IMPACTS OF PRESCRIBED FIRE ON POLYCYCLIC AROMATIC HYDROCARBON PRODUCTION AND CONTAMINANT PHOTO-TRANSFORMATION REDUCTIONS IN COASTAL PLAIN

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1000896
• Grant No.: 2014-67019-21615
• Cumulative Award Amt.: $499,000.00
• Proposal No.: 2013-02784
• Project Start Date: Jan 1, 2014
• Project End Date: Dec 31, 2018
• Grant Year: 2014
• Program Code: [A1401]- Foundational Program: Soil Health

Recipient Organization
CLEMSON UNIVERSITY
(N/A)
CLEMSON,SC 29634

Performing Department
(N/A)

Non Technical Summary
Climate change could lead to more frequent and severe droughts. Hot temperatures and dry conditions increase the likelihood of wildfires and pine beetle infestations. Prescribed burning is an essential forest management practice to reduce the susceptibility of forests to southern pine beetle attack and wildfire in the Southeastern U.S. However, production of carcinogenic polycyclic aromatic hydrocarbons (PAHs) from biomass burning is a significant health concern for both forest workers and local communities. Also, dissolved organic matter (DOM) leaching from pyrogenic organic matter, or dissolved black carbon (BC), could have different chemical characteristics compared to the DOM leaching from unburned detritus materials, and could alter transport and fate of contaminants of emerging concerns (CECs) and eventually affect source water quality. This four-year project will involve controlled field studies, laboratory studies, and a watershed monitoring study to evaluate prescribed burning practices, roles of DOM, and landscape processes on the formation and exports of PAHs and dissolved BC. Detritus materials will be collected from experimental plots with different burning schedules and frequency and will be incubated under field conditions. Isolated DOM fractions will be further tested for their propensities in photocatalytic oxidation and partitioning of PAHs and other CECs. An unmanaged and a managed 1st order watershed at Francis Marion National Forest have been monitored for DOM exports since 2003 and will be used to evaluate the landscape processes on the exports of PAHs and dissolved BC. The proposed study addresses the effects of severity and frequency of prescribed burns on the production and exports of PAHs and DOM in forested watersheds. The knowledge gained from combined laboratory and field studies will increase our understanding of (i) fundamental physical and biogeochemical processes controlling the formation and movement of PAHs and BC in forest ecosystems, and (ii) the roles of DOM in CECs transformation and transport in actively managed forests. Identifying the environmental factors controlling their production and transportation will help identify the best management practices that can achieve sustainable forestry and provide safe water to the nation.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
112	0320	2000	40%
133	0210	2000	40%
122	0611	3100	20%

Knowledge Area
133 - Pollution Prevention and Mitigation; 112 - Watershed Protection and Management; 122 - Management and Control of Forest and Range Fires;

Subject Of Investigation
0320 - Watersheds; 0611 - Conifer forests of the South; 0210 - Water resources;

Field Of Science
2000 - Chemistry; 3100 - Management;

Keywords

black carbon

foliar litter

forest fire

polycyclic aromatic hydrocarbons

Goals / Objectives
The goal of the proposed study is to increase understanding of the fundamental biogeochemical processes and forest management practices that control the production and movement of polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) in managed forested watershed. The proposed program addresses two important research questions related to forest management and the fates of contaminants of emerging concerns (CECs): 1. Can we control PAH and dissolved BC production and export through effective prescribed burn practices? 2. How does dissolved BC affect downstream biogeochemical processes and fate of contaminants of emerging concerns (CECs)? Research questions and hypotheses: Forest fires modify the chemical composition of the detritus layer on the forest floor, converting lignin and polysaccharide rich and relatively degradable carbon pools to polycyclic aromatic and charcoal rich and recalcitrant BC. Abundance of these carbon pools is affected by the schedule and frequency of prescribed burning, and corresponding forest management practices applied on the forested ecosystems. Importantly, detritus material in forested watersheds is the major terrestrial source of DOM to aquatic ecosystems, particularly the black water rivers of southeastern coastal plain. Inappropriate forest management practices could affect the quantity and quality of DOM export, eventually altering downstream biogeochemical processes and the fate of CECs. Specific hypotheses: I. Management Practices - Annual dormant season prescribed burning at low severity produces heavier and less mobile PAHs but greater amounts of dissolved BC when comparing to the higher temperature at periodic growth season burning. II. Roles of DOM - DOM leaching from pyrogenic organic matter contains a greater number of aromatic and nitrogen moieties than that of from naturally decomposed detritus materials, exhibiting greater partitioning and photocatalytic oxidation with hydrophobic organic pollutants. III. Landscape Processes -Repeated burning of the forest reduces the biomass of the detritus layer on the forest floor, resulting in a lower but relatively recalcitrant DOM export compared to unmanaged watersheds.

Project Methods
Overview In order to develop a mechanistic understanding of prescribed burning practices affecting downstream biogeochemical processes and the fates of CECs, both controlled studies and field investigations will be conducted to examine the formation and movement of PAHs and BC from the detritus layer in the forest floor. Fluxes and species of PAHs and DOM will be determined according to the methods stated in the section of analytical techniques section below. In addition, DOM leaching from a variety of pyrogenic organic matters at different periods after burning will be fractionated and isolated for determining their partitioning coefficients and photocatalytic properties with PAHs. Other biogeochemical parameters including nutrient dynamics will also be determined in order to establish linkages among forest fire practices, DOM export, and fate of PAHs and CECs. Specific Objectives Objective I:Management Practices - Evaluate frequency and severity of prescribed burns on the production and movement of PAHs and BC Objective II:Roles of DOM - Determine the roles of DOM and dissolved BC on transformation and transportation of PAHs and CECs Objective III:Landscape Processes - Quantify and characterize temporal variations of DOM and dissolved BC export from managed and unmanaged watersheds Approach The research team will apply both control studies and field investigations in the proposed study. There will be three major research experiments in the proposed program: I) Controlled Field Study, II) Controlled Lab Study, and III) Experimental Watershed, corresponding to the management practices, roles of DOM, and landscape processes, as listed in the three specific objectives, respectively. The controlled studies, including Controlled Field Study (Experiment I) and Controlled Lab Study (Experiment II), are to quantify the production and export of PAHs and dissolved BC under different management practices and to investigate the roles of dissolved BC controlling the fate of PAHs and other CECs. Experimental plots with different burning schedules and frequency have been established at Hobcaw Barony in Georgetown, South Carolina. Detritus materials will be collected from the experimental plots each year for field incubation. DOM collected from the field incubation will be fully characterized for their functional moieties and structures and PAH species. Fractionated DOM fractions will be further tested for their propensity in producing reactive oxygen species, reactivity in forming DBPs, and ability to partition PAHs. The Experimental Watershed Monitoring Study (Experiment III) is a field investigation and is to evaluate the roles of landscape processes on the production and export of PAHs and dissolved BC. An unmanaged and a managed 1st order watersheds at Francis Marion National Forest have been monitored for dissolved organic carbon exports since 2003. Our focus will be on the prescribed burn scheduled during spring 2013. With the results of the control study and field investigation, a box model describing production and role of dissolved BC in forested ecosystems under different fire practices will be developed. Means by which Results will be Analyzed, Assessed, or Interpreted Box Model - A box model will be developed to describe the production and transformation of PAHs and BC. Data generated from the controlled field study will provide useful connection among management practices, biomass, PAHs, and BC in forest floor, including woody biomass (Wwood), fresh litter (Wlitter), decomposed duff (Wduff), and pyrogenic organic matter (Wpyom). The field incubation study will yield concentrations of DOM and dissolved BC, and PAHs per unit mass of substrate. Data can be used to scale up for watershed scale budget estimation and will be compared with data from the watershed monitoring and other field studies. In addition, data generated from the partitioning coefficient and photocatalytic properties studies will be tabulated as references for the characteristics of dissolved BC. How Results or Products Will Be Used and Evaluated Outputs that can be adopted - Effects of severity and frequency of prescribed burns on the yields and distributions of PAHs and BC, as well as water quality will be tabulated and a box model describing PAH and dissolved BC production and transformation in detritus and water will be developed for reference so that forest landowners can adopt effective forest management practices to minimize PAH production and their impacts on water quality. Levels of PAH production during prescribed burns are valuable information for forestry workers and firefighters to evaluate their protective equipment from PAH exposure. Data generated from the partitioning coefficient and photocatalytic properties studies will also provide useful information for land and water resource managers and water treatment facilities to redesign treatment and management practices to minimize CECs in source waters. Results from this study will be conveyed to regulatory agencies, resource managers, local counties, planning and public work staffs, and other professional decision-makers. Evaluation Plan - The study consists of two tiers of quantitative indicator to measure the success of the project: 1) number and 2) impacts of deliverable products. The deliverable products here are referred to the peer-review publications, articles in newsletters and magazines, presentations, and workshops / field days. 1) Number of Publication and Presentation: The quantitative indicator in tier 1 simply measures the quantity of the project's output. The number of publication, presentation, and workshop delivered based on the results of this project will be reported. 2) Impacts of Deliverable Products - The quantitative indicator in tier 2 is to measure the quality of the research and extension works. Regarding the impacts of the research work, the Impact Factor of peer-review journals and times cited by other publications will be reported. The Impact Factor from the latest Journal Citation Reports® and the number of citation shown in the Web of KnowledgeSM will be used for this purpose. Regarding the impacts of extension education, the number of people attended the outreach activities (i.e. workshops / field days) will be documented.

