Accepted Manuscript Evidence for unmonitored coal ash spills in Sutton Lake, North Carolina: Implications for contamination of lake ecosystems Avner Vengosh, Ellen A. Cowan, Rachel M. Coyte, Andrew J. Kondash, Zhen Wang, Jessica E. Brandt, Gary S. Dwyer PII: DOI: Reference: S0048-9697(19)32221-1 https://doi.org/10.1016/j.scitotenv.2019.05.188 STOTEN 32349 To appear in: Science of the Total Environment Received date: Revised date: Accepted date: 20 March 2019 11 May 2019 14 May 2019 Please cite this article as: A. Vengosh, E.A. Cowan, R.M. Coyte, et al., Evidence for unmonitored coal ash spills in Sutton Lake, North Carolina: Implications for contamination of lake ecosystems, Science of the Total Environment, https://doi.org/ 10.1016/j.scitotenv.2019.05.188 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Evidence for unmonitored coal ash spills in Sutton Lake, North Carolina: Implications for contamination of lake ecosystems T Avner Vengosh1*, Ellen A. Cowan 2, Rachel M. Coyte1, Andrew J. Kondash1, Zhen Wang1, Jessica E. Brandt1, Gary S. Dwyer1 IP 1 CR Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, United States 2 AN US Department of Geological and Environmental Sciences, Appalachian State University, Boone, North Carolina 28608 United States *Corresponding author: Avner Vengosh (vengosh@duke.edu) M Keywords: ED Coal combustion residuals, spills, contamination, lake sediments, Hurricane Florence, AC CE PT geochemical tracers, magnetic susceptibility 1 ACCEPTED MANUSCRIPT Highlights 1. High concentrations of contaminants in coal ash pose environmental risks, particularly when coal ash leaks from storage facilities into the environment. 2. Analysis of magnetic susceptibility, visual confirmation of coal ash particles, trace T element distributions, and strontium isotope ratios of bottom sediments collected in 2015 IP and 2018 from Sutton Lake in eastern North Carolina revealed the presence of coal ash CR solids mixed with natural sediments. 3. The CCR-impacted sediments exceeded ecological screening standards in fresh water US lakes for multiple contaminants. AN 4. Porewater and leaching experiments of the CCR-impacted sediments show mobilization of soluble contaminants to the aquatic phase, potentially endanger the lake ecological M system. ED 5. The findings from this study imply that unmonitored coal ash spills may be more common than previously realized and other lakes near coal ash storage facilities, PT particularly in areas susceptible to hurricane events or frequent flooding, may also be AC CE impacted. 2 ACCEPTED MANUSCRIPT Abstract Coal combustion residuals (CCRs, also known as “coal ash”) contain high concentrations of toxic and carcinogenic elements that can pose ecological and human health risks upon their release to the environment. About half of the CCRs that are generated annually in the U.S. are T stored in coal ash impoundments and landfills, in most cases adjacent to coal plants and IP waterways. Leaking of coal ash ponds and CCR spills are major environmental concerns. One CR factor which may impact the safety of CCRs stored in impoundments and landfills is the storage area’s predisposition to flooding. The southeastern U.S., in particular, has a large number of coal US ash impoundments located in areas that are vulnerable to flooding. In order to test for the AN possible presence of CCR solids in lake sediments following Hurricane Florence, we analyzed the magnetic susceptibility, microscopic screening, trace element composition, and strontium M isotope ratios of bottom sediments collected in 2015 and in 2018 from Sutton Lake in eastern ED North Carolina and compared them to a reference lake. The results suggest multiple, apparently previously unmonitored, CCR spills into Sutton Lake from adjacent CCR storage sites. The PT enrichment of metals in Sutton Lake sediments, particularly those with known ecological impact CE such as As, Se, Cu, Sb, Ni, Cd, V, and Tl, was similar to or even higher than those in stream sediments impacted by the Tennessee Valley Authority (TVA) in Kingston, Tennessee, and the AC Dan River, North Carolina coal ash spills, and exceeded ecological screening standards for sediments. High levels of contaminants were also found in leachates extracted from Sutton Lake sediments and co-occurring pore water, reflecting their mobilization to the ambient environment. These findings highlight the risks of large-scale unmonitored spills of coal ash solids from storage facilities following major