## 3 Results
### Mercury Environmental Speciation
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Microbial Activities** & **Bel1** & **Bel2** & **Bel3** & **Yao1** & **Yao2** & **Yao3** \\ \hline MBC & 312.6 \(\pm\) 10.0 **c** & 385.9 \(\pm\) 21.5 **c** & 844.4 \(\pm\) 14.1 **b** & 223.1 \(\pm\) 10.8 **d** & 248.1 \(\pm\) 13.6 **d** & 1102 \(\pm\) 41 **a** \\ DH & 0.43 \(\pm\) 0.08 **d** & 0.34 \(\pm\) 0.02 **d** & 2.10 \(\pm\) 0.19 **b** & 0.46 \(\pm\) 0.07 **d** & 1.03 \(\pm\) 0.12 **c** & 5.80 \(\pm\) 0.44 **a** \\ B-Glu & 1.60 \(\pm\) 0.25 **a** & 1.46 \(\pm\) 0.78 **a** & 5.54 \(\pm\) 0.38 **a** & 1.38 \(\pm\) 0.10 **a** & 3.48 \(\pm\) 0.97 **a** & 18.6 \(\pm\) 3.4 **b** \\ Urease & 0.46 \(\pm\) 0.04 **c** & 0.70 \(\pm\) 0.02 **bc** & 1.52 \(\pm\) 0.06 **b** & 0.14 \(\pm\) 0.01 **d** & 0.29 \(\pm\) 0.02 **c** & 4.74 \(\pm\) 0.28 **a** \\ AcdP & 5.76 \(\pm\) 0.90 **bc** & 3.41 \(\pm\) 0.80 **c** & 11.78 \(\pm\) 1.70 **b** & 2.87 \(\pm\) 0.98 **c** & 10.98 \(\pm\) 0.94 **b** & 18.09 \(\pm\) 0.7 **a** \\ AlkP & 0.36 \(\pm\) 0.09 **c** & 4.17 \(\pm\) 0.70 **b** & 2.79 \(\pm\) 0.47 **c** & 1.02 \(\pm\) 0.57 **c** & 12.07 \(\pm\) 3.01 **a** & 4.02 \(\pm\) 0.52 **b** \\ Aryl & 1.57 \(\pm\) 0.27 **bc** & nd & 8.42 \(\pm\) 1.22 **b** & 1.04 \(\pm\) 0.36 **c** & 1.12 \(\pm\) 0.50 **bc** & 56.0 \(\pm\) 3.5 **a** \\ FDA & 1.22 \(\pm\) 0.12 **b** & 0.89 \(\pm\) 0.10 **b** & 1.28 \(\pm\) 0.09 **b** & 0.52 \(\pm\) 0.04 **c** & 0.49 \(\pm\) 0.02 **c** & 3.22 \(\pm\) 0.21 **a** \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Soil Microbial Biomass and soil enzymes activities involved in soil biogeochemical cycles in the six rehabilitated sites (\(n\) = 5, mean \(\pm\) SD). MBC: Soil microbial biomass carbon in mg\(\cdot\)kg\({}^{-1}\), DH: Dehydrogenase activity in \(\upg\) TPF (red-colored formazan) g\({}^{-1}\) soil h\({}^{-1}\), B-Glu, AcdP, AlkP and Aryl: \(\beta\)-glucosidase, Acid phosphatase, Alkaline phosphatase and Arylsulfatase activities in \(\upg\) pNP g\({}^{-1}\) soil h\({}^{-1}\), Urease: Urease activity in \(\upg\) NH\({}_{4}\)\({}^{+}\)-N g\({}^{-1}\) soil h\({}^{-1}\), FDA: Global microbial enzymes activities in \(\upg\) fluorescein g\({}^{-1}\) soil h\({}^{-1}\). For each parameter, values followed by different letters differ significantly with \(p\) < 0.05 with Tukey HSD test. * Total highly mobile and mobile mercury species  
The quantities of highly mobile mercury E1 (Table 3), and their percentage in relation to total mercury (Figure 2b), were significantly higher for site Yao1 with a percentage of 8% for E1. Yao1 was also the richest in water soluble mercury (F1) and bioavailable mercury (F3) with 4.56 and 2.93%, respectively. For the other rehabilitated sites, the percentages of fractions F1, F2 and F3 (Figure 2a) did not show significant differences. Concerning mobile and toxic (E2) mercury, the Bel2 and Yao3 sites had the lowest grades with percentages of 6.46% and 7.68%, while Yaoni's two non-restored sites had average grades of 31.1% and 44.3% respectively. E1 and E2 are correlated negatively with microbial parameters and TOC and positively with total clay and aluminum (Table 4). * Total semi-mobile mercury species  
The highest percentages were detected for sites Yao1, Bel2 and Bel3 with values of 51.9%, 59.2% and 61.3%, respectively. The Bel1 site had the lowest quantity and percentage of semi-mobile mercury with 23.7%. The semi-mobile mercury fraction did not have a significant effect on microbial parameters and was significantly correlated with clay and aluminum content.