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Weng S, Blatchley ER. Ultraviolet-induced effects on chloramine and cyanogen chloride formation from chlorination of amino acids. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:4269-4276. [PMID: 23560482 DOI: 10.1021/es400273w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ultraviolet (UV)-based treatment is commonly used to augment chlorination in swimming pools. However, the effects of combined application of UV254/chlorine on disinfection byproduct (DBP) formation are incompletely defined. To examine this issue, experiments were conducted with amino acids (l-arginine, l-histidine, and glycine) that are representative of those introduced to swimming pools via human body fluids. For each precursor, stepwise experiments were conducted with chlorination and UV254 exposure, with/without post-chlorination. Net formation and decomposition of chloramines and cyanogen chloride (CNCl) were measured for a range of chlorine/precursor (Cl/P) molar ratios and UV254 doses. Substantial production of NH2Cl from l-arginine and l-histidine was observed at Cl/P = 1.0 and 2.0 when post-chlorination was applied to UV254-irradiated samples. These results suggested a mechanism of rapid N-chlorination, followed by cleavage of NH3 by UV254 irradiation. CNCl formation was observed from UV254-irradiated samples of l-arginine and l-histidine when Cl/P = 2.0 and 3.0, as well as from glycine for Cl/P ≤ 1. Structurally related precursor compounds were examined for CNCl formation potential in chlorination/UV experiments. CNCl formation was promoted by UV254 exposure of chlorinated imidazole and guanidine compounds, which suggested that these groups contributed to CNCl formation. The results have implications with respect to the application of chlorine and UV for water treatment in swimming pools and other settings, such as water reuse and advanced oxidation processes.
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Affiliation(s)
- ShihChi Weng
- School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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52
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Determination of volatile N-nitrosamines in meat products by microwave-assisted extraction coupled with dispersive micro solid-phase extraction and gas chromatography – Chemical ionisation mass spectrometry. Food Chem 2013; 138:227-33. [DOI: 10.1016/j.foodchem.2012.09.119] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 09/12/2012] [Accepted: 09/23/2012] [Indexed: 11/21/2022]
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53
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Soltermann F, Lee M, Canonica S, von Gunten U. Enhanced N-nitrosamine formation in pool water by UV irradiation of chlorinated secondary amines in the presence of monochloramine. WATER RESEARCH 2013; 47:79-90. [PMID: 23098367 DOI: 10.1016/j.watres.2012.09.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/13/2012] [Accepted: 09/17/2012] [Indexed: 06/01/2023]
Abstract
N-Nitrosamines, in particular N-nitrosodimethylamine (NDMA), are carcinogens, which occur as chlorine disinfection by-products (DBPs) in swimming pools and hot tubs. UV treatment is a commonly used technique in swimming pools for disinfection and DBP attenuation. UV irradiation is known to efficiently degrade N-nitrosamines. However, UV irradiation (at λ = 254 nm) of chlorinated dimethylamine (CDMA) and monochloramine, two NDMA precursors present in swimming pool water, resulted in a substantial UV-induced NDMA formation (~1-2% molar yield based on initial CDMA concentration) simultaneously to NDMA photolysis. Maximum NDMA concentrations were found at UV doses in the range used for advanced oxidation (350-850 mJ cm(-2)). Very similar behaviour was found for other chlorinated secondary amines, namely diethylamine and morpholine. Effectiveness of UV irradiation for N-nitrosamine abatement depends on initial N-nitrosamine and precursor concentrations and the applied UV dose. N-Nitrosamine formation is hypothesized to occur via the reaction of nitric oxide or peroxynitrite with the secondary aminyl radical, which are products from the photolysis of monochloramine and chlorinated secondary amines, respectively. Experiments with pool water showed that similar trends were observed under pool water conditions. UV treatment (UV dose: ~360 mJ cm(-2)) slightly increased NDMA concentration in pool water instead of the anticipated 50% abatement in the absence of NDMA precursors.
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Affiliation(s)
- Fabian Soltermann
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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54
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Xiao F, Zhang X, Zhai H, Lo IMC, Tipoe GL, Yang M, Pan Y, Chen G. New halogenated disinfection byproducts in swimming pool water and their permeability across skin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:7112-7119. [PMID: 22697042 DOI: 10.1021/es3010656] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Chlorine is widely used for disinfecting public swimming pool water. The disinfectant chlorine, protecting swimmers from pathogenic infection in swimming, may be responsible for some adverse effects on swimmers' skin and health. In this study, numerous new halogenated disinfection byproducts (DBPs) in chlorinated pool water were detected with a powerful precursor ion scan method using electrospray ionization triple quadrupole mass spectrometry, with or without preseparation with ultra performance liquid chromatography. These new pool DBPs were demonstrated to be mainly halo(nitro)phenols, resulting from chlorination of human body substances (such as urine) in the presence of bromide. Among these new DBPs, 2,4-dibromophenol, 2,4-dichlorophenol, 2-bromophenol, 2,6-dibromo-4-nitrophenol, 2-bromo-6-chloro-4-nitrophenol, and 2,6-dichloro-4-nitrophenol were fully identified or confirmed. For 2,4-dibromophenol, 2,4-dichlorophenol and 2-bromophenol with pure standard compounds available, their permeability values across human skin were measured to be 0.031, 0.021, and 0.023 cm/h, respectively. The effects of chlorine on human skin were also investigated. The interaction of chlorine with epidermis was found to generate many new halogenated DBPs as well as common DBPs; the corneous layer was observed to become rough and even form larger pores after chlorine interaction. It is recommended that swimmers should avoid urinating in pools, and avoid prolonged swimming to reduce chlorine contact and prevent accelerated permeation of DBPs across skin.
