thumbnail

Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon

Journal of Environmental Quality

By:
, , , , , and
DOI: 10.2134/jeq2010.0030

Links

Abstract

This study was conducted to determine the main sources of dissolved organic carbon (DOC) and disinfection byproduct (DBP) precursors to the McKenzie River, Oregon (USA). Water samples collected from the mainstem, tributaries, and reservoir outflows were analyzed for DOC concentration and DBP formation potentials (trihalomethanes [THMFPs] and haloacetic acids [HAAFPs]). In addition, optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) were measured to provide insight into DOM composition and assess whether optical properties are useful proxies for DOC and DBP precursor concentrations. Optical properties indicative of composition suggest that DOM in the McKenzie River mainstem was primarily allochthonous - derived from soils and plant material in the upstream watershed. Downstream tributaries had higher DOC concentrations than mainstem sites (1.6 ?? 0.4 vs. 0.7 ?? 0.3 mg L-1) but comprised <5% of mainstem flows and had minimal effect on overall DBP precursor loads. Water exiting two large upstream reservoirs also had higher DOC concentrations than the mainstem site upstream of the reservoirs, but optical data did not support in situ algal production as a source of the added DOC during the study. Results suggest that the first major rain event in the fall contributes DOM with high DBP precursor content. Although there was interference in the absorbance spectra in downstream tributary samples, fluorescence data were strongly correlated to DOC concentration (R 2 = 0.98), THMFP (R2 = 0.98), and HAAFP (R2 = 0.96). These results highlight the value of using optical measurements for identifying the concentration and sources of DBP precursors in watersheds, which will help drinking water utilities improve source water monitoring and management programs. Copyright ?? 2010 by the American Society of Agronomy.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon
Series title:
Journal of Environmental Quality
DOI:
10.2134/jeq2010.0030
Volume
39
Issue:
6
Year Published:
2010
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Environmental Quality
First page:
2100
Last page:
2112
Number of Pages:
13