## 3 Results and Discussion
### Petroleum Hydrocarbon Composition of the Contaminated Soils  
TPH in the soils varied horizontally and vertically. The TPH in the surface soil layer ranged from 86 to 3350 mg/kg with a mean value of 1447 mg/kg. Location 3 had the highest level of TPH while Locations 1, 4, 5, 7 and 10 had TPH of less than 500 mg/kg (Figure 3). The C21-C35 fraction dominated the aliphatic hydrocarbon fraction, followed by C16-C21, C35-C40, C12-C16 and C10-C12. Fractions with a carbon number of less than 10 were not detected (Figure 4a). For the aromatic hydrocarbons, fractions with a carbon number of less than 12 and more than 35 were not detected. The concentrations of the detectable aromatic petroleum hydrocarbon fractions progressed in the following decreasing order: C21-C35 > C16-C21 > C12-C16 (Figure 4b). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Sampling Location** & **1** & **3** & **5** & **6** & **7** & **8** & **9** & **11** & **12** & **13** \\ \hline Naphthalene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Acenaphthylene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Acenaphthene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Fluorene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Phenanthrene & \textless{}1.0 & 5.2 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & 2 & 1 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Anthracene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Fluoranthene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Pyrene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Benzo(a)anthracene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Chrysene & \textless{}1.0 & 10 & 3.5 & 3.6 & 4.4 & 4.9 & 2.9 & 4.9 & 4.2 & \textless{}1.0 \\ Benzo(a)pyrene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Indeno(123-cd)pyrene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Dibenzo(ah)anthracene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Benzo(ghi)perylene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Benzo(b)fluoranthene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Benzo(k)fluoranthene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ Benzo(k)fluoranthene & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Concentrations (mg/kg) of PAHs in the oily sludge samples collected from the oilfield waste pit.