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Affiliation(s)
- Feng Xiao
- Environmental Engineering Program, Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
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55
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Weng S, Li J, Blatchley ER. Effects of UV 254 irradiation on residual chlorine and DBPs in chlorination of model organic-N precursors in swimming pools. WATER RESEARCH 2012; 46:2674-2682. [PMID: 22425148 DOI: 10.1016/j.watres.2012.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/11/2012] [Accepted: 02/11/2012] [Indexed: 05/31/2023]
Abstract
Ultraviolet (UV) irradiation is commonly applied as a secondary disinfection process in chlorinated pools. UV-based systems have been reported to yield improvements in swimming pool water and air chemistry, but to date these observations have been largely anecdotal. The objectives of this investigation were to evaluate the effects of UV irradiation on chlorination of important organic-N precursors in swimming pools. Creatinine, L-arginine, L-histidine, glycine, and urea, which comprise the majority of the organic-N in human sweat and urine, were selected as precursors for use in conducting batch experiments to examine the time-course behavior of several DBPs and residual chlorine, with and without UV(254) irradiation. In addition, water samples from two natatoria were subjected to monochromatic UV irradiation at wavelengths of 222 nm and 254 nm to evaluate changes of liquid-phase chemistry. UV(254) irradiation promoted formation and/or decay of several chlorinated N-DBPs and also increased the rate of free chlorine consumption. UV exposure resulted in loss of inorganic chloramines (e.g., NCl(3)) from solution. Dichloromethylamine (CH(3)NCl(2)) formation from creatinine was promoted by UV exposure, when free chlorine was present in solution; however, when free chlorine was depleted, CH(3)NCl(2) photodecay was observed. Dichloroacetonitrile (CNCHCl(2)) formation (from L-histidine and L-arginine) was promoted by UV(254) irradiation, as long as free chlorine was present in solution. Likewise, UV exposure was observed to amplify cyanogen chloride (CNCl) formation from chlorination of L-histidine, L-arginine, and glycine, up to the point of free chlorine depletion. The results from experiments involving UV irradiation of chlorinated swimming pool water were qualitatively consistent with the results of model experiments involving UV/chlorination of precursors in terms of the behavior of residual chlorine and DBPs measured in this study. The results indicate that UV(254) irradiation promotes several reactions that are involved in the formation and/or destruction of chlorinated N-DBPs in pool settings. Enhancement of DBP formation was consistent with a mechanism whereby a rate-limiting step in DBP formation was promoted by UV exposure. Promotion of these reactions also resulted in increases of free chlorine consumption rates.
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Affiliation(s)
- ShihChi Weng
- School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, USA
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56
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Fischer K, Fries E, Körner W, Schmalz C, Zwiener C. New developments in the trace analysis of organic water pollutants. Appl Microbiol Biotechnol 2012; 94:11-28. [DOI: 10.1007/s00253-012-3929-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/26/2012] [Accepted: 01/28/2012] [Indexed: 10/28/2022]
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57
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Dispersive micro-solid phase extraction combined with gas chromatography-chemical ionization mass spectrometry for the determination of N-nitrosamines in swimming pool water samples. Anal Bioanal Chem 2012; 402:2209-16. [PMID: 22222914 DOI: 10.1007/s00216-011-5681-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/12/2011] [Accepted: 12/18/2011] [Indexed: 10/14/2022]
Abstract
A simple sample pretreatment technique, dispersive micro-solid phase extraction, was applied for the extraction of N-nitrosodimethylamine (NDMA) and other four N-nitrosamines (NAs) from samples of swimming pool water. The parameters affecting the extraction efficiency were systematically investigated. The best extraction conditions involved immersing 75 mg of carbon molecular sieve, Carboxen™ 1003 (as an adsorbent), in a 50-mL water sample (pH 7.0) containing 5% sodium chloride in a sample tube. After 20 min of extraction by vigorous shaking, the adsorbent was collected on a filter and the NAs desorbed by treatment with 150 μL of dichloromethane. A 10-μL aliquot was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry using the selected ion storage mode. The limits of quantitation were <0.9 ng/L. The precision for these analytes, as indicated by relative standard deviations, were <8% for both intra- and inter-day analyses. Accuracy, expressed as the mean extraction recovery, was between 62% and 109%. A preliminary analysis of swimming pool water samples revealed that NDMA was present in the highest concentration, in the range from n.d. to 100 ng/L.
