Jump to main content
Jump to site search

Issue 9, 2014
Previous Article Next Article

Contaminant-mediated photobleaching of wetland chromophoric dissolved organic matter

Author affiliations

Abstract

Photolytic transformation of organic contaminants in wetlands can be mediated by chromophoric dissolved organic matter (CDOM), which in turn can lose its reactivity from photobleaching. We collected water from a small agricultural wetland (Ohio), Kawai Nui Marsh (Hawaii), the Everglades (Florida), and Okefenokee Swamp (Georgia) to assess the effect of photobleaching on the photofate of two herbicides, acetochlor and isoproturon. Analyte-spiked water samples were irradiated using a solar simulator and monitored for changes in CDOM light absorbance and dissolved oxygen. Photobleaching did not significantly impact the indirect photolysis rates of either herbicide over 24 hours of irradiation. Surprisingly, the opposite effect was observed with isoproturon, which accelerated DOM photobleaching. This phenomenon was more pronounced in higher-CDOM waters, and we believe that the redox pathway between triplet-state CDOM and isoproturon may be responsible for our observations. By contrast, acetochlor indirect photolysis was dependent on reaction with the hydroxyl radical and did not accelerate photobleaching of wetland water as much as isoproturon. Finally, herbicide indirect photolysis rate constants did not correlate strongly to any one chemical or optical property of the sampled waters.

Graphical abstract: Contaminant-mediated photobleaching of wetland chromophoric dissolved organic matter

Back to tab navigation

Publication details

The article was received on 03 Mar 2014, accepted on 17 Apr 2014 and first published on 17 Apr 2014


Article type: Paper
DOI: 10.1039/C4EM00138A
Author version
available:
Download author version (PDF)
Citation: Environ. Sci.: Processes Impacts, 2014,16, 2098-2107
  •   Request permissions

    Contaminant-mediated photobleaching of wetland chromophoric dissolved organic matter

    M. C. Langlois, L. K. Weavers and Y. Chin, Environ. Sci.: Processes Impacts, 2014, 16, 2098
    DOI: 10.1039/C4EM00138A

Search articles by author

Spotlight

Advertisements