Freshwater DOM quantity and quality from a two-component model of UV absorbance

WATER RESEARCH

卷:46

Article

Carter, Heather T.^1,3  Tipping, Edward¹  Koprivnjak, Jean-Francois²  Cookson, Brenda³  Hamilton-Taylor, John³ 

[1] Lancaster Environm Ctr, Ctr Ecol & Hydrol, Lancaster LA1 4AP, England

[2] Trent Univ, Environm & Resource Studies Program, Water Qual Ctr, Peterborough, ON K9J 7B8, Canada

[3] Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ, England

关键词: Dissolved organic carbon;    Dissolved organic matter;    Model;    UV absorbance;   

DOI  :  10.1016/j.watres.2012.05.021

来源: Elsevier

【 摘 要 】

We present a model that considers UV-absorbing dissolved organic matter (DOM) to consist of two components (A and B), each with a distinct and constant spectrum. Component A absorbs UV light strongly, and is therefore presumed to possess aromatic chromophores and hydrophobic character, whereas B absorbs weakly and can be assumed hydrophilic. We parameterised the model with dissolved organic carbon concentrations [DOC] and corresponding UV spectra for c. 1700 filtered surface water samples from North America and the United Kingdom, by optimising extinction coefficients for A and B, together with a small constant concentration of non-absorbing DOM (0.80 mg DOC L-1). Good unbiased predictions of [DOC] from absorbance data at 270 and 350 nm were obtained (r(2) = 0.98), the sum of squared residuals in [DOC] being reduced by 66% compared to a regression model fitted to absorbance at 270 nm alone. The parameterised model can use measured optical absorbance values at any pair of suitable wavelengths to calculate both [DOC] and the relative amounts of A and B in a water sample, i.e. measures of quantity and quality. Blind prediction of [DOC] was satisfactory for 9 of 11 independent data sets (181 of 213 individual samples). (C) 2012 Elsevier Ltd. All rights reserved.

【 授权许可】

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