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58
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Shah AD, Mitch WA. Halonitroalkanes, halonitriles, haloamides, and N-nitrosamines: a critical review of nitrogenous disinfection byproduct formation pathways. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:119-31. [PMID: 22112205 DOI: 10.1021/es203312s] [Citation(s) in RCA: 439] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Interest in the formation of nitrogenous disinfection byproducts (N-DBPs) has increased because toxicological research has indicated that they are often more genotoxic, cytotoxic, or carcinogenic than many of the carbonaceous disinfection byproducts (C-DBPs) that have been a focus for previous research. Moreover, population growth has forced utilities to exploit source waters impaired by wastewater effluents or algal blooms. Both waters feature higher levels of organic nitrogen, that might serve as N-DBP precursors. Utilities are exploring new disinfectant combinations to reduce the formation of regulated trihalomethanes and haloacetic acids. As some of these new combinations may promote N-DBP formation, characterization of N-DBP formation pathways is needed. Formation pathways for halonitroalkanes, halonitriles, haloamides, and N-nitrosamines associated with chlorine, ozone, chlorine dioxide, UV, and chloramine disinfection are critically reviewed. Several important themes emerge from the review. First, the formation pathways of the N-DBP families are partially linked because most of the pathways involve similar amine precursors. Second, it is unlikely that a disinfection scheme that is free of byproduct formation will be discovered. Disinfectant combinations should be optimized to reduce the overall exposure to toxic byproducts. Third, the understanding of formation pathways should be employed to devise methods of applying disinfectants that minimize byproduct formation while accomplishing pathogen reduction goals. Fourth, the well-characterized nature of the monomers constituting the biopolymers that likely dominate the organic nitrogen precursor pool should be exploited to predict the formation of byproducts likely to form at high yields.
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Affiliation(s)
- Amisha D Shah
- Department of Chemical and Environmental Engineering, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520, United States
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59
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Padhye LP, Hertzberg B, Yushin G, Huang CH. N-nitrosamines formation from secondary amines by nitrogen fixation on the surface of activated carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:8368-8376. [PMID: 21863897 DOI: 10.1021/es201696e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Our previous study demonstrated that many commercial activated carbon (AC) particles may catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. Because of the widespread usage of AC materials in numerous analytical and environmental applications, it is imperative to understand the reaction mechanism responsible for formation of nitrosamine on the surface of ACs to minimize their occurrence in water treatment systems and during analytical methods employing ACs. The study results show that the AC-catalyzed nitrosamine formation requires both atmospheric oxygen and nitrogen. AC's surface reactive sites react with molecular oxygen to form reactive oxygen species (ROS), which facilitate fixation of molecular nitrogen on the carbon surfaces to generate reactive nitrogen species (RNS) likely nitrous oxide and hydroxylamine that can react with adsorbed amines to form nitrosamines. AC's properties play a crucial role as more nitrosamine formation is associated with carbon surfaces with higher surface area, more surface defects, reduced surface properties, higher O(2) uptake capacity, and higher carbonyl group content. This study is a first of its kind on the nitrosamine formation mechanism involving nitrogen fixation on AC surfaces, and the information will be useful for minimization of nitrosamines in AC-based processes.
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Affiliation(s)
- Lokesh P Padhye
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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60
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Rayson MS, Mackie JC, Kennedy EM, Dlugogorski BZ. Experimental Study of Decomposition of Aqueous Nitrosyl Thiocyanate. Inorg Chem 2011; 50:7440-52. [DOI: 10.1021/ic102445d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Mark S. Rayson
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - John C. Mackie
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Eric M. Kennedy
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Bogdan Z. Dlugogorski
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
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61
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Nawrocki J, Andrzejewski P. Nitrosamines and water. JOURNAL OF HAZARDOUS MATERIALS 2011; 189:1-18. [PMID: 21353742 DOI: 10.1016/j.jhazmat.2011.02.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/17/2011] [Accepted: 02/03/2011] [Indexed: 05/30/2023]
Abstract
This paper provides an overview of all current issues that are connected to the presence of nitrosamines in water technology. N-nitrosodimethylamine (NDMA) is the most frequently detected member of this family. Nitrosamines became the hottest topic in drinking water science when they were identified as disinfection by-products (DBPs) in chloraminated waters. The danger that they pose to consumer health seems to be much higher than that from chlorinated DBPs. This review summarizes our contemporary knowledge of these compounds in water, their occurrence, and precursors of nitrosamines in drinking and wastewaters, in addition to attempts to remove nitrosamines from water. The paper also reviews our knowledge of the mechanisms of nitrosamine formation in water technology. The current, commonly accepted mechanism of NDMA formation during chloramination of drinking waters assumes that dichloramine reacts with dimethylamine, forms unsymmetrical dimethylhydrazine and further oxidizes to NDMA. The question to answer is which precursors are responsible for delivering the DMA moiety for the reaction since the presence of DMA in water cannot explain the quantities of NDMA that are formed. There are also reports that other oxidants that are commonly used in water technology may generate NDMA. However, the mechanisms of such transformations are unknown. Methods for the removal of nitrosamines from water are described briefly. However, the research that has been undertaken on such methods seems to be at an early stage of development. It is predicted that photolytic methods may have the greatest potential for technological application.
