TY - JOUR
T1 - Reaction Pathways and Kinetics of a Cyanobacterial Neurotoxin β-N-Methylamino-L-Alanine (BMAA) during Chlorination
AU - Chen, Yi Ting
AU - Chen, Wan Ru
AU - Liu, Zhi Quan
AU - Lin, Tsair Fuh
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/2/7
Y1 - 2017/2/7
N2 - 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 k1 is 5.0 × 104 M-1 s-1 at pH ∼7.0. The chlorinated intermediates were found to further react with free chlorine, exhibiting a second-order rate constant k3 = 16.8 M-1 s-1. After all free chlorine was consumed, the chlorinated intermediates autodecomposed slowly with a first order rate constant k2 = 0.003 min-1 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.
AB - 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 k1 is 5.0 × 104 M-1 s-1 at pH ∼7.0. The chlorinated intermediates were found to further react with free chlorine, exhibiting a second-order rate constant k3 = 16.8 M-1 s-1. After all free chlorine was consumed, the chlorinated intermediates autodecomposed slowly with a first order rate constant k2 = 0.003 min-1 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.
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U2 - 10.1021/acs.est.6b03553
DO - 10.1021/acs.est.6b03553
M3 - Article
C2 - 28075568
AN - SCOPUS:85020478616
SN - 0013-936X
VL - 51
SP - 1303
EP - 1311
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 3
ER -