## 3 Results
### Sorption Isotherms of Lindane and \(p\),\(p^{\prime}\)-DDE on CMs  
The parameters of the lindane and \(p\),\(p^{\prime}\)-DDE sorption isotherms for SC, BC450, BC850, and AC, fitted by the linear and Freundlich models, are presented in Table S2. Both the lindane and \(p\),\(p^{\prime}\)-DDE sorption isotherms for the four CMs were fitted better by the Freundlich model based on the \(R^{2}{}_{\rm adj}\) values. The sorption isotherms are shown in Figure 2. The Freundlich nonlinear coefficient \(n\) values for lindane sorbed by SC, BC450, BC850, and AC were 0.718, 0.818, 0.517, and 0.518, respectively, and the \(n\) values for \(p\),\(p^{\prime}\)-DDE were 0.478, 0.632, 0.385, and 0.770, respectively. The sorption of lindane and \(p\),\(p^{\prime}\)-DDE on CMs appeared to be highly nonlinear. The order of \(K_{\rm d}\) values for lindane sorption on the four CMs was AC (1443.0 Lg\({}^{-1}\)) \(>\) BC850 (77.0 Lg\({}^{-1}\)) \(>\) BC450 (40.8 Lg\({}^{-1}\)) \(>\) SC (38.0 Lg\({}^{-1}\)); the order of \(p\),\(p^{\prime}\)-DDE was AC (2926.2 Lg\({}^{-1}\)) \(>\) BC850 (565.2 Lg\({}^{-1}\)) \(>\) SC (318.1 Lg\({}^{-1}\)) \(>\) BC450 (122.3 Lg\({}^{-1}\)).  
Effects of SC with Different Contents on the Sorption of Lindane and \(p\),\(p^{\prime}\)-DDE by the Sediments  
The sorption isotherm parameters of lindane and \(p\),\(p^{\prime}\)-DDE on the sediments added by SC with different contents fitted by the linear and Freundlich models are presented in Table S3. Both the lindane and \(p\),\(p^{\prime}\)-DDE sorption isotherms were fitted better by the Freundlich model based on the \(R^{2}{}_{\rm adj}\) values. The sorption isotherms are shown in Figure 3. The Freundlich nonlinear coefficient \(n\) values for lindane sorbed on the sediments with 0.5% SC, 1.5% SC, 3.0% SC, 5.0% SC, and 9.0% SC  
Figure 1: Sorption isotherms of lindane and \(p\),\(p^{\prime}\)-DDE fitted by linear model on the sediments.  
were 0.778, 0.889, 0.785, 0.709, 0.585, and 0.492, respectively; and the \(n\) values for _p,p'_-DDE were 0.763, 0.907, 0.734, 0.743, 0.558, and 0.476, respectively. The \(K_{\rm d}\) values for lindane sorption on the sediments with different contents of SC increased in the following order: sediments (6.6 L-g\({}^{-1}\)) \(<\) sediments with 0.5% SC (11.9 L-g\({}^{-1}\)) \(<\) sediments with 1.5% SC (14.4 L-g\({}^{-1}\)) \(<\) sediments with 3.0% SC (23.5 L-g\({}^{-1}\)) \(<\) sediments with 5.0% SC (33.1 L-g\({}^{-1}\)) \(<\) sediments with 9.0% SC (49.4 L-g\({}^{-1}\)). The order of _p,p'_-DDE was sediments (25.7 L-g\({}^{-1}\)) \(<\) sediments with 0.5% SC(49.7 L-g\({}^{-1}\)) \(<\) sediments with 1.5% SC (65.0 L-g\({}^{-1}\)) \(<\) sediments with 3.0% SC (92.7 L-g\({}^{-1}\)) \(<\) sediments with 5.0% SC (145.8 L-g\({}^{-1}\)) \(<\) sediments with 9.0% SC (241.4 L-g\({}^{-1}\)), respectively. The \(K_{\rm d}\) values increased with the increase of SC contents in the sediments.  
Figure 3: Sorption isotherms of lindane (**a**) and _p,p'_-DDE (**b**) fitted by Freundlich model on the sediments with different contents of SC.  
Figure 2: Sorption isotherms of lindane (**a**) and _p,p'_-DDE (**b**) fitted by Freundlich model on different kinds of CMs.