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Affiliation(s)
- Jacek Nawrocki
- Laboratory of Water Treatment Technology, Faculty of Chemistry, A Mickiewicz University, Poznań, Poland.
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62
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Plewa MJ, Wagner ED, Mitch WA. Comparative Mammalian cell cytotoxicity of water concentrates from disinfected recreational pools. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:4159-4165. [PMID: 21466188 DOI: 10.1021/es104284h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Disinfection of recreational pools is essential to prevent outbreaks of infectious disease. Despite the health benefits of swimming, recent research demonstrated an association between the application of disinfectants to recreational pools and adverse health outcomes. Pool waters are extreme cases of disinfection that differ in important respects from disinfected drinking waters. Pool waters are continuously exposed to disinfectants over average residence times extending to months. Disinfection byproduct (DBP) precursors in pools include natural humic substances deriving from the tap water source plus inputs from bathers through urine, sweat, hair, skin, and consumer products including sunscreens and cosmetics. This study presents a systematic, chronic in vitro mammalian cell cytotoxicity analysis of different recreational waters with varied environmental conditions that were derived from a common tap water source. Recreational waters were significantly more toxic than their tap water source. Because trihalomethane concentrations are similar between tap waters and pool waters, using trihalomethanes to monitor exposure in epidemiological studies may not be the best metric. Of primary importance for cytotoxicity were illumination conditions. Pools subjected to a combination of ultraviolet light and free chlorine disinfection indoors, or outdoor sunlight exposure exhibited lower cytotoxicity than their indoor counterparts disinfected with free chlorine. Temperature and total organic carbon content, as an indirect measure of DBP precursors, were less important. Previous research on the same samples demonstrated the genotoxicity of an indoor pool disinfected with bromochlorodimethylhydantoin; the cytotoxicity of this sample was confirmed in the present study. While the association of reduced toxicity with illumination indicates that the agents responsible are photolabile, their identity is unclear. As a broad measure of adverse biological responses, cytotoxicity may be a useful metric to gauge the health impacts of alterations in pool operating conditions.
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Affiliation(s)
- Michael J Plewa
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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63
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Pozzi R, Bocchini P, Pinelli F, Galletti GC. Determination of nitrosamines in water by gas chromatography/chemical ionization/selective ion trapping mass spectrometry. J Chromatogr A 2011; 1218:1808-14. [PMID: 21377686 DOI: 10.1016/j.chroma.2011.02.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 11/25/2022]
Abstract
A gas chromatography/mass spectrometry (GC/MS) method for determination of nine N-nitrosamines (NAs) in water is described. Two ionization modes, electron impact (EI) and chemical ionization (CI) with methanol, as well as different ion analysis techniques, i.e. full scan, selected ion storage (SIS) and tandem mass spectrometry (MS/MS) were tested. Chemical ionization followed by SIS resulted the mass spectrometric method of choice, with detection limits in the range of 1-2ng/L. Solid Phase Extraction (SPE) with coconut charcoal cartridges was applied to extract NAs from real samples, according EPA Method 521. Drinking water samples were collected from seven surface- and two groundwater treatment plants. Three surface water treatment plants were sampled before and after addition of O(3)/ClO(2) to observe the effect of disinfection on NAs' formation. N-nitrosodiethylamine (NDEA), n-nitrosodipropylamine (NDPA), n-nitrosomorpholine (NMOR) and n-nitrosodibutylamine (NDBA) were found up to concentrations exceeding three times the risk level of 10ng/L set by the California Department of Public Health. Because dermal adsorption has been recently indicated as a new contamination route of exposure to NAs for people who practice swimming activity, water samples from five swimming pools in the Bologna (Italy) area were collected. N-nitrosopyrrolidine (NPYR) was detected in all samples at concentrations larger than 50ng/L, likely as a disinfection by-product from the amino acid precursor proline, a main constituent of skin collagen.
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Affiliation(s)
- Romina Pozzi
- Department of Chemistry "G. Ciamician", University of Bologna, via F. Selmi 2, I-40126 Bologna, Italy.
