Study On The Interaction Of Combined Phthalate Acid Ester(PAEs) In The Biodegradation Process

The effect of combined phthalate acid ester (PAEs) pollution, including dimethyl phthalate (DMP), diethyl phthalate (DEP), and bis (2-ethylhexyl) phthalate (DEHP), on the PAEs degradation by fungus F3(Isaria sp.) was studied in the liquid culture and soil culture condition. The migration of combined PAEs in soil-plant system and the interaction mechanism of combined PAEs in biodegradation were clarified.(1) Farmland soil of GaoZhou was investigated and PAEs in the contaminated soils was determined. Among6U.S.EPA priority pollutants of PAEs, the contents of DMP, DEP,DBP and DOP in all top soils exceeded the control limits of PAEs in American soil by100%,93.33%,93.33%and20%respectively. The comprehensive pollution index of PAEs in soil was between3.8and85.39, indicated the soil had been polluted seriously.(2) The interaction relationship between combined PAEs (DMP、DEP、DEHP) was studied by determining PAEs content and monitoring fungi biomass in the liquid culture condition. The results showed that F3strain had better degradation effect for2kinds of composite PAEs. The removed rate in the group DMP+DEP, DMP+DEHP and DEP+DEHP with the initial concentration of100mg/kg were70%,75%and85%respectively. The increase of PAEs concentration could promote the growth of F3strain, and the high concentration of PAEs did not inhibit the growth of F3strain. The study also showed that PAEs with low molecular weight was easier to be degraded.(3) PAEs content in different parts of Benincasa hispida and water was determined by solution cultrue experiments and discussed the migration and transformation of combined PAEs in plants. The results showed that the order of PAEs content in different parts of Benincasa hispida was as following:root> stem, wax gourd had enrichment characteristics for DEP and DEHP, and the migration characteristics of DEP and DEHP in Benincasa hispida was similar.(4) PAEs content in soil and plant was determined and the growth of plant was observed by pot experiment. The interaction mechanism of combined PAEs in the soil-plant system was studied. The results showed that two combined PAEs had different degrees of inhibition for Benincasa hispida gourd seedlings. But the inhibition for Benincasa hispida seedlings by the group DEP+DEHP was lower than that by DEP and DEHP independently. The order of PAEs content in different parts of plant was as following:root> stem> leaf. The PAEs content in Benincasa hispida of different treatment group had obvious differences. The accumulation content of DMP in stems and leaves decreased, indicated that the migration of DMP in the Benincasa hispida was inhibited, but the migration efficiency of DEP from stems to leaves in wax gourd increased in the group DMP+DEP. The accumulation content of DMP and DEHP in stems and leaves of wax gourd increased in the group DMP+DEHP. The accumulation content of DEP and DEHP in stems and leaves of Benincasa hispida decreased in the group DEP+DEHP, but the migration efficiency of DEP from stems to leaves in Benincasa hispida was improved.