Department of Environmental Engineering, Technical University of Denmark, Miljoevej Building 113, 2800, Kongens Lyngby, Denmark.
Environ Sci Pollut Res Int. 2010 Aug;17(7):1355-61. doi: 10.1007/s11356-010-0321-3. Epub 2010 Mar 26.
Chlorobenzoic acids (CBA) are intermediate products of the aerobic microbial degradation of PCB and several pesticides. This study explores the feasibility of using basket willows, Salix viminalis, to remove 4-CBA from polluted sites, which also might stimulate PCB degradation.
The removal of 4-CBA by willow trees was investigated with intact, septic willow trees growing in hydroponic solution and with sterile cell suspensions at concentrations of 5 mg/L and 50 mg/L 4-CBA. Nutrient solutions with different levels of ammonium and nitrate were prepared to achieve different pH levels. The concentration of 4-CBA was tracked over time and quantified by HPLC.
At the low level of 4-CBA (5 mg/L), willows removed 70% (pH 4.2) to 90% (pH 6.8), while 48% (pH 4.2) to 52% (pH 6.8) of the water was transpired. At the high 4-CBA level (50 mg/L), the pH varied between 4.4 and 4.6, and 10% to 30% of 4-CBA was removed, but only 5% to 9% of the water. In sterile cell suspensions, removal of 4-CBA by fresh biomass was much higher than removal by dead biomass.
The results indicate that 4-CBA is toxic to willow trees at 50 mg/L. The removal of 4-CBA from solution is by both passive processes (uptake with water, sorption to plant tissue) and metabolic processes of the plants.
Plants, such as willow trees, might assist in the degradation of PCB and their degradation products CBA.
氯苯甲酸（CBA）是 PCB 和几种农药有氧微生物降解的中间产物。本研究探讨了利用灌木柳（Salix viminalis）从污染地点去除 4-CBA 的可行性，这也可能刺激 PCB 的降解。
通过在水培溶液中生长的完整的、腐烂的柳树以及 5mg/L 和 50mg/L 4-CBA 的无菌细胞悬浮液，研究了柳树对 4-CBA 的去除作用。制备了不同铵和硝酸盐水平的营养溶液，以达到不同的 pH 值。通过 HPLC 跟踪和量化 4-CBA 的浓度随时间的变化。
在低浓度 4-CBA（5mg/L）下，柳树去除了 70%（pH4.2）至 90%（pH6.8），而 48%（pH4.2）至 52%（pH6.8）的水被蒸腾。在高浓度 4-CBA（50mg/L）下，pH 值在 4.4 和 4.6 之间变化，去除了 10%至 30%的 4-CBA，但只有 5%至 9%的水。在无菌细胞悬浮液中，新鲜生物量对 4-CBA 的去除远高于死亡生物量。
结果表明，50mg/L 的 4-CBA 对柳树有毒。4-CBA 从溶液中的去除是通过被动过程（与水一起摄取，吸附到植物组织）和植物的代谢过程。
柳树等植物可能有助于 PCB 及其降解产物 CBA 的降解。