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64
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Andra SS, Makris KC. Tobacco-specific nitrosamines in water: an unexplored environmental health risk. ENVIRONMENT INTERNATIONAL 2011; 37:412-417. [PMID: 21176967 DOI: 10.1016/j.envint.2010.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 10/21/2010] [Accepted: 11/05/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Syam S Andra
- Water and Health Laboratory, Cyprus International Institute for Environmental and Public Health in association with the Harvard School of Public Health, Cyprus University of Technology, Limassol, Cyprus
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65
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Liviac D, Creus A, Marcos R. Genotoxic evaluation of the non-halogenated disinfection by-products nitrosodimethylamine and nitrosodiethylamine. JOURNAL OF HAZARDOUS MATERIALS 2011; 185:613-618. [PMID: 20952128 DOI: 10.1016/j.jhazmat.2010.09.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 07/26/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Abstract
Disinfection by-products (DBPs) are chemicals that are produced as a result of chlorine being added to water for disinfection. As well as the halogenated DBPs, N-nitrosamines have recently been identified as DBPs, especially when amines and ammonia ions are present in raw water. In this work, the genotoxicity of two nitrosamines, namely nitrosodimethylamine (NDMA) and nitrosodiethylamine (NDEA), has been studied in cultured human cells. To evaluate their genotoxic potential two assays were used, the comet assay and the micronucleus test. The comet assay measures the induction of single and double-strand breaks, and also reveals the induced oxidative DNA damage by using endoIII and FPG enzymes. Chromosomal damage was evaluated by means of the cytokinesis-blocked micronucleus test. The results of the comet assay show that both compounds are slightly genotoxic but only at high concentrations, NDEA being more effective than NDMA. Enzyme treatments revealed that only NDEA was able to produce increased levels of oxidized bases, mainly in purine sites. The results obtained in the micronucleus assay, which measures the capacity of the tested agents to induce clastogenic and/or aneugenic effects, are negative for both of the nitrosamines evaluated, either using TK6 cells or human peripheral blood lymphocytes. Taking into account the very high concentrations needed to produce DNA damage, our data suggest a low, if existent, genotoxic risk associated with the presence of these compounds in drinking water.
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Affiliation(s)
- D Liviac
- Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Edifici Cn, Universitat Autònoma de Barcelona, 08193 Bellaterra, Cerdanyola del Vallès, Spain
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66
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Richardson SD, Postigo C. Drinking Water Disinfection By-products. THE HANDBOOK OF ENVIRONMENTAL CHEMISTRY 2011. [DOI: 10.1007/698_2011_125] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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67
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Kogevinas M, Villanueva CM, Font-Ribera L, Liviac D, Bustamante M, Espinoza F, Nieuwenhuijsen MJ, Espinosa A, Fernandez P, DeMarini DM, Grimalt JO, Grummt T, Marcos R. Genotoxic effects in swimmers exposed to disinfection by-products in indoor swimming pools. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1531-7. [PMID: 20833606 PMCID: PMC2974689 DOI: 10.1289/ehp.1001959] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 06/21/2010] [Accepted: 08/03/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND Exposure to disinfection by-products (DBPs) in drinking water has been associated with cancer risk. A recent study (Villanueva et al. 2007; Am J Epidemiol 165:148-156) found an increased bladder cancer risk among subjects attending swimming pools relative to those not attending. OBJECTIVES We evaluated adults who swam in chlorinated pools to determine whether exposure to DBPs in pool water is associated with biomarkers of genotoxicity. METHODS We collected blood, urine, and exhaled air samples from 49 nonsmoking adult volunteers before and after they swam for 40 min in an indoor chlorinated pool. We estimated associations between the concentrations of four trihalomethanes (THMs) in exhaled breath and changes in micronuclei (MN) and DNA damage (comet assay) in peripheral blood lymphocytes before and 1 hr after swimming; urine mutagenicity (Ames assay) before and 2 hr after swimming; and MN in exfoliated urothelial cells before and 2 weeks after swimming. We also estimated associations and interactions with polymorphisms in genes related to DNA repair or to DBP metabolism. RESULTS After swimming, the total concentration of the four THMs in exhaled breath was seven times higher than before swimming. The change in the frequency of micronucleated lymphocytes after swimming increased in association with higher exhaled concentrations of the brominated THMs (p = 0.03 for bromodichloromethane, p = 0.05 for chlorodibromomethane, p = 0.01 for bromoform) but not chloroform. Swimming was not associated with DNA damage detectable by the comet assay. Urine mutagenicity increased significantly after swimming, in association with the higher concentration of exhaled bromoform (p = 0.004). We found no significant associations with changes in micronucleated urothelial cells. CONCLUSIONS Our findings support potential genotoxic effects of exposure to DBPs from swimming pools. The positive health effects gained by swimming could be increased by reducing the potential health risks of pool water.
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Affiliation(s)
- Manolis Kogevinas
- Centre for Research in Environmental Epidemiology, Barcelona, Spain.
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Richardson SD, DeMarini DM, Kogevinas M, Fernandez P, Marco E, Lourencetti C, Ballesté C, Heederik D, Meliefste K, McKague AB, Marcos R, Font-Ribera L, Grimalt JO, Villanueva CM. What's in the pool? A comprehensive identification of disinfection by-products and assessment of mutagenicity of chlorinated and brominated swimming pool water. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1523-30. [PMID: 20833605 PMCID: PMC2974688 DOI: 10.1289/ehp.1001965] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 04/22/2010] [Accepted: 06/08/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. OBJECTIVES We performed a comprehensive identification of DBPs and disinfectant species in waters from public swimming pools in Barcelona, Catalonia, Spain, that disinfect with either chlorine or bromine and we determined the mutagenicity of the waters to compare with the analytical results. METHODS We used gas chromatography/mass spectrometry (GC/MS) to measure trihalomethanes in water, GC with electron capture detection for air, low- and high-resolution GC/MS to comprehensively identify DBPs, photometry to measure disinfectant species (free chlorine, monochloroamine, dichloramine, and trichloramine) in the waters, and an ion chromatography method to measure trichloramine in air. We assessed mutagenicity with the Salmonella mutagenicity assay. RESULTS We identified > 100 DBPs, including many nitrogen-containing DBPs that were likely formed from nitrogen-containing precursors from human inputs, such as urine, sweat, and skin cells. Many DBPs were new and have not been reported previously in either swimming pool or drinking waters. Bromoform levels were greater in brominated than in chlorinated pool waters, but we also identified many brominated DBPs in the chlorinated waters. The pool waters were mutagenic at levels similar to that of drinking water (approximately 1,200 revertants/L-equivalents in strain TA100-S9 mix). CONCLUSIONS This study identified many new DBPs not identified previously in swimming pool or drinking water and found that swimming pool waters are as mutagenic as typical drinking waters.
