| 1. |
- Andersson, Anna, et al.
(författare)
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Molecular changes among non-volatile disinfection by-products between drinking water treatment and consumer taps
- 2021
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Ingår i: Environmental Science. - : Royal Society of Chemistry. - 2053-1400 .- 2053-1419. ; 7:12, s. 2335-2345
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Tidskriftsartikel (refereegranskat)abstract
- The formation of disinfection by-products (DBPs) during drinking water treatment has been associated with various health concerns but the total DBP exposure is still unknown. In this study, molecular level non-target analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to study non-volatile DBPs, and how their composition changes during water distribution in four drinking water treatment plants (DWTPs) in Sweden using different types of raw water and disinfection processes. The largest portion of tap water DBP compositions were detected also at the DWTPs, highlighting that these DBP formulae were rather stable and contribute to human DBP exposure. Yet the number of detected DBPs decreased 14-48% between drinking water treatment and consumer taps in the three plants in which no mixing of water from other DWTPs in the distribution system occurred showing active DBP processing in the water distribution network. While considerable amounts of bromine-containing DBPs were detected upon chemical disinfection in some DWTPs, few of them were detected in the tap water samples, likely due to debromination by hydrolytic reactions. The overall fewer non-volatile DBPs detected in tap waters, along with changed distribution among chlorine and bromine DBPs, demonstrate that DBP mixtures are highly dynamic and that DBP measurements at DWTPs do not adequately reflect exposure at the point-of-use. Clearly, more knowledge about changes of DBP mixtures through the distribution system is needed to improve DBP exposure assessments.
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| 2. |
- Andersson, Anna, et al.
(författare)
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Selective removal of natural organic matter during drinking water production changes the composition of disinfection by-products
- 2020
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Ingår i: Environmental Science. - : ROYAL SOC CHEMISTRY. - 2053-1400 .- 2053-1419. ; 6:3, s. 779-794
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Tidskriftsartikel (refereegranskat)abstract
- Disinfection by-products (DBPs) are potentially toxic compounds formed upon chemical disinfection of drinking water. Controlling the levels and characteristics of dissolved organic matter (DOM) as precursor material for DBPs is a major target to reduce DBP formation. A pilot-scale treatment including suspended ion exchange (SIX (R)), a ceramic microfilter (CeraMac (R)) with in-line coagulation and optional pre-ozonation followed by granular activated carbon (GAC) filtration was compared with a conventional full-scale treatment based on DOM removal and DBP formation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), rapid fractionation, liquid chromatography organic carbon detection (LC-OCD), adsorbable organic halogens (AOX) and trihalomethane (THM) analysis. The new treatment combination showed different selectivity for DOM removal, compared to the conventional, leading to changes in composition of the DBPs formed. SIX (R) and GAC had the largest impacts on reducing AOX and THM formation potentials but the high adsorptive capacity of GAC affected the diversity of detected DBPs most. Chlorination and chloramination of pilot treated water with doses normally used in Sweden produced low levels of AOX compared to the full-scale treatment, but FT-ICR MS revealed an abundance of brominated DBP species in contrast with the conventional treatment, which were dominated by chlorinated DBPs. This finding was largely linked to the high DOM removal by the pilot treatment, causing an increased Br-/C ratio and a higher formation of HOBr. Potential increases in Br-DBPs are important to consider in minimizing health risks associated with DBPs, because of the supposed higher toxicity of Br-DBPs compared to Cl-DBPs.
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| 3. |
- Andersson, Anna, et al.
