Effect of carbon sources on the degredation of HCHs and DDTs in industrial polluted field soil

A large demand for organochlorine pesticides in China results in many contaminated sites in towns,limiting the subsequent development of land use.This study selected three different carbon sources as co-metabolism substrates and also compared the effects of three carbon sources to increase the biodegradation rate of HCHs and DDTs.In the experiment,the moisture was adjusted to 50%,zero-valent metal was added to reduce the redox potential and the aerobic /anaerobic cycle method was used.The result indicated that the addition of amendment A,B and C could enhance the degradation rates of HCHs and DDTs dramatically.The degradation rates of HCHs were higher.After 90 days,the ∑HCH concentration of the treatments with amendments(A,B,C) decreased from 73.37~85.71 mg · kg-1 to 15.88~38.21 mg · kg-1.The degradation rate increased by 19%~52% compared with the control.The maximum degradation rate of ∑HCH was 81% in 90 days.Degradation of DDTs was more difficult,and the ∑DDT concentration of the treatments with amendments(A,B,C) decreased from 91.68~119.79 mg · kg-1 to 45.1~60.7 mg · kg-1.The degradation rate increased by 39%~45% compared with the control.The maximum degradation rate of ∑DDT was 51% in 30 days.Amendment B with the highest C/N ratio and the lowest moisture is most efficient one to promote the biodegradation process,followed by C and A.