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Affiliation(s)
- Susan D Richardson
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30606, USA.
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69
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Jurado-Sánchez B, Ballesteros E, Gallego M. Screening of N-nitrosamines in tap and swimming pool waters using fast gas chromatography. J Sep Sci 2010; 33:610-6. [PMID: 20127916 DOI: 10.1002/jssc.200900679] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
N-Nitrosamines (NAms) are suspected human carcinogens that have been identified as drinking water and wastewater pollutants. In this work, a sensitive screening/confirmation method was proposed for the determination of the most toxic NAms that can be found in water samples (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine, N-nitrosomorpholine, N-nitrosopiperidine, and N-nitrosopyrrolidine). A sample volume of 250 mL was first preconcentrated in an automatic SPE unit and then the extract was concentrated to a final volume of 10 microL (providing a preconcentration factor of 25,000). Aliquots of the extract were subjected to a rapid screening process (1.6 min) by using a short capillary polar column (1.5 m length) and GC with nitrogen-phosphorous detection. In this way, the high number of samples to be tested routinely in a water laboratory is simplified due to a reduction in the analysis time. Thus, the screening method acts as a filter that indicates whether target analytes are present, above or below the cut-off level (3.8 or 10.4 ng/L), giving no false negatives at concentrations below the guide values for NAms in drinking water established by different countries. Positive samples (tap and swimming pool waters) were then confirmed by GC-MS detection.
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Affiliation(s)
- Beatriz Jurado-Sánchez
- Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, Córdoba, Spain
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70
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Padhye L, Wang P, Karanfil T, Huang CH. Unexpected role of activated carbon in promoting transformation of secondary amines to N-nitrosamines. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:4161-4168. [PMID: 20446739 DOI: 10.1021/es903916t] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Activated carbon (AC) is the most common solid phase extraction material used for analysis of nitrosamines in water. It is also widely used for the removal of organics in water treatment and as a catalyst or catalyst support in some industrial applications. In this study, it was discovered that AC materials can catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. All 11 commercial ACs tested in the study formed nitrosamines from secondary amines. Among the different ACs, the N-nitrosodimethylamine (NDMA) yield at pH 7.5 ranged from 0.001% to 0.01% of initial amount of aqueous dimethylamine (DMA) concentration, but at 0.05-0.29% of the amount of adsorbed DMA by AC. Nitrosamine yield increased with higher pH and for higher molecular weight secondary amines, probably because of increased adsorption of amines. Presence of oxygen was a critical factor in the transformation of secondary amines, since ACs with adsorbed secondary amines dried under air for longer period of time exhibited significantly higher nitrosamine yields. The AC-catalyzed nitrosamine formation was also observed in surface water and wastewater effluent samples. Properties of AC play an important role in the nitrosamine yields. Preliminary evaluation indicated that nitrosamine formation was higher on reduced than oxidized AC surfaces. Overall, the study results show that selecting ACs and reaction conditions are important to minimize analytical errors and undesirable formation associated with nitrosamines in water samples.
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Affiliation(s)
- Lokesh Padhye
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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71
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Kulshrestha P, McKinstry KC, Fernandez BO, Feelisch M, Mitch WA. Application of an optimized total N-nitrosamine (TONO) assay to pools: placing N-nitrosodimethylamine (NDMA) determinations into perspective. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:3369-3375. [PMID: 20355696 DOI: 10.1021/es100361f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Although N-nitrosodimethylamine (NDMA) has been the most prevalent N-nitrosamine detected in disinfected waters, it remains unclear whether NDMA is indeed the most significant N-nitrosamine or just one representative of a larger pool of N-nitrosamines. A widely used assay applied to quantify nitrite, S-nitrosothiols, and N-nitrosamines in biological samples involves their reduction to nitric oxide by acidic tri-iodide, followed by chemiluminescent detection of the evolved nitric oxide in the gas phase. We here describe an adaptation of this method for analyzing total N-nitrosamine (TONO) concentrations in disinfected pools. Optimal sensitivity for N-nitrosamines was obtained using a reduction solution containing 13.5 mL glacial acetic acid and 1 mL of an aqueous 540 g/L iodide and 114 g/L iodine solution held at 80 degrees C. The method detection limit for N-nitrosamines was 110 nM using 100 microL sample injections and NDMA as a standard. N-nitrosamines featuring a range of polarities were converted to nitric oxide with 75-103% efficiency compared to NDMA. Evaluation of potential interfering species indicated that only nitrite and S-nitrosothiols were a concern, but both interferences were effectively eliminated using group-specific sample pretreatments previously employed for biological samples. To evaluate the low TONO concentrations anticipated for pools, 1 L samples were extracted by continuous liquid-liquid extraction with ethyl acetate for 24 h, and concentrated to 1 mL. N-nitrosamine recovery during extraction ranged from 37-75%, and there was a potential for artifactual nitrosation of amines during solvent reflux in the presence of significant nitrite concentrations, but not at the low nitrite concentrations prevalent in most pools. Using the 1000-fold concentration factor and 56% average extraction efficiency, the method detection limit would be 62 pM (5 ng/L as NDMA). The TONO assay was applied to six pools and their common tap water source in conjunction with analysis for specific nitrosamines. Even accounting for the range of N-nitrosamine extraction recoveries, NDMA accounted for an average of only 13% (range 3-46%) of the total nitrosamine pool.
