## 3 Results and Discussions
### XRF Soil Analysis
#### 3.2.4 The Geo-Accumulation Index (I\({}_{\rm geo}\))  
As shown in Table 9, the I\({}_{\rm geo}\) values obtained by applying Equation (2), presented in Table 1, indicate the soil is moderately polluted for the majority of the samples and elements. The values ranged from \(-\)3.84 to 3.58 for all the locations and heavy metals. The maximum value for I\({}_{\rm geo}\) was found for Hg in the 5 PS location, at the playground area of the park, close to a road with intense vehicular traffic. At this location, the value is 3.58, a result that indicates the soil is moderately to strongly polluted with Hg. The average of all the positive I\({}_{\rm geo}\) values per location indicated the following order of location contamination: 6 \(>\) 4 \(>\) 1 \(>\) 5 \(>\) 7 \(>\) 9 \(>\) 2 \(>\) 3 \(>\) 8. The averages of all the positive I\({}_{\rm geo}\) values for heavy metals in the playground samples were in the following order: Hg \(>\) Cr \(>\) Ba \(>\) Ni \(>\) Cu \(>\) V \(>\) Pb \(>\) Zn \(>\) As. For the edge of the park samples close to important roads, the order was Hg \(>\) Cr \(>\) Ba \(>\) Cu \(=\) Pb \(>\) Ni \(=\) V \(>\) Zn \(>\) As. The I\({}_{\rm geo}\) value indicated that the playground samples were moderately polluted with Cr, and Ba and Hg presented a moderate to strong pollution case. Meanwhile, Co, Mn, Sb and Cd had only \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Element**} & \multicolumn{2}{c}{**1**} & \multicolumn{2}{c}{**2**} & \multicolumn{2}{c}{**3**} & \multicolumn{2}{c}{**4**} & \multicolumn{2}{c}{**5**} & \multicolumn{2}{c}{**6**} & \multicolumn{2}{c}{**7**} & \multicolumn{2}{c}{**8**} & \multicolumn{2}{c}{**9**} & \multicolumn{2}{c}{**10**} \\ \cline{2-19}  & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** & **PS** & **ES** \\ \hline Cu & 1.65 & 2.80 & 2.50 & 1.80 & 1.40 & 1.25 & 1.55 & 1.80 & 1.70 & 1.65 & 2.75 & 1.75 & 2.10 & 1.50 & 2.25 & 1.40 & 1.95 & 2.45 & 1.75 & 2.00 \\ Pb & 1.10 & 5.40 & 1.85 & 1.45 & 1.20 & 2.00 & 0.80 & 1.15 & 1.45 & 1.60 & 3.60 & 4.60 & 0.80 & 1.05 & 1.35 & 1.45 & 1.25 & 1.45 & 1.75 & 1.15 \\ As & 1.12 & 1.14 & 1.00 & 1.20 & 1.26 & 1.28 & 0.80 & 0.90 & 1.38 & 1.26 & 1.60 & 1.68 & 1.00 & 1.06 & 1.04 & 1.20 & 0.90 & 0.96 & 0.86 & 0.90 \\ Co & 0.16 & 0.17 & 0.23 & 0.25 & 0.15 & 0.22 & 0.23 & 0.20 & 0.17 & 0.16 & 0.25 & 0.26 & 0.17 & 0.19 & 0.18 & 0.19 & 0.17 & 0.18 & 0.15 & 0.21 \\ Cr & 2.40 & 2.17 & 2.00 & 1.93 & 2.20 & 2.23 & 2.53 & 2.50 & 2.13 & 2.07 & 1.83 & 1.67 & 2.60 & 2.43 & 2.27 & 2.13 & 1.97 & 1.97 & 1.63 & 2.37 \\ Ni & 2.55 & 2.17 & 2.00 & 11.0 & 2.40 & 1.55 & 2.05 & 2.10 & 1.95 & 2.40 & 1.50 & 2.85 & 2.15 & 2.10 & 1.15 & 1.70 & 2.05 & 1.40 & 1.95 & 1.25 \\ Mn & 0.80 & 0.73 & 0.78 & 0.71 & 0.87 & 0.82 & 0.89 & 0.81 & 0.81 & 0.82 & 0.80 & 0.84 & 0.93 & 0.86 & 0.77 & 0.85 & 0.83 & 0.76 & 0.90 & 0.86 \\ Zn & 1.13 & 3.84 & 1.65 & 1.29 & 1.43 & 1.62 & 1.23 & 1.24 & 1.37 & 1.28 & 2.13 & 2.21 & 1.20 & 1.30 & 1.17 & 1.05 & 1.38 & 1.19 & 1.56 & 1.39 \\ Hg & 9.00 & 1.00 & 1.00 & 9.00 & 1.00 & 9.00 & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 & 9.00 & 1.00 & 9.00 & 1.00 & 8.00 & 1.00 & 1.00 & 1.00 & 1.00 \\ V & 1.70 & 1.84 & 1.64 & 1.26 & 1.22 & 1.28 & 1.08 & 1.86 & 1.58 & 1.40 & 1.62 & 1.86 & 1.80 & 1.58 & 1.60 & 1.64 & 1.46 & 1.58 & 1.78 \\ Sb & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 & 0.11 & 0.11 \\ Ba & 1.65 & 2.61 & 2.17 & 1.93 & 1.58 & 1.87 & 2.56 & 2.24 & 2.58 & 1.75 & 1.85 & 2.16 & 2.41 & 2.39 & 2.04 & 1.89 & 2.00 & 1.72 & 2.00 & 2.01 \\ Cd & 0.15 & 0.14 & 0.07 & 0.10 & 0.12 & 0.12 & 0.09 & 0.13 & 0.15 & 0.16 & 0.17 & 0.23 & 0.10 & 0.14 & 0.16 & 0.08 & 0.14 & 0.13 & 0.25 & 0.10 \\ Ag & 1.75 & 1.80 & 1.65 & 1.40 & 1.70 & 1.85 & 1.70 & 1.80 & 1.65 & 1.60 & 1.75 & 1.70 & 1.65 & 1.65 & 1.75 & 1.70 & 1.60 & 1.70 & 1.70 & 1.70 \\ \hline \hline \end{tabular}
\end{table}