| Wastewater irrigation,as an important way to use waste water in China,can solve the problem of water shortage in farmland.However,unreasonable Wastewater irrigation will lead to excessive pollution of PAHs in soil.PAHs,persistent organic pollution material,can bioaccumulation and are difficult to degrade and more than 90% of they in sewage will transfer in soil.Therefore,it is significance to evaluate the remediation method in PAHs contaminated soil.Phytoremediation technology has the advantages of green environmental protection,low cost,simple operation,and no secondary pollution.It is the most potential remediation technology.Our study detected the remediation effect of Sunflower and Solanum nigrums,vermicompost,and Solanum nigrum stubble on the phenanthrene contaminated soil,which was used as the representative of PAHs pollution.Research results were as follow:?1?Low concentration of phenanthrene(?50mg·kg-1)could promote the growth of Solanum nigrum in the process of monoculture application,while high concentration(?100mg·kg-1)inhibited the growth of Solanum nigrum,and phenanthrene inhibited the growth of Sunflower.Intercropping could promote the growth of Sunflower and Solanum nigrum in different degrees.The distribution of phenanthrene during Sunflower and Solanum nigrum was that above-ground parts was lower than foot end,thereby it was main enrichment in foot and transfer little to above-ground.When the concentration of phenanthrene was constant,the removal rate of different planting patterns was as follows: intercropping of Sunflower and Solanum Nigrum>monoculture of Sunflower > monoculture of Solanum Nigrum > No plant treatment,indicating that intercropping can improve the removal rate of phenanthrene in the soil.Therefore,Sunflower and Solanum Nigrum intercropping can be used as an efficient repair mode for the remediation of phenanthrene contaminated soil.?2?After the application of the Vermicompost,the plant height and biomass of the Sunflower and the Solanum nigrum were increased in the phenanthrene contaminated soil.When the concentration of phenanthrene was ?100 mg·kg-1,the growth status of sunflower and solanum nigrum showned good adaptability in test group,but control treatment have an opposite result,indicating that the earthworm feces had the effect of improving the resistance of the plants to the invasion of the Phenanthrene.The removal rate was increased first and then decreased with the increase of the phenanthrene during plant Sunflower soil.When the concentration of phenanthrene was 50 mg·kg-1,the removal rate of phenanthrene in the test group,which was improved 20.43% than control,was 65.37% and get the highest.Under the same concentration of phenanthrene,the removal rate in experimental group were higher than the control.The removal rate of phenanthrene decreased with the increase of the concentration of phenanthrene during plant Solanum nigrum soil.When the phenanthrene was 200 mg·kg-1,the removal rate was 51.65% and 24.87% in test and control group,respectively.Under the same concentration of phenanthrene,the removal rate in experimental group were higher than the control?P<0.05?.In addition,the enrichment coefficient of sunflower and Solanum nigrum was higher in the experimental group than that in the control group?P<0.05?.Thereby,vermicompost can be used as enhancer to improve the repair potential of sunflower,Solanum nigrum on contaminants phenanthrene soil.?3?In the phenanthrene polluted soil,the first and the second crop of Solanum nigrum can grow normally and the plant height and biomass were enchanced in second crop.With the increase of initial concentration of phenanthrene,residual concentration decreased both in the first and the second crop soil.While with the same concentration,the removal rate of phenanthrene in the second crop soil was significantly higher than that in the first crop?P <0.05?.For example,with 200 mg·kg-1,the first crop soil residual concentration was 151.28 mg·kg-1,and the second was 93.42 mg·kg-1 which suggest 23.79% was improved.In addition,the enrichment coefficient of the second crop was higher than that of the first crop.These results indicate that Solanum nigrum have potential to repair phenanthrene polluted soil.?4?Soil enzyme activities showed that the activities of polyphenol oxidase and catalase were enhanced,to different extent,with the application of four treatments,such as plant,plant intercropping,applying vermicompost,and plant stubble.Furthermore,the four treatments also promote the degradation of phenanthrene and increase its removal rate. |
PDF Full Text Request