Chen Ying-Xu, Chen Hua-Lin, Xu Yun-Tai, Shen Meng-Wei
Department of Environmental Engineering, Huajiachi Campus, Zhejiang University, Hangzhou 310029, PR China.
Environ Int. 2004 Mar;30(1):31-7. doi: 10.1016/S0160-4120(03)00145-4.
The partitioning behavior of pentachlorophenol (PCP) in five sediments was studied using equilibrium sorption experiments and multiple cycles of sorption and desorption experiments. The results of the equilibrium sorption experiments showed that the isotherms of PCP on five sediments were linear and the partitioning coefficients (Kd) were proportional to the organic carbon content of the sediments. The average organic carbon content normalized partitioning coefficient (logK oc) of five sediments was 2.83 +/- 1.48. In multiple cycles of sorption and desorption experiments, the five sediments were found to exhibit statistically significant sorption-desorption hysteresis, and the hysteresis indices (HI) varied over a wide range (0.72 - 11.82). Correlations between the HI value and the percentage of lipid in the total organic matter in the sediment indicated that lipid was the main fraction to affect the hysteresis phenomenon, i.e., the higher the lipid percentage the greater the HI value. The hysteresis phenomenon was mostly caused by irreversible sorption of PCP on lipids, including entrapment by lipids, which induced the slow desorption rate from the sediment. Because of hysteresis in the sorption and desorption, the PCP ecological toxicity would be lower than expected.
采用平衡吸附实验以及多轮吸附和解吸实验，研究了五氯苯酚（PCP）在五种沉积物中的分配行为。平衡吸附实验结果表明，PCP在五种沉积物上的等温线呈线性，分配系数（Kd）与沉积物的有机碳含量成正比。五种沉积物的平均有机碳含量归一化分配系数（logKoc）为2.83±1.48。在多轮吸附和解吸实验中，发现这五种沉积物表现出具有统计学意义的吸附-解吸滞后现象，滞后指数（HI）在较宽范围内变化（0.72 - 11.82）。HI值与沉积物中总有机质中脂质百分比之间的相关性表明，脂质是影响滞后现象的主要部分，即脂质百分比越高，HI值越大。滞后现象主要是由PCP在脂质上的不可逆吸附引起的，包括被脂质截留，这导致了从沉积物中的缓慢解吸速率。由于吸附和解吸过程中的滞后现象，PCP的生态毒性将低于预期。