Progress 01/01/14 to 12/31/18

Outputs
Target Audience: Scientists and engineers who are interested in soil and water quality, carbon and nutrient cycles, as well as ecotoxicology and environmental safety. Local agencies, forest workers, land managers, and landowners who are managed the natural resources in the state of South Carolina and other southeastern states. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project was a good example of interdisciplinary and collaborative research, requiring knowledge and involving faculty from different universities and federal agencies in departments of environmental engineering, forestry, soil science and biogeochemistry. With supports from senior faculty members and scientists from collaborated institutes, this study provided training and opportunity for an assistant professor (Dr. Alex Chow), two post-doctoral scholar (Huan Chen and Hamed Majidzadeh), four graduate students (Adam Coates, Jun-Jian Wang, and Kuo-Pei Tsai, Wenbo Zhang), and five undergraduate students (Hunter Robinson, Luke Hatfield, Morgan Edwards, Joseph Carr, and Allison Acosta) to learn new analytical techniques, cultivate teaching skills, and establish their networks. Three PhD students and one MS students were graduated and Dr. Alex Chow, the PI of the project, was promoted to associate professor. Selected examples of training and professional development include: the PI, Dr. Alex Chow, organized symposia and presented oral presentations at 252nd American Chemical Society at Philadelphia PA and American Geophysical Union Annual Conference at San Francisco CA. With the supports from this NIFA grant, the PI collaborated with scientists at the Environmental Molecular Science Laboratory at Pacific Northwest National Laboratory, and was awarded access to Fourier Transform Ion Cyclotron Resonance (FT-ICR MS) for dissolved black carbon characterization. The PI was also appointed as a member of the Project Advisory Committee for the Water Research Foundation Project: WRF Project 4590 - Wildfire Impacts on Drinking Water Treatment Process performance: Development of Evaluation Protocols and Management Practices. Post-doctoral scholars and students established professional networks through presentations at professional conferences such as the International Water Association, the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, as well as American Chemical Society. In particular, a PhD student (Jun-Jian Wang) presented his research work about wildfire impacts on water quality in the 248th American Chemical Society meeting in San Francisco CA and was awarded with the 1st place prize for student oral presentations in the disinfection byproduct symposium. Also, two Ph.D. students attended a workshop offered by Colorado State University in Boulder, Colorado, which focused on the characterization of DOM through the use of fluorescence spectrometry and PARAFAC modeling. Ph.D. students (Thomas A. Coates and Mary-Frances Rogers) was able to coordinate and develop field laboratories and demonstrate forestry techniques for soil and forest management students at Horry Georgetown Technical College. How have the results been disseminated to communities of interest?Public disseminations of the technical results from these studies have been conducted through peer reviewed publications and presentations at national/regional forestry and environmental science venues. A total of thirteen (one is currently under review) peer-review research articles have been published and 14 poster and oral presentations were delivered in national and local professional conferences. In addition, the research team organized several symposiums and workshops related to forested watershed managements. Details were listed in the Products Section of this report. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Wildfire on Polycyclic Aromatic Hydrocarbon Production Based on the field observation and controlled studies, we developed a box model to illustrate the impacts of wildfire and prescribed fire on soil and surface water quality. First of all, the impacts of wildland fire on polycyclic aromatic hydrocarbon (PAH) production depended on fire severity. We quantified levels of 27 PAHs, including 16 U.S. Environmental Protection Agency regulated species, in nonburned forest soils and burned ash/soil samples covered with black ash (i.e., moderate burn intensity) or white ash (i.e., severe burn intensity) from a wildfire in California. The Σ16PAH concentrations (mean ± standard deviation; μg/kg) from ash/soil samples were moderate burn (893 ± 285) > severe burn (515 ± 333) ≈ nonburned soils (247 ± 58). Overall, fire intensity is critical in regulating soil PAH concentrations and profiles. Given the high erodibility of wildfire ash, these PAHs can be easily transported to rivers and reservoirs where they could impact the aquatic food web and drinking source water. Prescribed Fire on Soil and Water Quality Prescribed fire practice is used to reduce the fuel loading in forest floor and the risk of wildfire. Results from our experimental plots with different management practices demonstrated that prescribed fire did not significantly alter the overall soil and detritus chemistry, although detritus biomass was significantly reduced. Specifically, the fire temperature of prescribed burns in both growing and dormant season was about 300 oC or lower, and the peak temperatures only lasted for minutes. In other words, there were no damage on soils or no change in the chemistry of detrital layers. Moreover, the reduction of detritus biomass also reduced the dissolved organic carbon (DOC), tea-color-like substances, in surface water. Our experimental setting showed up to 40-50% reductions in DOC concentration. However, our study showed that water and DOC leached from burned detritus could affect algal growth, bacterial survival, and pollutants in source water compared to unburned detritus, and the effects could depends on fire intensity. Forest and water resource managers shall put efforts to reduce post-fire ash load in stream waters to minimize ecological impacts on source water. Also, authorities need to be particularly cautious about post-fire thunderstorm or spring snowmelt that would carry significant amount of ash into source water. Specific Accomplishments Specific Accomplishments are described below associated with the three objectives / hypotheses described in the proposal: I. Management Practices We conducted two field experiments to characterize any changes in detrital chemistry under different management practices, including annual dormant, annual growing, and biennial dormant burns. Our findings one more time confirmed that prescribed fires can decrease the amount of detrital material (fuel for the fire) and reduce the risk of wildfires. Despite changes in fuel loading and fuel structure as a result of short-term alterations in fire frequency and fire season in longleaf pine stands, long-term, frequent prescribed fire does not appear to significantly alter overall forest detrital chemical composition. From the results of this one-year field incubation study, frequent prescribed fire management have similar effect on overall chemical properties of the ground litter, regardless of the frequency or season of fire application. Results of this study confirmed that low-intensity prescribed fire effectively reduces the thickness of the forest O-horizon and decomposition rate that happens within, without qualitative impact on the chemical composition of the ground detritus. II. Roles of DOM We conducted both photochemical and microbial experiments to evaluate the roles of pyrogenic-DOC in source water. In the photochemical study, the reactive oxygen species (ROS) production by pyrogenic-derived dissolved organic matter (Py-DOC) and their impact on the survival of Escherichia coli under the light irradiation were investigated. Production of singlet oxygen and triplet-DOM were observed during the irradiation of Py-DOC. However, these ROS did not sufficiently inactive Escherichia coli. In contrast, Py-DOC could protect the E. coli from being inactive by the light irradiation. Furthermore, the nutrient leached from pyrogenic materials (i.e., burned detritus) would also promote the growth of E. coli. We also examined Py-DOC using high resolutions mass spectrometry and benzene polycarboxylic acid method found that condensed aromatic hydrocarbon or black carbon was only a small portion in Py-DOC. There were significant portions of compounds considered as lignin and carbohydrate fractions from burnt materials, even in high burning temperature (550 oC). In other experiments, we examine fire intensity on algal growth using both controlled-burned detritus and real wildfire ashes. Two freshwater green algae (Pseudokirchneriella subcapitata) and blue-green algae (Microcystis aeruginosa) were separately incubated in the mixture of cultural medium and pine (Pinus palustris) Py-DOC to demonstrate the effects of algal growth. Wildfire ash solution can cause different degrees of stimulation or ephemeral inhibition effects algae, depending on the exposure time as well as property and amount of ash solution. Also, algal could utilize and transform Py-DOC. Results of these experiments demonstrated that Py-DOC could affect microbial activities in aquatic environment. Forester and natural resource managers shall pay attention on source water quality when conducting prescribed fire practices. III) Landscape Processes With support from US Forest Service, 155 ha of a first-order watershed (WS80) in Santee Experimental Watershed was burned using aerial ignition in April 2016. Water exported from this watershed and an adjunct control watershed (WS77) were closely monitored through two different water sampling techniques, including bi-weekly grab sample and flow-proportion auto-sampler. Samples have been evaluated to study pre- and post- fire changes in DOC characteristics and nutrient dynamics. Results suggested long-term prescribed burned reduced both thickness of detrital layers and DOC exported from managed watersheds when comparing to the unmanaged watersheds. Carbon to Nitrogen ratio and DOC florescence excitation-emission matrix, did not show a significant difference between the managed and unmanaged watersheds. This indicated that the overall composition of DOC export was similar between both watersheds. However, differences in characteristics of DOC in molecular level from managed and unmanaged were observed when high resolution mass spectrometry was applied on the samples. Prescribed burned watersheds showed higher intensity and more unique formulas related to condensed aromatic hydrocarbons compared to unmanaged watersheds. These condensed aromatic hydrocarbons are likely of pyrogenic origin and formed during the prescribed fire treatment. It is possibly that these Py-DOC being masked by the overall DOC export; thus, there were no difference in overall composition or bulk characteristics of DOC in source water. In addition, we also evaluated water quality using benthic macroinvertebrate communities as indicators of water quality in aquatic systems. Before prescribed fire, the managed watershed (WS77) always had significantly more Amphipoda than unmanaged watersheds (WS80), while WS80 had significantly more Isopoda and Oligochaeta than WS 77, potentially due to differences of pH, oxygen content, and food availability.

