## 3 Results and Discussion
### TE Transfer in the Aerial Plant Parts of M. sylvestris
However, the calculated average Zn shoot concentration of 386 \(\mu\)g g\({}^{-1}\) of DW was higher in Area 3 (Table 4, \(p<0.05\)) compared to in the two other areas, which showed values of around 310 \(\mu\)g g\({}^{-1}\) of DW. Results also showed higher Zn concentrations in the leaves of plants grown in Area 3 compared to those of plants grown in the two other areas (Table 3, \(p<0.05\)). An extractable Zn concentration correlation might partially explain this cultivation area effect on the Zn shoot concentrations (\(p<0.05\), \(r=0.47\)). The difference in the shoot accumulation of Zn and Cd could be due to the fact that Zn is essential to the plant, contrary to Cd [43]. While the Pb concentrations in the flowers were higher than those in the stems (Table 3, \(p<0.05\)), the Pb concentrations in the leaves were equal to those in the flower and in the stems. The concentrations in the flowers were around 45 times higher than the one measured in the flowers of the control, suggesting the tolerance of _M. sylvestris_ to Pb, this element being not essential. The concentration of Pb in the three plant parts and the shoots (4.4-5.2 \(\mu\)g g\({}^{-1}\) of DW, Table 4) were not affected by the cultivation area (\(p>0.05\)). Concerning Cu, except for in the stems, the cultivation area did not change the concentration measured in the flowers and leaves (Table 3) and shoots (9.6-11.6 \(\mu\)g g \begin{table}
\begin{tabular}{c c c c c} \hline  & **Cd** & **Cu** & **Pb** & **Zn** \\ \hline \multirow{3}{*}{Area 1} & (Shoots) & 1.54 (0.27) & 11.6 (2.06) & 4.37 (2.9) & 315.38 (72.98) \({}^{1}\) \\  & BCF \({}_{\text{set}}\) & 0.246 (0.044) \({}^{\text{A}}\) & 0.133 (0.024) \({}^{\text{A}}\) & 0.006 (0.004) & 0.047 (0.011) \\  & BCF \({}_{\text{ext}}\) & 50.62 (12.32) \({}^{\text{A}}\) & 22.49 (5.13) \({}^{\text{A}}\) & 70.47 (45.41) & 66.31 (14.96) \\ \hline \multirow{3}{*}{Area 2} & (Shoots) & 1.55 (0.35) & 9.63 (1.52) & 4.72 (1.72) & 310.43 (61.08) \({}^{1}\) \\  & BCF \({}_{\text{set}}\) & 0.297 (0.068) \({}^{\text{B}}\) & 0.126 (0.02) \({}^{\text{A}}\) & 0.008 (0.003) & 0.051 (0.01) \\  & BCF \({}_{\text{ext}}\) & 45.04 (13.2) \({}^{\text{A}}\) & 17.49 (4.28) \({}^{\text{B}}\) & 78.53 (45.44) & 53.91 (11.35) \\ \hline \multirow{3}{*}{Area 3} & (Shoots) & 1.6 (0.27) & 10.40 (2.94) & 5.16 (3.43) & 386.37 (56.51) \({}^{2}\) \\  & BCF \({}_{\text{set}}\) & 0.181 (0.03) \({}^{\text{C}}\) & 0.103 (0.029) \({}^{\text{B}}\) & 0.005 (0.003) & 0.043 (0.004) \\ \cline{1-1}  & BCF \({}_{\text{ext}}\) & 33.54 (8.78) \({}^{\text{B}}\) & 16.74 (4.49) \({}^{\text{B}}\) & 93.52 (69.51) & 58.54 (17.56) \\ \hline \multirow{3}{*}{_M. sylvestris_ control} & (Shoots) & 0.25 (0.07) & 14.1 (3.3) & 0.42 (0.09) & 84 (29) \\ \cline{1-1}  & (Flower) & 0.44 & 7.8 & 0.22 & 47 \\ \hline \end{tabular} \(\overline{\text{BCF}}\) ext = [TE] shoots/[TE] sediment extractable, BCF tot = [TE] shoots/[TE] sediment total.  
\end{table} 
Table 4: TE concentration in the aerial part (shoots and flower, \(\mu\)g g\({}^{-1}\) DW) and bioconcentration factor (BCF) of _M. sylvestris_ L. cultivated in the three areas and TE concentration in the aerial part and flower of _M. sylvestris_ L. cultivated in the uncontaminated site (control). With the exception of the _M. sylvestris_ control flower (\(n=1\)), the results are reported as means \(\pm\) standard deviations (SD) (\(n=10\) for shoots from the 3 areas and corresponding BCF; \(n=3\) for shoots of _M. sylvestris_ control). Significant differences between areas are indicated by different letters or numbers at the level of \(\alpha=0.05\) (lowercase for BCF tot; uppercase for BCF ext, number for shoots). of DW, Table 4). Equal Cu concentrations were constantly measured in the leaves and flowers (\(p>0.05\)). As for Zn, Cu is an essential element. These concentrations correspond to physiological concentrations for most of the plants [43]. For the four TE, the calculated BCF totals were strongly inferior to 1, with a maximum of 0.297 for Cd and a minimum of 0.005 for Pb.