六六六在海河沉积物中的自然生物降解

Natural Biodegradation of HCHs in Sediments of Haihe River

为了解天然水体沉积物中六六六(HCHs)的自然生物降解行为,采集海河沉积物进行了实验室研究.结果表明:HCHs在海河表层沉积物及水/沉积物界面层中的生物降解均符合一级动力学方程,α-HCH、β-HCH、γ-HCH和δ-HCH的生物降解速率常数分别为1.45×10-2～6.02×10-2 d-1、9.8×10-3～3.39×10-2 d-1、2.00×10-2～8.58×10-2 d-1和1.42×10-2～5.40×10-2 d-1;4种HCH异构体的降解顺序为γ-HCH>α-HCH>δ-HCH>β-HCH;厌氧条件下HCHs的降解速率高于好氧条件,温度升高降解速率增大;水/沉积物界面层中HCHs的生物降解速率,除好氧条件下α-HCH和γ-HCH外,均高于表层沉积物.

In order to understand the natural biodegradation behavior of hexachlorocyclohexane （HCHs） in sediments of natural water, laboratory experiments were performed with sediments collected from Haihe River. The results show that the biodegradation process of HCHs in surface sediments and water-sediment interface of Haihe River fitted well with the first-order equation,and biodegradation rate constants were in the range of 1.45×10^- 2-6.02×10^- 2 d^-1 for α-HCH,9.8×10^- 3-3.39×10^- 2 d^- 1 for β-HCH,2.00×10^- 2- 8.58×10^-2 d^-1 for γ-HCH,and 1.42×10^- 2-5.40×10^-2 d^-1 for δ- HCH,respectively. The order of the biodegradability of the 4 HCH isomers is γ-HCH〉α-HCH〉δ-HCH〉β-HCH. Biodegradation rates of HCHs under anaerobic condition were higher than those under aerobic condition, and increased with the increase of temperature. Biodegradation rates of HCHs in water-sediment interface were higher than those in surface sediments except for α-HCH and γ-HCH under aerobic condition.