洪湖沉积物中有机氯农药的厌氧降解动力学

Anaerobic Degradation Kinetics of Organochlorine Pesticides from Sediments of Honghu Lake

通过模拟试验,对洪湖沉积物中的有机氯农药在厌氧条件下的降解动力学过程进行了研究。结果表明,在厌氧条件下天然沉积物中大部分有机氯农药均可缓慢降解,其中降解较明显的有γ-HCH、p,p′-DDT及o,p′-DDT,降解最慢的为β-HCH。p,p′-DDT在厌氧条件下的主要降解产物为p,p′-DDD,导致p,p′-DDD的含量有所上升。其他几种有机氯农药的降解速率顺序大致为:α-氯丹>α-HCH>HCB>p,p′-DDE,并且这几种有机氯农药的厌氧生物降解均符合准一级反应动力学方程,其厌氧降解动力学常数分别为k1=0.013 7 d-1,k2=0.007 8 d-1,k3=0.004 2 d-1,k4=0.000 5 d-1。

Abstract： The anaerobic degradation kinetic process of organochlorine pesticides （OCPs） from the sediments from Honghu Lake was studied with simulation experiment. The results showed that most of OCPs was degraded slowly in natural sediments under anaerobic condition. 3＇-HCH,p,p＇-DDT and o,p＇-DDT were degraded obviously. The degradation of I3-HCH was most slowly. Because main catabolite of p,p＇-DDT was p,p＇-DDD, the concentration of p,p＇-DDD was increased. The degrada- tion rate of α-ehlordane, ot-HCH, HCB and p,p＇-DDE was in the order of a-chlordane 〉 ct-HCH 〉 HCB 〉 p,p＇-DDE, with their anaerobic degradation fitting with first-order kinetic equation. Kinetic constants of α-chlordane, α-HCH, HCB and p ,p ＇-DDE were 0.013 7 d^-1, 0.007 8 d^-1, 0.004 2 d^-1 and 0.000 5 d^-1, respectively.