## 4 Results and Discussion
### Environmental Availability
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Element** & **As** & **Cd** & **Cr** & **Cu** & **Ni** & **Pb** & **Sb** & **T1** & **Zn** \\ \hline \multicolumn{10}{c}{Amended} \\ \multicolumn{10}{c}{Sil} \\ \multicolumn{10}{c}{T10} & \(4.94\pm 0.39\) & \(0.45\pm 0.04\) & \(0.13\pm 0.01\) & \(31.4\pm 2.72\) & \(4.71\pm 0.44\) & \(0.29\pm 0.03\) & \(7.56\pm 0.67\) & \(0.03\pm 0.003\) & \(52.9\pm 3.3\) \\ \multicolumn{10}{c}{T20} & \(3.75\pm 0.33\) & \(0.25\pm 0.02\) & \(0.16\pm 0.01\) & \(26.4\pm 2.5\) & \(2.06\pm 0.17\) & \(0.34\pm 0.07\) & \(4.47\pm 0.38\) & \(0.02\pm 0.002\) & \(9.55\pm 0.67\) \\ \multicolumn{10}{c}{T30} & \(1.07\pm 0.10\) & \(0.06\pm 0.01\) & \(0.12\pm 0.01\) & \(3.70\pm 0.33\) & \(6.46\pm 0.64\) & \(0.42\pm 0.04\) & \(0.68\pm 0.06\) & \(0.04\pm 0.004\) & \(3.47\pm 0.25\) \\ \multicolumn{10}{c}{T40} & \(0.84\pm 0.08\) & \(0.16\pm 0.02\) & \(0.11\pm 0.01\) & \(13.8\pm 1.23\) & \(41.88\pm 3.20\) & \(0.11\pm 0.01\) & \(0.62\pm 0.06\) & \(0.1\pm 0.01\) & \(126.5\pm 9.51\) \\ \multicolumn{10}{c}{T50} & \(0.99\pm 0.10\) & \(0.16\pm 0.02\) & \(0.11\pm 0.01\) & \(14.1\pm 1.0\) & \(11.58\pm 1.15\) & \(0.18\pm 0.02\) & \(1.05\pm 0.08\) & \(0.1\pm 0.01\) & \(1.01\pm 13\) \\ \multicolumn{10}{c}{T60} & \(2.38\pm 0.22\) & \(0.04\pm 0.004\) & \(0.11\pm 0.008\) & \(5.18\pm 0.46\) & \(0.86\pm 0.08\) & \(0.09\pm 0.007\) & \(5.03\pm 0.5\) & \(0.07\pm 0.006\) & \(0.73\pm 0.07\) \\ \multicolumn{10}{c}{T70} & \(1.36\pm 0.10\) & \(0.04\pm 0.004\) & \(0.21\pm 0.02\) & \(2.97\pm 0.27\) & \(1.96\pm 0.16\) & \(0.25\pm 0.02\) & \(1.85\pm 0.14\) & \(0.12\pm 0.01\) & \(12.6\pm 1.26\) \\ \hline \multicolumn{10}{c}{Control soil} \\ \multicolumn{10}{c}{ST10} & \(5.99\pm 0.58\) & \(7.29\pm 0.52\) & \(4.21\pm 0.40\) & \(6646\pm 614\) & \(162\pm 14\) & \(1.61\pm 0.16\) & \(6.39\pm 0.06\) & \(0.06\pm 0.004\) & \(3267\pm 224\) \\ \multicolumn{10}{c}{ST20} & \(3.03\pm 0.26\) & \(2.87\pm 0.27\) & \(1.92\pm 0.18\) & \(2045\pm 127\) & \(35.2\pm 2.4\) & \(2.69\pm 0.26\) & \(1.25\pm 0.11\) & \(0.09\pm 0.007\) & \(641\pm 61\) \\ \multicolumn{10}{c}{ST30} & \(2.26\pm 0.17\) & \(3.43\pm 0.39\) & \(2.01\pm 0.18\) & \(2831\pm 209\) & \(66.6\pm 5.8\) & \(0.44\pm 0.04\) & \(1.35\pm 0.13\) & \(0.12\pm 0.008\) & \(1309\pm 130\) \\ \multicolumn{10}{c}{ST40} & \(2.31\pm 0.21\) & \(2.91\pm 0.20\) & \(1.57\pm 0.10\) & \(2727\pm 204\) & \(61.1\pm 5.0\) & \(0.97\pm 0.07\) & \(1.45\pm 0.11\) & \(0.16\pm 0.02\) & \(1051\pm 84\) \\ \multicolumn{10}{c}{ST50} & \(1.89\pm 0.19\) & \(2.20\pm 0.22\) & \(1.13\pm 0.10\) & \(2191\pm 178\) & \(43.9\pm 4.2\) & \(0.46\pm 0.04\) & \(1.06\pm 0.07\) & \(0.2\pm 0.02\) & \(831\pm 76\) \\ \multicolumn{10}{c}{ST60} & \(35.9\pm 2.31\) & \(5.00\pm 0.48\) & \(4.80\pm 0.48\) & \(3136\pm 241\) & \(47.0\pm 3.3\) & \(0.39\pm 0.04\) & \(33.99\pm 3.04\) & \(0.43\pm 0.04\) & \(781\pm 78\) \\ \multicolumn{10}{c}{ST70} & \(45.1\pm 2.8\) & \(6.02\pm 0.58\) & \(7.80\pm 0.68\) & \(4437\pm 313\) & \(64.8\pm 4.8\) & \(0.61\pm 0.04\) & \(33.64\pm 2.82\) & \(0.56\pm 0.04\) & \(993\pm 74\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Trace element concentrations (\(\upmu\)g kg\({}^{-1}\)) extracted with deionized water from amended soil and control soil samples. water-extracted concentrations of PHE in the amended soil remained consistently lower than those of the control. The amounts of PHE extracted with EDTA varied noticeably depending on the element concerned and the sampling depth, in both the amended and the non-amended soil (Table 5). The use of EDTA as extracting reagent led to much higher (\(p<0.01\)) extraction yields than those determined with deionized water (Figure 8), as expected given its strong complex capacity [44]. The EDTA extraction method is capable of extracting PHE from all non-silicate bound phases, likely reflecting the metal availability in the long term [45]. Figure 8: Vertical distribution of trace element concentrations extracted by deionized water and EDTA from the two sampling sections (amended and control) of the soil profile.