黑藻、狐尾藻对重金属铅、镉、铬、钒污染水体的修复

Phytoremediation on heavy metal-polluted water of Pb,Cd,Cr and V by Hydrilla verticillata and Myriophyllum verticillatum

在实验室条件下研究水生植物黑藻和狐尾藻对水体中重金属Pb^(2+)、Cd^(2+)、Cr^(6+)和V^(5+)的削减效果以及不同浓度重金属对植物生理的影响。结果表明:狐尾藻和黑藻对Pb^(2+)均具有较好的削减效果,当Pb^(2+)浓度为15 mg/L时,二者的削减率分别达到98.38%、94.35%;黑藻对水体中Cd^(2+)(5 mg/L)和Cr^(6+)(0.2 mg/L)的削减率分别为96.53%和69.23%,远高于相同重金属浓度下狐尾藻对Cd^(2+)的削减率(70.23%)以及对Cr^(6+)的削减率(26.73%);但狐尾藻和黑藻对水体中V^(5+)的削减率均不高,当水体中V^(5+)浓度为2 mg/L时,二者的削减率分别为16.71%和19.23%。叶绿素a、相对细胞电导率测试结果表明:随着金属浓度的升高、培养时间的延长,叶绿素a含量呈下降趋势,相对细胞电导率增大;V^(5+)对黑藻、狐尾藻的胁迫程度较小,其次为Cd^(2+)和Cr^(6+),且黑藻的受胁迫程度大于狐尾藻的,而Pb^(2+)对两种藻类的胁迫程度相对较大。总之,黑藻和狐尾藻对水体中重金属Pb^(2+)、Cd^(2+)、Cr^(6+)和V^(5+)的污染均有一定的修复能力,且黑藻的效果优于狐尾藻的。

The reduction effect of heavy metal Pb2＋,Cd2＋,Cr6＋ and V5＋ in the contaminated water by Hydrilla verticillata and Myriophyllum verticillatum and the effects of these four heavy metals on the two macrophytes were studied under the experimental conditions.The results show that the reduction effect of Pb2＋ by Hydrilla verticillata and Myriophyllum verticillatum are the highest.When the concentration of Pb2＋ is 15 mg/L,the decrease rate reaches to 98.3% and 94.3%,respectively.Besides,the reduction effects of Cd2＋ （5 mg/L） and Cr6＋ （0.2 mg/L） by Hydrilla verticillata （96.5%,69.2%）are higher than those by Myriophyllum verticillatum （70.2%,26.7%）.The reduction effects of V5＋ by Hydrilla verticillata and Myriophyllum verticitlatum are the lowest.When the concentration of V5＋ is 2 mg/L,the reduction effects are only 16.7% and 19.2%,respectively.The test result indicates that the Chla content of Hydrilla verticillata and Myriophyllum verticillatum decline when the concentrations of Pb2＋,Cd2＋,Cr6＋ and V5＋increase,while the relative electrical condnctivity increases.And the influence degree becomes more obvious as the cultivate time goes by.V5＋ has the least influence on the physiological characters of two macrophytes,followed by Cr6＋ and Cd2＋.The Chla content and relative electrical conductivity of Myriophyllum verticillatum drops less than those of Hydrilla verticillata under Cr6＋ and Cd2＋ stress.The two macrophytes show a weak tolerance under Pb2＋ stress.Both Hydrilla verticillata and Myriophyllum verticillatum can be recommended for removal of Pb2＋,Cd2＋,Cr6＋ and V5＋ from the contaminated water,and Hydrilla verticillata has a better removal ability of heavy metal.