Table 8.
Pearson’s correlation coefficients between parameters of sewage sludge and concentrations of heavy metal fractions.
| Cd | F1 | F2 | F3 | F4 |
|---|---|---|---|---|
| ph | -* | −0.2487 | 0.3950 | 0.6567 |
| Eh | -* | −0.6903 | −0.3144 | 0.1519 |
| DM | -* | 0.0675 | 0.6888 | 0.2389 |
| OM | -* | 0.0493 | 0.6342 | 0.1709 |
| Cr | F1 | F2 | F3 | F4 |
| pH | 0.0624 | -* | 0.7280 | 0.6414 |
| Eh | −0.1557 | -* | 0.0872 | 0.0460 |
| DM | 0.8499 | -* | 0.3444 | 0.3007 |
| OM | 0.8356 | -* | 0.2720 | 0.2303 |
| Cu | F1 | F2 | F3 | F4 |
| ph | −0.8119 | −0.5937 | 0.4028 | 0.7781 |
| Eh | −0.4887 | −0.2252 | −0.2829 | 0.2106 |
| DM | 0.3224 | −0.1630 | 0.4778 | 0.1323 |
| OM | 0.3957 | −0.1056 | 0.4206 | 0.0513 |
| Ni | F1 | F2 | F3 | F4 |
| ph | 0.1668 | 0.6162 | 0.8836 | 0.5867 |
| Eh | −0.4328 | 0.2535 | 0.6893 | −0.1007 |
| DM | 0.7112 | −0.3795 | −0.1092 | 0.3833 |
| OM | 0.6677 | −0.4475 | −0.1637 | 0.3164 |
| Pb | F1 | F2 | F3 | F4 |
| ph | 0.1932 | −0.6909 | −0.1555 | 0.6942 |
| Eh | 0.4488 | −0.5595 | −0.4874 | 0.1307 |
| DM | 0.0486 | 0.0129 | 0.3426 | 0.2183 |
| OM | 0.0694 | 0.0776 | 0.3361 | 0.1439 |
| Zn | F1 | F2 | F3 | F4 |
| ph | −0.6627 | 0.7872 | 0.5452 | 0.7196 |
| Eh | −0.9238 | 0.4600 | −0.1032 | 0.1377 |
| DM | 0.4299 | −0.0416 | 0.5198 | 0.2137 |
| OM | 0.4601 | −0.1153 | 0.4616 | 0.1389 |
Bold—significant correlations at p < 0.05; * Concentration of heavy metal below the limit of detection at all sampling points (no statistical analysis).