Removal of Amino Acids, Biodegradable Organic Carbon and Chlorine Demand by Biological Filtration in Cold Water

Prévost, Martine; Gauthier, Claude; Hureïki, L.; Desjardins, Raymond L.; Servais, Pierre

doi:10.1080/09593331908616748

Cited by 15 publications

(9 citation statements)

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“…At Cl:N = 1.2, only one dichloramine peak was detected ( Figure S2b Although accurate chemical formula of the chlorinated products formed from tyrosine and detected by LC-HRMS could be determined from the measured accurate mass to charge ratio, LC-HRMS could not definitively indicate the position of the chlorine atoms, as chlorine wa s the first atom to be removed during fragmentation. Therefore, samples suspected to contain Nmonochlorotyrosine and N,N-dichlorotyrosine were analysed using 1 H NMR ( Figure S3) and 13 C NMR ( Figure S4 1.0 x 10 -5 s -1 2-(Chlorimino)-3-methylbutanoic acid → isobutyronitrile (k 7 )…”

Section: Resultsmentioning

confidence: 99%

“…Amino acid concentrations in natural waters can range from 20 to 10 000 μg L –1 , accounting for between 2 and 13% of dissolved organic carbon and up to 75% of dissolved organic nitrogen . In general, the concentration of combined amino acids such as proteins and peptides are four to five times higher than free amino acids. , Although free amino acids only contribute a small fraction of the total amino acids, ,, free amino acids are poorly removed during biological filtration, and concentrations of free amino acids can even increase after sand filtration . Hence, it is likely that free amino acids will be present in waters during drinking water disinfection.…”

Section: Introductionmentioning

confidence: 99%

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Chlorination of Amino Acids: Reaction Pathways and Reaction Rates

How

Linge

Busetti

et al. 2017

Environ. Sci. Technol.

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Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected byproducts. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modeling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4 × 10 M s) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9 × 10 M s), although some N-monochlorovaline degraded into isobutyraldehyde (1.0 × 10 s). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3 × 10 s) and N-chloroisobutyraldimine (1.2 × 10 s). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odor threshold concentration, resulting in aesthetic challenges and an unknown health risk.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chlorination of Amino Acids: Reaction Pathways and Reaction Rates

How

Linge

Busetti

et al. 2017

Environ. Sci. Technol.

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“…36−38 Although the concentration of free amino acids is only approximately onefifth of the total amino acids, 39 free amino acids are poorly removed by biological filtration, and thus, they are more likely to be present in waters than the combined amino acids during the disinfection process. 40 Consequently, free amino acids can react with chlorine disinfectants to produce N-chloro-α-amino acids under the water disinfection treatment. 14−22 HOCl has been found to be formed in vivo by the oxidation of a chloride ion with hydrogen peroxide catalyzed by the heme enzyme myeloperoxidase, 4 which is released from activated leukocytes, thus possibly reacting with amino acids to form N-chloro-αamino acids.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The growing population and limited water sources for drinking water have forced utilities to consider exploitation of waters impacted by algal blooms or upstream wastewater discharge, which are characterized by higher dissolved organic nitrogen (DON) levels, and amino acids constitute an important class of the DON pool. − Although the concentration of free amino acids is only approximately one-fifth of the total amino acids, free amino acids are poorly removed by biological filtration, and thus, they are more likely to be present in waters than the combined amino acids during the disinfection process . Consequently, free amino acids can react with chlorine disinfectants to produce N -chloro-α-amino acids under the water disinfection treatment. − HOCl has been found to be formed in vivo by the oxidation of a chloride ion with hydrogen peroxide catalyzed by the heme enzyme myeloperoxidase, which is released from activated leukocytes, thus possibly reacting with amino acids to form N -chloro-α-amino acids.…”

Section: Introductionmentioning

confidence: 99%

Degradation Mechanisms and Substituent Effects of N-Chloro-α-Amino Acids: A Computational Study

Zhao

Zhou

Han

et al. 2020

Environ. Sci. Technol.

