作 者 ：潘义宏,王宏镔*,谷兆萍,熊国焕,易锋
期 刊 ：生态学报 2010年 30卷 23期 页码：6430~6441
Keywords:macrophytes, translocation, accumulation, heavy metal,
摘 要 ：通过野外调查和室内分析，研究了云南阳宗海南北两区域自然生长的17种水生植物的生长状况及植物和对应水样、根区底泥中重金属（As、Zn、Cu、Cd、Pb）的含量。结果表明：植物长势良好，未发现受害症状。水体As严重污染，Pb轻度污染，Zn、Cu和Cd均未超标。9种沉水植物同时对As、Zn、Cu、Cd、Pb的富集系数（植物全株重金属含量与水中该元素含量的比值）远大于1，具有共富集特征。在平均含As 0.175 mg/L的水中，金鱼藻、黑藻、小眼子菜、八药水筛全株As平均含量分别为（150±7.3）、（179±35）、（92±31）、（265±21）mg/kg（干重），对As具有较强富集能力；对于8种湿生和挺水植物，北部采样点的喜旱莲子草、田栖稗、细叶小苦荬和长芒稗对As，长芒稗、细叶小苦荬、圆果雀稗、水蓼和风车草对Cd，海芋和圆果雀稗对Zn的富集系数（植物地上部重金属含量与底泥中该元素含量的比值）以及圆果雀稗对Cd和Zn转移系数（植物地上部重金属含量与根中该元素含量的比值）均大于1。聚类分析结果表明，金鱼藻、黑藻、八药水筛、小眼子菜、穗状狐尾藻5种水生植物同时对As、Zn、Cu、Cd、Pb具有较强的吸收和富集能力，在重金属复合污染水体修复中具有较大潜力。
Abstract:Phytoremediation technology has been widely advocated to treat polluted soil and water because it is cost-effective and environmental-friendly. Exploring suitable metal hyperaccumulators or tolerant plants is the key step for phytoremediating metal-contaminated environment. Up to now, about 500 plants have been identified as metal hyperaccumulators all over the world, but most of them are terrestrial plants, which restricted their application in aqueous environment. In 2008, Yangzong Lake, one of nine big lakes in Yunnan Province, China, was polluted by arsenic (As) released from a nearby factory. Average concentration of As in the water was up to 0.117 mg/L，suggesting that about 77 t As entered the lake. Twelve As hyperaccumulators were identified but they are all terrestrial ferns. Therefore, more attention should be paid to As accumulation in aquatic plants. In present study, the growth status and concentrations of heavy metals (As, Cd, Cu, Pb and Zn) in 17 macrophytes naturally grown in south and north regions of Yangzong lake were evaluated by field survey and laboratory analysis. Concentrations of these five metals in water and sediments were also determined and compared with those in the plants. Results indicated that all these collected plants grew well, without any toxic symptoms. The water body was heavily and slightly polluted by As and Pb, respectively, while the concentrations of Zn, Cu and Cd were below their corresponding environmental quality standards. For 9 submerged species (Ceratophyllum demersum, Hydrilla verticillata, Blyxa octandra, Potamogeton pusillus, Potamogeton lucens, Potamogeton delavayi, Potamogeton pectinatus, Myriophyllum spicatum and Chara braunii), their bioconcentration factors (defined as the ratio of heavy metal concentration in whole plant to that in water) for As, Zn, Cu, Cd and Pb were all greater than 1, which showed a co-accumulative character for these five elements. Growing in water averagely containing 0.175 mg As/L, C. demersum, H. verticillata, P. pusillus and B. octandra showed a strong ability to accumulate As, with average As concentrations of (150±7.3), (179±35), (92±31) and (265±21) mg/kg(dry weight), respectively. For 8 hygrophyte and emerged species at north site, bioconcentration factors (the ratio of heavy metal concentration in aboveground part to that in sediment) were greater than 1 in Alternanthera philoxeroides, Echinochloa oryzicola, Ixeridium gracile and Echinochloa caudata for As, E. caudata, I. gracile, Paspalum orbiculare, Polygonum hydropiper and Cyperus alternifolius for Cd, Alocasia macrorrhiza and P. orbiculare for Zn. And translocation factors (the ratio of heavy metal concentration in aboveground part to that in root) were greater than 1 in P. orbiculare for Zn and Cd. The roots of A. philoxeroides, A. macrorrhiza, E. caudata and P. orbiculare accumulated high concentrations of As. Cluster analysis showed that C. demersum, H. verticillata, B. octandra, P. pusillus and M. spicatum could uptake and accumulate As, Zn, Cu, Cd and Pb simultaneously and had a great potential for phytoremediating water body contaminated with multiple metals. In general, accumulation of As, Zn, Cu, Cd and Pb in all tested submerged species were greater than that in hygrophyte and emerged species.
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