Table 4 Number of samples exceeding threshold risk concentrations (TRC), potential risk concentration (PRC), and elevated risk concentrations (ERC) for four metals and three treatments
From: Low presence of potentially toxic elements in Singapore urban garden soils
TRC, PRC, ERC concentrationsa | |||||
|---|---|---|---|---|---|
Levela | Unit | Cd | Cu | Pb | Zn |
Background | mg/kg | 0.2 | 5 | 13 | 23 |
TRC | mg/kg | 0.5 | 46 | 57 | 100 |
PRC | mg/kg | 2 | 100 | 140 | 200 |
ERC | mg/kg | 10 | 200 | 400 | 700 |
Number of samples exceeding TRC, PRC, ERC thresholds | |||||
|---|---|---|---|---|---|
Threshold | Land cover | Cd | Cu | Pb | Zn |
TRC | Garden | 3 | 5 | 0 | 7 |
PRC | Garden | 2 | 0 | 0 | 0 |
ERC | Garden | 0 | 0 | 0 | 0 |
TRC | Park | 0 | 2 | 1 | 1 |
PRC | Park | 0 | 0 | 0 | 0 |
ERC | Park | 0 | 0 | 0 | 0 |
TRC | Woodland | 1 | 2 | 0 | 1 |
PRC | Woodland | 1 | 0 | 0 | 0 |
ERC | Woodland | 0 | 0 | 0 | 0 |