Table SI1 - Total Cr, Cu, Ni, and Zn concentrations (average ± SD; n = 4) in the top 10-cm soil layer unamended (S0/M0) or amended with sludge (S1 – S4) or spiked with metals (M1 – M4) after 3, 6, and 12 weeks of incubation.
Metal / Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Cr (mg/kg DW) / S0/M0 / 6.21 ± 0.75 / 6.47 ± 1.72 / 5.14 ± 1.08
S1 / 55.1 ± 40.5 / 49.3 ± 32.0 / 35.3 ± 14.9
S2 / 66.7 ± 24.2 / 69.4 ± 34.4 / 82.2 ± 32.4
S3 / 672 ± 225 / 240 ± 97.9 / 275 ± 218
S4 / 600 ± 198 / 888 ± 383 / 620 ± 323
M1 / 35.2 ± 9.33 / 36.3 ± 5.63 / 38.1 ± 2.52
M2 / 47.0 ± 8.31 / 53.9 ± 20.8 / 37.2 ± 7.11
M3 / 160 ± 23.6 / 170 ± 20.1 / 179 ± 36.7
M4 / 309 ± 87.9 / 344 ± 74.4 / 279 ± 96.0
Cu (mg/kg DW) / S0/M0 / 19.5 ± 2.98 / 20.8 ± 3.66 / 18.5 ± 3.29
S1 / 37.2 ± 18.5 / 28.3 ± 11.8 / 24.6 ± 5.34
S2 / 36.1 ± 7.58 / 37.7 ± 9.50 / 38.2 ± 10.9
S3 / 171 ± 52.8 / 72.6 ± 17.3 / 80.7 ± 28.4
S4 / 149 ± 48.8 / 180 ± 62.3 / 132 ± 60.3
M1 / 26.3 ± 6.49 / 28.7 ± 4.57 / 27.0 ± 3.52
M2 / 37.9 ± 4.58 / 35.5 ± 5.61 / 26.3 ± 4.92
M3 / 69.0 ± 8.74 / 69.4 ± 9.14 / 72.1 ± 17.7
M4 / 96.6 ± 22.7 / 113 ± 16.2 / 93.1 ± 18.3
Table SI1 (Continued)
Metal / Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Ni (mg/kg DW) / S0/M0 / 13.4 ± 1.20 / 13.9 ± 2.20 / 13.2 ± 2.10
S1 / 140 ± 94.8 / 111 ± 64.8 / 82.5 ± 35.7
S2 / 170 ± 63.1 / 165 ± 56.0 / 187.9 ± 60.4
S3 / 1021 ± 327 / 441 ± 140 / 506 ± 253
S4 / 909 ± 235 / 1179 ± 421 / 919 ± 444
M1 / 96.7 ± 29.3 / 88.5 ± 21.3 / 82.5 ± 7.64
M2 / 166 ± 29.5 / 130 ± 33.4 / 90.5 ± 21.0
M3 / 355 ± 46.1 / 304 ± 46.6 / 277 ± 52.4
M4 / 505 ± 103 / 489 ± 135 / 310 ± 58.0
Zn (mg/kg DW) / S0/M0 / 41.2 ± 6.26 / 48.9 ± 9.19 / 39.3 ± 6.50
S1 / 132 ± 94.0 / 136 ± 67.0 / 94.7 ± 40.0
S2 / 178 ± 35.0 / 167 ± 58.4 / 172 ± 81.4
S3 / 617 ± 120 / 368 ± 64.1 / 381 ± 108
S4 / 590 ± 105 / 797 ± 342 / 556 ± 161
M1 / 81.2 ± 44.6 / 139 ± 21.3 / 106 ± 33.4
M2 / 170 ± 27.9 / 152 ± 26.0 / 77.7 ± 32.4
M3 / 294 ± 31.5 / 290 ± 27.8 / 261 ± 48.8
M4 / 381 ± 61.1 / 392 ± 79.4 / 293 ± 33.2
Table SI2 - Slopes (with corresponding R2 value) of regressions of total Cr, Cu, Ni, and Zn concentrations as percentage of initial doses (% initial TMC) against time for different metals in unamended (S0/M0), sludge-amended (S1 – S4) and metal-spiked soils (M1 – M4).
