The two faces of DOC

Chris M. Wood, H. A. Al-Reasi, D. Scott Smith

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

Dissolved organic carbon (DOC), through its ability to complex metals and thereby reduce their bioavailability, plays a major role in ameliorating metal toxicity in natural waters. Indeed DOC is a key variable in the Biotic Ligand Model (BLM) for predicting metal toxicity on a site-specific basis. However, recent evidence indicates that all DOCs are not alike, but rather heterogeneous in their ability to protect organisms against metal toxicity, at least in fresh water. The degree of protection appears to correlate with optical properties, such that dark, aromatic-rich compounds of allochthonous origin, with greater humic acid content, are more effective in this regard, particularly against Cu, Ag, and Pb toxicity. The specific absorption coefficient of the DOC in the 300-350nm range (SAC 300-350) has proven to be a simple and effective index of this protective ability. PARAFAC, a multivariate statistical technique for analysis of excitation-emission fluorescence spectroscopy data, also holds promise for quantifying the humic-like and fulvic-like fluorophores, which tend to be positively and negatively correlated with protective ability, respectively. However, what has been largely missing in the toxicological realm is any appreciation that DOC may also affect the physiology of target organisms, such that part of the protection may occur by a mechanism other than metal complexation. Recently published evidence demonstrates that DOC has effects on Na + transport, diffusive permeability, and electrical properties of the gills in fish and crustaceans in a manner which will promote Na + homeostasis. These actions could thereby protect against metal toxicity by physiological mechanisms. Future research should investigate potential direct interactions of DOC molecules with the branchial epithelium. Incorporation of optical properties of DOC could be used to improve the predictive capabilities of the BLM.

Original languageEnglish
Pages (from-to)3-8
Number of pages6
JournalAquatic Toxicology
Volume105
Issue number3-4 SUPPL.
DOIs
Publication statusPublished - Oct 2011

Fingerprint

dissolved organic carbon
Carbon
metals
Metals
toxicity
metal
optical properties
optical property
ligand
fluorescence emission spectroscopy
Ligands
Humic Substances
electrical properties
fluorescence spectroscopy
electrical property
fluorescent dyes
Fluorescence Spectrometry
Coordination Complexes
organisms
absorption coefficient

Keywords

  • Aromaticity
  • Dissolved organic carbon
  • Gill physiology
  • Metal toxicity
  • Natural organic matter
  • PARAFAC

ASJC Scopus subject areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis

Cite this

The two faces of DOC. / Wood, Chris M.; Al-Reasi, H. A.; Smith, D. Scott.

In: Aquatic Toxicology, Vol. 105, No. 3-4 SUPPL., 10.2011, p. 3-8.

Research output: Contribution to journalArticle

Wood, CM, Al-Reasi, HA & Smith, DS 2011, 'The two faces of DOC', Aquatic Toxicology, vol. 105, no. 3-4 SUPPL., pp. 3-8. https://doi.org/10.1016/j.aquatox.2011.03.007
Wood, Chris M. ; Al-Reasi, H. A. ; Smith, D. Scott. / The two faces of DOC. In: Aquatic Toxicology. 2011 ; Vol. 105, No. 3-4 SUPPL. pp. 3-8.
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