.99 | - |
| Lipu | reference [39] | 0–15 cm | - | - | 50.11 | 40.77 | - | 53.65 | 46.98 | 0.19 |
| Chinese [35] | I | - | 0.15 | 15 | 35 | 35 | 100 | 40 | 90 | 0.2 |
| II (pH < 6.5) | - | 0.3 | 40 | 250 | 50 | 200 | 40 | 150 | 0.3 | |
| III | - | 1.5 | 40 | 500 | 400 | 500 | 200 | 300 | 1 | |
| Guangdong background values [31] | - | 0.078 | 8.9 | 36.0 | 17.0 | 47.3 | 14.4 | 50.5 | 0.056 | |
| Dutch [36] | Target values | - | 0.3 | 29 | 85 | 36 | 140 | 35 | 100 | 0.8 |
| Intervention values | - | 10 | 55 | 530 | 190 | 720 | 210 | 380 | 12 | |
I. the limits for protecting ecosystem; II. the maximum allowable concentrations of metals in agriculture soil of China; III. the upper limit values for regular growing of plants.