## 3 Results
### Activity Concentrations and Correlation of Radionuclides
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample NO**} & \multirow{2}{*}{**X Coordinate**} & \multirow{2}{*}{**Y Coordinate**} & \multicolumn{2}{c}{**\({}^{\mathbf{40}}\)K**} & \multicolumn{2}{c}{**\({}^{\mathbf{226}}\)Ra**} & \multicolumn{2}{c}{**\({}^{\mathbf{232}}\)Th**} & \multicolumn{2}{c}{**\({}^{\mathbf{228}}\)Ra**} \\ \cline{5-8}  & & & & & **Bq/kg** & \\ \hline S1 & 21\({}^{\circ}\)58\({}^{\prime}\)30.39\({}^{\prime\prime}\) N & 120\({}^{\circ}\)45\({}^{\prime}\)02.80\({}^{\prime\prime}\) E & 485.8 \(\pm\) 14.3 & 21.0 \(\pm\) 1.3 & 34.9 \(\pm\) 1.7 & 39.5 \(\pm\) 1.7 \\ S2 & 21\({}^{\circ}\)58\({}^{\prime}\)27.76\({}^{\prime\prime}\) N & 120\({}^{\circ}\)45\({}^{\prime}\)15.44\({}^{\prime\prime}\) E & 459.3 \(\pm\) 13.7 & 20.0 \(\pm\) 1.3 & 33.6 \(\pm\) 2.1 & 37.6 \(\pm\) 2.2 \\ S3 & 21\({}^{\circ}\)58\({}^{\prime}\)23.37\({}^{\prime\prime}\) N & 120\({}^{\circ}\)45\({}^{\prime}\)15.44\({}^{\prime\prime}\) E & 517.7 \(\pm\) 13.1 & 19.3 \(\pm\) 1.1 & 35.8 \(\pm\) 1.6 & 36.1 \(\pm\) 1.4 \\ S4 & 21\({}^{\circ}\)58\({}^{\prime}\)11.67\({}^{\prime\prime}\) N & 120\({}^{\circ}\)45\({}^{\prime}\)15.44\({}^{\prime\prime}\) E & 353.0 \(\pm\) 12.3 & 18.5 \(\pm\) 1.4 & 22.5 \(\pm\) 1.9 & 24.9 \(\pm\) 1.9 \\ S5 & 21\({}^{\circ}\)58\({}^{\prime}\)12.17\({}^{\prime\prime}\) N & 120\({}^{\circ}\)45\({}^{\prime}\)18.21\({}^{\prime\prime}\) E & 455.8 \(\pm\) 12.8 & 21.7 \(\pm\) 1.3 & 30.5 \(\pm\) 1.7 & 34.7 \(\pm\) 1.7 \\ S6 & 21\({}^{\circ}\)58\({}^{\prime}\)09.37\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)82.23\({}^{\prime\prime}\) E & 399.5 \(\pm\) 13.4 & 17.6 \(\pm\) 1.3 & 28.8 \(\pm\) 2.2 & 28.7 \(\pm\) 1.9 \\ S7 & 21\({}^{\circ}\)57\({}^{\prime}\)56.73\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)36.92\({}^{\prime\prime}\) E & 200.9 \(\pm\) 9.5 & 19.7 \(\pm\) 1.3 & 23.7 \(\pm\) 1.4 & 26.2 \(\pm\) 1.4 \\ S8 & 21\({}^{\circ}\)57\({}^{\prime}\)55.65\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)35.88\({}^{\prime\prime}\) E & 366.5 \(\pm\) 12.7 & 22.7 \(\pm\) 1.6 & 35.0 \(\pm\) 2.0 & 35.8 \(\pm\) 1.9 \\ S9 & 21\({}^{\circ}\)57\({}^{\prime}\)23.97\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)23.99\({}^{\prime\prime}\) E & 317.3 \(\pm\) 11.3 & 22.5 \(\pm\) 1.5 & 24.3 \(\pm\) 1.5 & 23.8 \(\pm\) 1.7 \\ S10 & 21\({}^{\circ}\)57\({}^{\prime}\)13.60\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)24.43\({}^{\prime\prime}\) E & 321.8 \(\pm\) 9.9 & 31.6 \(\pm\) 2.2 & 25.9 \(\pm\) 1.5 & 24.5 \(\pm\) 1.8 \\ S11 & 21\({}^{\circ}\)57\({}^{\prime}\)05.57\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)25.40\({}^{\prime\prime}\) E & 254.5 \(\pm\) 9.4 & 21.8 \(\pm\) 1.4 & 23.0 \(\pm\) 1.7 & 22.2 \(\pm\) 1.8 \\ S12 & 21\({}^{\circ}\)56\({}^{\prime}\)53.08\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)34.47\({}^{\prime\prime}\) E & 231.3 \(\pm\) 8.8 & 14.8 \(\pm\) 0.9 & 17.0 \(\pm\) 1.1 & 20.2 \(\pm\) 1.0 \\ S13 & 21\({}^{\circ}\)56\({}^{\prime}\)39.94\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)36.16\({}^{\prime\prime}\) E & 292.3 \(\pm\) 10.7 & 13.8 \(\pm\) 1.1 & 20.3 \(\pm\) 1.5 & 20.6 \(\pm\) 1.5 \\ S14 & 21\({}^{\circ}\)56\({}^{\prime}\)49.66\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)37.32\({}^{\prime\prime}\) E & 79.8 \(\pm\) 6.8 & 4.2 \(\pm\) 0.7 & 5.8 \(\pm\) 0.9 & 6.6 \(\pm\) 0.8 \\ S15 & 21\({}^{\circ}\)56\({}^{\prime}\)45.60\({}^{\prime\prime}\) N & 120\({}^{\circ}\)44\({}^{\prime}\)36.16\({}^{\prime\prime}\) E & 77.2 \(\pm\) 6.7 & 3.9 \(\pm\) 0.8 & 5.3 \(\pm\) 1.0 & 4.0 \(\pm\) 0.1 \\ S16 Additionally, Figure 2b shows that there was a strong positive correlation (r = 0.89, \(p<\) 0.001) between the activity concentrations of \({}^{232}\)Th and \({}^{40}\)K, as well as a positive correlation (r = 0.66, \(p<\) 0.001) between \({}^{226}\)Ra and \({}^{40}\)K. This correlation suggests that these radionuclides may have come from the same original sources and that they coexist at the sampling sites [6; 23; 30].