Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Prediction of Dissolved Organic Carbon Concentrations in Inland Waters Using Optical Proxies of Aromaticity

Murphy, Kathleen R. LU orcid (2025) In Environmental Science and Technology 59(31). p.16430-16442
Abstract

The chemical structures of dissolved organic compounds in natural waters, including the degree of aromaticity, affect their physical, chemical, and biological properties and ultimately the fate of carbon in aquatic systems and during water treatment. Herein, a new fluorescence-based aromaticity index named ARIX is shown to link the composition of aquatic dissolved organic matter to its aromaticity across diverse aquatic systems in both bulk DOM and extracts. ARIX predicts SUVA, a widely used proxy of aromaticity, more accurately than the prevailing optical indices. It also predicts the percentage of polycyclic aromatic and polyphenolic molecular formulas determined by FT-ICR MS and the ratio of “humic substances” to “building blocks”... (More)

The chemical structures of dissolved organic compounds in natural waters, including the degree of aromaticity, affect their physical, chemical, and biological properties and ultimately the fate of carbon in aquatic systems and during water treatment. Herein, a new fluorescence-based aromaticity index named ARIX is shown to link the composition of aquatic dissolved organic matter to its aromaticity across diverse aquatic systems in both bulk DOM and extracts. ARIX predicts SUVA, a widely used proxy of aromaticity, more accurately than the prevailing optical indices. It also predicts the percentage of polycyclic aromatic and polyphenolic molecular formulas determined by FT-ICR MS and the ratio of “humic substances” to “building blocks” fractions determined by LC-OCD, indicating that it is additionally a proxy of DOM molecular weight. In waterbodies exhibiting decoupling between DOC and absorbance linked to biogeochemical processing, DOC concentrations are more accurately predicted by using a multilinear model to account for interactions between light absorption and aromaticity. The results deliver new insights into widely discussed trends in DOM optical properties and the molecular structures underlying optical measurements in the aquatic milieu. They further represent an important step toward improved real-time monitoring of DOC concentration, reactivity, and fate.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ARINT, ARIX, CDOM, DOC, monitoring, spectral slope
in
Environmental Science and Technology
volume
59
issue
31
pages
13 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:40737533
  • scopus:105013331441
ISSN
0013-936X
DOI
10.1021/acs.est.5c05408
language
English
LU publication?
yes
id
5241e005-fa8e-432c-a6a4-b111e682bb81
date added to LUP
2025-11-05 15:26:29
date last changed
2025-12-17 19:34:39
@article{5241e005-fa8e-432c-a6a4-b111e682bb81,
  abstract     = {{<p>The chemical structures of dissolved organic compounds in natural waters, including the degree of aromaticity, affect their physical, chemical, and biological properties and ultimately the fate of carbon in aquatic systems and during water treatment. Herein, a new fluorescence-based aromaticity index named ARIX is shown to link the composition of aquatic dissolved organic matter to its aromaticity across diverse aquatic systems in both bulk DOM and extracts. ARIX predicts SUVA, a widely used proxy of aromaticity, more accurately than the prevailing optical indices. It also predicts the percentage of polycyclic aromatic and polyphenolic molecular formulas determined by FT-ICR MS and the ratio of “humic substances” to “building blocks” fractions determined by LC-OCD, indicating that it is additionally a proxy of DOM molecular weight. In waterbodies exhibiting decoupling between DOC and absorbance linked to biogeochemical processing, DOC concentrations are more accurately predicted by using a multilinear model to account for interactions between light absorption and aromaticity. The results deliver new insights into widely discussed trends in DOM optical properties and the molecular structures underlying optical measurements in the aquatic milieu. They further represent an important step toward improved real-time monitoring of DOC concentration, reactivity, and fate.</p>}},
  author       = {{Murphy, Kathleen R.}},
  issn         = {{0013-936X}},
  keywords     = {{ARINT; ARIX; CDOM; DOC; monitoring; spectral slope}},
  language     = {{eng}},
  number       = {{31}},
  pages        = {{16430--16442}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Environmental Science and Technology}},
  title        = {{Prediction of Dissolved Organic Carbon Concentrations in Inland Waters Using Optical Proxies of Aromaticity}},
  url          = {{http://dx.doi.org/10.1021/acs.est.5c05408}},
  doi          = {{10.1021/acs.est.5c05408}},
  volume       = {{59}},
  year         = {{2025}},
}