重金属复合污染对灯心草的生态毒性效应及重金属积累特性的影响

以现行土壤环境质量标准为浓度设置依据并结合实际污染土壤,通过盆栽试验研究了Cu、Cd、Pb、Zn、As5种重金属复合污染对灯心草的联合生理毒性效应及各重金属在灯心草植株内的积累和分布情况。结果表明,5种重金属复合污染对灯心草地上部生长有一定程度的抑制作用,当污染达土壤环境质量二级标准上限值,灯心草地上部生物量减产9.15%,但地下部生物量减产趋势不明显,灯心草分蘖数、株高与地上部干重呈显著正相关。生长在矿毒水和铅锌尾矿污染土壤中的灯心草,地上部生物量分别减产28.23%和37.1%,但POD、SOD和CAT3种酶活性均高于对照。在Cd、Pb、Cu、Zn、As复合污染条件下,各重金属在灯心草茎叶和根系中的积累和分布存在差异,且与土壤中重金属含量间存在一定的相关性。应用综合生态环境效益法,以灯心草为指示植物,可以将土壤环境质量二级标准上限值设定为土壤中5种重金属的临界毒性效应值。

The Eco-toxicological Effect of Cu, Cd, Pb, Zn and As Compound Pollution on Juncus Effuses and Its Accumulation Character of Heavy Metals

The eco-toxicology effects of Cu, Cd, Pb, Zn and As compound pollution on the growth and scavenging system of activated oxygen of Juncus Effuses as well as the accumulation and the distribution of heavy metals in Juncus Effuses were researched by using soil culturing. The concentrations of the heavy metals were designed referring to National Environmental Quality Standard for Soil and considering the practical application, the contaminated soil by lead/zinc mining tailings and mine toxic water were also used in the experiment. The aboveground biomass of Juncus Effuses was inhibited to some degree. When the dosages of the heavy metals added to the soils were closed to the Second Grade National Environmental Quality Standard for Soil (GB 15618-95), Juncus Effuses grew normally with its yield decrease by less than 10%, but the underground biomass was not decreased apparently. There were significant positive correlations between aboveground dry weight with the tiller number and plant height. Aboveground biomass of Juncus Effuses grew on the soil polluted by mine toxic water and lead/zinc mining tailings decreased 28.23% and 37.1% respectively, but the activity of POD, SOD and CAT were all higher than that of Juncus Effuses grew on the soil without being polluted by heavy metals, indicating that Juncus Effuses would be regarded as a good phytoremediation application prospects in removing heavy metals from contaminated soil. Under the compound stress of Cu, Cd, Pb, Zn and As, the accumulation and distribution of the heavy metals showed difference in the shoot and root and changed with the content of heavy metals in soil. The Second Grade National Environmental Quality Standard for Soil (GB 15618-95) could be formulated the eco-toxicological effect critical value for Cu, Cd, Pb, Zn and As in soil by using the eco-environmental effect method and the bio-indicating function of Juncus Effuses.