## 3 Results
### Analysis of Petroleum Hydrocarbons in Soil, Root and Shoot
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline  & & \multicolumn{6}{c}{**Content \(\pm\) SD (mg/kg Dry Mass Soil)**} \\ \cline{3-8}
**Parameter** & \multicolumn{2}{c}{**Initial Soil**} & \multicolumn{6}{c}{**After 180 Days**} \\ \cline{3-8}  & **DW** & **Soil DW-1** & **Soil DW-2** & **Soil DW-3** & **Soil DW-4** & **Soil DW-5** & **Soil DW-6** \\ \hline TPH & 5176.03 & 4223.45 & 3335.33 & 2890.1 & 2758.11 & 2381.96 & 4047.68 \\ \(\Sigma\)\(\mathrm{C_{2}}\)=\(\mathrm{C_{3}}\) & 26.31 & 20.36 & 7.58 & 3.44 & 2.52 & 1.98 & 18.75 \\ \(\Sigma\)\(\mathrm{C_{10}}\)=\(\mathrm{C_{21}}\) & 892.48 & 683.89 & 407.46 & 300.37 & 271.65 & 196.37 & 627.57 \\ \(\Sigma\)\(\mathrm{C_{22}}\)=\(\mathrm{C_{30}}\) & 1092.38 & 919.85 & 845.72 & 845.72 & 777.35 & 661.4 & 896.15 \\ \(\Sigma\)\(\mathrm{C31}\)=\(\mathrm{C_{36}}\) & 383.94 & 347.88 & 333.86 & 316.11 & 317.99 & 290.3 & 342.39 \\ isoprenoids & 169.93 & 159.37 & 147.65 & 142.73 & 141.63 & 135.23 & 156.52 \\ Unidentified aliphatic hydrocarbons & 2610.98 & 2092.1 & 1593.07 & 1347.24 & 1246.98 & 1096.69 & 2006.31 \\ \hline \multicolumn{8}{c}{**After 180 Days**} \\ \cline{3-8}
**Parameter** & \multicolumn{2}{c}{**Initial Soil**} & \multicolumn{2}{c}{**After 180 Days**} \\ \cline{3-8}
**OS** & \multicolumn{2}{c}{**Soil OS-1**} & \multicolumn{2}{c}{**Soil OS-2**} & \multicolumn{2}{c}{**Soil OS-3**} & \multicolumn{2}{c}{**Soil OS-4**} & \multicolumn{2}{c}{**Soil OS-5**} & \multicolumn{2}{c}{**Soil OS-6**} \\ \hline TPH & 4025.65 & 3145.08 & 2381.17 & 2021.52 & 1965.03 & 1591.26 & 2943.24 \\ \(\Sigma\)\(\mathrm{C_{6}}\)=\(\mathrm{C_{9}}\) & 4.09 & 2.99 & 0.8 & 0.46 & 0.39 & 0.28 & 2.75 \\ \(\Sigma\)\(\mathrm{C_{10}}\)=\(\mathrm{C_{21}}\) & 1013.77 & 735.64 & 422.35 & 352.87 & 258.55 & 191.87 & 658.24 \\ \(\Sigma\)\(\mathrm{C_{22}}\)=\(\mathrm{C_{30}}\) & 358.69 & 290.79 & 263.5 & 263.5 & 231.71 & 193.99 & 285.91 \\ \(\Sigma\)\(\mathrm{C_{31}}\)=\(\mathrm{C_{36}}\) & 200.59 & 179.49 & 172.95 & 153.23 & 164.76 & 144.65 & 176.54 \\ isoprenoids & 384.97 & 356.53 & 325.83 & 319.22 & 309.93 & 300.32 & 348.62 \\ Unidentified aliphatic hydrocarbons & 2063.54 & 1579.64 & 1195.74 & 963.57 & 999.69 & 760.15 & 1471.18 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Contents of selected groups of aliphatic hydrocarbons in the studied soils (Soil DW and Soil OS) before and after treatment with phytoremediation assisted by inoculation. Figure 3: TPH content of _Echinacea purpurea_ roots after 3 and 6 months of phytoremediation process aided by bioaugmentation in the tested systems. The tested soils significantly differed in the qualitative and quantitative composition of individual groups of polycyclic aromatic hydrocarbons. Soil taken from the pit area (Soil DW) had higher concentrations of naphthalene relative to the other PAHs. In contrast, in the soil taken from the oil spill site, the distribution of the different groups of PAHs was more even, with a slight predominance of three- and four-ring PAHs. In such case, it is extremely important to study the distribution of individual groups of polycyclic aromatic hydrocarbons, taking into account the number of hydrocarbon rings. Indeed, the efficiency of biodegradation and phytoremediation depends on the number of rings in the hydrocarbon molecule [17]. Qualitative and quantitative chromatographic analyses of PAHs showed that naphthalene was most readily degraded in both tested soils. Lower  
Figure 4: TPH content of _Echinacea purpurea_ shoots after 3 and 6 months of phytoremediation process aided by bioaugmentation in the tested systems. Figure 5: PAH content in soil after 3 and 6 months of bioaugmentation-assisted phytoremediation process in the studied systems. values of biodegradation coefficients were recorded for three-ring PAHs. Four-ring PAHs were definitely less biodegradable. Six-ring PAHs had by far the worst distribution.