Pollution Characteristics,Source Analysis And Ecological Risk Assessment Of OPEs And PAEs In Typical Facility Vegetable Field Soil In Hebei Province

Organophosphate esters(OPEs)and phthalate esters(PAEs)are two groups of semivolatile organic compounds that are often added to a variety of products as flame retardants and plasticizers.Due to physical additives,OPEs and PAEs are easy to be released into the surrounding environment during production,transportation,and the use of related products.As a basic environmental substrate,soil plays an important role in the migration and transformation of organic pollutants under the environment.China’s facility agriculture is mainly covered with plastic greenhouses,and covered with plastic film to raise the temperature meanwhile.Relevant studies showed that there are obvious PAEs and OPEs pollution in the soil environment,but any systematic study on the pollution of PAEs and OPEs in the soil of facility vegetable plots had not been systematic.OPEs and PAEs pollution characteristics in the soil samples of facility vegetable plots in Qingxian county,Cangzhou City,Hebei Province were studied in this study.The content of body research is as follows:(1)Pollution characteristics,source analysis and ecological risk assessment of Tri-OPEs in facility vegetable fields soil samples.The Σ13OPEs concentration in soil samples varied greatly,ranging from 39.60 ng/g dw to 730.52 ng/g dw,the average value was 97.67 ng/g dw.The concentration of Cl-Tri-OPEs > alkyl-Tri-OPEs > aryl-Tri-OPEs.Among the Tri-OPEs monomers,TCEP(33.94-682.18 ng/g dw)was the most abundant compound in soils,accounting for about 30%-99% of the concentration of Tri-OPEs.Pearson correlation analysis and principal component analysis were used to analyze the sources of Tri-OPEs in the soil.It was found that Tri-OPEs in the soil of the greenhouse vegetable plot were related to the comprehensive release of hydr-aulic oil,food packaging and paint,atmospheric deposition,wastewater/reclaimed water irrigation.Eight Tri-OPEs were assessed for ecological risk,ΣRQ ranged from 0.10-2.12(average 0.56),among which TCEP had the highest RQ value(average0.42),indicating moderate and high ecological risk,while other Tri-OPEs had relatively low ecological risk values.(2)The qualitative and quantitative methods of five Di-OPEs were established and optimized based on ultra performance liquid chromatography(UHPLC)electrostatic field orbital ion trap high resolution mass spectrometer.And the optimized method was applied to the analysis of Di-OPEs pollution characteristics and ecological risk assessment in facility vegetable fields soil samples.The results showed that the concentration of ΣDi-OPEs was 2.25ng/g dw-6.94 ng/g dw,with an average of 3.82 ng/g dw.Dn BP and DPh P were the main pollutants in the soil samples,accounting for 23.43%-75.71% and 16.30%-35.89% of ΣDiOPEs,respectively.The possible factors affecting the concentration of Di-OPEs in soil environment were analyzed,and it was found that the concentration of Di-OPEs in soil increased with the increase of mulching years.The distribution characteristics of Di-OPEs congeners were also different in soils with different fertilizers,which may be because different fertilizers lead to changes in soil microbial quantitative enzyme activities and soil physical and chemical properties,thus affecting the distribution of Di-OPEs in soil.The concentration of DiOPEs and its parent organic Tri-OPEs was compared and the correlation analysis was carried out.The results showed that BCEP might be derived from the degradation of TCEP,and other Di-OPEs werw mainly derived from its application in industrial products.(3)Pollution characteristics,source analysis and ecological risk assessment of PAEs in facility vegetable fields soil samples.The results show that the concentration range of Σ15OPEs was 463.90 ng/g dw to 4836.55 ng/g dw.DEHP and DBP were the main pollutants in soil samples,and the concentrations ranged from ND-3050.01 ng/g dw and ND-2093.63 ng/g dw,accounting for 0.00-63.06% and 0.00-58.59% of ΣPAEs,respectively.The factors affecting the concentration of PAEs were analyzed,the results showed that TOC is the main factor affecting the concentration of PAEs.The sources of PAEs in facility vegetable fields soil were analyzed,and it was found that PAEs in the soil of facility vegetable plot was related to wastewater/reclaimed water irrigation,fertilizer,pesticide and mulching film application.The results of ecological risk assessment showed that the RQ > 0.1 of DBP in some soil samples,which was at moderate or high-risk level and needed special attention.