storm events and contamination of nearby water resources throughout the southeastern U.S. 3 ACCEPTED MANUSCRIPT 1. Introduction The adequate storage and management of coal combustion residuals (CCRs) is a major challenge facing energy utilities in the U.S. (U.S. EPA, 2015; Punshon, 2003). CCRs represent T one of the largest industrial solid waste streams in the U.S. and typically contain high IP concentrations of toxic and carcinogenic elements, which, upon release to the environment, CR could pose human health and ecological risks (Cordoba et al., 2012; Dreesen et al., 1977; US Izquierdo and Querol, 2012; Kosson et al., 2002; Meij and Winkel, 2007; 2009; Nelson et al., 2010; Swaine, 1992, 1994; Thorneloe et al., 2010; Twardowska, 2003). Over 100 million tons of AN CCRs are generated annually; about half is reused, mostly by the cement industry (about 33%), while the other half is stored in open impoundments and landfills (U.S. EPA, 2015 ). Even with M the reduction of coal combustion and decommissioning of coal plants in the U.S. due to the rise ED of shale gas (Kharecha et al., 2010), CCR storage remains a major public policy and PT environmental problem. There is significant evidence of leaking of CCR storage facilities and contamination of underlying groundwater and associated surface waters (Harkness et al., 2016; CE Rowe et al., 2002; Ruhl et al., 2012). The safe storage of CCRs in coal ash ponds and landfill AC sites can also be affected by natural disasters, such as hurricanes. This is particularly relevant in the southeastern U.S., where large numbers of coal ash impoundments are actively used or are in the process of being decommissioned. Previous studies have addressed the environmental risks associated with CCR disposal through investigation of the distribution of toxic and carcinogenic elements in coals and CCRs, (Cordoba et al., 2012; Dai et al., 2014; 2018; Lauer et al., 2015; Meij and Winkel, 2009; Silva et al., 2012; Swaine, 1992; 1994; Swanson et al., 2013) by exploring the mechanisms that control 4 ACCEPTED MANUSCRIPT the mobilization of contaminants from CCRs, (Izquierdo and Querol, 2012; Kosson et al., 2002; Liu et al., 2013; Schwartz et al., 2016; 2016; Thorneloe et al., 2010) and via monitoring cases where associated surface water and groundwater were impacted by: (1) major coal ash spills such as the Tennessee Valley Authority (TVA) in Kingston, Tennessee (Cowan et al., 2013; 2015; T Ruhl et al., 2009; 2010; 2014) and the Dan River, North Carolina (Cowan et al., 2017; Shin et IP al., 2017; Yang et al., 2015) spills; (2) the disposal of CCR effluents (Dreesen et al., 1977; Ruhl CR et al., 2012); and (3) leaking of coal ash impoundments (Harkness et al., 2016) . Since the installation of high-efficiency cold-side electrostatic precipitators (ESPs), fabric filters, and wet US flue gas desulphurization (FGD) in all U.S. thermoelectric plants, the conventional wisdom has AN been that any CCR environmental impact is related to either long-term fluid leaking from inadequate CCR storage infrastructure or acute impacts from major infrastructure failure and M spills (Harkness et al., 2016; Lemly, 2018; Lemly and Skorupa, 2012; Ruhl et al., 2009; 2010; ED 2012). This study presents evidence for the presence of CCR solids in lake bottom sediments and contamination of the aquatic system. CCR transport from coal ash ponds to the adjacent lakes PT could result from flooding, such as happened during Hurricane Florence in 2018, although other CE mechanisms such as unintentional CCR release and past dumping practices or historic CCR placement in the lake cannot be ruled out. AC This study presents the risks for unmonitored CCR spills through investigation of Sutton Lake near Wilmington, North Carolina (Fig. 1) and demonstrates the vulnerability of decommissioned CCR storage sites to hurricane events and the potential of CCR transport to nearby water resources. Since the early 1970’s, a 4.45 km2 impoundment known as Sutton Lake was used for cooling the nearby Sutton coal-fired steam plant. In 2013, the coal-fired plant was retired and replaced with a 625-MW natural gas combined-cycle plant. The CCRs, which have 5 ACCEPTED MANUSCRIPT been generated for decades, have been stored in impoundments and a landfill adjacent to Sutton Lake, which is widely used for boating and fishing, and plays host to abundant wildlife. In September 2018, a Category 4 major hurricane (Hurricane Florence) hit eastern North Carolina and caused significant