| DDT is one of the most prevalent environmental pollutants being detected in most living organisms.DDT was concentrated in fatty tissues and bioaccumulated in the food chain, also made in thesoil, water, atmosphere pollution severely. Research was conducted to assess the effect of dissipation of DDTin soil with pumpkin. Two kinds of artificial surfactants were used to enhance the contaminant to uptake bypumpkin. And different concentration of low molecular weight organic acids were used to study thedesorption of DDT from soil.The samples were extracted with acetone and petroleum ether by soxhlet extraction method to extractDDT. Plant tissues were used for triturator to extract the target compounds. Samples were cleaned up withsodium acid. The HP 4890 equipped with ECD detector and HP-5 30.0 m×320μm×0.25μm capillarycolumn was used to analysis DDT. Nitrogen at 1.0 ml min-1 was used as carrier gas. The columntemperature was programmed. The different addition level of soil, pumpkin plant was 0.02 mg kg-1,0.2 mgkg-1,the recovery rate of DDT was separately 96.9%～109.3%, 91.3%～95.0%, and C.V. was 3.2%～14.0%.The recovery was all exceed 80% and measured up to residual analysis. The LOD (limit of detection, LOD)of this method was 3.2×10-12g and the LOQ(limit of quantification, LOQ) for soil, pumpkin plant was0.0013 mg kg-1.DDT was detected in all pumpkin tissues, including roots, stem and leaves. The concentration of DDTincreasing order is leaves＜stems＜roots. The concentrations were the greatest in the roots, nearly 7 timeshigher than that in leaves.60 days later, The contaminant of DDT presented in the soil was significantlylower than that in the previously, the degradation rate ranged from 29.5 to 31.6%, unamended treatmentwas only 14.4%. Pumpkin enhanced uptake the organic contaminant. In the rhizosphere soil, theconcentration of DDT was lower than the bulk soil. In order to enhance the rate of plant remedy, using twokinds of artificial surfactants, the pumpkin grew well balanced in the CMC of artificial surfactants. Forexample in the high level treatment, with the concentration of SDBS was 140.0 mg L-1, the concentration ofroots was about 126 ng g-1(plant), which was 3 times higher than that of in treatment unfortified samples.Interestingly, 60 days later, the contaminant of DDT present in soil was significantly lower in thepreviously. With using SBDS and Tween60 removed 84% and 75% of the contaminant in the soil. Throughaddition of surfactant, the organic contaminant was enhanced to uptake.Five low molecular weight organic acid(citric acid, oxalic acid, malic acid, acetic acid, lacticacid)were used to desoption the DDT from two kinds of soil contain 450 ng g-1 DDT by put 10g soil in the flask at 25℃, and extracted for 8h by difference concentration of organic acids(100ml). Petroleum etherwas used to extract the DDT from water, then 5ml sodium acid was used to purify, and GC-ECD was usedto analysis. In the conclusion, with the concentration of organic acid increased, videlicet the solution of pHdecreased, the soil adsorbability became weaken. When the concentration of organic acid was lower, itnearly the organic acid of root exudates, in this concentration of organic acids did enhance the organic DDTuptake, it was higher than other treatment.
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