Department of Environmental Engineering and Global Water Quality Research Center, National Cheng Kung University , Tainan City 70101, Taiwan.
Environ Sci Technol. 2017 Feb 7;51(3):1303-1311. doi: 10.1021/acs.est.6b03553. Epub 2017 Jan 30.
β-N-Methylamino-L-alanine (BMAA), a probable cause of the amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC), or Alzheimer's disease, has been identified in more than 20 cyanobacterial genera. However, its removal and fate in drinking water has never been reported before. In this study, the reaction of BMAA with chlorine, a common drinking-water oxidant/disinfectant, was investigated. A liquid chromatograph coupled with a triple quadrupole mass spectrometer was employed to quantify BMAA and its intermediates. Upon chlorination, four chlorinated intermediates, each with one or two chlorines, were identified. The disappearance of BMAA caused by chlorine follows a second-order reaction, with the rate constant k is 5.0 × 10 M s at pH ∼7.0. The chlorinated intermediates were found to further react with free chlorine, exhibiting a second-order rate constant k = 16.8 M s. After all free chlorine was consumed, the chlorinated intermediates autodecomposed slowly with a first order rate constant k = 0.003 min; when a reductant was added, these chlorinated intermediates were then reduced back to BMAA. The results as described shed a useful light on the reactivity, appearance, and removal of BMAA in the chlorination process of a drinking-water system.
β-N-甲基氨基-L-丙氨酸（BMAA）是肌萎缩侧索硬化症/帕金森病-痴呆症复合征（ALS/PDC）或阿尔茨海默病的可能病因，已在 20 多种蓝藻属中被发现。然而，BMAA 在饮用水中的去除和归宿以前从未被报道过。在这项研究中，研究了 BMAA 与氯（一种常见的饮用水氧化剂/消毒剂）的反应。采用液相色谱-串联三重四极杆质谱联用仪定量测定 BMAA 及其中间产物。氯化后，鉴定出 4 种氯代中间产物，每个中间产物含 1 个或 2 个氯原子。在 pH 值约为 7.0 时，氯对 BMAA 的去除遵循二级反应，速率常数 k 为 5.0×10 M s。氯代中间产物进一步与游离氯反应，表现出二级速率常数 k = 16.8 M s。当所有游离氯被消耗后，氯代中间产物缓慢自动分解，一级速率常数 k = 0.003 min；当添加还原剂时，这些氯代中间产物又被还原回 BMAA。所述结果阐明了在饮用水系统氯化过程中 BMAA 的反应性、出现和去除。