flooding of the major river systems, including the Cape Fear River T adjacent to Sutton Lake. The flooding caused a breach of the barrier between Sutton Lake and IP the Cape Fear River, allowing flow of the upstream Cape Fear River through Sutton Lake and CR back to the downstream river (Fig. 1). The possible transport of CCRs from the nearby impoundment and landfill became a major public concern, yet those concerns were not US confirmed with independent testing for the presence of CCRs in the lake and river sediments. AN In order to determine the possible presence of CCR particles in Sutton Lake, multiple geochemical and physical diagnostic proxies were used to analyze the lake-bottom sediments. M Previous studies have shown that CCRs are enriched in several trace metals (e.g., boron, arsenic, ED selenium, molybdenum) (Fletcher et al., 2014; Harkness et al., 2016; Izquierdo and Querol, 2012; Ruhl et al., 2009; 2010; 2012; Schwartz et al., 2016; 2018; Swanson et al., 2013; Tian et PT al., 2018; Twardowska, 2003; Zhao et al., 2018), have a distinctive strontium isotope fingerprint CE (Ruhl et al., 2014), and are characterized by elevated magnetic susceptibility resulting from combustion of pyrite-containing coals (Cowan et al., 2013; 2015; 2017; Flanders, 1999; Grimley AC et al., 2017; Gune et al., 2016). In this study, these different and independent proxies were integrated to evaluate the possible presence of CCRs in the bottom sediments of Sutton Lake compared to sediments from an upstream portion of the Cape Fear River and a reference lake (Lake Waccamaw) that is not associated with CCR disposal. In addition, the mobilization of various elements from CCR-impacted sediments were evaluated through differential leaching experiments and via measurement of trace elements in pore water associated with impacted 6 ACCEPTED MANUSCRIPT sediments. Given that contamination of sediment pore water can trigger bioaccumulation through the ecosystem (Brandt et al., 2017; 2018), this could have grave implications for ecosystem Methodology 2.1. Sediments sources and sampling sites IP 2. T health. CR This study focuses on Sutton Lake, which for decades (1972-2013) was used as cooling water for and received CCR effluents from the nearby L.V. Sutton Steam Plant. In November 2013, the coal-fired units were retired and replaced by with a 625-MW natural gas combined- US cycle plant. We also studied Lake Waccamaw in coastal North Carolina (Fig. 1) which was used as a reference lake without known CCR impact. On October 22nd 2018, we collected sediments AN samples within near-surface sediments from the lake at seven sites in Sutton Lake and three in the Cape Fear River (Fig. 1). We also studied three sediment samples from Sutton Lake and three M sediment samples from Lake Waccamaw that were collected in 2015 (Brandt, 2018; Brandt et al., 2017; 2018). The 2015 samples were collected as part of the previous study and archived, ED and then analyzed along with the 2018 samples collected from this study. Lake sediments were collected using a box corer, transported back to Duke University, and dried and homogenized 2.2. PT within 48 hours. Analytical procedures CE Sediment samples were processed via (1) full digestion using HF-nitric combined acids for total dissolution of the sediments; (2) leaching with DI water in a 1:10 ratio for water AC extraction of soluble elements; (3) leaching in 1N HNO3; (4) strontium isotopes measurements; and (5) frequency-dependent mass-specific magnetic susceptibility measurement. 2.2.1. Magnetic susceptibility Frequency-dependent mass-specific magnetic susceptibility ( ) was measured at low ( LF 0.46 KHz) and high ( HF 4.6 KHz) frequencies on 6.02-cm3 plastic cubes packed with dry sediment using a Bartington Instruments MS-3 meter with a dual-frequency MS2B sensor at Appalachian State University (Cowan et al., 2013; 2015; 2017). The volume-specific magnetic susceptibility values ( ) were converted into mass specific susceptibility ( ) to account for 7 ACCEPTED MANUSCRIPT samples with different densities. The volume-magnetic susceptibility ( ) is divided by the bulk density of the sample to obtain a mass-specific magnetic susceptibility expressed in units of m3/kg (Dearing, 1999). Percent frequency-dependent magnetic susceptibility ( calculated as: FD % =( LF- HF/ LF ) x 100. A high FD% indicates FD %) is the presence of ultrafine (<0.03 m) superparamagnetic ferromagnetic minerals (Dearing, 1999), typical for soils, % (Magiera et