黑麦草对TCP污染土壤的修复研究

Ryegrass phytoremedial effect of TCP on the contaminated soil

通过生物盆栽试验研究了黑麦草(Lolium multiflorum L)对2,4,6-三氯酚(TCP)污染土壤的修复作用及其对污染土壤中微生物生物量碳、多酚氧化酶和过氧化氢酶活性的影响。结果表明,培养75 d后土壤中TCP的可提取态质量比随着时间延长而逐渐减少,黑麦草加快了土壤中可提取态TCP质量比的下降。在TCP质量比为1mg·kg^(-1)、10 mg·kg^(-1)、100 mg·kg^(-1)的处理中,种植黑麦草的去除率分别为92.5%、78.2%、55.6%,无植物处理的去除率分别为56.3%、49.2%、37.5%。黑麦草在TCP各质量比处理的污染土壤中能够存活,状态良好。种植植物土壤中的微生物生物量碳以及多酚氧化酶和过氧化氢酶的活性都存在增加的趋势,明显高于对照土壤(p<0.05),提高了土壤植物和微生物对污染物的降解能力。同时,高质量比处理对酶的活性也有一定的抑制作用。由于土壤自身具有修复TCP污染的自然本能,种植黑麦草具有强化TCP污染土壤的修复作用,可以通过促进黑麦草生长,增加土壤酶的活性,增强土壤微生物活性,提高黑麦草修复TCP污染士壤的能力。

The present paper is concerned about its authors＇ experimental investigation and experimental studies of the bioremediation effect of 2,4,6- triehlorophenol （TCP） on the growth of ryegrass （ Lolium multiflorum L） at different concentrations and the effects of TCP on the content change of the microbiological biomass C, polyphonic oxidize and catalos through our pot-cultivation experiments in the simulated TCP contaminated soil. The whole experiment has been laid out by using ryegrass for decontaminating or purifying the organic pollutantcontaminated soil in an eco-friendly-environment and a properly co ditioned low-cost technology. The results of our experiments show that the extractable concentration of TCP in the soil-grown ITegrass tends to drop gradually with the incubation whereas the ryegrass plantation helped to enhance the degradation rate of TCP in the soil with the extractable concentration of TCP remarkably dropping in the ryegrass pots than in CK（pots without ryegrass）（p 〈 0.05 ）. After 75-days pot experimentation, the degradation rate of TCP added at the rate of 1 mg·kg^-1, 10 mg·kg^-1 and 100 mg·kg^-1 treatment with the presence of ryegrass proves to reach 92.5%, 78.2% and 55.6%, respectively; whereas the degradation rate in the soil with no ryegrass was merely 56.3%, 49.2% and 37.5%, respectively. Thus the ryegrass proved to be able to help decontaminate the soil. And it was also found that ryegrass is rather tolerant to TCP, but highest TCP concentration（ 100 mg·kg^-1）may also affect ryegrass growth slightly. Ryegrass plantation also proves to enhance the activities of polyphenol oxidase, catalase and increase the content of microbiological biomass C than in CK（p 〈 0.05）, thus promoting the degradation rate of TCP in the soil. The study has thus indicated that the ryegrass plantation tends to contribute to the bioremediation of contaminated soil-surface with TCP, though high concentration of TCP is likely to inhibit the soil＇s biological activities. Therefore, it is recommended to plant more ryegrass, enhance the soil enzyme activity and the microbial activity so as to improve the effect of TCP-contaminated soil＇s bioremediation.