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生态毒理

张杭君,贾秀英,薛大伟,胡赐明,马俊.固氮鱼腥藻Anabaena sphaerica和念珠藻Nostoc muscorum对有机氯农药林丹的降解效应和机理[J].环境科学学报,2010,30(5):1057-1061

Lindane degradation by nitrogen fixing Anabaena sphaerica and Nostoc muscorum:Degradation characteristics and mechanisms

摘要：研究了固氮鱼腥藻A.sphaerica和念珠藻N.muscorum对林丹(γ-HCH)的降解效应及机理.结果表明,在初始藻种叶绿素含量约为37mg·L^-1,林丹起始浓度均为0.2mg·L^-1条件下,A.sphaerica和N.muscorum均能明显降解林丹,5d降解率分别为66.1%和69.5%,其降解半衰期分别为3.19和3.23d.在培养过程中,0.2mg·L^-1林丹并不会抑制两种固氮藻的生长,培养5d后,叶绿素a的含量分别增加0.82倍和1.36倍.升高温度和增强光照均能增加林丹的降解率.相对于N₂,NaNO₃作为唯一氮源更能刺激固氮蓝藻对林丹的降解,对于A.sphaerica和N.muscorum,其对林丹的5d降解率分别增加44.6%和40.5%.气质联用检测结果表明,脱去HCl生成γ-五氯环己烯是两种固氮蓝藻降解林丹的主要脱氯分子机理.

Abstract：The degradation of lindane by the nitrogen fixing species Anabaena.sphaerica and Nostoc muscorum was investigated. The removal efficiencies after 5 days for A. sphaerica and N. muscorum were 66.1% and 69.5%,respectively,at the initial concentration of 0.2 mg·L^-1. The half-life was 3.19 d for A. sphaerica and 3.23 d for N. muscorum. At an initial concentration of 0.2 mg·L^-1,lindane will not inhibit the growth of these cyanobacteria,however,the chlorophyll-a of the cyanobacteria increased 0.82 and 1.36 times,respectively. Both high temperature and high light intensity can increase the degradation rate of lindane. F_or A. sphaerica and N. muscorum,the removal efficiency can increase 44.6% or 40.5% when NaNO₃ or N₂ is used as the only nitrogen source. GC-MSanalysis demonstrated that the molecular mechanism of lindane degradation in these cyanobacteria involved dechlorination of lindane to γ-pentachlorocyclohexene in the first step.