Publications

• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2019 Citation: Chow AT, Dahlgren RA (2019) Molecular characterization of black carbon in wildland fire ashes. Presented at Soil Science Society of America Annual Meeting, San Diego CA (Jan 6-9, 2019).
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Majidzadeh H and Chow AT (2018) Forest management improves water quality by altering detrital chemical composition. Presented at Fire Continuum Conference, Missoula, MT (May 21-24, 2018)
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Chow AT (2018) Forest fire alters dissolved organic matter exports from forested watersheds: Impacts on water quality and treatability. Presented at Fire Continuum Conference, Missoula MT. (May 21-24, 2018).
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Wang JJ, Dahlgren RA, and Chow AT (2014) Impacts of the rim fire on disinfection byproduct precursors in forested watersheds. Oral presentation at the Disinfection Byproduct Symposium, American Chemical Society Fall Meeting, San Francisco, CA (Aug 10 ⿿ 14, 2014).
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Zhang W, Olivares C, Uzun H, Erdem CU, Trettin C, Liu Y, Robinson ER, Karanfil T, and Chow AT (2016) Exports of dissolved organic carbon following prescribed fire on forested watersheds: Implications for watershed management for drinking water supply. Presented at AGU Fall Meeting, San Francisco CA (Dec 14-18, 2016) [Abstract B23A-0559].
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Erdem CU, Uzun H, Karanfil T, and Chow AT (2016) Forest fire and drinking water quality. Presented at the South Carolina Environmental Conference, Myrtle Beach SC (March 13-15, 2016).
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Olivares C, Dahlgren RA, Trettin C, Wang GG, Wong PK, and Chow AT (2016) Exports of dissolved organic carbon and disinfection by-product precursors from prescribed burnt forests. Presented at the AFRI and NIEQP Project Directors Meeting, Washington, D.C (October 12-13, 2016).
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Olivares C, Zhang W, Uzun H, Erdem CU, Coates TA, Rogers MF, Karanfil T, and Chow AT (2016) Exports of dissolved organic carbon and disinfection by-product precursors from prescribed burnt forests. Presented at the 252th American Chemical Society (ACS) Fall Meeting, Philadelphia, PA (August 21-25, 2016).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Chow AT (2015) Impacts of Wildfire on Dissolved Organic Matter and Disinfection Byproduct Precursors in Forested Watersheds. Oral presentation at the IWA Specialist Conference on Natural Organic Matter in Water, Malmö, Sweden (September 7-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Rogers MF (2015) Effects of Prescribed Fire on Dissolved Organic Matter in Coastal Plain Forested Watersheds. Poster presentation at the IWA Specialist Conference on Natural Organic Matter in Water, Malmö, Sweden (September 7-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Rogers MF, Tsai KP, Coates TA, and Chow AT (2015) Effects of Prescribed Fire on Dissolved Organic Matter in Coastal Plain Forested Watersheds. Poster presentation at the Piedmont-South Atlantic Coast Cooperative Ecosystem Study Unit, Athens, GA (September 9-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Coates T and Chow AT (2015) What is black carbon and why should I care? Poster Presentation at the James C. Kennedy Waterfowl and Wetlands Center Dedication Ceremony, Georgetown, SC (November 24, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, Ersan MS, Karanfil T, and Chow AT (2015) Temporal variation of chemical characteristics of soil and dissolved black carbon in surface soils after wildfire. Oral Presentation at ASA, CSSA, and SSSA Annual Meeting, Minneapolis, MN (Nov 17, 2015).
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Coates T, Chow AT, Hagan DL, Waldrop TA, Wang GG, Bridges Jr. WC, Rogers MR, and Dozier JH (2018) Thermocouple probe orientation affects prescribed fire behavior estimation. Journal of Environmental Quality 47(1): 170-176.
• Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Majidzadeh H, Chen H, Coates TA, Tsai KP, Olivares C, Trettin C, Uzun H, Karanfil T, and Chow AT (Under Review) Periodic prescribed fire is an effective watershed management strategy to reduce organic matter export and disinfection byproduct precursors in source water. Submitted to International Journal of Wildland Fire on Oct 2018.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Chen H, Chow AT, Li XW, Ni HG, Dahlgren RA, Xeng H, and Wang JJ (2018) Wildfire burn intensity affects the quantity and speciation of PAH in soils. ACS Space and Earth Chemistry 2(12): 1262-1270.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Chen H, Blosser GD, Majidzadeh H, Liu XJ, Conner WH, and Chow AT (2018) Integration of an automated identification-quantification pipeline and statistical techniques for pyrolysis GC/MS tracking of the molecular fingerprints of natural organic matter. Journal of Analytical and Applied Pyrolysis 134: 371-380.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Coates T, Chow AT, Hagan D, Wang GG, Bridges Jr. W, and Dozier J (2017) Frequent prescribed burning as a long-term practice in longleaf pine forests does not affect detrital chemical composition. Journal of Environmental Quality 46: 1020-1027.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Tsai KP, Uzun H, Karanfil T, and Chow AT (2017) Dynamic changes of disinfection byproduct precursors following exposures of Microcystis aeruginosa to wildfire ash solutions. Environmental Science & Technology 51(15): 8272-8282.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Tsai KP and Chow AT. (2016) Growing algae alter spectroscopic characteristics and chlorine reactivity of dissolved organic matter from thermally-altered forest litters. Environmental Science & Technology 50(15): 7991-8000.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Wang JJ, Dahlgren RA, Ersan M&, Karanfil T, Chow AT (2016) Temporal variations of disinfection byproduct precursors in wildfire detritus. Water Research 99: 66-73.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Ng TW, Li BB, Chow AT, and Wong PK (2016) Effects of bromide on inactivation efficacy and disinfection byproduct formation in photocatalytic inactivation. Journal of Photochemistry and Photobiology A: Chemistry 324: 145-151.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, and Chow AT (2015) Controlled burning of forest detritus altering spectroscopic characteristics and chlorine reactivity of dissolved organic matter: Effects of temperature and oxygen availability. Environmental Science & Technology 49: 14019-14027.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, Ersan M&, Karanfil T, Chow AT (2015) Wildfire altering terrestrial precursors of disinfection byproducts in forest detritus. Environmental Science & Technology 49: 5921-5929.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Tsai KP (2017) Alternations of Disinfection Byproduct Formation Following Exposures of Algae to Wildfire Ash Solutions and Copper Algaecide. PhD Dissertation, Clemson University.
• Type: Book Chapters Status: Published Year Published: 2015 Citation: Majidzadeh H&, Wang JJ, and Chow AT (2015) Forest fire alters dissolved organic matter and disinfection byproduct precursors exports from forested watersheds ⿿ Part I: A controlled laboratory study. In, Disinfection Byproducts in Drinking Water - Occurrence, Formation, Health Effects, and Control. Karanfil et al. Eds., American Chemical Society Symposium Book. Chapter 15, pp 271-292.
• Type: Book Chapters Status: Published Year Published: 2015 Citation: Tsai KP, Rogers MF, Chow AT, and Diaz F (2015) Forest fire alters dissolved organic matter and disinfection byproduct precursors exports from forested watersheds ⿿ Part II: A controlled field study. In, Disinfection Byproducts in Drinking Water - Occurrence, Formation, Health Effects, and Control. Karanfil et al. Eds., American Chemical Society Symposium Book. Chapter 16, pp. 293-306.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Ng TW, Chow AT, and Wong PK (2014) Duel roles of dissolved organic matter in photo-irradiated Fe(III)-contained waters. Journal of Photochemistry and Photobiology A: Chemistry 290: 116-124.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Coates TA (2017) Forest Management in Coastal Pine Forests: An Investigation of Prescribed Fire Behavior, Detrital Chemical Composition, and Potential Water Quality Impacts. PhD Dissertation, Clemson University.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Zhang WB (2017) Effects of Prescribed Forest Fire on Water Quality and Aquatic Biota in the Southeastern US. MS Thesis, Clemson University.
• Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Wang JJ (2015) Disinfection byproduct precursors in detritus materials of fire-affected watersheds. PhD Dissertation, Clemson University.
• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2019 Citation: Coates TA, Hagan D, Chow AT, Dozier JH (2019) Long term effects of prescribed fire on forest soils: Lessons from the Southeastern Coastal Plain. Presented at Soil Science Society of America Annual Meeting, San Diego CA (Jan 6-9, 2019).

