氟苯尼考对铜绿微囊藻的急性和慢性毒理效应

Acute and Chronic Exposure of Florfenicol on Microcystis aeruginosa

水环境中抗生素污染产生的效应具有潜在风险,目前有关抗生素毒性效应的研究大多集中在急性暴露模式,慢性暴露模式下的相关研究尚显不足。文章选择水生环境中典型的模式生物——铜绿微囊藻作为受试物种,通过急性暴露和慢性暴露实验,分别探讨了氟苯尼考对藻细胞的生长、光合色素合成、氧化应激和微囊藻毒素释放的影响。结果表明,急性暴露期间氟苯尼考对铜绿微囊藻生长的96 h-EC_(50)为200.73μg/L,计算所得的风险熵(RQ>1.0)表明环境相关浓度氟苯尼考的潜在生态风险相当大。慢性暴露期间,3μg/L氟苯尼考暴露16 d后对铜绿微囊藻的生长抑制率达到2.58%(p<0.05),表明氟苯尼考对水生生物构成了持久而稳定的威胁。同时还发现,较高浓度组(>25μg/L)的铜绿微囊藻表现出自我调节作用,其叶绿素a、超氧化物歧化酶和过氧化氢酶活性趋于上升以抵御胁迫。上述研究结果可为全面评估氟苯尼考的生态风险及抗生素的合理利用提供科学依据。

The effects of antibiotics in the aquatic environment may potentially pose risks.However,comparatively less data are available regarding the chronic effects of antibiotic exposure as most of the eco-toxicological studies focus on acute effects.To further investigate the toxic effects on algae,Microcystis aeruginosa was selected as the test organism and the effects of florfenicol(FFC)on algal cell growth,photosynthetic pigments,oxidative stress and microcystin release were investigated through acute and chronic exposure experiments,respectively.The results indicated that during acute exposure,the 96 h-EC_(50)for FFC on M.aeruginosa was 200.73μg/L,and the calculated risk quotient(RQ>1.0)indicated that FFC posed a considerable ecological risk at actual environmental concentrations.During chronic exposure,after 16 d of exposure to FFC(3μg/L),the growth inhibition rate of M.aeruginosa reached 2.58%(p<0.05)indicating that FFC presented a persistent and stable threat to aquatic organisms.Meanwhile,the higher concentration group of M.aeruginosa(>25μg/L)showed self-recovery,with chlorophyll a,superoxide dismutase(SOD)and catalase(CAT)activities tending to rise.The above research results provided a scientific basis for a comprehensive assessment of the ecological risk of FFC and the rational use of antibiotics.