Time (independent variable)Sludge-amended soils / Metal-spiked soils
Metal / S0/M0 / S1 / S2 / S3 / S4 / M1 / M2 / M3 / M4
% of initial TMC (dependent variable) / Cr / -0.038a* (0.243) / -3.30 (0.077) / -3.76 (0.235) / -4.17 (0.041) / -0.030a (0.050) / 0.009a (0.003) / -0.022a (0.094) / -0.937 (0.050) / -0.014a (0.052)
Cu / -0.005a (0.013) / -3.08 (0.163) / -2.82 (0.244) / -3.52 (0.069) / -0.038a (0.225) / 0.007a (0.044) / -0.030a* (0.460) / -0.011a (0.074) / -0.413 (0.010)
Ni / -0.002a (0.004) / -3.74 (0.106) / -2.14 (0.204) / -3.06 (0.045) / -0.030a (0.155) / -0.007a (0.027) / -0.042a* (0.421) / -0.052a* (0.611) / -0.054a* (0.630)
Zn / -1.69 (0.055) / -3.20 (0.119) / -2.28 (0.230) / -1.90 (0.050) / -0.019a (0.099) / 0.003a (0.002) / -0.056a* (0.421) / -0.035a* (0.512) / -0.031a* (0.486)
* - statistically significant (p ≤ 0.01); slopes were obtained using normal linear equation except those with a that were obtained using the exponential equation.
Table SI3 – 0.01M CaCl2 extractable Cr, Cu, Ni, and Zn concentrations (average ± SD; n = 4) in the top 10-cm soil layer unamended (S0/M0) or amended with sludge (S1 – S4) or spiked with metals (M1 – M4) after 3, 6, and 12 weeks of incubation.
Metal / Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Cr (mg/kg DW) / S0/M0 / < 0.249 / < 0.249 / < 0.249
S1 / < 0.249 / < 0.249 / < 0.249
S2 / < 0.249 / < 0.249 / < 0.249
S3 / < 0.249 / < 0.249 / < 0.249
S4 / < 0.249 / < 0.249 / < 0.249
M1 / < 0.249 / < 0.249 / < 0.249
M2 / < 0.249 / < 0.249 / < 0.249
M3 / 0.434 ± 0.118 / < 0.249 / 0.254 ± 0.017
M4 / 0.832 ± 0.113 / 0.567 ± 0.054 / 0.684 ± 0.107
Cu (mg/kg DW) / S0/M0 / < 0.349 / < 0.349 / < 0.349
S1 / < 0.349 / < 0.349 / < 0.349
S2 / < 0.349 / < 0.349 / < 0.349
S3 / < 0.349 / < 0.349 / < 0.349
S4 / < 0.349 / < 0.349 / < 0.349
M1 / < 0.349 / < 0.349 / < 0.349
M2 / < 0.349 / < 0.349 / < 0.349
M3 / 0.368 ± 0.046 / 0.468 ± 0.102 / 0.363 ± 0.149
M4 / 2.97 ± 0.227 / 2.22 ± 0.219 / 1.26 ± 0.132
Table SI3 (Continued)
Metal / Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Ni (mg/kg DW) / S0/M0 / 0.501 ± 0.461 / 0.428 ± 0.707 / < 0.427
S1 / 2.04 ± 0.256 / 2.30 ± 0.239 / 3.25 ± 1.62
S2 / 2.80 ± 0.408 / 2.99 ± 0.481 / 3.35 ± 0.734