Progress 01/01/17 to 12/31/17

Outputs
Target Audience: Scientists and engineers who are interested in soil and water quality, carbon and nutrient cycles, as well as ecotoxicology and environmental safety. Local agencies, forest workers, land managers, and landowners who are managed the natural resources in the state of South Carolina and other southeastern states. Changes/Problems:Because of the delay in prescribed fire in WS77 and Hurricane Matthew in 2016 landed on our study sites, we had applied for one-year no cost extension and the request have been approved. The current end date of this project is December 31, 2018. What opportunities for training and professional development has the project provided?This grant provided supports for three graduate students this year. Kuo-Pei Tsai, PhD in Forest Resource, graduated in August 2017 Thomas Adam Coates, PhD in Forest Resources, graduate in August 2017 Wenbo Zhang, MS Wildlife and Fisheries Biology, graduate in December 2017. How have the results been disseminated to communities of interest?Public disseminations of the technical results from these studies have been conducted through peer reviewed publications and presentations at national/regional forestry and environmental science venues. Three research articles were published. Several manuscripts are in preparation for submission to peer review journals. What do you plan to do during the next reporting period to accomplish the goals?I. Management Practices The field incubation study examining DOM leaching from different management practices completed in 2017. The leachates are used for some ongoing photochemical and microbial transformation studies, as described in the Objective II of the original proposal. In the last year of the project, we will summarize all the field observations and data for peer reviewed publications. II. Roles of DOM Several laboratory studies have been conducting to examine photochemical and microbial transformations of DOM leached from thermally altered detrital materials. In addition, we applied ultra-high resolution mass spectrometry to investigate DOM composition and evaluate the biogeochemical roles in aquatic environments. In the last year of the project, we will focus on data analysis and prepare manuscripts to summarize the findings. III. Landscape Processes By April 2017, the one-year post-fire field monitoring on WS77, WS79, and WS 80 was completed. No further field measurements will be conducted after. We are collaborating with Environmental Molecular Sciences Laboratory to characterize DOM composition using high-resolution mass spectrometry. Currently, the publication of chemical DOM changes upon prescribed fire and long-term implications for DOM export is being drafted and is planned to submit in early 2018.

Impacts
What was accomplished under these goals? I. Management Practices We conducted two field experiments to quantify the productions and exports of dissolved organic matter (DOM), including dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from forest detritus layers under different management practices, including annual dormant, annual growing, and biennial dormant burns. These practices were implemented at the experimental plots mainly with longleaf pine (Pinus palustris) at the Tom Yakwey Wildlife Center Heritage Preserve in Georgetown, South Carolina in 2015 and 2016. Fuel mass per unit area in the plots were determined before and after each treatment in order to determine the consequences of management practices in changing the forest fuel loading and detritus chemistry. The first field experiment was to determine the prescribed fire practices on detrital chemistry. We selected nine plots, each approximately 2.5-5 acres (1-2 ha) in size, had been burned 5-8 times since 2004, and specifically, were burned in both 2013 and 2014. These nine plots were randomly allocated for burning in both 2015 and 2016 as follows: three annual dormant (2015 and 2016 burns), three annual growing (2015 only), three biennial dormant (2016 only). Short-term comparisons of both fire frequency and season can be evaluated using this design. We also selected one, 16-acre (6.5 ha) site that has gone unburned since 1978 as the long-term control. To determine the fire effects on detrital composition, we applied thermal couples to determine fire temperature and samples were collected for pyrolysis-gas chromatography mass spectrometry. Results of these studies are reported on Coates et al. (2017) and (2018). To determine the leaching capacity changes of components, litter materials were soaked in distilled deionized water for one and six days. Basic water quality parameters, such as pH, conductivity, and concentrations of dissolved organic carbon (DOC), dissolve nitrogen (DN), NO3-, NO2-, and dissolved organic nitrogen (DON) were measured after filtering through 0.45 um membrane filters. Optical properties (e.g., E2/E3, UV254, HIX, Humic-Like components) of DOM were determined from selected samples. We expect this leaching experiments will be completed in Spring 2018. The second field experiment was to characterize DOC and DON exports from burnt detritus. Detritus were collected from the first field experiment as described above. One kg of litter samples were wrapped with aluminum screen into a "tea-bag" shape and placed in (2x2x1ft) custom-made open-top aluminum trays in an open field at Hobcaw Barony, Georgetown, SC. Chemical constituents leached from these detrital materials were fully characterized in order to determine the temporal effects of DOC, DON, and nutrients after wildland fire. As precipitation fell over these materials, water was collected in glass carboys as it saturated the materials and drained through the trays. Total water volume that contacted with litters was calculated and recorded carefully for each tray. Selected samples were collected for nutrient analyses during one-year period between January 2016 to December 2016. Unmanaged had the highest total carbon export in both solid and dissolved states, while all managed treatments did not have a significant difference. Field experiments and chemical analyses were completed. Manuscripts are under preparation. II. Roles of DOM We conducted laboratory studies to evaluate photochemical and microbial transformations of DOM in source water. In the photochemical study, the reactive oxygen species (ROS) production by DOM and their impact on the survival of Escherichia coli under the light irradiation were investigated. Production of singlet oxygen and triplet stage DOM were observed during the irradiation of DOM. However, these ROS did not inactive Escherichia coli. In contrast, the DOM would protect the E. coli from being inactive by the light irradiation. Furthermore, the nutrient in the DOM would also promote the growth of E. coli. The results of this study provide valuable information on the potential impact of the DOM on the bacterial survival and ROS production in natural aquatic environment. Currently we are examining the DOM composition using high resolution mass spectrometry. Manuscript is under preparation. In addition to a study examining fire temperature on algal blooming under controlled condition (published in ES&T in 2016), we examine fire severity on algal blooming using real wildfire ashes. Microcystis aeruginosa was cultured in the medium containing low and high concentrations [10% and 65% (v/v)] of black and white ash water extracts (BE and WE) to (1) compare M. aeruginosa population and growth rate in the absence and presence of black and white ash water extracts with low and high concentrations; (2) evaluate alterations of DOM spectroscopic characteristics. Algal population was monitored every day throughout the entire experiment by measuring optical density at 680 nm (OD680). These results suggest that wildfire ash solution can cause different degrees of stimulation or ephemeral inhibition effects on M. aeruginosa population, depending on the exposure time as well as property and amount of ash solution. Result of this study is reported in Tsai et al. (2017). III) Landscape Processes With support from US Forest Service, 155 ha of a first-order watershed (WS80) in Santee Experimental Watershed was burned using aerial ignition in April 2016. Water exported from this watershed and an adjunct control watershed (WS77) were closely monitored through two different water sampling techniques, including bi-weekly grab sample and flow-proportion auto-sampler. Samples have been evaluated to study pre- and post- fire changes in DOM characteristics and nutrient dynamics. In general, WS 77 showed lower DOC levels compared to the unmanaged WS80. However, analyzing only DOC values do not show a significant difference between the watersheds under prescribed fire treatment and the reference one, potentially attributed to fire-related DOC export changes being masked by the overall DOC export, as well as seasonality. Normalizing DOC with respect to DTN (dissolved total nitrogen), revealed that DOC/DTN overlap in pre-fire and long-term post-fire conditions. This indicated that the overall composition of DOM export was similar between both watersheds. However, during the first-flush (early June 2016), there was a decoupling of the DOC/DTN values, where the watershed under prescribed fire treatment, WS 77, had a higher value than the reference watershed. This suggested that an additional source of DOM with lower DTN was introduced in WS 77. To examine the exports of PAH and changes in DOM composition, we applied high resolution mass spectrometry (i.e., Fourier transform ion cyclotron resonance mass spectrometry) to determine characterize DOM from WS77 and WS80. Preliminary results indicated that WS77 showed higher intensity and more unique formulas related to condensed aromatic hydrocarbons compared to WS80. These condensed aromatic hydrocarbons are likely of pyrogenic origin and formed during the prescribed fire treatment. Data analysis is undergoing to characterize the nature of oxygen and nitrogen-containing formulae during prescribed fire. In addition to chemical parameters, we also evaluate water quality using biological indicator. Sediment samples were collected every 2 weeks for one year to determine any changes of macroinvertebrate community due to the prescribed fire practice. This study is also conducted on WS77 and WS80. Benthic macroinvertebrate communities are commonly used as indicators of water quality in aquatic systems. Before fire WS77 always had significantly more Amphipoda than WS80, while WS80 had significantly more Isopoda and Oligochaeta than WS 77, potentially due to differences of pH, oxygen content, and food availability. Field experiments were completed and a manuscript is under preparation.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Tsai KP, Uzun H, Karanfil T, and Chow AT (2017) Dynamic changes of disinfection byproduct precursors following exposures of Microcystis aeruginosa to wildfire ash solutions. Environmental Science & Technology 51(15): 8272-9292.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Coates T, Chow AT, Hagan D, Wang GG, Bridges Jr. W, and Dozier J (2017) Frequent prescribed burning as a long-term practice in longleaf pine forests does not affect detrital chemical composition. Journal of Environmental Quality 46: 1020-1027.
• Type: Theses/Dissertations Status: Accepted Year Published: 2017 Citation: Zhang WB (2017) Effects of Prescribed Forest Fire on Water Quality and Aquatic Biota in the Southeastern US. MS Thesis, Clemson University.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2018 Citation: Coates T, Chow AT, Hagan DL, Waldrop TA, Geoff GG, Bridges Jr. WC, Rogers MR, and Dozier JH (In Press) Thermocouple probe orientation affects prescribed fire behavior estimation. Journal of Environmental Quality.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Coates TA (2017) Forest Management in Coastal Pine Forests: An Investigation of Prescribed Fire Behavior, Detrital Chemical Composition, and Potential Water Quality Impacts. PhD Dissertation, Clemson University.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Tsai KP (2017) Alternations of Disinfection Byproduct Formation Following Exposures of Algae to Wildfire Ash Solutions and Copper Algaecide. PhD Dissertation, Clemson University.

