低剂量UV-C/H_2O_2联用灭活铜绿微囊藻及影响因素

Inactivation Effects of UV-C/H_2O_2 at Low Doses on Microcystis aeruginosa and Its Influence Factors

以我国典型水华蓝藻铜绿微囊藻为研究对象，考察低剂量UV—C／H2O2联用工艺的快速除藻效果并与单独H2O2处理进行对比，通过测定藻细胞光合活性及胞内氧化压力以分析杀藻机制，通过测定胞外MC—LR浓度以评价藻毒素释放风险，并考察了水中存在的有机物及还原性无机物对低剂量UV—C／H2O2杀藻效果的影响。结果表明，20mJ／cm^2的UV—C与≥100μmol／L的H2O2联用具有6h内快速杀藻效果，藻细胞灭活率〉1-lg，UV—C和H2O2表现出协同效应，所需H2O2剂量显著低于单独H2O2处理的。低剂量UV—C／H2O2处理引起光合活性降低及胞内氧化压力升高，应是藻细胞死亡的重要原因。快速杀藻过程中伴随胞外MC—LR浓度升高6～9倍的风险。水中的有机物及还原性无机物将显著削弱低剂量uV—C／H2O2的除藻效果。

The inactivation effects of UV-C/H2O2 at low doses on Microcystis aeruginosa, a typical blooming cyanobacterial species in China, were investigated, and the comparison with sole H2O2 treatment was performed. The variations of photosynthetic activity and intraeellular reactive oxygen species （ROS） were measured for inactivation mechanism analysis. The extracellular MC-LR concentration was determined to assess the risk of microeystin release. The impact of organic matters and reducing inorganic matter in water on cell inactivation by UV-C/H2O2 at low doses was tested. The results indicated that the combined treatment with UV-C of 20 mJ/cm^2 andH2O2 of more than 100 μmol/L could induce Microcystis aeruginosa inactivation for larger than 1-1g in 6 h, showing a synergic effect of UV-C and H2O2. The dose of H2O2 required for Microcystis aeruginosa inactivation when combined with UV-C was significantly lower than that of sole H2O2 treatment. The marked reduction in photosynthetic activity as well as the increase in intracellular ROS were observed and largely accounted for inactivation of Microcystis aeruginosa. The rapid lysis of Microcystis aeruginosa caused a 6 to 9 fold increase in the extracellular MC-LR concentration. The existence of organic matter and reduced inorganic matter in water could significantly reduce the inactivation effects of UV-C/H2O2 at low doses on Microcystis aeruginosa.