Table 1.
Variation in concentrations of heavy metals in biosolids due to region and nature of wastewater generated.
| Country | Zn | Cu | Cr | Pb | Ni | Cd | Hg |
|---|---|---|---|---|---|---|---|
| USA (1977) | 1740.0 | 850.0 | 890.0 | 300.0 | 82.0 | 19.0 | 3.0 |
| USA (2002) | 750.0 | 511.0 | 35.0 | 65.0 | 23.0 | 2.3 | 1.5 |
| France (1999) | 761.0 | 286.0 | 4.5 | 107.0 | 35.0 | 4.5 | 2.1 |
| France (2017) | 60–200 | 20–100 | 30–100 | 70–100 | 15–70 | 0.5–1.5 | 0.1–1.0 |
| China (2018) | 674.0 | 204.0 | 236.0 | 26.0 | 334.0 | 0.9 | 0.9 |
| Concentration limit, EPA (2002) | 7500.0 | 4300.0 | ND | 840.0 | 420.0 | 85.0 | 57.0 |
ND = not determined. All values are in mg/kg [98].