(författare)
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Waterworks-specific composition of drinking water disinfection by-products
- 2019
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Ingår i: Environmental Science. - Cambridge : Royal Society of Chemistry. - 2053-1400 .- 2053-1419. ; :5, s. 861-872
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Tidskriftsartikel (refereegranskat)abstract
- Reactions between chemical disinfectants and natural organic matter (NOM) upon drinking water treatment result in formation of potentially harmful disinfection by-products (DBPs). The diversity of DBPs formed is high and a large portion remains unknown. Previous studies have shown that non-volatile DBPs are important, as much of the total toxicity from DBPs has been related to this fraction. To further understand the composition and variation of DBPs associated with this fraction, non-target analysis with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to detect DBPs at four Swedish waterworks using different types of raw water and treatments. Samples were collected five times covering a full year. A common group of DBPs formed at all four waterworks was detected, suggesting a similar pool of DBP precursors in all raw waters that might be related to phenolic moieties. However, the largest proportion (64–92%) of the assigned chlorinated and brominated molecular formulae were unique, i.e. were solely found in one of the four waterworks. In contrast, the compositional variations of NOM in the raw waters and samples collected prior to chemical disinfection were rather limited.This indicated that waterworks-specific DBPs presumably originated from matrix effects at the point of disinfection, primarily explained by differences in bromide levels, disinfectants (chlorine versus chloramine) and different relative abundances of isomers among the NOM compositions studied. The large variation of observed DBPs in the toxicologically relevant non-volatile fraction indicates that non-targeted monitoring strategies might be valuable to ensure relevant DBP monitoring in the future.
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| 4. |
- Gonsior, Michael, et al.
(författare)
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Changes in Dissolved Organic Matter during the Treatment Processes of a Drinking Water Plant in Sweden and Formation of Previously Unknown Disinfection Byproducts
- 2014
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Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 48:21, s. 12714-12722
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Tidskriftsartikel (refereegranskat)abstract
- The changes in dissolved organic matter (DOM) throughout the treatment processes in a drinking water treatment plant in Sweden and the formation of disinfection byproducts (DBPs) were evaluated by using ultra-high-resolution mass spectrometry (resolution of similar to 500000 at m/z 400) and nuclear magnetic resonance (NMR). Mass spectrometric results revealed that flocculation induced substantial changes in the DOM and caused quantitative removal of DOM constituents that usually are associated with DBP formation While half of the chromophoric DOM (CDOM) was removed by flocculation, similar to 4-5 mg L-1 total organic carbon remained in the finished water. A conservative approach revealed the formation of similar to 800 mass spectrometry ions with unambiguous molecular formula assignments that contained at least one halogen atom. These molecules likely represented new DBPs, which could not be prevented by the flocculation process. The most abundant m/z peaks, associated with formed DBPs, could be assigned to C5HO3Cl3, C5HO3Cl2Br, C5HO3ClBr2 using isotope simulation patterns. Other halogen-containing formulas suggested the presence of halogenated polyphenolic and aromatic acid-type structures, which was supported by possible structures that matched the lower molecular mass range (maximum of 10 carbon atoms) of these DBPs. H-1 NMR before and after disinfection revealed an similar to 2% change in the overall H-1 NMR signals supporting a significant change in the DOM caused by disinfection. This study underlines the fact that a large and increasing number of people are exposed to a very diverse pool of organohalogens through water by both drinking and uptake through the skin upon contact. Nontarget analytical approaches are indispensable for revealing the magnitude of this exposure and to test alternative ways to reduce it.
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| 5. |
- Gonsior, Michael, et al.
(författare)
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Chemodiversity of dissolved organic matter in the Amazon Basin
- 2016
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Ingår i: Biogeosciences. - : COPERNICUS GESELLSCHAFT MBH. - 1726-4170 .- 1726-4189. ; 13:14, s. 4279-4290
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Tidskriftsartikel (refereegranskat)abstract
- Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajos River areas to characterize the molecular DOM composition and distribution. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur-and nitrogen-containing molecules in this white water river system. Waters from the Tapajos main stem did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary, even after mixing with the main stem of the Amazon River. Beside ubiquitous DOM at average H / C and O / C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.
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| 6. |
- Gonsior, Michael, et al.
