Effect of prescribed fires on the export of dissolved organic matter, precursors of disinfection by-products, and water treatability

WATER RESEARCH

卷:187

Article

Uzun, Habibullah¹  Zhang, Wenbo²  Olivares, Christopher I.³  Erdem, Cagri Utku⁴  Coates, T. Adam⁵  Karanfil, Tanju⁴  Chow, Alex T.^2,4 

[1] Marmara Univ, Dept Environm Engn, TR-34722 Istanbul, Turkey

[2] Clemson Univ, Biogeochem & Environm Qual Res Grp, Georgetown, SC 29442 USA

[3] Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA

[4] Clemson Univ, Dept Environm Engn & Earth Sci, Anderson, SC 29625 USA

[5] Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, Blacksburg, VA 24061 USA

关键词: Prescribed fire;    DOM leaching and composition;    DBP precursors;    Coagulation;   

DOI  :  10.1016/j.watres.2020.116385

来源: Elsevier

【 摘 要 】

In this study, we report for the first time the effect of prescribed fires on the export of dissolved organic matter (DOM) and precursors of disinfectant by-products (DBPs) from periodically (every 2-3 years) and seasonally (i.e., dormant and growing) burned forest fuel materials (i.e., live vegetation, woody debris, and detritus [litter and duff]) and treatability of its rainwater leachate. Periodically applied (every 2-3 years for 40 years) prescribed fires decreased total fuel load (62 10%), primarily detrital mass (75 +/- 2%). How-ever, functional groups (i.e., phenolic compounds, proteins, carbohydrates, aromatic [1-ring], polycyclic aromatic hydrocarbons [PAHs], and lipids) attached to DOM of ground solid materials did not change significantly. Outside rainwater leaching (from forest fuel materials) experiments showed that the leaching capacity of dissolved organic carbon (DOC) from burned litter samples decreased by 40 +/- 20% regardless of burning season when compared to unburned litter samples. The leaching of total dissolved nitrogen (TDN), dissolved organic nitrogen (DON), ammonium (NH4+), and reactive phosphorus (PO43-) from burned materials decreased between 40 and 70% when compared to unburned materials. Also, DOM composition was affected by prescribed fire, which partially consumed humic-like substances based on fluorescence analyses. Thus, periodically applied prescribed fires also resulted in a reduction of trihalomethane (THM) (42 +/- 23%) and haloacetic acid (HAA) (42 +/- 20%) formation potentials (FPs), while DOC normalized reactivity of THM and HAA FPs did not change significantly. Additionally, the leaching of Nnitrosodimethylamine (NDMA) precursors, bromide ion (Br-), and selected elements (K, Ca, Mg, Mn, Fe, S, Na, B, and Al) were not significantly affected by prescribed fires. Finally, coagulant (i.e., alum and ferric) dose requirements and coagulation efficiencies were similar (i.e., removal of DOC, precursors of THMs and HAAs were 52-56%, 69-70%, 78-79%, respectively) in unburned and pre-burned leachate samples. (c) 2020 Elsevier Ltd. All rights reserved.

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