Progress 01/01/16 to 12/31/16

Outputs
Target Audience:1. Scientists and engineers who are interested in soil and water quality, carbon and nutrient cycles, as well as ecotoxicology and environmental safety. 2. Local agencies, forest workers, land managers, and landowners who are managed the natural resources in the state of South Carolina and other southeastern states. Changes/Problems:Hurricane Matthew landed on Winyah Bay SC in early October 2016 and destructed some of our field setups and equipment used in our field incubation study, as described in the Task 1 of the original proposal. The field experiments were set back up as soon as the field site was safely accessible. However, the data point for this storm event was not be able to record. This field study started on January 2016 and the detrital materials were exposed to field conditions for over 9 months. Leachates from these detrital materials in this storm event should be small comparing to the overall leachates in the one-year study. We believe the impacts of the missing data point on the overall C and N yield determinations should be minimal. What opportunities for training and professional development has the project provided?Students have been provided opportunities to give professional presentations in national conferences, learn lab skills, and cultivate their teaching skills The PI, Dr. Alex Chow, organized symposia and presented oral presentations at 252nd American Chemical Society at Philadelphia PA and American Geophysical Union Annual Conference at San Francisco CA. One Ph.D. student (Kuo-Pei Tsai) and one MS student (Wenbo Zhange) were able to attend American Geophysical Union conference presented the research results. One PhD student (Adam Coates) also presented his research results to the 5th International Fire Behavior and Fuels Conference, Portland, OR. How have the results been disseminated to communities of interest?Public disseminations of the technical results from these studies have been conducted through through peer reviewed publications and presentations at national/regional forestry and environmental science venues. Three research articles were published. Several manuscripts are in preparation for submission to peer review journals. Oral and poster presentations were presented at 252ned American Chemical Society at Philadelphia PA and American Geophysical Union Annual Conference at San Francisco CA. What do you plan to do during the next reporting period to accomplish the goals?I. Management Practices The field incubation study examining DOM leaching from different management practices will be end in January 2017. Some of the leachates will be used for photochemical and microbial transformation studies, as described in the Objective II of the original proposal. In this year, we will summarize all the field observations and data for peer reviewed publications. II. Roles of DOM Several laboratory studies have been conducting to examine photochemical and microbial transformations of DOM leached from thermally altered detrital materials. In addition, we applied ultra-high resolution mass spectrometry to investigate DOM composition and evaluate the biogeochemical roles in aquatic environments. In the last year of the project, we will focus on data analysis and prepare manuscripts to summarize the findings. III. Landscape Processes By April 2017, the one-year post-fire field monitoring on WS77, WS79, and WS 80 will be completed. No further field measurements will be conducted after. In 2017, we will focus on data analysis and prepare manuscripts for this field study.

Impacts
What was accomplished under these goals? I. Management Practices In the Objective I, we conducted two field experiments to quantify the productions and exports of dissolved organic matter (DOM), including dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from forest detritus layers under different management practices, including annual dormant, annual growing, and biennial dormant burns. These practices were implemented at the experimental plots mainly with longleaf pint (Pinus palustris) at the Tom Yakwey Wildlife Center Heritage Preserve in Georgetown, South Carolina in 2015 and 2016. The first field experiment was to determine the prescribed fire practices on detrital chemistry. We selected nine plots, each approximately 2.5-5 acres (1-2 ha) in size, had been burned 5-8 times since 2004, and specifically, were burned in both 2013 and 2014. These nine plots were randomly allocated for burning in both 2015 and 2016 as follows: three annual dormant (2015 and 2016 burns), three annual growing (2015 only), three biennial dormant (2016 only). Short-term comparisons of both fire frequency and season can be evaluated using this design. We also selected one, 16-acre (6.5 ha) site that has gone unburned since 1978 as the long-term control. Results demonstrated that fuel loading (both mass and depth) was greatest in the long-term, unburned plot. This was largely affected by a significant increase in litter and duff materials. There were no significant differences in post-fire detrital chemistry among the annual dormant, annual growing, and biennial dormant locations. There were no significant differences in detrital chemistry between the long-term, unburned location and the burned locations. The use of thermocouples proved ineffective in producing estimates that correlate with fire intensity. The second field experiment was to characterize DOC and DON exports from burnt detritus. Detritus were collected from the first field experiment as described above. One kg of litter samples were wrapped with aluminum screen into a "tea-bag" shape and placed in (2x2x1ft) custom-made open-top aluminum trays in an open field at Hobcaw Barony, Georgetown, SC. Chemical constituents leached from these detrital materials were fully characterized in order to determine the temporal effects of DOC, DON, and nutrients after wildland fire. As precipitation fell over these materials, water was collected in glass carboys as it saturated the materials and drained through the trays. Total water volume that contacted with litters was calculated and recorded carefully for each tray. Samples were collected immediately after each rainstorm during one-year period between January 2016 to December 2016. Preliminary results demonstrated that there was always higher DOC in trays with unmanaged forest detritus, compared to the burnt detritus. Also, pH of the unmanaged forest detritus was always lower than the other treatments and blank. Most of the volatile fine litter debris was flushed out in the first few rain events. Our findings suggest that prescribed burns overall reduce the export of DOC compared to an unmanaged site. However, the season of prescribed burn did not make a difference. II. Roles of DOM In the Objective II, we conducted laboratory studies to evaluate photochemical and microbial transformations of DOM in source water. In the photochemical study, the reactive oxygen species (ROS) production by DOM and their impact on the survival of Escherichia coli under the light irradiation were investigated. Production of singlet oxygen and triplet stage DOM were observed during the irradiation of DOM. However, these ROS did not inactive Escherichia coli. In contrast, the DOM would protect the E. coli from being inactive by the light irradiation. Furthermore, the nutrient in the DOM would also promote the growth of E. coli. The results of this study provide valuable information on the potential impact of the DOM on the bacterial survival and ROS production in natural aquatic environment. In the microbial study, two freshwater green algae (Pseudokirchneriella subcapitata) and blue-green algae (Microcystis aeruginosa) were separately incubated in the mixture of cultural medium and pine (Pinus palustris) litter-derived thermally-derived DOMs (TA-DOM) (50 °C, 250 °C, and 400 °C) over 7 days to demonstrate the effects of algal growth on alterations in DOM composition. TA-DOM optical and chemical characteristics were quantified by absorption and fluorescence spectroscopy and chlorination-based reactivity experiments. After the inoculation with P. subcapitata, TA-DOM aromaticity (indicated by SUVA254) increased from 1.19 to 1.90 L/mg/m for 50 °C-extract but decreased from 4.95 to 3.75 L/mg/m for 400 °C-extract. The fraction of tyrosine-like components decreased from 25.9 to 9.3% for 50 °C extract but increased from 0.9 to 1.3% for 400 °C-extract. Same patterns were also observed for M. aeruginosa. Growing algae generally increased chlorine reactivities and formations of trihalomethanes, haloacetonitriles, chloral hydrate, and haloketones. Our data suggest that the biodegradable dissolved organic carbon in TA-DOM decreases as fire intensity (i.e., temperature) increases. Post-fire algal blooms can increase chlorine reactivity of fire-affected terrestrial DOM. III) Landscape Processes In the Objective III, with support from US Forest Service, 155 ha of a first-order watershed (WS80) in Santee Experimental Watershed was burned using aerial ignition in April 2016. Water exported from this watershed and an adjunct control watershed (WS77) were closely monitored through two different water sampling techniques, including bi-weekly grab sample and flow-proportion auto-sampler. Samples have been evaluated to study pre- and post- fire changes in DOM characteristics and nutrient dynamics. In general, WS 77 showed lower DOC levels compared to the unmanaged WS80. However, analyzing only DOC values do not show a significant difference between the watersheds under prescribed fire treatment and the reference one, potentially attributed to fire-related DOC export changes being masked by the overall DOC export, as well as seasonality (increased DOC export was expected in the summer, particularly after a no-flow period in the gauging station outflow). Normalizing DOC with respect to DTN (dissolved total nitrogen), revealed that DOC/DTN overlap in pre-fire and long-term post-fire conditions. This indicated that the overall composition of DOM export was similar between both watersheds. However, during the first-flush (early June 2016), there was a decoupling of the DOC/DTN values, where the watershed under prescribed fire treatment, WS 77, had a higher value than the reference watershed. This suggested that an additional source of DOM with lower DTN was introduced in WS 77. In addition to chemical parameters, we also evaluate water quality using biological indicator. Sediment samples were collected every 2 weeks for one year to determine any changes of macroinvertebrate community due to the prescribed fire practice. This study is also conducted on WS77 and WS80. Benthic macroinvertebrate communities are commonly used as indicators of water quality in aquatic systems. Before fire WS77 always had significantly more Amphipoda than WS80, while WS80 had significantly more Isopoda and Oligochaeta than WS 77, potentially due to differences of pH, oxygen content, and food availability. After almost 5 months of recovery they have yet to show any differences as significant as our baseline data before fire.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Tsai KP and Chow AT. (2016) Growing algae alter spectroscopic characteristics and chlorine reactivity of dissolved organic matter from thermally-altered forest litters. Environmental Science & Technology 50(15): 7991-8000.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Wang JJ, Dahlgren RA, Ersan M&, Karanfil T, Chow AT (2016) Temporal variations of disinfection byproduct precursors in wildfire detritus. Water Research 99: 66-73.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Ng TW, Li BB, Chow AT, and Wong PK (2016) Effects of bromide on inactivation efficacy and disinfection byproduct formation in photocatalytic inactivation. Journal of Photochemistry and Photobiology A: Chemistry 324: 145-151.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Zhang W, Olivares C, Uzun H, Erdem CU, Trettin C, Liu Y, Robinson ER, Karanfil T, and Chow AT (2016) Exports of dissolved organic carbon following prescribed fire on forested watersheds: Implications for watershed management for drinking water supply. Presented at AGU Fall Meeting, San Francisco CA (Dec 14-18, 2016) [Abstract B23A-0559].
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Erdem CU, Uzun H, Karanfil T, and Chow AT (2016) Forest fire and drinking water quality. Presented at the South Carolina Environmental Conference, Myrtle Beach SC (March 13-15, 2016).
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Coates TA (2016) Black Carbon Production as a Result of Prescribed Fire in Coastal Longleaf Pine Forests (Presented). Presented at the 5th International Fire Behavior and Fuels Conference, Portland, OR (April 13, 2016).
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Olivares C, Dahlgren RA, Trettin C, Wang GG, Wong PK, and Chow AT (2016) Exports of dissolved organic carbon and disinfection by-product precursors from prescribed burnt forests. Presented at the AFRI and NIEQP Project Directors Meeting, Washington, D.C (October 12-13, 2016).
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Olivares C, Zhang W, Uzun H, Erdem CU, Coates TA, Rogers MF, Karanfil T, and Chow AT (2016) Exports of dissolved organic carbon and disinfection by-product precursors from prescribed burnt forests. Presented at the 252th American Chemical Society (ACS) Fall Meeting, Philadelphia, PA (August 21-25, 2016).

Progress 01/01/15 to 12/31/15

Outputs
Target Audience:1. Scientists and engineers who are interested in soil and water quality, carbon and nutrient cycles, as well as ecotoxicology and environmental safety. 2. Local agencies, forest workers, land managers, and landowners who manage the natural resources in the state of South Carolina and other southeastern states. Changes/Problems:An aerial, dormant season burn was initially scheduled for Watershed 77 of the Santee Experimental Forest during winter/spring 2015 but a culmination of factors resulted in its postponement. The aerial ignition burning window is very narrow at the Francis Marion National Forest. The weather conditions did not permit for the burn to occur. Even given ideal conditions, a limited number of day are available to burn. A major highway, South Carolina Highway 41, is located adjacent to Watershed 77; therefore, along with humidity and moisture conditions, wind direction and speed have to be ideal as to not impact visibility. Burning conditions were not ideal for the US Forest Service and resulted in the postponement of the aerial ignition fire until winter/spring 2016. Also, the field incubation study initially designated to begin in summer 2015 after the prescribed burn will now commence in January 2016. What opportunities for training and professional development has the project provided?Students have been provided opportunities to give professional presentations in national conferences, learn lab skills, and cultivate their teaching skills. Mr. Jun-Jian Wang, PhD student, had an oral preparation at the 2015 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meeting in Minneapolis MN. Miss Mary-Frances Rogers, PhD student, had a poster presentation and attended a workshop focusing on PARAFAC modeling and fluorescence spectroscopy offered through at the Internal Water Association's Specialist Conference on Natural Organic Matter in Water, Malmö, Sweden. Mr. Thomas A. Coates, PhD student, was able to coordinate and develop field laboratories and demonstrate forestry techniques for soil and forest management students at Horry Georgetown Technical College with the assistance of another Ph.D. student (Mary-Frances Rogers). How have the results been disseminated to communities of interest?Public disseminations of the technical results from these studies have been conducted through two avenues. First, key technical details were disseminated through peer reviewed publications and presentations at national/regional forestry and environmental science venues. Two research articles and two book chapters were published. Two manuscripts are in preparation for submission to peer review journals. Oral and poster presentations were presented at the International Water Association's Specialist Conference on Natural Organic Matter in Water, Malmö, Sweden (September 9-10, 2015), at the Piedmont-South Atlantic Coast Cooperative Ecosystem Study Unit, Athens, GA (September 9-10, 2015), and the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meeting in Minneapolis MN (Nov 15-18, 2015). Second, we disseminated the results of the research study to local natural resource agencies, forest workers and landowners at the field day associated with the Fifth Interagency Conference on Research in the Watersheds (March 4, 2015), North Charleston, SC and at the James C. Kennedy Waterfowl and Wetlands Center Dedication Ceremony, Georgetown, SC (November 24, 2015). Detailed information can be found in the product section of this project report. What do you plan to do during the next reporting period to accomplish the goals? I. Management Practices Burning during the dormant season will be conducted at the Tom Yawkey Wildlife Center Heritage Preserve in 2016. Fire frequency (annual or biennial) will be the variable of interest for these burns. The field incubation study examining detritus material from the 2015 dormant vs growing season fires will be started in January 2016. These samples will be placed in aluminum trays on January 2016 and leachate will be collected and analyzed to determine the effects of burning on potential export products. Leachate will be collected and analyzed for at least one year. II. Role of DOM An additional laboratory investigation of the effect of fire temperature on black carbon production will be conducted in early 2016 using pine and oak litter obtained from the Tom Yawkey Wildlife Center Heritage Preserve. A split-tube furnace will be used to heat litter material at different temperatures to determine how burning temperature affects black carbon production and subsequent characterization and treatability. III. Landscape Processes The experimental watershed WS77 in the Francisco Marion National Forest is scheduled to burn in winter 2015. Sampling and surveys are currently being conducted according to the methods described in the proposal. Additional water and soil samples will be continuously collected after the watershed is burnt.

Impacts
What was accomplished under these goals? I. Management Practices - Dormant and Growing Season Prescribed Burn The field site in Georgetown, South Carolina at the Tom Yawkey Wildlife Center Heritage Preserve was identified in early January 2015. Portions of this property have been frequently burned since 1978. Fifteen blocks were identified for treatment implementation at this site to evaluate the effects of fire frequency and season on black carbon production. Pre-treatment fuels data were obtained during the dormant season, 2015. Additionally, overstory trees and understory vegetation were tallied and soil samples were taken prior to burning. Dormant season burning took place on three tracts at the Tom Yawkey Wildlife Center Heritage Preserve March 9-11, 2015. Growing season burning took place on three tracts May 5-6, 2015. Post-treatment fuels were assessed immediately after burning. Ash samples were taken immediately after burning as well. Soil samples were taken directly after burning and have been taken every 4 months since the tracts were burned. Type K thermocouples connected to HOBO Dataloggers were used to assess maximum burning temperature, burning duration (total duration and duration greater than 60oC), and net heat flux (total and beyond 60oC). These thermocouples were installed vertically (extending 25 cm above the litter-soil interface) and horizontally (extending horizontally at the litter-soil interface) to determine if thermocouple orientation affects heating estimation. Fuel loading was not a significant predictor of maximum burning temperature or burning duration in either season on forest stands that have been frequently burned. Maximum burning temperature did not differ between the dormant and growing season burns regardless of thermocouple orientation. Duration of heating and net heat flux differed by season and differed as a result of thermocouple orientation. Thermocouples installed at the litter-soil interface obtained consistently higher temperatures, longer durations, and greater heat fluxes than thermocouples extending 28 cm above the litter-soil interface. Litter, soil, and ash samples collected before and after burning at the Tom Yawkey Wildlife Center Heritage Preserve are being examined for black carbon characterization using analytical pyrolysis/GC-MS to determine the effects of prescribed fire frequency on vegetation dynamics and subsequent black carbon production. Processing of these samples is currently in progress and a manuscript regarding fire temperature and black carbon production is under preparation. II. Role of DOM The potential impact of the dissolved black carbon (BC) in surface sunlit water was examined. Different black carbon was prepared by pyrolysis or thermal oxidation of litter from ponderosa pine and white fir at 250 and 400oC. Then the dissolved black carbon was extracted and used for subsequent studies. The photodegradation of dissolved BC irradiated with a sunlight simulator was investigated. The three-dimensional fluorescent excitation-emission matrix (EEM) spectra, absorption spectra from 200-600 nm, and total organic carbon (TOC) of the solution at different time intervals were determined. All of the dissolved BC was degraded under light irradiation. Protein-like substances are less prone to light degradation than humic-like substances. The effects of dissolved black carbon on bacterial survival under light irradiation were also studied. The viability of Escherichia coli under light irradiation in the presence of different dissolved BC was determined. The results showed that the dissolved BC can protect bacterial cells from inactivation by the light irradiation. Furthermore, dissolved BC from pyrolyzed samples was relatively weaker in protection power. The bacterial regrowth potential (BRP) of the dissolved BC was determined. E. coli was inoculated in solution with different dissolved BC and incubated in the dark at 25oC for 24 h. All the dissolved BC samples show an increase in viable E. coli concentration after incubation, indicating that the dissolved BC can promote the growth of bacterial cells in aquatic systems. Finally, the generation of different reactive oxygen species (ROS), including singlet oxygen (1O2), hydroxyl radical (?OH) and triplet state dissolved organic matter (3DOM*), of different dissolved BC under light irradiation were determined. Furfuryl alcohol (FFA), para-chlorobenzoic acid (pCBA), 2,4,6-trimethylphenol (TMP) were used as probes for the detection of s1O2,•OH and 3DOM*, respectively. A significant generation of 1O2 and 3DOM* by the irradiated BC was observed, while the production of ?OH was limited. The production of 1O2 is affected by the thermal treatment of BC. For the same temperature treatment, the generation of 1O2 in pyrolyzed samples was lower than that of the thermally oxidized samples. The results of the study showed that different thermal treatment of organic matter affects their properties and their sequential impact to the aquatic environment, including the protection of bacterial cells, bacterial regrowth potential, as well as ROS generation. In general, pyrolyzed samples would provide less protection to bacterial cells under light irradiation and produce less ROS than thermally oxidized samples. A manuscript of the laboratory study is in preparation. III. Landscape Processes In preparation for the anticipated fire in 2015, pre-treatment fuels data were collected using Brown's Planar Intersect Method on Watersheds 77 and 80. Continued monitoring of outflow waters from Watersheds 77 and 80 in the Francis Marion National Forest are being evaluated for dissolved organic matter characterization via ultraviolent and fluorescence spectroscopy. Dissolved organic carbon values were measured using ultraviolet absorbance scanning from 200 to 700 nm with a Shimadzu UV-1800. Fluorescence spectroscopy was measured using a Shimadzu RF-5301. In addition, monthly outflow water samples were collected from November 2014 to present for DOM characterization. Historical dissolved organic carbon, ultraviolent absorbance, fluorescence data, and flow data are currently being compiled and analyzed from 2003-2015. Dissolved organic carbon (DOC) concentrations in water exported from Watershed 77 were generally significantly lower than in Watershed 80.

Publications

• Type: Book Chapters Status: Published Year Published: 2015 Citation: Tsai KP, Rogers MF, Chow AT, Diaz F (2015) Forest fire alters dissolved organic matter and disinfection byproduct precursors in forested watersheds - Part II: A controlled field study. In, Occurrence, Formation, Health Effects, and Control of Disinfection Byproduct. Karanfil et al. Eds. American Chemical Society Symposium Book, Chapter 16: 293-306
• Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Wang JJ (2015) Disinfection byproduct precursors in detritus materials of fire-affected watersheds. PhD Dissertation, Clemson University.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Chow AT (2015) Impacts of Wildfire on Dissolved Organic Matter and Disinfection Byproduct Precursors in Forested Watersheds. Oral presentation at the IWA Specialist Conference on Natural Organic Matter in Water, Malm�, Sweden (September 7-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Rogers MF (2015) Effects of Prescribed Fire on Dissolved Organic Matter in Coastal Plain Forested Watersheds. Poster presentation at the IWA Specialist Conference on Natural Organic Matter in Water, Malm�, Sweden (September 7-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Chow AT, Rogers MF Coates TA, Tsai, KP (2015) Impacts of Prescribed Fire on Polycyclic Aromatic Hydrocarbon Production and Contaminant Photo-transformation Reductions in Coastal Plain. Poster Presentation at the USDA-NIFA NIWQP and AFRI Annual Project Directors meeting, July 28-29, 2015, Greensboro, NC.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Rogers MF, Tsai KP, Coates TA, and Chow AT (2015) Effects of Prescribed Fire on Dissolved Organic Matter in Coastal Plain Forested Watersheds. Poster presentation at the Piedmont-South Atlantic Coast Cooperative Ecosystem Study Unit, Athens, GA (September 9-10, 2015).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, Ersan MS, Karanfil T, and Chow AT (2015) Temporal variation of chemical characteristics of soil and dissolved black carbon in surface soils after wildfire. Oral Presentation at ASA, CSSA, and SSSA Annual Meeting, Minneapolis, MN (Nov 17, 2015).
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, and Chow AT (2015) Controlled Burning of Forest Detritus Alerting Spectroscopic Characteristics and Chlorine Reactivity of Dissolved Organic Matter Effects of Temperature and Oxygen Availability. Environmental Science & Technology 49(24):14019-14027.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang JJ, Dahlgren RA, Ersan M, Karanfil T, and Chow AT (2015) Wildfire alters terrestrial precursors of disinfection byproduct precursors in drinking water. Environmental Science & Technology 49(10): 5921-5929.
• Type: Book Chapters Status: Published Year Published: 2015 Citation: Majidzadeh H, Wang JJ, and Chow AT (2015) Forest fire alters dissolved organic matter and disinfection byproduct precursors in forested watersheds - Part I: A controlled laboratory study. In, Occurrence, Formation, Health Effects, and Control of Disinfection Byproducts. Karanfil et al. Eds. American Chemical Society Symposium Book, Chapter 15: 271-292.

Progress 01/01/14 to 12/31/14

Outputs
Target Audience: Scientists and engineers who are interested in soil and water quality, carbon and nutrient cycles, as well as ecotoxicology and environmental safety. Local agencies, forest workers, land managers, and landowners who are managed the natural resources in the state of South Carolina and other southeastern states. Changes/Problems: In the original proposal, growing and dormant season prescribed burn practices on the experimental plots at Hobcaw Barony were proposed to start on 2014, as described in Task 1. Unfortunately, the fuels and substrates in the experimental plots were so moist after several heavy rainstorms in winter 2014 that burning was not feasible. The possible date for burning conflicted with the schedules of the land manager in Hobcaw Barony. Dormant season burning could not be conducted at that time. Only growing season burning was conducted in May 2014. In order to catch up and avoid the same problems this year, we will conduct the burning in the Yawkey Wildlife Center in addition to the burning at Hobcaw Barony in 2015. Yawkey Wildlife Center is located about 10 km South of Hobcaw Barony and is managed by South Carolina Department of Natural Resources (SCDNR). Prescribed burning practices have been implemented in the center since the 1970's with a detailed long-term record. Also, SCDNR has enough staff to ensure the experimental plots can be burned in a timely manner. All the experimental plots described in the proposal will be burned this year. For the same reason, the field incubation as stated in Task 2 is expected to start this summer. In the original proposal, we proposed to study effects of prescribed fire on water quality. With permission from the Program Manager Dr. James Dobrowolski (email communication), we also examined the impacts of wildfire on soil and water quality. Soil and water samples were collected from five sites in the Tuolumne River Watershed within the Stanislaus National Forest on October 3, 2013, December 17, 2013, and August 5, 2014, representing three scenarios after the California Rim Fire, immediately after fire, after 1st rainstorm event, and one year after fire, respectively. The five sites represented different vegetation and forest structures including chaparral, oak woodlands, Ponderosa pine, and mixed conifer forest. White (hot) and black (cooler) ashes were separately collected because they are good indicators of the burn temperature. Triplicate surface ash and soil cores (0 - 5 cm) were collected within each site. Samples were collected at 20 m interval within each transect. In addition, 3 - 5 water samples (2 L each) from nearby streams were collected during each sampling event. For comparison, non-burned detritus samples were collected from a non-burned forest located about 2 km north of the northern-most burned-area sampling site near Cherry Lake. We obtained additional funding from a National Science Foundation RAPID proposal to cover the cost of this synergistic research. Therefore, this additional study will not affect the study plan and the budget in the original proposal. What opportunities for training and professional development has the project provided? This project is a good example of interdisciplinary and collaborative research, requiring knowledge and involving faculty from different universities and federal agencies in departments of environmental engineering, forestry, soil science and biogeochemistry. This study provided training and opportunity for an assistant professor (Dr. Alex Chow) and four PhD students (Adam Coates, Mary-Frances Rogers, Jun-Jian Wang, and Kuo-Pei Tsai) to learn new analytical techniques and establish their networks. For example, the PI (Dr. Alex Chow) submitted a RAPID user access proposal to the Environmental Molecular Science Laboratory at Pacific Northwest National Laboratory and was awarded access to Fourier Transform Ion Cyclotron Resonance (FT-ICR MS) for dissolved black carbon characterization. The PI was appointed as a member of the Project Advisory Committee for the Water Research Foundation Project: WRF Project 4590 - Wildfire Impacts on Drinking Water Treatment Process performance: Development of Evaluation Protocols and Management Practices. A PhD student (Jun-Jian Wang) presented his research work in the 248th American Chemical Society meeting in San Francisco CA and was awarded with the 1st place prize for student oral presentations in the disinfection byproduct symposium. Two Ph.D. students (Jun-Jian Wang and Mary-Frances Rogers) attended a workshop offered by Colorado State University in Boulder, Colorado, which focused on the characterization of DOM through the use of fluorescence spectrometry and PARAFAC modeling. How have the results been disseminated to communities of interest? Public disseminations of the technical results from these studies have been conducted through two avenues. First, key technical details were disseminated through peer reviewed publications and presentations at national/regional forestry and environmental science venues. One research article was published and three manuscripts had been submitted to peer review journals. An oral presentation was presented in American Chemical Society National Meeting on August 10-14, 2014. Second, we disseminate the results of the research study to local agencies, forest workers and landowners in technical meetings hosted at the Baruch Institute: 1) 2014 Hobcaw Research Symposium on May 2, 2014, 2) Open House of Baruch Institute on Sept 23, 2014, and 3) Fire Program on Oct 30-31, 2014. Detailed information can be found in the product section of this project report. What do you plan to do during the next reporting period to accomplish the goals? I. Management Practices All the experimental plots including annual and periodic burning practices at the Yawkey Wildlife Center and Hobcaw Barony are scheduled to burn in winter and summer 2015 Vegetation and soil samples have been collected and other field surveys will be conducted before and after fire according to the methods described in the proposal. Results and data of these experiments will be available and reported in the next reporting period. II. Roles of DOM In the 1st year of the study, we examined photocatalytic properties of DOM using commercial standards as described in the Accomplishment section. In the 2nd year study, we will use burnt foliar litters from both controlled laboratory burning study and real forest fire field samples. Characterization of black carbon and reaction intermediates during photochemical reaction such as production of H2O2 will be tested. We expect this study will take 18-24 months. Parts of these controlled laboratory studies will be reported in the next reporting period. III. Landscape Processes The experimental watershed WS77 in the Francisco Marion National Forest is scheduled to burn in winter 2015. Sampling and surveys are currently being conducted according to the methods described in the proposal. Additional water and soil samples will be continuously collected after the watershed is burnt. Data and results of the watershed study shall be available at the end of the 2nd year study.