(författare)
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Molecular characterization of effluent organic matter identified by ultrahigh resolution mass spectrometry
- 2011
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Ingår i: WATER RESEARCH. - : Elsevier Science B.V., Amsterdam.. - 0043-1354. ; 45:9, s. 2943-2953
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Tidskriftsartikel (refereegranskat)abstract
- Effluent dissolved organic matter (EfOM) collected from the secondary-treated wastewater of the Orange County Sanitation District (OCSD) located in Fountain Valley, California, USA was compared to natural organic matter collected from the Suwannee River (SRNOM), Florida using ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Furthermore, the two different treatment processes at OCSD, activated sludge and trickling filter, were separately investigated. The blend of these two effluents was further evaluated after it had passed through the microfiltration process of the Advanced Water Purification Facility (AWPF) at Orange County Water District (OCWD). EfOM contained 872 different m/z peaks that were unambiguously assigned to exact molecular formulae containing a single sulfur atom and carbon, hydrogen and oxygen atoms (CHOS formulae). In contrast, the SRNOM sample only contained 152 CHOS formulae. The trend in CHO molecular compositions was opposite with 2500 CHO formulae assigned for SRNOM but only about 1000 for EfOM. The CHOS-derived mass peaks with highest abundances in EfOM could be attributed to surfactants such as linear alkyl benzene sulfonates (LAS), their co-products dialkyl tetralin sulfonates (DATS) and their biodegraded metabolites such as sulfophenyl carboxylic acids (SPC). The differences between the treatments were found minor with greater differences between sampling dates than treatment methods used. (C) 2011 Elsevier Ltd. All rights reserved.
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| 7. |
- Gonsior, Michael, et al.
(författare)
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Photochemical Production of Polyols arising from Significant Photo-transformation of Dissolved Organic Matter in the Oligotrophic Surface Ocean
- 2014
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Ingår i: Marine Chemistry. - : Elsevier. - 0304-4203 .- 1872-7581. ; 163, s. 10-18
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Tidskriftsartikel (refereegranskat)abstract
- Ultrahigh resolution mass spectrometry of marine dissolved organic matter (DOM) has suggested the presence of many common molecular compositions throughout the open ocean. The majority of these supposedly ubiquitous molecules was concluded to represent the refractory marine DOM pool. This study demonstrates that 24 h of exposure of Atlantic and Pacific surface DOM to simulated sunlight causes phototransformation of about half of these supposedly refractory molecular compositions. It is suggested that these transformations are related to indirect photobleaching possibly involving reactive oxygen species (e.g. hydroxyl radicals), because very little change in the fluorescent component of the DOM (FDOM) was observed during the photo-degradation experiments. A significant decline in average mass with distinct decrease of average O/C ratios and concomitant increase of H/C ratios was observed. NMR spectra revealed a decrease in aromatic and olefinic unsaturation and the formation of a limited and near identical suite of oxygenated aliphatic compounds in both Atlantic and Pacific surface DOM. Their NMR characteristics indicated a mixture of about 10 polyols that are plausible products of convergent pathways of photochemical carbohydrate decomposition and oxidation of functionalized, branched aliphatic compounds. These prominent photochemical signature molecules amounted to -2% of total proton NMR integral and are expected to be quickly consumed by various microorganisms in the open ocean. These results may suggest a fast photo-induced large-scale cycling of DOM within the surface ocean dynamic equilibrium of photo- and bio-transformations. (C) 2014 Elsevier B.V. All rights reserved.
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| 8. |
- Lavonen, Elin, et al.
(författare)
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Selective Chlorination of Natural Organic Matter: Identification of Previously Unknown Disinfection Byproducts
- 2013
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Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 47:5, s. 2264-2271
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Tidskriftsartikel (refereegranskat)abstract
- Natural organic matter (NOM) serve as precursors for disinfection byproducts (DBPs) in drinking water production making NOM removal essential in predisinfection treatment processes. We identified molecular formulas of chlorinated DBPs after chlorination and chloramination in four Swedish surface water treatment plants (WTPs) using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chlorine-containing formulas were detected before and after disinfection and were therefore classified to identify DBPs. In total, 499 DBPs were detected, of which 230 have not been reported earlier. The byproducts had, as a group, significantly lower ratio of hydrogen to carbon (H/C) and significantly higher average carbon oxidation state (Cos), double bond equivalents per carbon (DBE/C) and ratio of oxygen to carbon (O/C) compared to Cl-containing components present before disinfection and CHO formulas in samples taken both before and after disinfection. Electrophilic substitution, the proposed most significant reaction pathway for chlorination of NOM, results in carbon oxidation and decreased H/C while O/C and DBE/C is left unchanged. Because the identified DBPs had significantly higher DBE/C and O/C than the CHO formulas we concluded that chlorination of NOM during disinfection is selective toward components with relatively high double bond equivalency and number of oxygen atoms per carbon. Furthermore, choice of disinfectant, dose, and predisinfection treatment at the different WTPs resulted in distinct patterns in the occurrence of DBP formulas.
