## 4 Conclusions  
Both the optimised extraction methods (MAE and UE) coupled with GC-MS were found to be efficient in determining the PAHs with high accuracy and precision. The type of clean-up method, either filtering only or filtering followed by SPE, showed a significant impact on the concentrations of PAHs obtained. The filtered plus SPE-cleaned samples gave higher concentrations than only filtered samples; thus, it can be recommended for daily analysis of PAHs.  
Pyrene was found to be the dominating PAH in both sediment and sludge samples. However, all the PAHs were within the maximum allowable concentration except for DahA in all sampling sites except for 14a. The PAHs in the investigated areas were found to be a result of pyrolytic sources; from the incineration of biomass, such as burning of waste in landfill, fumes from industries, etc. All the sampling sites were shown to be highly contaminated with PAHs, with TEQ and MEQ of DahA suggesting carcinogenic and mutagenic risk. The ILCR values of DahA also suggested high potential carcinogenic risk through dermal exposure for adults than children. Therefore, the continuous use of regulations such as NEMWA as a guideline for proper pollution monitoring is of importance to safeguud human health.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app13095619/sl](https://www.mdpi.com/article/10.3390/app13095619/sl)]([https://www.mdpi.com/article/10.3390/app13095619/sl](https://www.mdpi.com/article/10.3390/app13095619/sl)), Table S1: UE extraction solvent; Table S2: UE extraction solvent volume; Table S3: UE extraction time; Table S4: MAE extraction solvent; Table S5: UE/MAE method validation.  
**Author Contributions:** Conceptualization, P.M. and S.N.; Methodology, P.M. and S.N.; Validation, P.M. and S.N.; Formal Analysis, S.N.; Investigation, S.N.; Resources, P.M. and M.M.; Data Curation, S.N.; Writing--Original Draft Preparation, S.N.; Writing--Review and Editing, P.M. and S.N.; Supervision, P.M. and M.M.; Project Administration, P.M. and S.N.; Funding Acquisition, P.M. and M.M. All authors have read and agreed to the published version of the manuscript.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Variables** & **Child** & **Adult** & **Reference** \\ \hline Body weight, BW (kg) & 15 & 71.9 & [52] \\ \hline Permeability coefficient, Kp (cm/h) (DahA) & 2.3 & & [38] \\ \hline Exposure time, ET (h/day) & 8 & [47] \\ \hline Exposure frequency, EF (days/year) & 313 & [47] \\ \hline Averaging time, AT (day) & 64.63 \(\times\) 365 days = 23,590 & [53] \\ \hline Conversion factor, CF & \(1\times 10^{-6}\) & [47] \\ \hline ILCR\({}_{\text{derm}}\) (\(\mu\)g/kg/day)-sediments & 1.92 \(\times\) 10\({}^{-1}\) & 4.98 \(\times\) 10\({}^{-1}\) \\ \hline ILCR\({}_{\text{derm}}\) (\(\mu\)g/kg/day)-sludge & 1.01 \(\times\) 10\({}^{-1}\) & 2.62 \(\times\) 10\({}^{-1}\) & This study \\ \hline \hline \end{tabular}  
Life expectancy of an average South African is 65 years.  
\end{table}
Table 4: _Cont._  
**Funding:** This research was funded by [Umgeni Water and National Research Foundation of South Africa under Thuthukal] grant number [121869].  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All the data collected in this work have been added to the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest.