## 3 Results
### Trace Metal Enrichment  
In contrast to the pseudo-total concentrations, the element enrichment indicated by the enrichment factor (EF) partially demonstrates fewer differences between the different sample groups (Figure 3). In particular, the EF of Cr and V indicates rather minor enrichments in RS. In comparison to the different sample groups, the EF of V shows similar median values (median value: CS = 2.6; SS = 2.6; RS = 2.9) and variations without being significantly different to each other. For Cr, the enrichment in RS is significantly lower than in SS or CS (median value: CS = 3.0; SS = 3.2; RS = 2.8). The EF median values of As show  
Figure 2: The element concentrations (As, Cd, Cr, Mn, Ni, Pb, V, Zn) of samples from catchment soils (CS, _n_: 89), river sediments (SS, _n_: 35), and reservoir sediments (RS, _n_: 50). The boxplots contain the element-specific concentrations of all sampling areas (black squares = mean values; crossbars = median values; x = minimum/maximum value; whiskers include the 5 th to 95 th percentile, the boxes include the 25 th to 75 th percentile). Significant differences were determined by Kruskal–Wallis H-test and Dunn–Bonferroni post-hoc test and are related to \(p\leq 0.01\). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Asympt.** \\ **Sig** \\ \end{tabular} & **Al** & **As** & **Cd** & **Cr** & **Fe** & **Mn** & **Ni** & **Pb** & **V** & **Zn** \\ \hline \hline \
\begin{tabular}{c} **Conc.** \\ \end{tabular} & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** & \(\leq\)**0.01** \\ \hline \hline
\begin{tabular}{c} EF \\ \end{tabular} & - & 0.74 & \(\leq\)**0.01** & \(\leq\)**0.01** & - & \(\leq\)**0.01** & \(\leq\)**0.01** & 0.13 & 0.29 & \(\leq\)**0.01** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Asymptotic significances (Kruskal–Wallis H test; \(p\leq 0.01\) in bold letters) between the sample groups (CS, SS, RS) in reference on the element concentrations (Conc.) and the enrichment factors (EF). a similarly homogeneous picture in the comparison of the sample groups, whereby the enrichment is generally slightly higher (median value: CS = 3.7; SS = 3.8; RS = 3.4). The elements Cd, Ni, Pb, and Zn are enriched in a higher degree in SS and/or RS. According to the pattern of their pseudo-total concentrations, the EF of Cd (median value: CS = 1.9; SS = 2.7; RS = 8.2) and Zn (median value: CS = 2.4; SS = 3.6; RS = 5.0) indicate the lowest enrichments in the group of the CS, while RS are the most enriched. The elements Mn and Ni are rather slightly enriched in CS, reach significantly higher enrichments in RS, and they are the most enriched (Mn median value: CS = 3.1; SS = 7.2; RS = 3.9; Ni median value: CS = 3.6; SS = 6.5; RS = 4.8) in SS. Pb shows the highest median value (CS = 5.9; SS = 4.1; RS = 5.4) and the largest variation in the group of CS, although mean values and variation are less differently pronounced than for Cd, Ni, or Zn. In comparison to the pseudo-total concentrations, the presence of significant differences of the EF between the investigated sample groups is restricted to the elements Cr, Cd, Mn, Ni, and Zn (Table 3). In the case of Cr, significant differences rely on the significantly lower enrichment in RS. In contrast, significant differences of Cd, Mn, Ni, and Zn rely on the fact that the EF of SS and/or RS is significantly higher than the EF of CS. Figure 3: The element-specific enrichment factors (Al, As, Cd, Cr, Mn, Ni, Pb, V, Zn) of samples from catchment soils (CS, _n_: 89), river sediments (SS, _n_: 35), and reservoir sediments (RS, _n_: 50). The boxplots contain the element-specific enrichment factors of all sampling areas of a sample group (black squares = mean values; crossbars = median values; x = minimum/maximum value; whiskers include the 5 th to 95 th percentile, the boxes include the 25 th to 75 th percentile).