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| 9. |
- Lavonen, Elin, et al.
(författare)
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Tracking changes in the optical properties and molecular composition of dissolved organic matter during drinking water production
- 2015
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 85, s. 286-294
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Tidskriftsartikel (refereegranskat)abstract
- Absorbance, 3D fluorescence and ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) were used to explain patterns in the removal of chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) at the molecular level during drinking water production at four large drinking water treatment plants in Sweden. When dissolved organic carbon (DOC) removal was low, shifts in the dissolved organic matter (DOM) composition could not be detected with commonly used DOG-normalized parameters (e.g. specific UV254 absorbance SUVA), but was clearly observed by using differential absorbance and fluorescence or ESI-FT-ICR-MS. In addition, we took a novel approach by identifying how optical parameters were correlated to the elemental composition of DOM by using rank correlation to connect optical properties to chemical formulas assigned to mass peaks from FT-ICR-MS analyses. Coagulation treatment selectively removed FDOM at longer emission wavelengths (450-600 nm), which significantly correlated with chemical formulas containing oxidized carbon (average carbon oxidation state >= 0), low hydrogen to carbon ratios (H/C: average +/- SD = 0.83 +/- 0.13), and abundant oxygen-containing functional groups (O/C = 0.62 +/- 0.10). Slow sand filtration was less efficient in removing DOM, yet selectively targeted FDOM at shorter emission wavelengths (between 300 and 450 nm), which commonly represents algal rather than terrestrial sources. This shorter wavelength FDOM correlated with chemical formulas containing reduced carbon (average carbon oxidation state <= 0), with relatively few carbon-carbon double bonds (H/C = 1.32 +/- 0.16) and less oxygen per carbon (O/C = 0.43 +/- 0.10) than those removed during coagulation. By coupling optical approaches with FT-ICR-MS to characterize DOM, we were for the first time able to confirm the molecular composition of absorbing and fluorescing DOM selectively targeted during drinking water treatment.
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| 10. |
- Li, Siyu, et al.
(författare)
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Comprehensive assessment of dissolved organic matter processing in the Amazon River and its major tributaries revealed by positive and negative electrospray mass spectrometry and NMR spectroscopy
- 2023
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Ingår i: Science of the Total Environment. - : ELSEVIER. - 0048-9697 .- 1879-1026. ; 857
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Tidskriftsartikel (refereegranskat)abstract
- Rivers are natural biogeochemical systems shaping the fates of dissolved organic matter (DOM) from leaving soils to reaching the oceans. This study focuses on Amazon basin DOM processing employing negative and positive electro-spray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI[+/-] FT-ICR MS) and nuclear mag-netic resonance spectroscopy (NMR) to reveal effects of major processes on the compositional space and structural characteristics of black, white and clear water systems. These include non-conservative mixing at the confluences of (1) Solimoes and the Negro River, (2) the Amazon River and the Madeira River, and (3) in-stream processing of Amazon River DOM between the Madeira River and the Tapajos River. The Negro River (black water) supplies more highly oxygenated and high molecular weight compounds, whereas the Solimoes and Madeira Rivers (white water) contribute more CHNO and CHOS molecules to the Amazon River main stem. Aliphatic CHO and abundant CHNO compounds prevail in Tapajos River DOM (clear water), likely originating from primary production. Sorption onto particles and heterotrophic microbial degradation are probably the principal mechanisms for the observed changes in DOM composition in the Amazon River and its tributaries.
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