Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV 89193-9954, USA; Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, CO 80309, USA.
Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, CO 80309, USA.
Water Res. 2014 Apr 1;52:251-9. doi: 10.1016/j.watres.2013.11.001. Epub 2013 Nov 12.
The release of intracellular microcystin-LR (MC-LR), 2-methylisoborneol (MIB), and geosmin was investigated after the oxidation of three cyanobacteria (Microcystis aeruginosa (MA), Oscillatoria sp. (OSC), and Lyngbya sp. (LYN)). During the oxidation of 200,000 cells/mL of MA, release of intracellular MC-LR exceeded the World Health Organization (WHO) guideline of 1 μg/L during the lowest oxidant exposures (CT) tested: ozone (0 mg-min/L, below the ozone demand), chlorine (<40 mg-min/L), chlorine dioxide (<560 mg-min/L), and chloramine (<640 mg-min/L). As the CT increased, ozone, chlorine, and chlorine dioxide were able to oxidize the released MC-LR. During the oxidation of OSC (2800 cells/mL) and LYN (1600 cells/mL), release of intracellular MIB and geosmin exceeded reported threshold odor values after exposure to chlorine, chlorine dioxide, and chloramine, which have low reactivity with these taste and odor compounds. Ozone oxidation of OSC yielded an increase in MIB concentration at lower exposures (≤2.9 mg-min/L), likely due to insufficient oxidation by hydroxyl radicals. The release of intracellular organic matter (IOM) was also measured to determine the potential of bulk measurements to act as a surrogate for cyanotoxins and metabolite release. In all cases, the dissolved organic carbon (DOC) release was less than 0.25 mgC/L, which lacked the sensitivity to indicate the release of MC-LR, MIB, or geosmin. The fluorescence index proved to be a more sensitive indicator of intracellular organic matter release than DOC for MA. These results illustrate that toxic or odorous compounds may be released from cyanobacteria cells during oxidation processes with minimal changes in the DOC concentration.
研究了三种蓝藻（铜绿微囊藻（MA）、颤藻（OSC）和束丝藻（LYN））氧化后细胞内微囊藻毒素-LR（MC-LR）、2-甲基异莰醇（MIB）和土臭素的释放情况。在氧化 20 万细胞/毫升 MA 的过程中，在最低氧化剂暴露量（CT）下，细胞内 MC-LR 的释放超过了世界卫生组织（WHO）1μg/L 的指导值：臭氧（0mg-min/L，低于臭氧需求）、氯（<40mg-min/L）、二氧化氯（<560mg-min/L）和氯胺（<640mg-min/L）。随着 CT 的增加，臭氧、氯和二氧化氯能够氧化释放的 MC-LR。在氧化 OSC（2800 个细胞/毫升）和 LYN（1600 个细胞/毫升）的过程中，在暴露于氯、二氧化氯和氯胺后，细胞内 MIB 和土臭素的释放超过了报告的阈值气味值，这些氧化剂与这些异味化合物的反应性较低。臭氧氧化 OSC 在较低暴露量（≤2.9mg-min/L）下会增加 MIB 浓度，这可能是由于羟基自由基的氧化不足所致。还测量了细胞内有机物（IOM）的释放，以确定批量测量作为蓝藻毒素和代谢物释放的替代物的潜力。在所有情况下，溶解有机碳（DOC）的释放都小于 0.25mgC/L，缺乏指示 MC-LR、MIB 或土臭素释放的灵敏度。荧光指数被证明是 MA 细胞内有机物释放的比 DOC 更敏感的指标。这些结果表明，有毒或有异味的化合物可能会在氧化过程中从蓝藻细胞中释放出来，而 DOC 浓度的变化很小。
