Effects And Mechanism On Phytoremediation Of PAHs-contaminated Soil Using Echinacea Purpurea (L.)

With the rapid development of industry, polycyclic aromatic hydrocarbons (PAHs), as a kind of persistent organic pollutants, are widespread and more deleterious in the environment. Petroleum can cause environmental problems easily when being exploited and transported. And PAHs in the petroleum-contaminated soil not only can reduce the quality of soil, but also cause health problems through bioaccumulation. Thus, we need to come up with a convenient, efficient and safe remediation technology.We have selected fluoranthene, pyrene, benzo (a) anthracene, chrysene, benzo (b) fluoran-thene, benzo (k) fluoranthene, benz (a) pyrene, dibenzo (a,h) anthracene as target pollutants in the present research, for studing PAHs-contaminated soil after phytoremediation using Ech-inacea purpurea (L.). After planting of Echinacea purpurea (L.) for 0,60,120, and 150 days, PAHs levels and enzyme activities were determined in the contaminated soil around Shengli Oilfield in order to understand the mechanisms of the phytoremediation process.Results demonstrated that there was a highest removal rate of PAHs after 120-day phyto-remediation using Echinacea purpurea (L.). The removal rates of PAHs in the rhizosphere soil were 86.57%～99.39%,33.24%～61.20% higher than the unplanted soil at the same time. The activities of dehydrogenase and polyphenoloxidase were increased in the rhizosph-ere soil, suggesting an enzyme-promoting biodegradation mechanism, which is a very import-ant mechanism for phytoremediation process. In addition, pH of alkaline contaminated soil is lower, and the content of organic matter, total and available nitrogen, available phosphorus, and cation exchange capacity were heighten, implying the role of Echinacea purpurea (L.) in improving soil quality after phytoremediation.