Low water treatability efficiency of wildfire-induced dissolved organic matter and disinfection by-product precursors

Megafire affects stream sediment flux and dissolved organic matter reactivity, but land use dominates nutrient dynamics in semiarid watersheds

“…While this study suggests that downstream nutrient dynamics are more influenced by human land use than wildfire, it confirms the strong influence of wildfire and extreme precipitation on sediment and DOM delivery. Because wildfires in many regions occur upstream of municipal water sources, the risk of sediment blockage and DOM contamination of drinking water sources remains serious [ 34 , 179 , 180 ]. Likewise, the increasing extent and severity of wildfires in many regions threaten human life and infrastructure at the wildland-urban interface and human health at continental scales via air pollution [ 24 , 181 – 185 ].…”

Emerging investigator series: physicochemical properties of wildfire ash and implications for particle stability in surface waters

“…Black ash leached lower organic carbon (8.0 AE 3.1 mg C g −1 ) and nitrogen (0.7 AE 0.3 mg N g −1 ) than dark gray ash, which is consistent with the Chen et al (2020) study that also reported lower organic carbon leached from black wildre ash (3.05 mg C g −1 material). 27 Overall, the higher water extractable organic carbon of gray and dark gray ash compared to unburned soil suggests greater stability of ash particles. Therefore, ash particles may not naturally occulate and settle out in surface waters, and may be transported downstream.…”

“…Previous work has characterized post-re dissolved organic matter (DOM) and DOM leached from wildre ash. [25][26][27][28] Meanwhile, most studies that investigate the physical and chemical properties of dry ash have evaluated laboratory produced ash, [29][30][31] and wildre ash research has mainly focused on hydrological properties. [32][33][34] Therefore, the objective of this study was to evaluate the properties of wildre ash of various combustion completeness from 2020 Oregon and California res and form comparisons to unburned soils to better understand how the surface charge of ash inuences stability.…”

Challenges in quantifying and characterizing dissolved organic carbon: Sampling, isolation, storage, and analysis

“…For instance, Chow et al (2003) used deionized water, NaCl, and CaCl 2 to evaluate the effect of salinity, sodicity, and liming effects on the quantity and reactivity of DOC in agricultural soils. Chen, Uzun, et al (2020) used rainwater as extracting agents on wildfire ash to simulate the effects of post-fire rainfall. In addition, alkaline solutions such as NaOH have been used to extract organic C from soils, but this method extracts significantly more C than readily water-soluble DOC.…”

“…Following this procedure, centrifugation or filtering is used to separate the solution phase from targeted solid materials for subsequent analysis. Dissolved organic C obtained from this procedure is commonly referred as water extractable organic C. This method has been widely applied to diverse environmental matrices from natural landscapes, such as soils, sediments (Chow et al., 2003; Zhang et al., 2009), foliar litter, and detritus (Chen, Liu, et al., 2020); anthropogenic materials, such as biochar (Soong et al., 2014) and wastewater sludge (Bolan et al., 1996); and materials remaining after disasters, such as wildfire ash (Chen, Uzun, et al., 2020; Wang, Dahlgren, Ersan, et al., 2015). Because water extraction is an operating procedure, the drying method and particle size of the solid materials as well as the ratio, time, and temperature of solid–water mixing could affect the chemistry and composition of DOC (i.e., water extractable organic C) in waters (Bolan et al., 1996; Guigue et al., 2014; Soong et al., 2014).…”