Abstract: The degradation of hexachloroethane （HCE） in the paddy soil and the effect of sulfate on sulfate\|reducing bacteria were investigated through simulating different environmental conditions. Results showed that the degradation rate of HCE increased with the increasing initial HCE concentration in the soil， However， the degradation rate of HCE decreased when it reached a certain quality concentration （≥60 mg·kg-1）. The degradation activity of sulfate\|reducing bacteria （SRB） was enhanced and the HCE degradation rate was speeded up with the increasing soil sulfate. But the growth of sulfate\|reducing bacteria and the degradation of HCE were restrained when sulfate was excessive（≥60 mg·kg-1）. The soil pH and Eh values were optimal for the growth of sulfate\|reducing bacteria after 21 days with addition of sulfate and HCE， and then the rate of sulfate degration also reached the maximum. The result showed the degradation of HCE was accelerated through controlling the soil pH and Eh values or adding proper concentration of sulfate to soil in order to reduce the risk of HCE in soil.

Key words: hexachloroethane, dechlorinate, anaerobic, sulfate-reducing bacteria