## 3 Results and Discussion  
### Trace Elements Concentrations in Plant Species  
All of the collected plants were assayed for trace element concentrations in a mixture of leaves and flower samples, except for _O. picensis_ (OP), for which an additional leaf sample was also collected in La Greda (LG leaves). Table 2 summarizes the results' average and the range of measured concentrations on a dry-weight basis, according to the different species and sampling locations. The values are classified as toxic or non-toxic, and the hyperaccumulation limits for the plants, according to the values reported by [PERSON] et al. [1], are also summarized in Table 2 and Figure 2.  
Figure 2: Mean trace element (TE) concentration (mg kg\({}^{-1}\)) at each sampling location according to the plant species: _O. picensis_’ TEs in major (**A.1**) and in minor (**A.2**) concentrations; _S. velutina_’s TEs in major (**B.1**) and in minor (**B.2**) concentrations; and _A. subfusiformis_’ TEs in major (**C.1**) and in minor (**C.2**) concentrations. \begin{table}
\begin{tabular}{c|c c c c c c c c c c c c c} \hline  & \multicolumn{1}{c}{Parameters} & \(\Delta\)C & \(\Delta\)R & \(\Delta\)R & \(\Delta\)C & \(\Delta\)R & \(\Delta\)C & \(\Delta\)R & \(\Delta\)R & \(\Delta\)R & \(\Delta\)R & \(\Delta\)C \\ \hline  & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\ \cline{2-15}  & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\ \hline \multicolumn{15}{c}{**C**} \\ \multicolumn{15}{c}{**C**The concentrations measured showed that no hyperaccumulator plants are present in any location, as reported in previous studies [12]. However, among the three different selected species, _O. picensis_ (OP) plants showed the highest concentrations of trace elements in their component structures (leaves and flowers). The average trace element concentrations in this species decreased in the following order (Table 2): Cu > Mn > Zn > Pb/Cr for LM and LG, but Mn > Zn > Cu > V for CH, following a slightly similar but not identical trend to the corresponding concentrations in the soil samples: Mn > Cu > Zn > V for LM, but Cu > Mn > Zn > V for LG and Mn > Zn > V>Cu for CH (Table 3). Table 3 summarizes the physicochemical characteristics and trace element levels found in the composite soil samples collected at the sampling locations, and some reference soil quality standards guidelines are also given for comparison. In this species (OP), the highest concentrations were found in Los Maitenes (LM), except for Mn and Zn, whose highest concentrations were reached in La Greda (LG). The difference in the elemental concentrations between these sampling sites is probably related to the soil chemical characteristics and corresponding concentrations in soil samples (Table 3). Thus, near the industrial complex Cu, Zn, As, and Pb soil concentrations were higher in LG than in LM, and consequently, the potential to accumulate these metals by OP species may be more significant at this site. However, interestingly, OP species tended to accumulate a higher quantity of Cu, As, and Pb in LM, even though the concentration of these elements in soil was lower than in LG. This fact may be explained by the different soil characteristics of these locations since the physicochemical properties of the soil also influence the behavior, phytobioavailability, and toxicity of trace elements.