S3 / 5.85 ± 1.07 / 5.23 ± 0.750 / 5.20 ± 0.516
S4 / 7.75 ± 0.666 / 7.06 ± 1.41 / 5.83 ± 0.601
M1 / 22.7 ± 2.54 / 25.6 ± 2.60 / 22.2 ± 1.18
M2 / 35.5 ± 4.24 / 36.4 ± 3.94 / 32.1 ± 3.76
M3 / 185 ± 27.0 / 206 ± 18.5 / 163 ± 51.7
M4 / 697 ± 95.2 / 354 ± 111 / 188 ± 9.88
Zn (mg/kg DW) / S0/M0 / < 0.108 / < 0.108 / < 0.108
S1 / 0.896 ± 0.140 / 0.799 ± 0.114 / 1.13 ± 0.158
S2 / 1.36 ± 0.135 / 1.57 ± 0.491 / 2.44 ± 1.10
S3 / 0.711 ± 0.239 / 0.459 ± 0.182 / 0.799 ± 0.308
S4 / 0.344 ± 0.094 / 0.396 ± 0.029 / 0.354 ± 0.204
M1 / 12.1 ± 1.31 / 16.1 ± 2.45 / 12.4 ± 1.04
M2 / 28.3 ± 2.23 / 27.9 ± 3.80 / 22.2 ± 2.58
M3 / 145 ± 10.2 / 176 ± 24.7 / 122 ± 32.7
M4 / 611 ± 93.9 / 317 ± 103 / 160 ± 27.4
Table SI4 - Slopes of the regressions (with corresponding R2 value) of 0.01M CaCl2 extractable Cr, Cu, Ni, and Zn concentrations as percentage of total metal concentration (% TMC) against time for different metals in unamended (S0/M0), sludge-amended (S1 – S4) and metal-spiked soils (M1 – M4).
Time (independent variable)Sludge-amended soils / Metal-spiked soils
Metal / S0/M0 / S1 / S2 / S3 / S4 / M1 / M2 / M3 / M4
% TMC (dependent variable) / Cr / 0.015c (0.004) / 0.018ac (0.010) / 0.007ac (0.002) / -0.003c (0.092) / 0.001c (0.417) / -0.010c (0.143) / 0.008c (0.129) / -0.046a (0.264) / -0.023a (0.072)
Cu / ND / ND / ND / ND / ND / ND / ND / -0.030ab (0.305) / -0.066a* (0.577)
Ni / -0.054 (0.003) / 0.088a (0.325) / 0.055a (0.282) / 0.007a (0.003) / -0.004a (0.003) / -0.437 (0.076) / 0.590 (0.119) / 0.365 (0.014) / -0.060a* (0.471)
Zn / -0.115bc (0.016) / 0.060a (0.166) / 0.035ab (0.374) / -0.007a (0.003) / -0.025a (0.035) / -0.706 (0.353) / 0.571 (0.122) / -0.015a (0.092) / -0.087a* (0.639)
* - statistically significant (p ≤ 0.01); ND – not determined; slopes were obtained using normal linear equation except those with a that were obtained using the exponential equation; b – using values arcsin transformed; C – Slopes generated from values below the detection limit.
Table SI5 - total volume of percolate and Cr, Cu, Ni, and Zn concentrations in the percolates collected from soils unamended (S0/M0) or amended with sludge (S1 – S4) or spiked with metals (M1 – M4) after 3, 6, and 12 weeks of incubation (average ± SD; n = 4).
Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Percolate volume (ml) / S0/M0 / 20 ± 0.82 / 69 ± 5.6 / 294 ± 4.9
S1 / 18 ± 1.0a / 77 ± 1.4c / 267 ± 1.0a
S2 / 20 ± 0.8 / 85 ± 12 / 249 ± 19
S3 / 0 / 0 / 201 ± 0.82
S4 / 3.0b / 85 ± 7.1 / 174 ± 7.5
M1 / 16 ± 0.82 / 67 ± 0.58a / 209 ± 0.82
M2 / 16 ± 4.5 / 61 ± 19 / 209 ± 12
M3 / 0 / 98 ± 0.82 / 271 ± 0.82
M4 / 20 ± 0.82 / 98 ± 11 / 271 ± 17
Table SI5 (Continued)
Treatment / Incubation period3 weeks / 6 weeks / 12 weeks
Ni (mg/L) / S0/M0 / 0.04 ± 0.02 / 0.03 ± 0.01 / 0.04 ± 0.02
S1 / 0.05 ± 0.01a / 0.04 ± 0.002c / 0.03 ± 0.02a
S2 / 0.03 ± 0.02 / 0.05 ± 0.02 / 0.08 ± 0.02
S3 / - / - / 0.06 ± 0.02
S4 / 0.05b / 0.07 ± 0.02 / 0.08 ± 0.02
M1 / 0.10 ± 0.10 / 0.04 ± 0.02a / 0.01 ± 0.01
M2 / 0.13 ± 0.04 / 0.06 ± 0.03 / 0.13 ± 0.06
M3 / - / 0.55 ± 0.13 / 1.5 ± 0.76
M4 / 3.6 ± 1.7 / 4.8 ± 2.4 / 2.9 ± 1.5
Zn (mg/L) / S0/M0 / 0.03 ± 0.02 / 0.05 ± 0.003 / 0.01 ± 0.01
S1 / 0.05 ± 0.04a / 0.04 ± 0.03c / 0.02 ± 0.01a
S2 / 0.02 ± 0.01 / 0.04 ± 0.01 / 0.15 ± 0.04
S3 / - / - / 0.07 ± 0.06
S4 / 0.45b / 0.06 ± 0.04 / 0.21 ± 0.07
M1 / 0.03 ± 0.02 / 0.01 ± 0.01a / 0.01 ± 0.004
M2 / 0.10 ± 0.02 / 0.05 ± 0.02 / 0.04 ± 0.02
M3 / - / 0.25 ± 0.13 / 0.78 ± 0.31
M4 / 1.4 ± 0.68 / 0.43 ± 0.36 / 1.3 ± 0.53
a – n=3; b – n=2; c – n=1.
Table SI6 - Slopes of the linear regressions (with corresponding R2 value) of Ni and Zn concentrations in percolates as percentage of total metal concentration (% TMC) against time for different metals in unameded (S0/M0), sludge-amended (S1 – S4) and metal-spiked soils (M1 – M4).
Time (independent variable)Sludge-amended soils / Metal-spiked soils
Metal / S0/M0 / S1 / S2 / S3 / S4 / M1 / M2 / M3 / M4
% TMC (dependent variable) / Ni / 0.229b* (0.720) / 0.001* (0.982) / 0.116b* (0.939) / NP / 0.0001* (0.753) / 0.000 (0.004) / 0.002* (0.800) / 0.012 (0.656) / 0.480b* (0.585)
Zn / 0.022b (0.082) / 0.000 (0.613) / 0.182b* (0.974) / NP / 0.001* (0.824) / 0.000 (0.298) / 0.052b* (0.636) / 0.007* (0.758) / 0.432b* (0.791)
* - statistically significant (p ≤ 0.01); NP - no percolate available; b – using values arcsin transformed.
Figure SI1 – Development with time of total Cr (first row) and Cu (second row) concentrations in sludge-amended (S0 – S4; left) and metal-spiked (M0 – M4; right) soils incubated in microcosms on top of a layer of clean soil. Concentrations are expressed as percentage of initial concentrations. S0, S1, S2, S3, S4 – sludge-amended soils with 0, 11, 15, 55, 75 t DW sludge ha-1, respectively; M0, M1, M2, M3, M4 – metal-spiked soils simulating the metal content in S0, S1, S2, S3, and S4, respectively. T0, T1, T2, T3 – 0, 3, 6, and 12 weeks sampling. Values mean regression slopes. * statistical significance (p ≤ 0.01).
Figure SI2 - Development with time of extractable Cr (left) and Cu (right) concentrations in metal-spiked soils (M0 – M4) incubated in microcosms on top of a layer of clean soil. Concentrations are expressed as percentage of total concentration. Values mean regression slopes. * statistical significance (p ≤ 0.01). See Figure SI1 for treatment codes and sampling dates.