al., 2011). The percent ash in each sample was determined by point counting using a Leica DMLP polarizing microscope IP measured for FD T whereas fly ash typically has low with a Swift model F automated point counter. Smear slides were made by taking a small amount cube and distributing it in distilled water across a 27-mm x 49-mm CR of dry sample from the glass slide. Upon drying, the sample was permanently mounted under a coverslip with epoxy US having a refractive index of 1.520 (Loctite Impruv 363). Slides were counted under 200x magnification using a standard point counting method devised to quantify ash within riverbed AN sediment at the TVA Kingston spill (RJ Lee Group, 2010). Only particles that fell under the crosshairs were counted to reach 300 counts. Particles were identified as coal ash based on M Fisher et al. (1978) and included spheres, amorphous ash, and lacy particles. Mineral grains included clay-size particles as well as silt and sand grains. Organic matter included fibrous plant ED fragments as well as freshwater microfossils, mostly diatoms. If the crosshairs landed on an empty space or if the particle could not be assigned to one of the above groups, the stage was PT advanced to the next point. 2.2.2. Sediments extraction CE 34 ± 1 mg of sediment samples were weighed in 10-mL Teflon vials and digested overnight at 90−100 °C on a hotplate in a HF-HNO3 mixture (v/v=3 mL: 2 mL; optimal grade). AC The digested samples were then dried down completely and re-digested overnight at 90−100 °C in a mixture of 15-M HNO3 (1 mL), H2O2 (1 mL; Optima grade), and quartz-distilled (QD) water (5 mL). Following the re-digestion, 0.2-mL aliquot of each digest (7 mL in total) was diluted to 2 mL for the measurement of trace element concentrations on a VG PlasmaQuad-3 inductively coupled plasma mass spectrometry (ICP-MS). The accuracy was assessed by measuring the National Institute of Standards and Technology (NIST) standard reference material (SRM) for trace elements in coal fly ash, SRM 1633a (Table 1). 2.2.3. Leaching procedure 8 ACCEPTED MANUSCRIPT Each sample underwent two leaching procedures, one using DI water and one using 1-M Optima Nitric Acid. Samples were leached in 50-mL centrifuge tubes, with about 4 grams of solid and 40 grams of liquid being used in each experiment. Tubes were placed on a New Brunswick Scientific C1 Platform Shaker and mixed at 180 rpm for 24 hours. Each leachate was extracted using a 30-mL syringe, filtered using 0.45-µm syringe filters, and collected in a 60-mL acid washed HDPE bottle. DI leachates were then acidified using 7 molar Optima Nitric Acid to T pH 2 before analysis by ICP-MS. To remove organic interference, 1 mL of digestate was added IP to 800 uL of 15N-nitric acid in Teflon vials. The mixture was then capped and heated at 100 C CR on a hotplate for 48 hours after which 200 uL of hydrogen peroxide was added to the mixture and allowed to react. US 2.2.4. Analytical procedure Trace elements were analyzed by inductively coupled plasma mass spectrometry (ICP- AN MS) on a VG PlasmaQuad-3 after gravimetric dilution in 2% HNO3. Detection limits were evaluated by multiplying the standard deviation of repeated blank measurements by three and dividing by the slope of the external standard. Strontium was separated using Eichrom Sr- M specific ion exchange resin. 87Sr/86Sr ratios were measured on a Thermo Fisher Triton thermal ED ionization mass spectrometer at Duke University in positive mode using single Re filaments with a precision of ±0.000006 on repeated measurements of NIST SRM 987 standard (mean=0.71062, Evidence for coal ash solids in bottom sediments of Sutton Lake AC 3.1. Results CE 3. PT n=98). The presence of CCRs in Sutton Lake sediments (Fig. 1) was evaluated by testing the magnetic susceptibility and geochemistry of the sediments. Previous studies have shown that combustion of coal containing iron sulfide (pyrite and marcasite) causes the formation of magnetic minerals such as spherical magnetite in CCRs (Flanders, 1999). Low-field magnetic susceptibility ( LF) was shown to be strongly positively correlated with total coal ash in riverbed samples impacted by previous CCR spills at the Kingston Fossil Plant (TVA) (Cowan et al., 9 ACCEPTED MANUSCRIPT 2015) and Dan River Steam Plant (Duke Energy) (Cowan et al., 2017), with low frequency dependence commonly reflecting presence of coal ash (Magiera et al., 2011). The magnetic susceptibility measured in sediments from Sutton Lake ranged