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Affiliation(s)
- Pankaj Kulshrestha
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, New Haven, Connecticut 06520, USA
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72
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LaKind JS, Richardson SD, Blount BC. The good, the bad, and the volatile: can we have both healthy pools and healthy people? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:3205-3210. [PMID: 20222731 DOI: 10.1021/es903241k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Swimming is a healthful activity that comes with increased risk of exposure to pathogenic microorganisms and disinfection agents/byproducts.
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Affiliation(s)
- Judy S LaKind
- LaKind Associates, LLC, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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73
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Liviac D, Wagner ED, Mitch WA, Altonji MJ, Plewa MJ. Genotoxicity of water concentrates from recreational pools after various disinfection methods. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:3527-3532. [PMID: 20380372 DOI: 10.1021/es903593w] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Swimming and hot tub bathing are popular exercises and diversions. Disinfection of recreational pools is essential to prevent outbreaks of infectious disease. Recent research demonstrated an association between the application of disinfectants to recreational pools and adverse health outcomes. These pool waters represent extreme cases of disinfection that differ from disinfecting drinking waters. Pool waters are continuously exposed to disinfectants over average residence times extending to months. Disinfection byproduct (DBP) precursors include natural humic substances plus inputs from bathers through urine, sweat, hair, skin, and consumer products including cosmetics and sunscreens. This study presents a systematic mammalian cell genotoxicity analysis to evaluate different recreational waters derived from a common tap water source. The data demonstrated that all disinfected recreational pool water samples induced more genomic DNA damage than the source tap water. The type of disinfectant and illumination conditions altered the genotoxicity of the water. Accordingly, care should be taken in the disinfectant employed to treat recreational pool waters. The genotoxicity data suggest that brominating agents should be avoided. Combining chlorine with UV may be beneficial as compared to chlorination alone. During the recycling of pool water the organic carbon could be removed prior to disinfection. Behavior modification by swimmers may be critical in reducing the genotoxicity of pool water. Actions such as showering before entering the water and informing patrons about the potential harm from urinating in a pool could reduce the precursors of toxic DBPs.
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Affiliation(s)
- Danae Liviac
- Grup de Mutagenesi, Departament de Genetica i de Microbiologia, Edifici Cn, Universitat Autonoma de Barcelona, Bellaterra, Cerdanyola del Valles, Spain
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74
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Kemper JM, Walse SS, Mitch WA. Quaternary amines as nitrosamine precursors: a role for consumer products? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1224-31. [PMID: 20085252 DOI: 10.1021/es902840h] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nitrosamine formation has been associated with wastewater-impacted waters, but specific precursors within wastewater effluents have not been identified. Experiments indicated that nitrosamines form in low yields from quaternary amines, and that the nitrosamines form from the quaternary amines themselves, not just lower order amine impurities. Polymeric and benzylated quaternary amines were more potent precursors than monomeric quaternary alkylamines. Pretreatment of quaternary amines with ozone or free chlorine, which deactivate lower order amine impurities, did not significantly reduce nitrosamine formation. The nitrosamine formation pathway is unclear but experiments indicated that transformation of quaternary amines to lower order amine precursors via Hofmann elimination was not involved. Experiments suggest that the pathway may involve quaternary amine degradation by amidogen or chloramino radicals formed from chloramines. Quaternary amines are significant constituents of consumer products, including shampoos, detergents, and fabric softeners. Although quaternary amines may be removed by sedimentation during wastewater treatment, their importance should be evaluated on a case-by-case basis. The high loadings from consumer products may enable the portion not removed to serve as precursors.
