| The phthalate esters?PAEs?are commonly found in the soil of vegetable bases in China,especially the detection rate and pollution level of Di-n-butyl phthaiate?DnBP?.Humic acid?HA?and Fulvic acid?FA?are important components of soil humus and play an important role in the degradation of soil organic pollutants.In this paper,DnBP was used as the target pollutant.The effects of HA and FA on the degradation kinetics of DnBP and the changes of soil microbial activity and quantity in farmland soil of Xinmin vegetable base in Shenyang were studied in order to understand the degradation behavior of PAEs in soil.It provides theoretical basis and data basis for bioremediation of contaminated soil.The results are as follows:?1?The degradation of DnBP in soil accords with the first-order reaction kinetics equation.The application of HA and FA to contaminated soil promotes the degradation of DnBP,and its half-life in soil is shortened.Within the experimental concentration range,HA treatment groups The half-life was 2.8434.532 d,and the half-life of each treatment group was 2.4403.430 d,which was 0.5610.894 times and 0.4810.677 times of the control treatment,respectively.?2?The addition of HA promoted the basal respiration,soil catalase and dehydrogenase activities of DnBP-contaminated soil.The addition of FA also promoted the basal respiration of DnBP-contaminated soil,and the catalase activity showed low.The concentration of FA(10 mg·g-120 mg·g-1)promoted the inhibition of high concentration of FA(40 mg·g-1160 mg·g-1);FA was the main activity of soil dehydrogenase It is a promoting effect,and the treatment of high concentration of FA(40 mg·g-1160 mg·g-1)has a significant effect on the dehydrogenase activity.Correlation analysis showed that there was a positive correlation between HA dosage and DnBP degradation rate,soil respiration rate and soil catalase,and a significant positive correlation with soil dehydrogenase activity.The amount of FA was positively correlated with the degradation rate of DnBP in soil,and was significantly negatively correlated with catalase activity,and was significantly positively correlated with soil respiration intensity and dehydrogenase activity.Path analysis showed that there was an indirect effect between HA,FA and DnBP degradation in addition to the direct effect.?3?The addition of HA and FA promoted the proliferation of bacteria,fungi and actinomycetes.The number of microorganisms increased first and then decreased with the addition of HA and FA.The correlation analysis showed that the microbial quantity and soil DnBP degradation rate and soil microorganisms.There was a significant positive correlation between the activities,and the number of microorganisms had a significant dose-effect relationship with the concentrations of HA and FA.80 mg·g-11 HA and 40mg·g-1FA were most beneficial to the proliferation of microorganisms.?4?The addition of HA and FA promotes the life activity and reproduction of microorganisms,thus showing the increase of soil respiration intensity and the enhancement of soil enzyme activity.The intense microbial activity is beneficial to the decomposition of organic matter in the soil,and the addition of HA and FA is accelerated.The degradation rate of DnBP in soil increased the degradation of DnBP. |
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