over three orders of magnitude, from 6.06 x 10-9 m3/kg for sediments containing no visual evidence of coal ash to 6.21 x 10-6 T m3/kg for sediments with visual evidence of coal ash (Table 2). Coal ash particles were optically IP observed in sediment samples and each contained a mix of spherical ash and non-spherical CR amorphous particles (Fig 2). All observed morphologies in sediments from Sutton Lake were previously described as components of fly ash (Fisher et al., 1978; Hower, 2012) and were LF and observed percentage of fly ash particles (Fig. 2) reflects the presence and AN between US found in our previous studies (Cowan et al., 2013; 2017). High correlation (R2 = 0.95; p<0.001) mixing of CCRs with naturally occurring sediments in Sutton Lake. The effectiveness of LF at Sutton Lake sediments is aided by the high abundances M detecting CCRs with distinctive ED of quartz and CaCO3 minerals as well as organic matter in the sediment, which do not contribute to the magnetic signal of the bulk sediments. PT A second line of independent evidence is the distribution of trace elements in Sutton Lake CE sediments. The concentrations of trace elements in Sutton Lake sediments and a coal fly ash standard (NIST 1633c) were compared to those in sediments from Lake Waccamaw, which is AC used as a reference (non-impacted) lake since it is located in similar geological setting without coal ash input (Table 3). Sediments from Sutton Lake are enriched by one to two orders of magnitude in CCR-related elements relative to those in Lake Waccamaw, with conspicuously high enrichments of Cu, As, Se, Mo, Sb, and Tl (Figs. 2 and 3). Those elements are known to be enriched in CCRs (Cordoba et al., 2012; Dreesen et al., 1977; Fletcher et al., 2014; Harkness et al., 2016; Izquierdo and Querol, 2012; Kosson et al., 2002; Meij and Winkel, 2007; 2009; Rowe 10 ACCEPTED MANUSCRIPT et al., 2002; Schwartz et al., 2016; 2018; Swaine, 1992; 1994; Swanson et al., 2013; Thorneloe et al., 2010; Tian et al., 2018; Twardowska, 2003; Zhao et al., 2018), which is consistent with the enrichment measured in the fly ash standard, providing further support for the presence and mixing of CCR solids in Sutton Lake sediments. The observed high correlations between the T concentrations of these elements (i.e., Se versus As R2=0.82, p=0.008; n=6; Sb vs. Mo R2=0.53, IP p=0.06; n=6; Fig. 2), indicate mixing between CCRs and naturally occurring sediments. CR A third line of evidence for the presence of CCRs in Lake Sutton sediments is the distinctive Sr isotope ratio of the Sutton Lake sediments. The 87Sr/86Sr ratios of sediments from US Lake Sutton (full digestion) varied between 0.71129 to 0.71386, which overlaps with the Sr/86Sr ratios reported for the Appalachian coals (0.7117 to 0.7126; Fig. 4) (Vengosh et al., AN 87 2013), which have been used for North Carolina coal plants (Ruhl et al., 2012). M Thus, combined, there are three independent indicators for the presence of CCRs in ED Sutton Lake sediments after Hurricane Florence. During Hurricane Florence, the flow rates in the Cape Fear River exceeded the annual flow rates by 10-fold (Fig. 5), which resulted in the river PT overflowing through the lake and surrounding areas, including the adjacent coal ash pond and CE landfills (Fig. 1). The data from our sampling at different sites in the lake suggest transport and deposition of CCRs particles in different parts of the lake. Downstream from Sutton Lake, AC sediments in Cape Fear River (Fig. 1; n=2) show relatively low metals concentrations compared to the lake sediments. The downstream Cape Fear River sediments had slightly higher concentrations of Ni, Cu, and As relative to those in sediments from the upstream Cape Fear River (Table 3), which could reflect very small presence of CCRs solids in the downstream river sediments. Further investigation is needed to fully evaluate the possible migration of CCRs solids downstream in the Cape Fear River. 