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Affiliation(s)
- Jerome M Kemper
- Department of Chemical Engineering, Yale University, New Haven, Connecticut 06520, USA
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75
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Schäfer AI, Mitch W, Walewijk S, Munoz A, Teuten E, Reinhard M. Chapter 7 Micropollutants in Water Recycling: A Case Study of N-Nitrosodimethylamine (NDMA) Exposure from Water versus Food. SUSTAINABLE WATER FOR THE FUTURE: WATER RECYCLING VERSUS DESALINATION 2010. [DOI: 10.1016/s1871-2711(09)00207-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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76
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Walse SS, Plewa MJ, Mitch WA. Exploring Amino Acid Side Chain Decomposition Using Enzymatic Digestion and HPLC-MS: Combined Lysine Transformations in Chlorinated Waters. Anal Chem 2009; 81:7650-9. [DOI: 10.1021/ac901064u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Spencer S. Walse
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520-8286, and Department of Crop Sciences, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801
| | - Michael J. Plewa
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520-8286, and Department of Crop Sciences, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801
| | - William A. Mitch
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520-8286, and Department of Crop Sciences, College of Agricultural, Consumer, and Environmental Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801
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77
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Affiliation(s)
- Susan D. Richardson
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30605
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78
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Kemper JM, Westerhoff P, Dotson A, Mitch WA. Nitrosamine, dimethylnitramine, and chloropicrin formation during strong base anion-exchange treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:466-472. [PMID: 19238981 DOI: 10.1021/es802460n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Strong base anion-exchange resins represent an important option for water utilities and homeowners to address growing concerns with nitrate, arsenate, and perchlorate contamination of source waters. Most commercially available anion-exchange resins employ quaternary amine functional groups. Previous research has provided contradictory evidence regarding whether these resins serve as sources of nitrosamines, considered as highly carcinogenic nitrogenous disinfection byproducts (N-DBPs), even without disinfectants. For three common varieties of commercial anion-exchange resins, we evaluated the importance of releases of nitrosamines, and two other N-DBPs (dimethylnitramine and chloropicrin), when the resins were subjected to typical column flow conditions with and without free chlorine or chloramine application upstream or downstream of the columns. In the absence of disinfectants, fresh trimethylamine- and tributylamine-based type 1 and dimethylethanolamine-based type 2 anion-exchange resins usually released 2-10 ng/L nitrosamines, likely due to shedding of manufacturing impurities, with excursions of up to 20 ng/L following regeneration. However, the lack of significant nitrosamine release in a full-scale anion-exchange treatment system after multiple regeneration cycles indicates that releases may eventually subside. Resins also shed organic precursors that might contribute to nitrosamine formation within distribution systems when chloramines are applied downstream. With free chlorine or chloramine application upstream, nitrosamine concentrations were more significant, at 20-100 ng/L for the type 1 resins and approximately 400 ng/L for the type 2 resin. However, chloropicrin formation was lowest for the type 2 resin. Dimethylnitramine formation was significant with free chlorine application upstream but negligible with chloramines. Although no N-DBPs were detected in cation-exchange-based consumer point-of-use devices exposed to chlorinated or chloraminated waters, our results indicate that inclusion of anion-exchange resins in these devices, as in laboratory deionized water systems, would likely be problematic.
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Affiliation(s)
- Jerome M Kemper
- Department of Chemical Engineering, Yale University, Mason Laboratory 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
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79
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Chao MR, Chang YZ, Wong RH, Hu CW. Time course evaluation of N-nitrosodialkylamines-induced DNA alkylation and oxidation in liver of mosquito fish. Mutat Res 2009; 660:33-39. [PMID: 19007796 DOI: 10.1016/j.mrfmmm.2008.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 05/27/2023]
Abstract
Here we simultaneously measured N7-alkylguanines and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in liver of small fish, respectively, to assess the time course of the formation and removal of alkylation and oxidative damage to DNA caused by N-nitrosodialkylamines. Mosquito fish (Gambusia affinis) were killed at various times during (4 days) and post-exposure (16 days) to N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) alone or their combination with concentrations of 10 and 50mg/l. The modified guanine adducts were sensitively and selectively quantitated by isotope-dilution LC-MS/MS methods. During exposure, N7-methylguanine (N7-MeG) and N7-ethylguanine (N7-EtG) in liver DNA increased with the duration and dose of N-nitrosodialkylamine exposure, while 8-oxodG was dose-dependently induced within 1 day. It was found that NDMA formed substantially more N7-alkylated guanines and 8-oxodG than NDEA on the basis of adducts formed per micromolar concentration, suggesting that NDMA can be more easily bioactivated than NDEA to form reactive alkylating agents with the concomitant formation of oxygen radicals. After cessation of exposure, N7-alkylguanines remained elevated for 1 day and then gradually decreased over time but still higher than the background levels, even at day 16 (half-lives of 7-8 days). However, 8-oxodG was excised quickly from liver DNA and returned to the background level within 4 days post-exposure (half-lives less than 2 days). Taken together, this study firstly demonstrated that in addition to alkylation, N-nitrosodialkylamines can concurrently cause oxidative damage to DNA in vivo.
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Affiliation(s)
- Mu-Rong Chao
- Department of Occupational Safety and Health, Chung Shan Medical University, Taichung 402, Taiwan
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80
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Drobnic F. Impacto sobre la salud de los compuestos utilizados en el tratamiento del agua en las piscinas. Estado de la cuestión. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s1886-6581(09)70107-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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81
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Richardson SD. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues. Anal Chem 2008; 80:4373-402. [DOI: 10.1021/ac800660d] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susan D. Richardson
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30605
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