## 4 Results and Discussion
### Environmental Availability
\begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Element**} & \multicolumn{1}{c}{**As**} & \multicolumn{1}{c}{**Cd**} & \multicolumn{1}{c}{**Cr**} & \multicolumn{1}{c}{**Cu**} & \multicolumn{1}{c}{**Ni**} & \multicolumn{1}{c}{**Pb**} & \multicolumn{1}{c}{**Sb**} & \multicolumn{1}{c}{**Tl**} & \multicolumn{1}{c}{**Zn**} \\ \hline \multicolumn{10}{l}{Anended} \\ soil & \(29.8\pm 2.6\) & \(39.2\pm 3.5\) & \(3.08\pm 0.29\) & \(10.877\pm 1739\) & \(101\pm 8\) & \(129\pm 11\) & \(16.7\pm 1.3\) & \(0.07\pm 0.006\) & \(13.419\pm 940\) \\ T20 & \(10.9\pm 0.9\) & \(23.5\pm 1.9\) & \(5.59\pm 0.5\) & \(6517\pm 639\) & \(42\pm 3\) & \(162\pm 14\) & \(12.3\pm 0.8\) & \(0.07\pm 0.004\) & \(3951\pm 388\) \\ T30 & \(5.9\pm 0.6\) & \(4.08\pm 0.39\) & \(4.58\pm 0.3\) & \(3261+266\) & \(42\pm 3\) & \(334\pm 28\) & \(5.8\pm 0.5\) & \(0.40\pm 0.03\) & \(1577\pm 118\) \\ T40 & \(11.2\pm 0.9\) & \(31.5\pm 0.27\) & \(4.21\pm 0.38\) & \(2383\pm 223\) & \(36.1\pm 2.5\) & \(289\pm 19\) & \(14.4\pm 1.3\) & \(0.75\pm 0.005\) & \(873\pm 77\) \\ T50 & \(15.4\pm 1.4\) & \(4.34\pm 0.32\) & \(3.87\pm 0.32\) & \(3062\pm 246\) & \(31.5\pm 2.3\) & \(444\pm 42\) & \(18.4\pm 1.7\) & \(0.93\pm 0.07\) & \(813\pm 81\) \\ T60 & \(37.7\pm 2.2\) & \(10.2\pm 0.7\) & \(11.5\pm 1.1\) & \(4775\pm 408\) & \(201\pm 18\) & \(589\pm 36\) & \(44.7\pm 3.9\) & \(0.71\pm 0.07\) & \(3315\pm 294\) \\ T65 & \(25.0\pm 2.0\) & \(5.35\pm 0.93\) & \(4.76\pm 0.45\) & \(3557\pm 302\) & \(41.1\pm 3.9\) & \(402\pm 30\) & \(24.9\pm 2.4\) & \(1.23\pm 0.10\) & \(1101\pm 108\) \\ \hline \multicolumn{10}{l}{Control soil} \\ STI0 & \(116\pm 11\) & \(7.37\pm 0.73\) & \(30.9\pm 2.2\) & \(13.126\pm 1260\) & \(154\pm 12\) & \(142\pm 12\) & \(69.8\pm 6.9\) & \(0.07\pm 0.01\) & \(2624\pm 213\) \\ STI20 & \(13.3\pm 1.2\) & \(3.67\pm 0.32\) & \(8.87\pm 0.67\) & \(4479\pm 434\) & \(38.1\pm 3.2\) & \(473\pm 42\) & \(7.77\pm 0.66\) & \(0.16\pm 0.01\) & \(898\pm 56\) \\ STI30 & \(77.6\pm 4.9\) & \(3.79\pm 0.37\) & \(23.1\pm 2.1\) & \(6143\pm 355\) & \(68.2\pm 4.4\) & \(190\pm 14\) & \(32.9\pm 2.4\) & \(0.53\pm 0.04\) & \(1206\pm 108\) \\ STI40 & \(57.9\pm 5.5\) & \(3.09\pm 0.26\) & \(117\pm 7\) & \(6642\pm 660\) & \(63.4\pm 5.4\) & \(179\pm 16\) & \(35.1\pm 3.2\) & \(0.69\pm 0.05\) & \(788\pm 46\) \\ STI50 & \(42.4\pm 4.4\) & \(3.17\pm 0.31\) & \(8.28\pm 0.82\) & \(4723\pm 359\) & \(457.5\pm 3.9\) & \(145\pm 12\) & \(22.3\pm 1.4\) & \(11.15\pm 0.11\) & \(624\pm 55\) \\ STI60 & \(578\pm 49\) & \(8.87\pm 0.77\) & \(35.1\pm 3.1\) & \(14.663\pm 1371\) & \(57.2\pm 5.3\) & \(452\pm 40\) & \(125\pm 7\) & \(1.71\pm 0.15\) & \(1017\pm 97\) \\ STI70 & \(477\pm 40\) & \(8.09\pm 0.81\) & \(44.4\pm 3.7\) & \(15.627\pm 1561\) & \(75.5\pm 7.3\) & \(579\pm 57\) & \(135\pm 10\) & \(1.75\pm 0.12\) & \(1137\pm 99\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Trace element concentrations (ug kg\({}^{-1}\)) extracted with 0.05 mol L\({}^{-1}\) EDTA from amended soil and control soil samples. Certainly, Zn and Cu were the most abundant PHE in the topsoil extracts of the amended plot, where the EDTA-extracted concentrations reached up to 13,419 \(\upmu\) kg\({}^{-1}\) and 10,877 \(\upmu\)g kg\({}^{-1}\), respectively. Despite the high levels of Zn and Cu measured in the extracts, the mobilizable fraction of Zn was 1.58%, and that for Cu accounted for only 0.90%. The maximum contents of Pb (402-589 \(\upmu\)g kg\({}^{-1}\)) were extracted from the subsoil samples (50-70 cm depth), while the remaining PHE were at lower concentration in the extracts (mostly below 50 \(\upmu\)g kg\({}^{-1}\)) over the entire soil profile. The amended upper surface layer (0-10 cm depth) had a significant increase (\(p<0.01\)) in the levels of Zn and Cd in comparison with the control soil. It was also found that the soil cores were significantly enriched (\(p<0.01\)) in the EDTA-extracted concentrations of Zn over the entire profile of the amended plot, as well as in those of Cd, Cu, and Sb at the depth of 10-20 cm, and Pb at 20-60 cm depth.