11 ACCEPTED MANUSCRIPT The sample analysis in this study also included the lake sediments from Sutton Lake collected by Brandt et al. (2015) and Brandt (2018) two years after the decommissioning of the Sutton Coal Plant (Table 3). Similar to the lines of evidence for the presence of CCRs in the lake sediments post Hurricane Florence, the data show that the 2015 Sutton Lake sediments also T contained CCR solids. This is demonstrated by the elevated magnetic susceptibility (Fig. 2A) IP and trace metals distribution that mimic the abundance of metals in fly ash standard as CR normalized to the reference lake (Figs. 2 and 3). A comparison of the mean values of trace elements measured in Sutton Lake in 2018 relative to the mean values in sediments from Sutton US Lake collected in 2015 shows similar concentrations (Table 4). These results suggest that CCR AN solids were previously (i.e., prior to 2018 flooding event) transported to the lake and accumulated in different parts of Sutton Lake (Fig. 1), regardless of the operation of the coal M plant, which was already phasing out in 2013. Figure 5 presents the flow rates in the Cape Fear ED River during the last 35 years (USGS dataset, 2018) and demonstrates that Hurricane Florence was not alone in generating high river flows above baseline, as many other storm events have PT also generated abnormal high flow rates that could result in the flooding of adjacent CCR storage CE facilitates and the transport of CCR particles into Sutton Lake. While we link the presence of CCRs in bottom sediments of Sutton Lake to flooding AC events, CCR transport as a result of human errors cannot be excluded; the close proximity of the landfill and coal ash ponds to the lake (Fig. 1), coupled with operation activities, both routine and related to the transition from impoundments to landfills, could also result in unreported CCRs spills. Likewise, historic CCR disposal practices at the site cannot be excluded. In order to test the likelihood of CCRs mobilization as part of the routine operations, data of annual fluxes of effluents discharge from the outfall of the coal ash pond in Sutton Lake and the concentrations 12 ACCEPTED MANUSCRIPT of solids reported in these effluents were examined. Mass-balance calculations for possible transport of CCR solids from the outfall of Sutton Lake using data of North Carolina Department of Environment and Natural Resources (2018) (Table 5) indicate that effluents containing total suspended solids (TSS) of 4.5 mg/L (the mean value during 2010-2013; North Carolina T Department of Environment and Natural Resources, 2018) with known discharge rates (mean IP value of 6.4x109 L per year) could not have any meaningful contribution to the mass of the upper CR 25 cm of Sutton Lake bottom sediments (Table 5). Therefore, it seems that CCR transport to Sutton Lake was not from continuous discharge of CCR solids in effluents under routine AN 3.2. US operation conditions. Contaminants in sediments and mobilization to the ecosystem M Metal concentrations in Sutton Lake sediments collected in 2015 and 2018 were enriched ED by one to two orders of magnitude compared to their concentrations in the reference lake (Lake Waccamaw) (Figs. 3 and 6). The concentrations of contaminants known to have ecological PT impacts found in Sutton Lake sediments were lower (As), similar (Cd), or even higher (Se, Ni, CE Sb, Cu, V, Co, Pb) than those measured in impacted river sediments from the Kingston, Tennessee (Tetra Tech Report, 2008) and the Dan River, North Carolina (N.C. Water Quality AC Report, 2018) coal ash spills (Fig. 6), implying a serious ecological threat, comparable to previous known coal ash spills. Metal concentrations found in Sutton Lake sediments exceeded the freshwater sediment screening benchmarks values (Fig. 6) developed to define fresh-waterlake toxicity potential (Ingersoll et al., 2001; Long et al., 2006; Long et al., 2000; MacDonald et al., 2000; MacDonald, 2003), which are commonly used by the U.S. EPA as sediment quality guidelines in evaluating threshold-effect concentrations (MacDonald, 2003). 13 ACCEPTED MANUSCRIPT Previous studies have shown that the conditions prevailing on the lake or river sediments would control the mobilization of contaminants from solid CCRs into the ambient aquatic system. In particular, the redox state would control redox-sensitive elements. For example, under reducing conditions elements like As would preferentially mobilize and become enriched in pore T water associated with CCRs. In contrast, under oxidizing conditions, elements like Se are IP preferentially mobilized (Ruhl et al., 2010; Schwartz et al., 2016; 2018). Other factors such as CR the pH would determine the leachability of metals (low-pH) relative to metalloids (high-pH). Thus, combined oxidation-reduction potential (ORP) and pH would determine the speciation and US mobility of elements from CCRs (Schwartz et al., 2016; 2018). AN In addition to the measurement of metals in the sediments (total digestion), leaching experiments