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Chinese Journal of Ecology ›› 2023, Vol. 42 ›› Issue (4): 933-945.doi: 10.13292/j.1000-4890.202304.003

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Phytoremediation effect of Rudbeckia hirta on crude oil-contaminated soils in the Loess Plateau of eastern Gansu Province.

WANG Jincheng1,2,3,4, JING Mingbo3, ZHANG Wei1,2, ZHANG Gaosen1,2, ZHANG Binglin1,2, LIU Guangxiu1,2*   

  1. (1Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; 2Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, Lanzhou 730000, China; 3Gansu Key Laboratory of Protection and Utilization for Biological Resources and Ecological Restoration, Longdong University, Qingyang 745000, Gansu, China; 4University of Chinese Academy of Sciences, Beijing 100049, China).

  • Online:2023-04-03 Published:2023-04-04

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Abstract: To evaluate the phytoremediation effects of Rudbeckia hirta on the crude oil-contaminated soils in Longdong of the Loess Plateau, a five-month in situ remediation experiment was carried out in PetroChina Changqing Oilfield Company. We analyzed the removal rates of total petroleum hydrocarbons (TPH), plant growth indices, soil physicochemical properties, soil enzyme activities, and microbial community structure in root-zone soils of R. hirta with different contents of crude oil. The results showed that: (1) In the contaminated soils with 3%, 6%, and 8% crude oil, TPH removal rates were 73.44%, 81.28%, and 36.80%, respectively; (2) The contaminated soils with 6% or less crude oil significantly promoted plant height, root length, root dry weight, root vigor and root-shoot ratio of R. hirta, but that with 8% or higher crude oil significantly inhibited plant growth (P<0.05); (3) Compared with CK, planting R. hirta effectively increased the contents of soil available N, available P, the activities of dehydrogenase, polyphenol oxidase, urease and alkaline phosphatase in root-zone soil, and significantly reduced pH of root-zone soil (P<0.05). (4) Results of LEfSe analysis showed that the genera Idiomarina, Halomonas, Halanaerobium, Balneolaceae, Fodinicurvataceae, Cellulomonas, Alcanivorax, Fodinicurvata were indicators of soil differences in the root zone of R. hirta under the range of 3%-6% oil concentration. (5) The results of non-metric multidimensional scaling (NMDS) ordination and variance decomposition analysis showed that phytoremediation effects of R. hirta improved TPH removal rates by increasing root vigor, root dry weight and root-shoot ratio, activities of dehydrogenase, polyphenol oxidase and urease, available N content, and the richness and diversity of microorganisms of root-zone soil when crude oil concentration was at 6% or less. In summary, our results indicated that R. hirta could be potentially used for phytoremediation of crude oil-contaminated soil in Longdong of the Loess Plateau, but the crude oil concentration should not exceed 6%.


Key words: crude oil-contaminated soil, phytoremediation, Rudbeckia hirta, Loess Plateau, site remediation.