修复白洋淀镉污染水体的沉水植物筛选试验

为了筛选出适宜修复白洋淀镉(Cd)污染水体的沉水植物,该研究通过室内模拟试验,分析了四种沉水植物黑藻、狐尾藻、金鱼藻和菹草对Cd的耐受性及对底泥Cd的富集和迁移能力。结果表明:(1)通过毒性测试研究,Cd对黑藻、狐尾藻、金鱼藻及菹草的4 d-EC₅₀(半数抑制浓度)分别为0.51、0.81、0.03、0.12 mg·L^-1,狐尾藻对Cd的耐性最强,黑藻次之,金鱼藻对Cd的耐性最低; 四种沉水植物对Cd的最大富集量分别为27.89、15.28、22.54、32.74 g·kg^-1,菹草对Cd的富集能力最强,黑藻次之,狐尾藻对Cd的富集能力最低。(2)通过Cd污染底泥修复研究,黑藻、狐尾藻和菹草体内Cd富集量整体表现为根>叶片和茎(P<0.05); 地上部、根对Cd的富集能力分别表现为黑藻>菹草>狐尾藻,菹草>黑藻>狐尾藻; 三种沉水植物对Cd的迁移能力则表现为黑藻>狐尾藻>菹草。总之,黑藻对底泥中Cd富集和迁移能力均较强,且耐性较高,是最适合修复白洋淀Cd污染水体的沉水植物。

Screening of submerged macrophytes for phytoremediation of cadmium-contaminated water in Baiyangdian Lake

In order to screen the suitable submerged macrophytes for phytoremediation of cadmium(Cd)-contaminated water in Baiyangdian Lake, which is the largest freshwater lake in North China, indoor simulation experiments were conducted to investigate the tolerance of Cd, and accumulation and transportation of Cd from contaminated sediment by four kinds of submerged macrophytes which were Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus. The results were as follows:(1)Results of the toxicity test showed that 4 d-EC₅₀ of Cd for Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus were 0.51, 0.81, 0.03 and 0.12 mg·L^-1, respectively. The tolerance for Cd from high to low was Myriophyllum verticillatum, Hydrilla verticillata, Potamogeton crispus and Ceratophyllum demersum. Myriophyllum verticillatum showed the strongest tolerance for Cd. In addition, the maximal concentrations of Cd for Hydrilla verticillata, Myriophyllum verticillatum, Ceratophyllum demersum and Potamogeton crispus were 27.89, 15.28, 22.54 and 32.74 g·kg^-1, respectively. Potamogeton crispus had the strongest accumulation capability of Cd, followed by Hydrilla verticillata, and Myriophyllum verticillatum had the lowest.(2)The results of remediation Cd-contaminated sediment by Hydrilla verticillata, Myriophyllum verticillatum and Potamogeton crispus indicated that accumulation of Cd in roots was significantly higher than that in leaves and stems(P<0.05). Furthermore, concentrations of Cd in shoots of submerged plants decreased in order of Hydrilla verticillata > Potamogeton crispus > Myriophyllum verticillatum, while contents of Cd in roots decreased in order of Potamogeton crispus > Hydrilla verticillata > Myriophyllum verticillatum. Moreover, the transportation capability of Cd from Cd-contaminated sediment to plants in the pattern of Hydrilla verticillata > Myriophyllum verticillatum > Potamogeton crispus. In summary, due to the higher tolerance, accumulation and transportation ability of Cd, Hydrilla verticillata is the most suitable submerged macrophyte for remediation of Cd-contaminated water in Baiyangdian Lake.