were conducted in order to test the relationships between the occurrence of metals in M the bulk sediments to metals in water and acid (1 N nitric acid) leachates. The results show that ED the concentrations of trace elements in the water and acid leachates generally follow the concentrations of the bulk sediments (Table 6). A comparison of the concentrations of trace PT elements in the leachates from Sutton Lake sediments to those in leachates of sediments from the CE reference lake (Lake Waccamaw), shows one- to two-orders of magnitude enrichments of trace metals in both water and acid leachates in Sutton Lake sediments relative to those in Lake AC Waccamaw. Similar enrichment factors were observed for metal concentrations in bulk sediments from the two lakes. Furthermore, the enrichment factor distribution pattern in the water leachates (Fig. 3) mimics the patterns observed for the bulk sediments, reflecting the high reactivity of the Sutton Lake sediments and the mobilization of toxic elements that are known to be enriched in CCRs. 14 ACCEPTED MANUSCRIPT In addition, pore water data collected in 2015 from Sutton Lake and Lake Waccamaw reported in Brandt et al. (2018) and Brandt (2018) used to further evaluate the mobilization of CCR-contaminants to the ambient environment. The data show that trace metal concentrations in the pore water extracted from the 2015 Lake Sutton sediments (Brandt, 2018) were T systematically higher than those in pore water collected from Lake Waccamaw sediments (Fig. IP 3). Several of the metals that were conspicuously enriched in the bulk sediments and water and CR acid leachates were also highly enriched in the pore water, including Cu, Mo As, Se, Sb, and Tl (Fig. 3). These results are consistent with high levels of CCR-contaminants measured in pore US water from sediments impacted by the 2008 Kingston TVA coal ash spill into the Emory River, AN Tennessee (Ruhl et al., 2010). The pore water extracted from Emory River sediments covered by coal ash downstream from the spill site had elevated arsenic (up to 2000 g/L) and boron (Ruhl M et al., 2010). While the concentrations of B and As in the pore water from Sutton Lake (175 and ED 18.7 g/L, respectively) collected in 2015 (Brandt, 2018) were lower than those measured in the PT Kingston spill impacted river, they were significantly higher than pore water from the background lake (17.5 and 1.1 g/L, respectively) reflecting the mobilization of CCR- environment. CE contaminants and the potential of negative impact of the spilled CCRs solids on the ambient AC The Sr isotope ratios obtained from the bulk Sutton Lake sediments, water leachates from Sutton Lake sediments, 2015 Sutton pore water, 2015 Lake Waccamaw sediment water leachates, and 2015 Lake Waccamaw pore water were compared (Fig. 4). The 87Sr/86Sr ratios of the water leachates of Sutton Lake (0.710082±0.0002) were lower than those of the bulk sediments (0.71257±0.00107; Fig. 4), reflecting selective mobilization towards a lower 87Sr/86Sr ratio in the water-soluble Sr. The Sr isotope ratio of the water-soluble Sr was identical to the 15 ACCEPTED MANUSCRIPT 87 Sr/86Sr ratios measured in Sutton Lake in 2015 (0.71008±8x10-5) (Brandt et al., 2018), suggesting a similar differential Sr isotope leachability. Likewise, the 87Sr/86Sr ratio in watersoluble Sr from Waccamaw sediments is identical to the ratio in pore water collected from Lake Waccamaw in 2015 (Fig. 4). Consequently, the Sr isotope data indicate that the occurrence of T CCRs in Sutton Lake sediment resulted in mobilization of Sr with a higher 87Sr/86Sr ratio to the IP aquatic phase relative to the Sr isotope ratio in the pore water from the reference lake. The CR observation of differential modification of lower 87Sr/86Sr ratios in the aquatic phase relative to the bulk sediments is consistent with the results of leaching experiments conducted in CCRs US originated from Appalachian coals (Ruhl et al., 2014). AN Data from the leaching experiments conducted in this study show high mobilization of many of the trace elements known to be enriched in CCRs (Fig. 3), which is consistent with the M known distribution of trace elements in CCRs (Meij and Winkel, 2007; 2009; Swaine, 1992; ED 1994; Swanson et al., 2013; Thorneloe et al., 2010; Tian et al., 2018; Twardowska, 2003). The mobilization and enrichment of toxic elements in co-existing pore water could induce PT bioaccumulation of toxic metals (U.S. EPA, 2015; Fletcher et al., 2014; Greeley et al., 2016; CE Rowe et al., 2002) as demonstrated by high Se concentrations in fish tissues (Brandt et al., 2017) and Sr isotope ratios in fish otoliths (Brandt et al., 2018). Consequently, chronic migration of AC CCR solids to lakes, as demonstrated from Sutton Lake, would result in long-term bioaccumulation in the ecological system. 