# Estimating Tetrachloroethene Sorption Coefficients Based on Soil Properties in Organic-Poor Soils
## 3 Results and Discussion
### Statistical Data Analysis  
Table 3 presents the descriptive statistics of the input data used for the multivariate analysis. The measured \(K_{\rm d}\) values were generally low, with an overall mean of 0.92 \(\pm\) 0.46 L kg\({}^{-1}\), indicating limited sorption capacity for PCE in these low-organic-carbon soils. The generally narrow range of \(K_{\rm d}\) values (0.38-2.27 L kg\({}^{-1}\)) suggests a degree of uniformity in sorption behavior among the studied soil samples. The working hypothesis suggested that the observed variations in \(K_{\rm d}\) values were primarily attributable to differences in soil physicochemical properties. This assumption forms the basis for subsequent multivariate analysis to elucidate the specific soil characteristics influencing PCE sorption in these low-organic-carbon environments. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{\(K_{\rm d}\) (L kg\({}^{-1}\)) **Estimated**} & \multicolumn{4}{c}{**Linear Regression**} & \multicolumn{4}{c}{**Linear Regression**} \\ \cline{3-13}  & & & \multicolumn{2}{c}{**K\({}_{\rm d}\) (L kg\({}^{-1}\))**} & \multirow{2}{*}{\(R^{2}\)} & **Sum** & \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Estimated**} & \multirow{2}{*}{**K\({}_{\rm d}\) (L kg\({}^{-1}\))**} & \multirow{2}{*}{**R\({}^{2}\)**} & **Sum** \\  & & & **Measured** & & & & & & & **Measured** & & **R\({}^{2}\)** \\ \hline  
\hline \hline \end{tabular}
\end{table} 
Table 2: Measured and estimated linear sorption coefficients \(K_{\rm d}\). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Variable**} & \multirow{2}{*}{**Number of Samples**} & \multirow{2}{*}{**Mean**} & \multicolumn{2}{c}{**Standard**} & \multirow{2}{*}{**Variance**} & \multirow{2}{*}{**Minimum**} & \multirow{2}{*}{**Median**} & \multirow{2}{*}{**Maximum**} \\  & & & & **Deviation** & & & & \\ \hline \(K_{\rm d}\) (L kg\({}^{-1}\)) & 34 & 0.92 & 0.43 & 0.18 & 0.38 & 0.84 & 2.27 \\
**OC** (\(\%\)) & 34 & 0.28 & 0.21 & 0.04 & 0.05 & 0.25 & 0.81 \\
**Clay** (\(\%\)) & 34 & 24.9 & 17.2 & 296.8 & 0.0 & 21.0 & 64.9 \\
**Silt** (\(\%\)) & 34 & 36.8 & 18.1 & 326.7 & 5.1 & 34.4 & 71.2 \\
**Sand** (\(\%\)) & 34 & 38.3 & 24.5 & 598.7 & 5.0 & 31.2 & 88.9 \\
**Si** (\(\%\)) & 34 & 33.41 & 3.51 & 12.32 & 25.23 & 33.71 & 40.65 \\
**Al** (\(\%\)) & 34 & 10.27 & 2.65 & 7.05 & 5.30 & 10.46 & 14.26 \\ \(\rho_{\rm s}\) (g cm\({}^{-3}\)) & 34 & 2.54 & 0.29 & 0.09 & 2.05 & 2.53 & 4.09 \\ \(\rho_{\rm b}\) (g cm\({}^{-3}\)) & 34 & 1.18 & 0.13 & 0.02 & 0.80 & 1.21 & 1.43 \\ \(\epsilon\) (\(\%\)) & 34 & 53.2 & 5.4 & 29.1 & 43.5 & 53.3 & 67.3 \\
**SSA** (m\({}^{2}\) g\({}^{-1}\)) & 21 & 24.2 & 17.1 & 289.9 & 0.4 & 19.9 & 64.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Descriptive statistics of input data. Correlations between soil properties and \(K_{\text{d}}\) values were examined to identify the key components governing PCE sorption in soils. Pearson's correlation tests were conducted, with the null hypothesis evaluated against a stated significance level (\(\alpha=0.05\)). The most relevant properties were OC content, SSA, clay and sand content (Figure 1). Calculated \(p\)-values below the significance level (\(\alpha=0.05\)) confirmed the statistical significance of these correlations. Higher values of Pearson's coefficients for SSA and clay content (0.679 and 0.510, respectively) indicate enhanced PCE sorption in soils with smaller particle sizes and consequently higher surface areas. \(K_{\text{d}}\) values showed a positive correlation with OC content (0.614), despite OC levels being <1%. Sand content demonstrated a moderate negative correlation with \(K_{\text{d}}\) values (\(-0.424\)), indicating reduced PCE sorption capacity in sandy soils. Other soil properties displayed non-significant correlations.