# Seasonal Pollution Levels and Heavy Metal Contamination in the Jukskei River, South Africa
## 3 Results and Discussion
### Pearson Correlation Matrix
There is a high correlation between U and As in the dry season. As was shown to have a high concentration in the dry season, probably due to less impact of runoff water and the aerobic environment [79; 80]. As is a poisonous element and can be elevated in water bodies by pH and redox potential [29]. Fe pollution in the river was significant and the results showed that Fe is higher than the background concentration and likely a result of anthropogenic sources. East of Johannesburg, where the river starts and traverses around informal, formal, and industrial areas, is the site of major economic activities where waste management by-laws are not fully followed and enforced. The positive correlation between Th and U indicates similar sources and is probably the impact of previous gold mining activities. Abandoned mines and mine dumps are the source of the acid mine drainage that is menacing environmental waters in Johannesburg [81; 82]. Among the things that have made it easier for metals to be mobilized from host rocks into the water supply system through acid mine drainage are intricate geochemical processes that include oxidation-reduction [83]. The results for both water and sediment in the dry season indicate pollution in the Jukskei River. The negative correlation in the dry season for As-Hg was in agreement with a study in Mara River, Tanzania [84]. This might be due to the fact that in river \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variables** & **As** & **Cd** & **Hg** & **Pb** & **Th** & **U** & **Fe** \\ \hline As & \(1\) & 0.369 & 0.52 & 0.558 & 0.113 & 0.204 & 0.71 \\ Cd & 0.369 & \(1\) & 0.434 & 0.633 & 0.242 & 0.269 & 0.777 \\ Hg & 0.52 & 0.434 & \(1\) & \(-\)0.053 & 0.118 & 0.231 & 0.306 \\ Pb & 0.558 & 0.633 & \(-\)0.053 & \(1\) & \(-\)0.105 & \(-\)0.118 & 0.872 \\ Th & 0.113 & 0.242 & 0.118 & \(-\)0.105 & \(1\) & 0.71 & 0.087 \\ U & 0.204 & 0.269 & 0.231 & \(-\)0.118 & 0.71 & \(1\) & 0.273 \\ Fe & 0.71 & 0.777 & 0.306 & 0.872 & 0.087 & 0.273 & \(1\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Wet season Pearson correlation matrix. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variables** & **As** & **Cd** & **Hg** & **Pb** & **Th** & **U** & **Fe** \\ \hline As & \(1\) & 0.903 & \(-\)0.846 & 0.978 & 0.306 & 0.505 & 0.915 \\ Cd & 0.903 & \(1\) & \(-\)0.749 & \(0.934\) & \(0.238\) & 0.288 & 0.779 \\ Hg & \(-\)0.846 & \(-\)0.749 & \(1\) & \(-\)0.762 & \(-\)0.652 & \(-\)0.734 & \(-\)0.853 \\ Pb & 0.978 & 0.934 & \(-\)0.762 & \(1\) & 0.193 & 0.339 & 0.875 \\ Th & 0.306 & 0.238 & \(-\)0.652 & 0.193 & \(1\) & 0.479 & 0.565 \\ U & 0.505 & 0.288 & \(-\)0.734 & 0.339 & 0.479 & \(1\) & 0.424 \\ Fe & 0.915 & 0.779 & \(-\)0.853 & 0.875 & 0.565 & 0.424 & \(1\) \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Dry season Pearson correlation matrix. sediments, there is a negative association between Hg and As, meaning they might have been different sources, particularly during the dry season where undisturbed Hg can settle in the bottom sediments [85]. In the wet season there is a moderate positive correlation between As-Hg, where in the wet season the rains can cause As-Hg to be resuspended, or they are similarly affected by the urban pollutant runoff from the same sources [86]. The complete potential ecological risk index (RI) values were computed following [PERSON]'s potential ecological risk index assessment [33]. The potential ecological risk grading standard is used to evaluate the results presented in Table 9. The comprehensive potential ecological RI across the nine sampling points shows values exceeding 600, indicating a serious overall level of potential ecological risk during the dry season. For wet season sampling points, Juk-P1 and Juk-P2 show moderate risks, with the other sampling points showing low-grade ecological risks. In recent times, the Jukskei River has received considerable coverage of the pollution that is taking place, and there were startling conclusions that have been reached recently.