Study On The Distribution Characteristics And Bioremediation Of PAHs In Farmland Soil Around The Coking Area

The research analysises the content and distribution of PAHs in farmland soil around the Xiaoyi coking area;and studies by microbial manure and mushroom residue as nutrition additives to enhance Alfalfa remediation of soil PAHs,analysis of the restoration of soil PAHs Removal rate,soil enzyme activity and microbial diversity.Research shows:(1)0-20cm soil layer of farmland around coking area,the content of PAHs is 664.78-1549.66ug/kg,average is 992ug/kg,The main content in the Philippines,acenaphthene,benzo(b)fluoranthene and fluoranthene.With the increase of the distance from the coking plant chimney,the content of PAHs decreased gradually.20-40cm soil layer of farmland around coking area,the content of PAHs is 248.2-471.99ug/kg,average is 340.34ug/kg,The main content in acenaphthylene and fluoranthene,phenanthrene and fluorene.(2)Six sampling points in the 0-20cm soil layer the total PAHs content and monomer PAHs are higher than that of 20-40cm,0-20cm soil layer PAHs mainly in the number of more than the Fourth Ring,,The content of over Fourth Ring PAHs in the 20-40cm layer is lower than that of the surface layer.(3)0-20cm soil layer six sampling points comprehensive pollution index is 3.27-7.71.20-40cm soil layer six sampling points sample comprehensive pollution index is 1.19-2.87.In 0-20cm soil layer,the benzo[a]pyrene pollution index(P)of six sampling points is 1.02-2.63,In20-40cm soil layer,the benzo[a]pyrene pollution index(P)of six sampling points points is 0.33-0.65.(4)Fertilizer,mushroom residue and mushroom residue-fertilizer are added in Alfalfa,the biomass of stem and leaf is 2.84-5.79g/pot,and the root biomass is 1.2-1.59g/pot,GZ+AL,JF+GZ+AL stem and leaf biomass are significantly higher than that of AL treatment,the root biomass is not significantly different.The content of PAHs in roots is 17.48-42.96ug/kg,the content of PAHs in stems and leaves is 3.24-6.72ug/kg,and the content of total PAHs is AL>JF+AL>GZ+AL>JF+GZ+AL.The bioconcentration factor is 0.021-0.043,the transfer coefficient is 0.09-0.37,and the extraction efficiency is 0.0018-0.0025,the use of mushroom residue and fertilizer increased in alfalfa transport,reduce the absorption of PAHs..(5)In45d,the soil PAHs content is CK>AL>JF>JF+AL>GZ>JF+GZ>GZ+AL>JF+GZ+AL,in JF+GZ+AL treatment,The PAHs content is the lowest,and is significantly different from other treatments.After 90d PAHs content is CK>JF>GZ>AL>JF+AL>JF+GZ>GZ+AL>JF+GZ+AL.At the same time,the contents of 16 PAHs in each treatment were decreased;with the increase in the number of benzene ring,high ring PAHs more difficult degradation;The content of PAHs in GZ+AL and JF+GZ+AL was significantly lower than that of AL treatment.JF+GZ+AL repair soil PAHs best effect,(6)In 45d,soil dehydrogenase activity of JF,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatment significantly increased 16.05-54.77mg/kg compared with CK treatment.90d after treatment,soil dehydrogenase activity of GZ,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatment significantly increased 23.6-74.99mg/kg compared with CK treatment.At the same time the dehydrogenase activity of single planting alfalfa dehydrogenase activity is stronger than a single addition of mushroom residue and fertilizer,The dehydrogenase activity of each combination treatment is higher than that of the combined treatment.The dehydrogenase activity of JF+GZ+AL is significantly higher than that of other treatments.(7)In 45d,soil polyphenol oxidase activity of JF,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatment significantly increased 0.17-0.37mg/g compared with CK treatment.90d after treatment,soil polyphenol oxidase activity of JF+GZ,AL,JF+AL,JF+AL,GZ+AL,JF+GZ+ALtreatment significantly increased0.18-0.55mg/g compared with CK treatment.At the same time,The polyphenol oxidase activity of each combination treatment is higher than that of the combined treatment,and the polyphenol oxidase activity in JF+GZ+AL treatment is highest.(8)In 45d,microbial biomass carbon of GZ,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatment are significantly different from CK treatment.90d after treatment,microbial biomass carbon of JF,GZ,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatment are significantly different from CK treatment.At the same time,the effect of adding mushroom residue on soil microbial biomass carbon was greater,and the microbial biomass carbon was higher than that of other treatments.In 45d?90d,microbial biomass nitrogenof GZ,JF+GZ,JF+AL,GZ+AL,JF+GZ+AL treatment are significantly different from CK treatment.The effects of mushroom residue on soil microbial biomass nitrogen is stronger than plants,fertilizer.The microbial biomass nitrogen of each combination treatment is higher than that of the combined treatment.(9)In 45d,The bacteria PLFA of each treatment is significantly different from CK treatment.The bacteria PLFA of JF+GZ+AL treatment is significantly different from other treatments.The fungus PLFA of JF+GZ,GZ+AL,JF+GZ+ALtreatments are significantly different from CK treatment.The actinomycetes PLFA of GZ,JF+GZ,GZ+AL,JF+GZ+AL treatments are significantly different from CK treatment.The total PLFA of each treatment(except JF treatment)is significantly different from CK treatment.90d after treatment,The bacteria PLFA of each treatment is significantly different from CK treatment,The bacteria of JF+GZ+AL treatment is highest.The fungus PLFA of GZ,JF+GZ,JF+AL,GZ+AL,JF+GZ+ALtreatments are significantly different from CK treatment,The fungus PLFA of GZ+AL treatment is highest.The actinomycetes PLFA of GZ,JF+GZ,AL,JF+AL,GZ+AL,JF+GZ+AL treatments are significantly different from CK treatment.The actinomycetes PLFA of JF+GZ+AL is highest.The total PLFA of GZ,JF+GZ,JF+AL,GZ+AL,JF+GZ+AL treatments are significantly different from CK treatment.The total PLFA of GZ+AL is highest.At the same time,JF+GZ+AL and GZ+AL had the highest content of PLFA.(10)The activity of dehydrogenase,polyphenol oxidase activity,microbial biomass carbon content,total PLFA of each treatment is significantly correlated with PAHs Removal rate.The change of dehydrogenase,polyphenol oxidase,microbial biomass carbon and PLFA in soil can be used as the basis for the degradation of PAHs in soil.