School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, China.
Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, Hohai University, Nanjing, 210046, China.
Environ Sci Pollut Res Int. 2023 Apr;30(16):47873-47881. doi: 10.1007/s11356-023-25754-7. Epub 2023 Feb 7.
β-N-methylamino-L-alanine (BMAA), which has been considered as an environmental factor that caused amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) or Alzheimer's disease, could be produced by a variety of genera cyanobacteria. BMAA is widely present in water sources contaminated by cyanobacteria and may threaten human health through drinking water. Although oxidants commonly used in drinking water plants such as chlorine, ozone, hydrogen peroxide, and hydroxyl radicals have been shown to effectively degrade BMAA, there are limited studies on the mechanism of BMAA degradation by different oxidants, especially ozone. This work systematically explored the effectiveness of BMAA ozonation degradation, investigated the effect of the operating parameters on the effectiveness of degradation, and speculated on the pathways of BMAA decomposition. The results showed that BMAA could be quickly eliminated by ozone, and the removal rates of BMAA were nearly 100% in pure water, but the removal rates were reduced in actual water. BMAA was primarily degraded by direct oxidation of ozone molecules in acidic and near-neutral conditions, and indirect oxidation of •OH accounted for the main part under strong alkaline conditions. The pH value had a significant effect on the decomposition of BMAA, and the degradation rate of BMAA was fastest at near-neutral pH value. The degradation rates of TOC were significantly lower than that of BMAA, indicating that by-products were generated during the degradation process. Three by-products ([M-H] = 105, 90, and 88) were identified by UPLC-MS/MS, and the degradation pathways of BMAA were proposed. The production of by-products was attributed to the fracture of the C-N bonds. This work is helpful for the in-depth understanding on the mechanism and demonstration of the feasibility of the oxidation of BMAA by the ozone process. HIGHLIGHTS: • The reaction of ozonation BMAA was easy to occur. • The degradation rate was fast under near-neutral conditions. • Direct oxidation under neural conditions was the main pathway for ozone degradation of BMAA. • Three products were detected, and the reaction path was inferred.
β-N-甲基氨基-L-丙氨酸（BMAA）被认为是引起肌萎缩侧索硬化症/帕金森病-痴呆症复合征（ALS/PDC）或阿尔茨海默病的环境因素，它可以由多种属蓝藻产生。BMAA 广泛存在于受蓝藻污染的水源中，可能通过饮用水对人类健康构成威胁。虽然氯、臭氧、过氧化氢和羟基自由基等常用于饮用水厂的氧化剂已被证明可以有效地降解 BMAA，但关于不同氧化剂降解 BMAA 的机制，特别是臭氧的机制，研究有限。本工作系统地研究了 BMAA 臭氧化降解的效果，考察了操作参数对降解效果的影响，并推测了 BMAA 分解的途径。结果表明，臭氧能迅速消除 BMAA，在纯水中 BMAA 的去除率接近 100%，但在实际水中去除率降低。在酸性和近中性条件下，BMAA 主要通过臭氧分子的直接氧化降解，在强碱性条件下，•OH 的间接氧化占主要部分。pH 值对 BMAA 的分解有显著影响，在近中性 pH 值下，BMAA 的降解速度最快。TOC 的降解速率明显低于 BMAA，表明在降解过程中产生了副产物。通过 UPLC-MS/MS 鉴定了三种副产物([M-H] = 105、90 和 88)，并提出了 BMAA 的降解途径。副产物的产生归因于 C-N 键的断裂。这项工作有助于深入了解臭氧过程氧化 BMAA 的机制和可行性的论证。 要点： • 臭氧化 BMAA 的反应容易发生。 • 在近中性条件下，降解速度较快。 • 中性条件下的直接氧化是臭氧降解 BMAA 的主要途径。 • 检测到三种产物，并推断出反应路径。
