# Spatial Mobility of U and Th in a U-enriched Area (Central Portugal)
## 3 Results and Discussion  
### Geochemistry of Stream Sediments and Soils  
The average, median, and standard deviation of physicochemical parameters, potentially toxic elements, and rare earth elements concentrations from stream sediments, soils, and mine dumps from the Canto Lagar area are presented in Table 2.  
Almost all of the element contents detected in stream sediments, soils, and mine dumps showed a huge variation, with values up to Fe--42,559 mg/kg, U--4541 mg/kg, As--171 mg/kg, Cu--171 mg/kg, Zn--157 mg/kg, Pb--71 mg/kg, and Th--63 mg/kg, associated with the natural environment but also with the mine contribution. The highest As, U, Pb, and Th were found on the mine dumps. Otherwise, the highest REE (417.5 mg/kg), Zn (134.9 mg/kg), Cu (171.4 mg/kg), Cs (61.5 mg/kg), Ba (59.7 mg/kg), and Ni (19.5 mg/kg) contents occurred in soils and reflect the geogenic influence, associated with the background lithologies cropping out of the area. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Accuracy** & **Precision** \\ \hline
**Concentration Relatively** & \(\overline{\Delta lgC}=\left|lg\overline{C_{i}}-lgC_{s}\right|\) & \(\lambda=\sqrt{\frac{\sum_{i=1}^{n}\left(lgC_{i}-lgC_{s}\right)^{2}}{n-1}}\) \\ \hline \textless{}3 DL & \textless{}0.024 & 0.031 \\ \textgreater{}3 DL & \textless{}0.015 & 0.018 \\ \hline \hline \(\overline{C_{i}}\)—standard average values of \(BCR_{i}\); in sediments, soils, and mine dumps; \(C_{i}\)—standard average values of BCR; \(C_{s}\)—value recommended for standards BCR; \(n\)—total samples inserted in the sample pack. \\ \end{tabular}
\end{table} 
Table 1: References for accuracy and precision of obtained results. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c c} \hline  & & **pH** & **EC** & **OM** & **Fe** & **Mn** & **Cr** & **Cu** & **Zn** & **As** & **Cs** & **Zr** & **Ba** & **RE** & **W** & **Pb** & **Th** & **U** \\ \hline \multicolumn{11}{c}{**mg/kg**} \\ \hline \multirow{6}{*}{**Stream sediments. upstream**} & Median & 6.04 & 22.60 & 1.67 & 1.65 & 0.05 & 4.95 & 12.77 & 96.03 & 18.31 & 19.22 & 0.68 & 30.74 & 262.73 & 1.26 & 18.01 & 25.56 & 131.86 \\ \cline{2-11}  & Minimum & 5.99 & 12.70 & 0.79 & 1.61 & 0.03 & 4.14 & 11.48 & 81.34 & 13.70 & 17.29 & 0.34 & 23.09 & 218.30 & 1.05 & 12.98 & 20.36 & 102.48 \\ \cline{2-11}  & Maximum & 6.13 & 34.20 & 2.64 & 1.98 & 0.07 & 5.58 & 21.34 & 102.08 & 22.53 & 21.42 & 0.96 & 35.40 & 327.12 & 1.62 & 22.02 & 30.26 & 182.75 \\ \cline{2-11}  & St deviation & 0.08 & 10.85 & 0.93 & 0.20 & 0.02 & 0.74 & 5.46 & 10.54 & 4.43 & 2.08 & 0.31 & 6.67 & 57.09 & 0.32 & 4.61 & 4.65 & 44.25 \\ \cline{2-11}  & N & 3 & & & & & & & & & & & & & & & & & \\ \hline \multirow{6}{*}{**Stream sediments. downstream**} & Median & 5.92 & 55.16 & 2.99 & 1.88 & 0.03 & 9.29 & 17.01 & 108.06 & 13.24 & 8.86 & 0.49 & 30.10 & 234.19 & 2.00 & 23.15 & 18.97 & 87.70 \\ \cline{2-11}  & Median & 4.40 & 25.10 & 1.02 & 1.33 & 0.02 & 3.14 & 3.70 & 64.34 & 4.04 & 7.41 & 0.12 & 10.78 & 177.13 & 0.56 & 9.60 & 8.95 & 19.01 \\ \cline{2-11}  & Maximum & 6.42 & 154.20 & 5.82 & 1.97 & 0.06 & 13.76 & 30.27 & 157.14 & 35.88 & 13.74 & 3.45 & 47.70 & 355.99 & 4.76 & 31.78 & 32.02 & 454.04 \\ \cline{2-11}  & St deviation & 0.56 & 35.85 & 1.35 & 0.24 & 0.01 & 3.04 & 7.52 & 28.81 & 8.99 & 1.73 & 0.98 & 9.67 & 50.00 & 1.36 & 6.90 & 6.94 & 125.78 \\ \cline{2-11}  & N & 11 & & & & & & & & & & & & & & & & & & \\ \hline \multirow{6}{*}{**Soil. background**} & Median & 5.36 & 23.12 & 2.99 & 1.98 & 0.05 & 6.20 & 30.84 & 91.34 & 15.34 & 25.56 & 0.93 & 39.18 & 303.98 & 1.03 & 18.43 & 38.14 & 50.14 \\ \cline{2-11}  & Minimum & 5.09 & 12.80 & 2.13 & 1.51 & 0.03 & 4.59 & 7.06 & 73.27 & 11.18 & 10.52 & 0.36 & 23.46 & 26 The variation of the physicochemical parameters, trace elements, and REE concentrations in stream sediments, soils, and mine dumps are represented as boxplots (Figure 2). The \(Y\)-axis depicts the concentration of each element.