Heavy metals | Average ± stdev (mg/kg) | USEPA standards (mg/kg) |
Cu | 172.56 ± 61.53 | 4300 |
Pb | 75.86 ± 1.63 | 840 |
Zn | 218.73 ± 8.35 | 7500 |
Mn | 157.96 ± 21.67 | NA |