Effects of nature organic matters and hydrated metal oxides on the anaerobic degradation of lindane, p, p '-DDT and HCB in sediments

Effects of natural organic matters( NOM) and hydrated metal oxides( HMO) in sediments on the anaerobic degradation of gamma-666, p,p'-DDT and HCB were investigated by means of removing NOM and HMO in Liaohe River sediments sequentially. The results showed that the anaerobic degradation of gamma-666, p,p'-DDT and HCB followed pseudo-first-order kinetics in different sediments. But, the extents and rates of degradation were different, even the other conditions remained the same. Anaerobic degradation rates of gamma-666, p,p'-DDT and HCB were 0.020 d(-1), 0.009 d(-1) and 0.035 month(-1) respectively for the sediments without additional carbon resources. However, with addition of carbon resources, the anaerobic degradation rates of gamma-666, p,p'-DDT and HCB were 0.071 d(-1), 0.054 d(-1) and 0.088 month(-1) in the original sediments respectively. After removing NOM, the rates were decreased to 0.047 d(-1), 0.037 d(-1) and 0.066 month(-1); in the sediments removed NOM and HMO, the rates were increased to 0.067 d(-1) , 0.059 d(-1) and 0.086 month(-1). These results indicated that NOM in the sediments accelerated the anaerobic degradation of gamma-666, p,p'-DDT and HCB; the HMO inhibited the anaerobic degradation of gamma-666, p,p'-DDT and HCB.