Research On Microbial Remediation Technology Of PAHs-OPEs In Co-Contaminated Soil

The soil is an important foundation of the sustainable development of human and society,and is the natural resource for human being.With the deepening of the severity of soil pollution in China,it has led to the continuous decline of the environmental quality of cultivated land,and the residue of toxic and harmful substances in agricultural products has become more and more prominent,which has become an important factor restricting the development of agriculture and agricultural economy.The potential risks of pollutants from agricultural soils through agricultural products have become a major focus in the field of environmental safety.The human and land resources in China are relatively low and the high quality cultivated land resources are limited.therefore,the practical technology of economic research and development,effective remediation and production of compound polluted soil is of great significance to ensure the ecological environment safety of soil-crop system and to realize the clean production of agriculture and the sustainable utilization of land resources.Based on the previous laboratory research work,the PAHs and OPEs pollution of agricultural soils in Shenyang facilities were investigated and evaluated,and two kinds of organic pollutants,polycyclic aromatic hydrocarbons?PAHs?and organic phosphate?OPEs?,which widely existed in farmland soil,were taken as the target pollutants.taking common fruit-like vegetables?tomato,hot pepper,cucumber and eggplant?,rhizomes and vegetables?carrot,white radish and lettuce?and leaf vegetables?Chinese cabbage,lettuce,rape and spinach?as research objects,adding the high-efficiency degrading bacteria?N?and the biological surfactant rhamnose ester?RL?of the laboratory with independent intellectual property in the process of plant growth,comparing the natural condition group?CK?,applying the rhamnose ester group?RL?,applying the high-efficiency degradation bacteria group?N?and the compound measure group?RL+N?to the remediation effect of the PAHs and the OPEs polluted soil and the accumulation amount of PAHs and the OPEs in different types of vegetables in the repair process,And an ecological safety analysis is carried out to screen the PAHs and the OPEs polluted soil remediation technology suitable for edge production and edge repair.The main research results are as follows:?1?The pollution characteristics of agricultural soil PAHs and OPEs in Shenbei typical facilities were investigated,the pollution sources were analyzed and the pollution risk assessment was carried out.The results showed that:There were 14 PAHs in the surface soil,and the concentration of PAHs in the soil was higher than that of the low-ring PAHs.The average concentration of soil PAHs was511.78ug/kg,which was 5.12 times higher than that of Canadian agricultural soil PAHs standard?100ug/kg?.According to the PAHs pollution classification standard proposed by Maliszewska-Kordybach?1996?,the soil PAHs pollution in the study area is at the level of mild pollution.The relative abundance method and isomer ratio method were used to analyze the combustion of biomass and coal in soil;The toxicity equivalence factor?TEF?was used to calculate the PAHs toxicity equivalent(TEQ_BaP)of 59.404 in the agricultural soil of the typical facility in Shenbei,Among them,Chr,BaA,BkF,BaP,BbF and DbA 6 were 58.761,accounting for 98.62%of total TEQ_BaP.The pollution risk of PAHs in soil was evaluated by 10 kinds of PAHs?Nap,Phe,An,Fla,Chr,BaA,BkF,BaP,BEP,InP?as specified in the Dutch soil quality standard.The average residual concentration of 13 species in the surface soil was328.11ug/kg.Among them,Alkyl phosphate,chlorophosphate and aromatic phosphate accounted for 70.45%,18.39%and 5.60%respectively.The risk entropy?RQ?method is used to evaluate the ecological risk of the soil OPEs.The results show that the OPEs in the soil is 1.0965,indicating that there is a certain potential ecological risk in the soil in the soil.?2?Based on the research results of the earlier stage,a single plant?11 common vegetables?,the plant rhamnose ester?RL 5 mg/kg?and the plant high-efficiency degrading bacteria?N 500 ml/m²?were carried out on the PAHs and the OPEs composite polluted soil.Field repair of the high-efficiency degrading bacteria?N 500ml/m²?of the plant rhamnose ester?RL 5 mg/kg?.The results showed that:The removal efficiency of PAHs in soil was obvious from 4.16%to 38.15%.The soil PAHs removal effect of different restoration measures is the RL+N+plant>N+plant>RL+plant>single plant,the content of PAHs in the plant body is20.13⁶8.54ug/kg,and leaf vegetables>rhizomes>fruit;But the removal effect on the soil is not obvious,the residual concentration generally exhibits a level of CK>N>RL>RL+N,The content of OPEs in plant was 16.63⁶0.67ug/kg,and showed leafy vegetables>fruits>roots.The effect of the soil pollutant removal and the residual content of the pollutants in the plant are comprehensively compared,the removal rate of the soil PAHs in the"high-efficiency degradation bacteria cucumber of rhamnose ester"is 38.15%,the removal of OPEs is 5.05ug/kg.The residues of PAHs and OPEs in cucumber were 20.13ug/kg and33.06ug/kg.The removal rate of the soil PAHs in the"high-efficiency degradation bacteria tomato of rhamnose ester"is 35.93%,the residues of PAHs and OPEs in tomato were 31.94ug/kg and 29.16ug/kg.It is obviously better than other measures:it owns potential with edge-production and variable repair,and it can be used as a PAHs or PAHs-OPEs composite polluted soil for substantial green repair technology.