title: Wildfire altering terrestrial precursors of disinfection byproducts in forest detritus.
abstract: Wildfire occurrence and intensity are increasing worldwide causing severe disturbances to forest watersheds used for potable water supply. The effects of wildfire on drinking water quality are not well understood, especially in terms of terrestrial dissolved organic matter (DOM) and DOM-associated formation of disinfection byproducts (DBP). As the forest floor layer is a major source of terrestrial DOM, we investigated characteristics and DBP formation of water extractable organic matter (WEOM) from the 0-5 cm depth of nonburned detritus (control) and burned detritus with black ash (moderate severity) and white ash (high severity) associated with the 2013 Rim Fire in California. Spectroscopic results suggested that the aromaticity of WEOM followed white ash > control > black ash and fluorescence region II (excitation 220-250 nm; emission 330-380 nm) of the emission-excitation-matrix was identified as a potential burn severity indicator. Compared to the control, WEOM from white and black ashes had lower reactivity in forming trihalomethanes (55%-of-control) and haloacetic acids (67%-of-control), but higher reactivity in forming the more carcinogenic haloacetonitrile after chlorination (244%-of-control) and N-nitrosodimethylamine after chloramination (229%-of-control). There was no change in reactivity for chloral hydrate formation, while WEOM from black ash showed a higher reactivity for haloketone formation (150%-of-control). Because wildfire consumed a large portion of organic matter from the detritus layer, there was lower water extractable organic carbon (27%-of-control) and organic nitrogen (19%-of-control) yields in ashes. Consequently, the wildfire caused an overall reduction in water extractable terrestrial DBP precursor yield from detritus materials.
authors.affiliation: †Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, South Carolina 29442, United States.
authors.forename: Jun-Jian
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: ‡Department of Land, Air and Water Resources, University of California-Davis, Davis, California 95616, United States.
authors.forename: Randy A
authors.initials: RA
authors.lastname: Dahlgren
authors.affiliation: §Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, South Carolina 29625, United States.
authors.forename: Mahmut S
authors.initials: MS
authors.lastname: Erşan
authors.affiliation: §Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, South Carolina 29625, United States.
authors.forename: Tanju
authors.initials: T
authors.lastname: Karanfil
authors.affiliation: †Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, South Carolina 29442, United States.
authors.forename: Alex T
authors.initials: AT
authors.lastname: Chow
mesh_terms: D001966:Bromine / Q000032:analysis; D002140:California; D002244:Carbon / Q000032:analysis; D004128:Dimethylnitrosamine / Q000032:analysis; D004203:Disinfection; D005390:Fires; D005453:Fluorescence; D065928:Forests; D054879:Halogenation; D009584:Nitrogen / Q000032:analysis; D022882:Trihalomethanes / Q000032:analysis; D060753:Water Quality
chemical_list: D022882:Trihalomethanes; D002244:Carbon; D004128:Dimethylnitrosamine; D009584:Nitrogen; D001966:Bromine