Tracking changes in the optical properties and molecular composition of dissolved organic matter during drinking water production

WATER RESEARCH

卷:85

Article

Lavonen, E. E.¹  Kothawala, D. N.^1,2  Tranvik, L. J.²  Gonsior, M.^3,4  Schmitt-Kopplin, P.^5,6  Kohler, S. J.¹ 

[1] Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, S-75007 Uppsala, Sweden

[2] Uppsala Univ, Dept Ecol & Genet Limnol, S-75236 Uppsala, Sweden

[3] Linkoping Univ, Unit Environm Change, Dept Themat Studies, S-58183 Linkoping, Sweden

[4] Univ Maryland, Ctr Environm Sci, Chesapeake Biol Lab, Solomons, MD 20688 USA

[5] Helmholtz Zentrum Munchen, German Res Ctr Environm Hlth, Analyt BioGeoChem, D-85764 Neuherberg, Germany

[6] Tech Univ Munich, Analyt Food Chem, D-85354 Freising Weihenstephan, Germany

关键词: Dissolved organic matter;    Drinking water;    Absorbance;    Fluorescence;    FT-ICR-MS;   

DOI  :  10.1016/j.watres.2015.08.024

来源: Elsevier

【 摘 要 】

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. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

【 授权许可】

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