## 3 Results and Discussion
### Influence of Grain Size Distribution, Land Use, and Total Organic Carbon on Heavy Metal Content
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Shapiro–Wilk Test**} & \multicolumn{1}{c}{**Fisher Test**} & \multicolumn{1}{c}{**T-Test**} & \multicolumn{1}{c}{**Mann-Whitney Test**} \\ \hline \multirow{2}{*}{Aluminum (Al)} & \(p\)-value upstream samples & 0.8864 & \multirow{2}{*}{0.6621} & \multirow{2}{*}{0.09037} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.128 & & & \\ \hline \multirow{2}{*}{Arsenic (As)} & \(p\)-value upstream samples & 0.02253 & \multirow{2}{*}{0.004996} & \multirow{2}{*}{-} & \multirow{2}{*}{1} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.5165 & & & \\ \hline \multirow{2}{*}{Barium (Ba)} & \(p\)-value upstream samples & 0.1354 & \multirow{2}{*}{0.2719} & \multirow{2}{*}{0.2205} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.5276 & & & \\ \hline \multirow{2}{*}{Beryllium (Be)} & \(p\)-value upstream samples & 0.2535 & \multirow{2}{*}{0.7138} & \multirow{2}{*}{**0.02941**} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.2384 & & & \\ \hline \multirow{2}{*}{Cobalt (Co)} & \(p\)-value upstream samples & 0.6676 & \multirow{2}{*}{0.3893} & \multirow{2}{*}{0.1136} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.01355 & & & \\ \hline \multirow{2}{*}{Chromium (Cr)} & \(p\)-value upstream samples & 0.2625 & \multirow{2}{*}{0.7067} & \multirow{2}{*}{**0.04032**} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.5937 & & & \\ \hline \multirow{2}{*}{Copper (Cu)} & \(p\)-value upstream samples & 0.6274 & \multirow{2}{*}{0.8748} & \multirow{2}{*}{0.07862} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.2954 & & & \\ \hline \multirow{2}{*}{Iron (Fe)} & \(p\)-value upstream samples & 0.8858 & \multirow{2}{*}{0.8671} & \multirow{2}{*}{0.08686} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.1382 & & & \\ \hline \multirow{2}{*}{Manganese (Mn)} & \(p\)-value upstream samples & 0.1568 & \multirow{2}{*}{0.2926} & \multirow{2}{*}{0.4462} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.101 & & & \\ \hline \multirow{2}{*}{Nickel (Ni)} & \(p\)-value upstream samples & 0.5631 & \multirow{2}{*}{0.7326} & \multirow{2}{*}{**0.02553**} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.4024 & & & \\ \hline \multirow{2}{*}{Lead (Pb)} & \(p\)-value upstream samples & 0.1532 & \multirow{2}{*}{0.4118} & \multirow{2}{*}{0.17} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.6442 & & & \\ \hline \multirow{2}{*}{Antimony (Sb)} & \(p\)-value upstream samples & 0.03497 & \multirow{2}{*}{0.6717} & \multirow{2}{*}{0.6092} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.2405 & & & \\ \hline \multirow{2}{*}{Thallium (TI)} & \(p\)-value upstream samples & 0.101 & \multirow{2}{*}{0.06233} & \multirow{2}{*}{0.8174} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.001158 & & & \\ \hline \multirow{2}{*}{Vanadium (V)} & \(p\)-value upstream samples & 0.8618 & \multirow{2}{*}{0.4634} & \multirow{2}{*}{0.1309} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.09543 & & & \\ \hline \multirow{2}{*}{Zinc (Zn)} & \(p\)-value upstream samples & 0.5218 & \multirow{2}{*}{0.546} & \multirow{2}{*}{0.1233} & \multirow{2}{*}{-} \\ \cline{2-2} \cline{5-6}  & \(p\)-value downstream samples & 0.3177 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Test results for heavy metals of the San Giuliano reservoir. The materials sampled at the Camastra and San Giuliano reservoirs are mainly characterized by sandy fractions downstream and by silt-clay fractions upstream. In the samples taken in the reservoir areas closest to the dams, the sand content is consistently above 50%, averaging 64.3% \(\pm\) 32.9%.