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N-Chloro-α-amino acids formed in the chlorination disinfection treatment of water or wastewater and in living organisms have attracted extensive attention due to the potential toxicities of themselves and their decomposition products. The degradation mechanisms of three N-chloro-α-amino acids, i.e., N-chloro-glycine, N-chloro-alanine, and N-chloro-valine, have been systematically investigated using quantum chemical computations. The results indicate that N-chloro-α-amino acid anions undergo two competitive degradation pathways: a concerted Grob fragmentation (CGF) and β-elimination (β-E). Generally, the former predominates over the latter under neutral conditions and finally generates amines and carbonyls, while the latter is preferred under base-promoted conditions and mainly produces the respective α-keto acid anions or nitriles in the end. To gain deeper insights into the substitution effects, in view of the advantages of quantum chemical computations, a number of real or designed N-chloro-α-amino acids with traditional electron-donating groups (EDG) or electron-withdrawing groups (EWG) have been studied. All of the substituted N-chloro-α-amino acids, regardless of the type and position of substituents, are kinetically more favorable than N-monochloro-glycine for degradation via the CGF pathway. Moreover, conjugated EDG substituted on the N-terminal facilitate both CGF and β-E reactions, whereas conjugated EDG and EWG on the α-carbon are only favorable for the CGF and β-E reactions, respectively. These results are expected to expand our understanding of organic N-chloramine degradation mechanisms and chlorination reaction characteristics.

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“…However, amines can comprise a significant portion of NOM, particularly when algae or sewage effluent contribute to the organic load. Only 50% of total dissolved amino acids were removed during biological filtration [Prévost et al,1998], hence it is likely that these amines will be chlorinated during water chlorination, forming organic N ‐chloramines [Bull et al,2006, 2011]. In addition, a free chlorine residual is maintained to the tap to suppress bacterial regrowth, meaning that N ‐chloramine formation is likely to occur when this free chlorine reacts with amines in saliva and stomach contents.…”

Section: Introductionmentioning

confidence: 99%

In vitro toxicity and genotoxicity assessment of disinfection by‐products, organic N‐chloramines

Laingam

Froscio

Bull³

et al. 2011

Environ and Mol Mutagen

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Disinfection by-products (DBPs) are of concern to both water industries and health authorities. Although several classes of DBPs have been studied, and there are regulated safe levels in disinfected water for some, a large portion of DBPs are not characterized, and need further investigation. Organic N-chloramines are a group of DBPs, which can be formed during common disinfection processes such as chlorination and chloramination, but little is known in terms of their toxicological significance if consumed in drinking water. Only a few in vitro studies using bacterial assays have reported some genotoxic potential of organic N-chloramines, largely in the context of inflammatory processes in the body rather than exposure through drinking water. In this study, we investigated 16 organic N-chloramines produced by chlorination of model amino acids and amines. It was found that within the drinking water-relevant micromolar concentration range, four compounds were both cytotoxic and genotoxic to mammalian cells. A small reduction of cellular GSH was also observed in the treatment with these four compounds, but not of a magnitude to account for the cytotoxicity and genotoxicity. The results presented in this study demonstrate that some organic N-chloramines, at low concentrations that might be present in disinfected water, can be harmful to mammalian cells.

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Removal of Amino Acids, Biodegradable Organic Carbon and Chlorine Demand by Biological Filtration in Cold Water

Cited by 15 publications

References 0 publications

Chlorination of Amino Acids: Reaction Pathways and Reaction Rates

Chlorination of Amino Acids: Reaction Pathways and Reaction Rates

Degradation Mechanisms and Substituent Effects of N-Chloro-α-Amino Acids: A Computational Study

In vitro toxicity and genotoxicity assessment of disinfection by‐products, organic N‐chloramines

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