Impacts
What was accomplished under these goals? Accomplishments are described below associated with the three objectives / hypotheses described in the proposal: I. Management Practices Different management practices could affect fire intensity during prescribed burn. In order to determine the effects of fire intensity on the characterization and productions of dissolved black carbon, selected foliar litters were burnt at the laboratory using muffle furnace in the 1st year study. In addition, field samples of the growing season burn from the experimental plots at Hobcaw Barony were collected. Burnt foliar litters from both controlled laboratory studies and experimental plots were extracted with water to obtain water extractable organic matter (WEOM). WEOM were characterized using UV/VIS absorption, fluorescence spectrometry and disinfection byproduct formation tests. Results demonstrated the effects of forest fire significantly alter DOM leachability and compositions from the substrates. Two manuscripts based on the results of this study were prepared and submitted for peer review publications. Please see Product section for full citation. II. Roles of DOM A variety of reactive oxidative species (ROS) can be generated in photo-irradiated dissolved organic matter (DOM). The role of DOM is unclear because both photosensitizing and inhibitory effects of DOM on ROS have been observed. In the 1st year of the study, we conducted a controlled laboratory study investigating the effect of DOM on photochemical oxidation in Fe(III) containing water using Escherichia coli as a biological probe. Four different sizes and sources of DOM, including citrate, Pony Lake fulvic acid (PLFA), Suwannee River fulvic acid (SRFA), and Suwannee River humic acid (SRHA) were examined. Individual DOM, spiked with Fe(III) and H2O2 solutions, was inoculated with a known amount of E. coli and then was irradiated with simulated sun-light at pH 7 for 8 h. Experiments demonstrated that SRFA served as a strong photosensitizer, resulting a 5-log E. coli inactivation in the photo-irradiated Fe(III)-SRFA system. In contrast, SRHA served as a strong inhibitor because no E. coli inactivation was observed in the Fe(III)-SRHA system. Both citrate and PLFA served as a weak inhibitor because their efficiencies for bacterial inactivation were slightly lower than the DOM-free system. Results of this study were published in a peer review journal. Please see Product section for full citation. III. Landscape Processes In addition to studies examining the impacts of prescribed fire, we investigated the consequences of a high severity wildfire (2013 Yosemite's Rim fire) on drinking-source water quality. Specifically, soil and water samples were collected along a 13-km transect spanning the north-south axis of the fire in the Tuolumne River Watershed within the Stanislaus National Forest on October 2013, December 2013, and August 2014, representing three scenarios - immediately after fire (no rainfall), after 1st rainstorm event, and one year after fire, respectively. Samples were analyzed for 16 EPA regulated polycyclic aromatic hydrocarbon and formation potentials for a variety of disinfection byproducts (DBPs) including carbonaceous, nitrogenous, and oxygenated DBPs were examined following chlorination and chloramination. Significant levels of sixteen EPA regulated PAHs were detected in the burnt material (black and white ash samples) at the soil surface, but only a relatively low level of naphthalene (max = 0.19 µg/L) was detected in water samples. Although we did not observe significant levels (P < 0.05 µg/L) of PAHs in water, a variety of condensed aromatic compounds were observed in water extracts using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. In addition, DOM leaching from burnt materials had a lower formation potential in forming carbonaceous DBPs such as reductions in trihalomethanes (THMs) and haloacetic acids (HAAs) formation by 45% and 33%, respectively, when comparing to non-burnt foliar litter. However, an increase in formation of nitrogenous-DBPs including haloacetonitrile (HANs) (after chlorination) and N-nitrosodimethylamine (NDMA) (after chloramination) by 144% and 129%, respectively, was observed. Overall, wildfire consumed a large portion of organic matter (OM) from the detritus layer resulting in a reduction of water extractable organic carbon (WEOC-73%) and organic nitrogen (WEON-81%) yields when compared to the control. Consequently, the wildfire caused an overall reduction in water extractable terrestrial DBP precursor yield from detritus materials. A manuscript based on the results of this study was prepared and submitted for peer review publications. Results were also presented in a national conference. Please see Product section for full citation.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Ng TW, Chow AT, and Wong PK (2014) Dual roles of dissolved organic matter in photo-irradiated Fe(III)-contained waters. Journal of Photochemistry and Photobiology A: Chemistry 290: 116-124.
• Type: Book Chapters Status: Under Review Year Published: 2015 Citation: Majidzadeh H, Wang JJ, and Chow AT. (Submitted - In Revision) Forest fire alters dissolved organic matter and disinfection byproduct precursors in forested watersheds - Part I: A controlled laboratory study. In, Occurrence, Formation, Health Effects, and Control of Disinfection Byproducts. Karanfil et al. Eds. American Chemical Society Symposium Book.
• Type: Book Chapters Status: Under Review Year Published: 2015 Citation: Tsai KP, Rogers MF, and Chow AT. (Submitted) Forest fire alters dissolved organic matter and disinfection byproduct precursors in forested watersheds - Part II: A controlled field study. In, Occurrence, Formation, Health Effects, and Control of Disinfection Byproduct. Karanfil et al. Eds. American Chemical Society Symposium Book.
• Type: Journal Articles Status: Under Review Year Published: 2015 Citation: Wang JJ, Dahlgren RA, Ersan M, Karanfil T, and Chow AT (Submitted - In Revision) Wildfire alters terrestrial precursors of disinfection byproduct precursors in drinking water. Environmental Science & Technology.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Chow AT, Wang G, Trettin C, Dahlgren RA, Wong PK (2014) Impacts of prescribed fire on polycyclic aromatic hydrocarbon production and contaminant transformation reactions in coastal plain. Presented at the 2014 USDA NIFA Project Director Meeting, Arlington VA (Oct 28-29, 2014)
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Wang JJ, Dahlgren RA, and Chow AT (2014) Impacts of the rim fire on disinfection byproduct precursors in forested watersheds. Oral presentation at the Disinfection Byproduct Symposium, American Chemical Society Fall Meeting, San Francsico, CA (Aug 10-14, 2014)
• Type: Other Status: Published Year Published: 2014 Citation: Rogers MR (2014) Field methods and survey techniques for fire management practices. Poster presentation at the 2014 Hobcaw Research Symposium, Georgetown SC (May 2, 2014)
• Type: Other Status: Published Year Published: 2014 Citation: Chow AT (2014) Forest fire and water quality. Oral presentation at the Clemson Coastal Fire Program, Georgetown SC (Oct 30 - 31, 2014).