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Most studies on the treatment of chlorinated contaminants by Fe(0) focus on aqueous system tests.However,few is known about the effectiveness of these tests for degrading chlorinated contaminants such as 1,1,1-trichloroethane (TCA) in soil.In this work,the reductive degradation performance of 1,1,1- TCA by Fe(0) was thoroughly investigated in a soil slurry system.The effects of various factors including acid-washed iron,the initial 1,1,1-TCA concentration,Fe(0) dosage,slurry pH,and common constituents in groundwater and soil such as Cl-,HCO3-,SO42-,NO3-anions and humic acid (HA) were evaluated.The experimental results showed that 1,1,1-TCA could be effectively degraded in 12 h for an initial Fe(O) dosage of 10 g L-1 and a soil/water mass ratio of 1/5.The soil slurry experiments showed two-stage degradation kinetics: a slow reaction in the first stage and a fast reductive degradation of 1,1,1-TCA in the second stage.The reductive degradation of 1,1,1-TCA was expedited as the mass concentration of Fe(O) increased.In addition,high pHs adversely affected the degradation of 1,1,1-TCA over a pH range of 5.4-8.0,and the reductive degradation efficiency decreased with increasing slurry pH.The initial 1,1,1-TCA concentration and the presence of Cl-and SO42-anions had negligible effects.HCO3-anions had a acceerative effect on 1,1,1-TCA removal,and both NO3-and HA had inhibitory effects.A Cl-mass balance showed that the amount of Cl-ions released into the soil slurry system during the 1,1,1-TCA degradation increased with increasing reaction time,suggesting that the main degradation mechanism of 1,1,1-TCA by Fe(O) in a soil slurry system was reductive dechlorination with 1,1-DCA as the main intermediate.In conclusion,this study provides a theoretical basis for the practical application of the remediation of contaminated sites containing chlorinated solvent.