# Seasonal Pollution Levels and Heavy Metal Contamination in the Jukskei River, South Africa
## 3 Results and Discussion
### Pearson Correlation Matrix  
A crucial tool for assessing the strength of a linear relationship between two elements and linking similar pollution sources and distribution routes is the Pearson correlation matrix [67]. In Pearson correlation analysis (Tables 7 and 8), a coefficient value of 1 for each pair indicates a perfect correlation, while a value of zero may deviate from the correlation [68]. The result of 0.558 in the correlation analysis of the wet season indicates a high link between As-Pb. Additionally, there is a high correlation between As-Hg and a moderate correlation between Hg-Cd during the wet season. Furthermore, there is a high correlation between Pb-Cd but it is not significant, with \(p=0.143\), according to the \(p\)-values for Pb-Cd derived from ANOVA calculations. A \(p>0.005\) suggests that there is no substantial link between Pb-Cd, according to the literature [69]. In the wet season, Fe, which is used as a reference metal, has a significant correlation with Pb-As with the \(p\)-values of \(1.40\times 10^{-7}\) and \(1.32\times 10^{-7}\), respectively, which means they probably have the same source. The ANOVA calculations for the dry season reveal the significant correlations of Th and U with \(p\)-values of \(1.01\times 10^{-6}\), which shows that the two heavy metals might have similar sources. It is observed in the wet season that the correlation of heavy metals is moderate, and this can be due to increased runoff from rain, which carries higher concentrations of metals from land sources like agricultural fields, industrial waste, \begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**Sampling Seasons** & **Sample ID** & **As** & **Cd** & **Hg** & **Pb** & **Th** & **U** \\ \hline Dry & Juls-P1 & 0.37 & 0.36 & 38.6 & 5.65 & 0.13 & 0.05 \\ Wet & Juls-P1 & 0.4 & 0.16 & 1.98 & 1.99 & 0.26 & 0.16 \\ \hline Dry & Juls-P2 & 0.44 & 0 & 467 & 1.91 & 0.29 & 0.13 \\ Wet & Juls-P2 & 0.19 & 0.16 & 0.28 & 12.98 & 0.13 & 0.05 \\ \hline Dry & Juls-P3 & 0.54 & 0.34 & 355 & 2.41 & 5.47 & 0.24 \\ Wet & Juls-P3 & 0.14 & 0.3 & 0.28 & 1 & 0.13 & 0.05 \\ \hline Dry & Juls-P4 & 0.38 & 0.2 & 551 & 1.58 & 0.49 & 0.19 \\ Wet & Juls-P5 & 0.28 & 0 & 0.98 & 0.8 & 0.28 & 0.1 \\ \hline Dry & Juls-P5 & 0.44 & 0.4 & 840 & 1.63 & 0.74 & 0.23 \\ Wet & Juls-P5 & 0.13 & 0 & 0.32 & 1.09 & 0.33 & 0.32 \\ \hline Dry & Juls-DS-1 & 0.29 & 0.47 & 297 & 2.44 & 0.24 & 0.09 \\ Wet & Juls-DS-6 & 0.12 & 0.23 & 0.78 & 2.12 & 0.4 & 0.16 \\ \hline Dry & Juls-DS-6 & 0.54 & 0.28 & 677 & 1.66 & 0.44 & 0.21 \\ Wet & Juls-DS-8 & 0.12 & 0 & 0.61 & 2.29 & 0.72 & 0.19 \\ \hline Dry & Juls-DS-8 & 0.59 & 0.52 & 1257 & 3.53 & 0.65 & 0.29 \\ Wet & Juls-DS-9 & 0.08 & 0.24 & 1.19 & 1.29 & 0.24 & 0.13 \\ \hline Dry & Juls-DS-9 & 0.20 & 0.12 & 138 & 0.75 & 0.30 & 0.07 \\ Wet & Juls-DS-9 & 0.09 & 0.22 & 1.00 & 1.48 & 0.43 & 0.15 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Sediment enrichment factor for dry and wet season. and urban areas [70]. As the water flow slows down during the wet season, the metals accumulate in the sediment and the mechanism of sedimentation is dependent on the grain type [71]. In the dry season, for the reference metal Fe, its \(p\)-values show a significant correlation with As, Cd, Pb, Th, and U with \(p\)-values of 0.001, 0.001, 0.001, 0.001, and 0.001, respectively. In the dry season there is a perfect correlation between As-Cd, Pb-Cd, and Pb-As. The As-Pb correlation finding is comparable to the finding in Korotao River, Bangladesh [72] and the plain river network region, southern China [73]. The strong correlation between Cd and Pb may be associated due to a similar source as they are wastes from industries like mining, battery recycling, and smelting [74; 75]. The strong correlation between Cd and Pb followed other trends from other studies [76; 77; 78]. Strong correlation between heavy metals indicates that they most likely come from comparable human anthropogenic sources such as mining operations or agricultural activities and industrial wastewater discharge.