## 3 Results and Discussion
### Metal Analysis
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Site**} & \multirow{2}{*}{**Substrate**} & \multirow{2}{*}{**Season**} & \multicolumn{2}{c}{**PTotal**} & \multicolumn{2}{c}{**Leading Test**} & \multicolumn{2}{c}{**SEP Tessier (\%)**} & \multicolumn{2}{c}{**MF**} \\ \cline{3-10}  & & & \multicolumn{2}{c}{**0.01 M CaCl\({}_{1}\)**} & \multicolumn{2}{c}{**(\%)**} & \multicolumn{2}{c}{**F1**} & \multicolumn{2}{c}{**F2**} & \multicolumn{2}{c}{**F3**} & \multicolumn{2}{c}{**F4**} & \multicolumn{2}{c}{**F5**} \\ \hline S12 & Soil & Dry & 21.4 & 0.92 & 4.31 & & & & & 46.13 & 9.9 \\  & & Rainy & 16.9 & 0.83 & 4.90 & & & & & 41.98 & 7.1 \\  & Sediment & Dry & 26.9 & 0.80 & 2.98 & & & & & 37.82 & 10.2 \\  & & Rainy & 45.8 & 0.21 & 0.46 & & & & & 24.52 & 11.2 \\ \hline S15 & Soil & Dry & 37.4 & 2.18 & 5.82 & & & & & 23.54 & 8.8 \\  & & Rainy & 15.7 & 0.44 & 2.80 & & & & & 36.08 & 5.7 \\  & Sediment & Dry & 50.5 & 0.29 & 0.58 & & & & & 22.78 & 11.5 \\  & & Rainy & 37.7 & 0.10 & 0.27 & & & & 24.24 & 9.1 \\ \hline S22 & Soil & Dry & 70.2 & 0.95 & 1.35 & & & & & 17.61 & 12.4 \\  & & Rainy & 65.4 & 0.73 & 1.12 & & & & 22.72 & 14.9 \\  & Sediment & Dry & 64.6 & 0.48 & 0.74 & & & & & 22.08 & 14.3 \\  & & Rainy & 221.6 & 1.05 & 0.47 & & & & & 14.01 & 31.0 \\ \hline S24 & Soil & Dry & 40.5 & 1.67 & 4.13 & & & & & 24.46 & 9.9 \\  & & Rainy & 22.1 & 0.28 & 1.26 & & & & & 29.51 & 6.5 \\  & Sediment & Dry & 37.1 & 0.78 & 7.81 & & & & 40.56 & 15.0 \\  & & Rainy & 42.2 & 0.14 & 0.33 & & & & & 28.32 & 12.0 \\ \hline  & & & & & & & & & & & \\  & & & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: _Cont._ \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Soil Dry**} \\ \hline S1 \(>\) S2 \(>\) S4 \(>\) S22 \(>\) S24 \(>\) S15 \(>\) S6 \(>\) S12 \\
**Soil Rainy** \\ S2 \(>\) S1 \(>\) S4 \(>\) S22 \(>\) S24 \(>\) S6 \(>\) S12 \(>\) S15 \\
**Segment Dry** \\ S1 \(>\) S2 \(>\) S4 \(>\) S22 \(>\) S15 \(>\) S24 \(>\) S12 \(>\) S6 \\
**Segment Rainy** \\ S1 \(>\) S2 \(>\) S22 \(>\) S12 \(>\) S6 \(>\) S24 \(>\) S4 \(>\) S15 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Total concentration order of lead analyzed by substrate/season. Probable Effect Level (PEL) in Freshwater Sediment to obtain preliminary data on metal concentration in surface sediments. TEL values represent the concentration of a chemical below which adverse effects are expected to occur rarely and PEL values represent the concentration of a chemical, above which adverse biological effects are expected to occur frequently [49]. The results showed that Pb concentration of surface sediments in all of sites were above the TEL value of 35.0 mg kg\({}^{-1}\), except in two cases (S6 and S12, both in dry season). When compared to the PEL value of 91.3 mg kg\({}^{-1}\), the S1 and S2 sites were found 46 and 10 times higher than QG, respectively; the site S4 in dry season and S22 in rainy season also showed higher values than the reference. Leaching tests, fast preliminary screenings to evaluate a potential toxicity of metal [50,51], showed that sediment samples from S1, S2 in rainy season and S4 in dry season leached the highest concentrations (20.24, 15.18 and 17.12 mg kg\({}^{-1}\), respectively). Taking into account the weak ionic strength of CaCl\({}_{2}\) 0.01M, these results suggest a significant amount of potentially mobile Pb, and an increased risk for the environment. Statistical analysis did not demonstrate a correlation between this mobility and any physiochemical variable (\(p<0.05\)), indicating the significant geochemical complexity of the sample and the need to further investigate the chemical composition of the sample [52]. Sequential extraction was conducted in order to assess the metal fractionation and the relative ability of metal in the soil and sediment samples.