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A platform for research: civil engineering, architecture and urbanism
Photochemical Degradation of Saxitoxins in Surface Waters
https://orcid.org/0000-0003-2438-2341
https://orcid.org/0000-0002-0374-9549
https://orcid.org/0000-0001-8400-3142
https://orcid.org/0000-0002-3311-9089
Photochemical degradation has been shown to be a significant pathway in the environmental fate of many cyanotoxins, compounds produced by harmful cyanobacteria. However, there has been a lack of research on the photochemical fate of saxitoxins. This project evaluated the direct and sensitized photodegradation of three saxitoxin analogues including saxitoxin (STX), gonyautoxin-2 and −3 (GTX 2/3), and n-sulfocarbamoyl-gonyautoxin-1 and −2 (C 1/2). Irradiation of STX and analogues in the presence or absence of dissolved organic matter (DOM) revealed that none of the toxins undergo direct photolysis at pH 6 or 8, and only STX and GTX 2/3 undergo sensitized photolysis at pH 8. Sensitized photolysis half-lives ranged from 1 to 10 h for STX and GTX 2/3. The contribution of reactive intermediates including singlet oxygen (1O2), triplet-state dissolved organic matter (3DOM*), and hydroxyl radicals (•OH) was assessed, with 3DOM* accounting for the majority of STX and GTX 2/3 degradation. Additionally, three transformation product candidates were identified for the photolysis of STX, and an electron-transfer mechanism was proposed. The kinetics, mechanism, and products of saxitoxin phototransformation are essential to understanding the persistence of these toxins in surface waters and assessing the impacts of harmful algal blooms.
This work contributes to efforts to understand the threats associated with harmful algal blooms by outlining the photochemical fate of saxitoxins.
Photochemical Degradation of Saxitoxins in Surface Waters
https://orcid.org/0000-0003-2438-2341
https://orcid.org/0000-0002-0374-9549
https://orcid.org/0000-0001-8400-3142
https://orcid.org/0000-0002-3311-9089
Photochemical degradation has been shown to be a significant pathway in the environmental fate of many cyanotoxins, compounds produced by harmful cyanobacteria. However, there has been a lack of research on the photochemical fate of saxitoxins. This project evaluated the direct and sensitized photodegradation of three saxitoxin analogues including saxitoxin (STX), gonyautoxin-2 and −3 (GTX 2/3), and n-sulfocarbamoyl-gonyautoxin-1 and −2 (C 1/2). Irradiation of STX and analogues in the presence or absence of dissolved organic matter (DOM) revealed that none of the toxins undergo direct photolysis at pH 6 or 8, and only STX and GTX 2/3 undergo sensitized photolysis at pH 8. Sensitized photolysis half-lives ranged from 1 to 10 h for STX and GTX 2/3. The contribution of reactive intermediates including singlet oxygen (1O2), triplet-state dissolved organic matter (3DOM*), and hydroxyl radicals (•OH) was assessed, with 3DOM* accounting for the majority of STX and GTX 2/3 degradation. Additionally, three transformation product candidates were identified for the photolysis of STX, and an electron-transfer mechanism was proposed. The kinetics, mechanism, and products of saxitoxin phototransformation are essential to understanding the persistence of these toxins in surface waters and assessing the impacts of harmful algal blooms.
This work contributes to efforts to understand the threats associated with harmful algal blooms by outlining the photochemical fate of saxitoxins.
Photochemical Degradation of Saxitoxins in Surface Waters
https://orcid.org/0000-0003-2438-2341
https://orcid.org/0000-0002-0374-9549
https://orcid.org/0000-0001-8400-3142
https://orcid.org/0000-0002-3311-9089
Photochemical degradation has been shown to be a significant pathway in the environmental fate of many cyanotoxins, compounds produced by harmful cyanobacteria. However, there has been a lack of research on the photochemical fate of saxitoxins. This project evaluated the direct and sensitized photodegradation of three saxitoxin analogues including saxitoxin (STX), gonyautoxin-2 and −3 (GTX 2/3), and n-sulfocarbamoyl-gonyautoxin-1 and −2 (C 1/2). Irradiation of STX and analogues in the presence or absence of dissolved organic matter (DOM) revealed that none of the toxins undergo direct photolysis at pH 6 or 8, and only STX and GTX 2/3 undergo sensitized photolysis at pH 8. Sensitized photolysis half-lives ranged from 1 to 10 h for STX and GTX 2/3. The contribution of reactive intermediates including singlet oxygen (1O2), triplet-state dissolved organic matter (3DOM*), and hydroxyl radicals (•OH) was assessed, with 3DOM* accounting for the majority of STX and GTX 2/3 degradation. Additionally, three transformation product candidates were identified for the photolysis of STX, and an electron-transfer mechanism was proposed. The kinetics, mechanism, and products of saxitoxin phototransformation are essential to understanding the persistence of these toxins in surface waters and assessing the impacts of harmful algal blooms.
This work contributes to efforts to understand the threats associated with harmful algal blooms by outlining the photochemical fate of saxitoxins.
Photochemical Degradation of Saxitoxins in Surface Waters
Norris, Kari E. (author) / Kurtz, Tyler (author) / Wang, Shiru (author) / Zeng, Teng (author) / Leresche, Frank (author) / Rosario-Ortiz, Fernando L. (author)
ACS ES&T Water ; 4 ; 346-354
2024-02-09
Article (Journal)
Electronic Resource
English
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