Restored wetlands as a source of disinfection byproduct precursors.

The effects of a restored wetland system in the Sacramento Valley, California on the production of dissolved organic carbon (DOC) and nitrogen (DON) and the formation potential of common disinfection byproducts (DBPs: trihalomethanes, haloacetonitriles, and chloral hydrate) were examined. Additionally, the effects of photodegradation and microbial degradation on dissolved organic matter properties and reactivitywith respect to DBP formation potential (DBP-FP) were evaluated. The wetlands increased DOC and DON concentrations by a factor of 2.2 and 1.9 times, respectively, but had little influence on the DOC and DON quality as compared to their source waters. The increase in DOC and DON concentrations increased the formation potential of all DBP species by >100%. Solar radiation and microbial degradation reduced the trihalomethane formation potential by 24 and 10%, respectively, during a 14 day incubation. In contrast, the chloral hydrate formation potential was increased by 22% after phototreatment. Results indicate that current flood-pulse management practices with a 2-3 week residence time could lead to wetlands acting as a source of DBP precursors. Enhanced DBP-FP is especially important as these wetlands contribute to a watershed that is a drinking water source for more than 23 million people.

[1]  S. R. Daniel,et al.  Effect of a Constructed Wetland on Disinfection Byproducts: Removal Processes and Production of Precursors , 2000 .

[2]  Yin-Tak Woo,et al.  Haloacetonitriles vs. regulated haloacetic acids: are nitrogen-containing DBPs more toxic? , 2007, Environmental science & technology.

[3]  Wontae Lee,et al.  Dissolved organic nitrogen as a precursor for chloroform, dichloroacetonitrile, N-nitrosodimethylamine, and trichloronitromethane. , 2007, Environmental science & technology.

[4]  Paul Westerhoff,et al.  Dissolved organic nitrogen in drinking water supplies: a review , 2002 .

[5]  W. Horwath,et al.  Spectrophotometric Determination of Nitrate with a Single Reagent , 2003 .

[6]  J. Newbold,et al.  Organic matter transport in New York City drinking-water-supply watersheds , 2006, Journal of the North American Benthological Society.

[7]  D. McKnight,et al.  Chemical characterization of DOM in channels of a seasonal wetland , 2007, Aquatic Sciences.

[8]  P. Westerhoff,et al.  Factors affecting formation of haloacetonitriles, haloketones, chloropicrin and cyanogen halides during chloramination. , 2007, Water research.

[9]  D. Reckhow,et al.  Watershed sources of disinfection byproduct precursors , 2004 .

[10]  R. Dahlgren,et al.  Watershed sources of disinfection byproduct precursors in the Sacramento and San Joaquin Rivers, California. , 2007, Environmental science & technology.

[11]  A. Kent,et al.  Sources of methylmercury to a wetland-dominated lake in northern Wisconsin. , 2005, Environmental science & technology.

[12]  D. Bossio,et al.  Dissolved organic carbon and disinfection by-product precursor release from managed peat soils. , 2004, Journal of environmental quality.

[13]  R. Wetzel,et al.  Photochemical and microbial decomposition of chromophoric dissolved organic matter during long (months–years) exposures , 2004 .

[14]  R. Dahlgren,et al.  Physical and chemical fractionation of dissolved organic matter and trihalomethane precursors: A review , 2005 .

[15]  Lawrence A. Baker,et al.  Transformations in dissolved organic carbon through constructed wetlands , 2000 .

[16]  R. Scott Summers,et al.  Assessing DBP yield: uniform formation conditions , 1996 .

[17]  Chi-Wang Li,et al.  Monitoring DBP formation with differential UV spectroscopy , 1998 .

[18]  R. Wetzel,et al.  Photochemical transformations and bacterial utilization of high-molecular-weight dissolved organic carbon in a southern Louisiana tidal stream (Bayou Trepagnier) , 2003 .

[19]  I. Obernosterer,et al.  Competition between biological and photochemical processes in the mineralization of dissolved organic carbon , 2004 .

[20]  Treavor H. Boyer,et al.  Bench-scale testing of a magnetic ion exchange resin for removal of disinfection by-product precursors. , 2005, Water research.

[21]  J. Stoddard,et al.  Dissolved organic carbon trends resulting from changes in atmospheric deposition chemistry , 2007, Nature.

[22]  P. Singer.  Humic Substances as Precursors for Potentially Harmful Disinfection By-Products , 1999 .

[23]  M. Salkinoja-Salonen,et al.  Photochemical mineralization of synthetic lignin in lake water indicates enhanced turnover of aromatic organic matter under solar radiation , 2004, Biodegradation.

[24]  Tim R. Moore,et al.  Environmental chemistry: Browning the waters , 2006, Nature.