title: Molecular and Spectroscopic Characterization of Water Extractable Organic Matter from Thermally Altered Soils Reveal Insight into Disinfection Byproduct Precursors.
abstract: To characterize the effects of thermal-alteration on water extractable organic matter (WEOM), soil samples were heated in a laboratory at 225, 350, and 500 °C. Next, heated and unheated soils were leached, filtered, and analyzed for dissolved organic carbon (DOC) concentration, optical properties, molecular size distribution, molecular composition, and disinfection byproduct (DBP) formation following the addition of chlorine. The soils heated to 225 °C leached the greatest DOC and had the highest C- and N-DBP precursor reactivity per unit carbon compared to the unheated material or soils heated to 350 or 500 °C. The molecular weight of the soluble compounds decreased with increasing heating temperature. Compared to the unheated soil leachates, all DBP yields were higher for the leachates of soils heated to 225 °C. However, only haloacetonitrile yields (μg/mgC) were higher for leachates of the soils heated to 350 °C, whereas trihalomethane, haloacetic acid and chloropicrin yields were lower compared to unheated soil leachates. Soluble N-containing compounds comprised a high number of molecular formulas for leachates of heated soils, which may explain the higher yield of haloacetonitriles for heated soil leachates. Overall, heating soils altered the quantity, quality, and reactivity of the WEOM pool. These results may be useful for inferring how thermal alteration of soil by wildfire can affect water quality.
authors.affiliation: Department of Civil, Environmental and Architectural Engineering, University of Colorado , 4001 Discovery Drive, Boulder, Colorado 80309-0607, United States.|National Ecological Observatory Network (NEON) , 1685 38th Street, Suite 100, Boulder, Colorado 80301, United States.
authors.forename: Kaelin M
authors.identifier: 0000-0002-0443-0070
authors.initials: KM
authors.lastname: Cawley
authors.affiliation: Department of Civil, Environmental and Architectural Engineering, University of Colorado , 4001 Discovery Drive, Boulder, Colorado 80309-0607, United States.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Hohner
authors.affiliation: National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Podgorski
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: William T
authors.initials: WT
authors.lastname: Cooper
authors.affiliation: Department of Civil, Environmental and Architectural Engineering, University of Colorado , 4001 Discovery Drive, Boulder, Colorado 80309-0607, United States.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Korak
authors.affiliation: Department of Civil, Environmental and Architectural Engineering, University of Colorado , 4001 Discovery Drive, Boulder, Colorado 80309-0607, United States.
authors.forename: Fernando L
authors.initials: FL
authors.lastname: Rosario-Ortiz
mesh_terms: D002244:Carbon / Q000737:chemistry; D004203:Disinfection; D012987:Soil; D022882:Trihalomethanes; D014867:Water
chemical_list: D012987:Soil; D022882:Trihalomethanes; D014867:Water; D002244:Carbon