## 3 Results and Discussion
### Grouping of the Elements  
Samples extracted in places close to mining activity in the Aconcagua basin and vegetable and fruit crop areas in the Casablanca River basin are evaluated (Table 5). It is evident that arsenic contributes largely to Factor 1 (90.5%), copper entirely to Factor 3 (100%), and lead with zinc, to a large extent, to Factor 2 (59.0% and 73.5%, respectively) in the Aconcagua basin. In the Casablanca River basin, unlike in the previous case, arsenic contributes largely to Factor 2 (79.3%), and copper, lead, and zinc contribute to Factor 1 (86.2%, 68.6%, and 68.7%, respectively), leaving Factor 3 as a residual of the four metals. Finally, the data associated with fruit crop areas showed that arsenic contributes to Factor 1 (81.9%), copper, to a large extent, to Factor 3 (82.1%), accompanied by lead in smaller quantities (44.5%), and finally, lead to Factor 2 (64.1%). Regarding the source of origin of the heavy metals influencing each factor (summarized in Table 6), in the case of arsenic, although the dominant source in soils is geological and therefore depends, to some extent, on the concentration in the parent rock material, additional contributions can be derived locally from industrial sources, such as smelting and fossil fuel combustion products, and agricultural sources, such as pesticides and phosphate  
Figure 4: Cluster analysis plot for heavy metals As, Cu, Pb, and Zn (mg/kg) for the soils of the studied areas: (**left**) Aconcagua River basin and (**right**) Casablanca River basin. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{6}{c}{**Aconcagua River Basin**} & \multicolumn{6}{c}{**Casablanca River Basin**} \\ \hline  & \multicolumn{3}{c}{**Mining Activities**} & \multicolumn{3}{c}{**Vegetable Crops**} & \multicolumn{3}{c}{**Fruit Crops**} \\  & **Factor 1** & **Factor 2** & **Factor 3** & **Factor 1** & **Factor 2** & **Factor 3** & **Factor 1** & **Factor 2** & **Factor 3** \\ \hline As & 90.5\% & 8.4\% & 1.1\% & 8.1\% & 79.3\% & 12.6\% & 81.9\% & 18.1\% & 0\% \\ Cu & 0\% & 0\% & 100\% & 86.2\% & 13.8\% & 0.0\% & 17.9\% & 0\% & 82.1\% \\ Pb & 37.2\% & 59.0\% & 3.7\% & 68.6\% & 0\% & 31.4\% & 0\% & 64.1\% & 35.9\% \\ Zn & 24.0\% & 73.5\% & 2.5\% & 68.7\% & 7.3\% & 24.0\% & 13.4\% & 42.1\% & 44.5\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Percentage contribution of heavy metals to each factor in the Aconcagua River basin and Casablanca River basin. fertilizers. Arsenic concentrations well above the background values have been found in sediments and soils contaminated by the products of mining activity, including mine tailings and effluents [34]. Copper's origin lies in the effect of mining on soils in the country, where numerous studies have revealed a high degree of heavy metal contamination in areas near tailings and smelters. It is essential to mention the presence of mining activity in the Aconcagua basin, where the primary extraction material is copper. It also stands out as one of the areas with the soil most contaminated by the mining industry [35]. In the case of lead, its presence can be important even decades after the polluting source has been eliminated, for example, the content in paints and fuels before the 1990s or irrigation with sewage water, which has been treated 100% since 2013 but which toxic residues will remain in the soil for a long time. Although there are no direct studies in the country, soils surrounding roads and railways are expected to have high levels of contamination due to combustion, spills, and activities associated with transport routes [35]. Regarding zinc, it is estimated that its presence in the topsoil is, on the one hand, of natural origin, resulting from the contributions of the soil's parent materials, and, on the other hand, from the intensity of soil formation factors, especially rainfall. Finally, vegetables can absorb heavy metals through the roots or leaves.