4. Discussion Ruhl et al. (2012) showed that pore water from lakes in North Carolina located near coal ash ponds and impacted by discharge of CCR effluents had systematically elevated CCR- 16 ACCEPTED MANUSCRIPT contaminant levels such as B and As compared to pore water from a reference lake without CCR input. They suggested that the elevated levels of CCR-contaminants in the pore water (Fig. 7; see location in Fig. 1) originated from discharge of the CCR effluents from the nearby coal ash impoundments (Ruhl et al., 2012). Likewise, several other studies have highlighted the T negative impact of the discharge of effluents from coal ash ponds outfalls and the IP bioaccumulation of toxic elements like Se due to the discharge of CCR-enriched effluents CR (Brandt, 2018; Brandt et al., 2017; Lemly, 2018; Lemly and Skorupa, 2012). Yet the data presented in this study suggest that transport and accumulation of CCR solids in the sediments US of impacted lakes, followed by mobilization of CCR-contaminants to the pore water could also AN cause this contamination. Based on the presence of CCR solids in Sutton Lake in 2015, two years after the decommissioning of the coal plant, combined with large-scale occurrence of M CCR-contaminants in pore water across North Carolina (Ruhl et al., 2012) shown in Fig. 5, it is ED hypothesized that the case of Sutton Lake may be not unique and that CCR solids may have been transported from disposal sites and accumulated in adjacent lakes at many additional sites PT throughout the southeastern U.S. CE Figure 1 presents the paths of major hurricanes during the last two decades, demonstrating the vulnerability of CCR disposal sites to major flooding events like Hurricane Florence in 2018. AC Likewise, hydrographs from major river systems in North Carolina show systematically high flow rates in major river systems of North Carolina during the last 30 years (Fig. 5), reflecting multiple weather events that could cause flooding and CCR solids transport to adjacent lakes. Observations in Sutton Lake and pore water data (Ruhl et al., 2012) from lake sediments all over North Carolina (Fig. 5) indicate a much wider scale phenomenon; CCRs are not restricted to designated disposal sites such as impoundments and landfills but are also present in lakes 17 ACCEPTED MANUSCRIPT adjacent to these disposal sites. This implies that the distribution and impact of CCRs in the environment is far larger than previously thought. The high concentrations of toxic metals above the acceptable ecological thresholds we found in Sutton Lake sediments requires protection and remediation measures, especially due to the extensive use of Sutton Lake for fishing and T recreation. Future studies should look to test the hypothesis that other lake systems in the Conclusions US 5. CR potential ecological and human health implications. IP southeast near CCR disposal facilities contain significant CCR solids and evaluation of the AN This study presents new data that show evidence for the presence of coal ash solids in sediments from Sutton Lake in eastern North Carolina. The variations of magnetic susceptibility, M trace metals distribution, and strontium isotope ratios suggest mixing of CCRs solids and the ED local sediments at different locations in the lake. We found evidence for the presence of CCR solids in near-surface sediments from the lake in samples collected in 2015 and 2018 (post PT Hurricane Florence), and suggest that flooding events may have caused the transport of CCRs CE solids from the adjacent CCR storage sites near the lake and accumulation in the lake-bottom sediments. Other mechanisms such as unintentional CCR release and past dumping practices or AC historic CCR placement in the lake cannot be ruled out. The high concentrations of several contaminants in Sutton Lake sediments are similar to, and even exceed, for some elements, the concentrations of contaminants in impacted sediments reported for previous coal ash spills like the Kingston and the Dan River spills, and were also above the regulated ecological guidelines for contaminants in sediments from freshwater lakes. The unmonitored spills of CCRs solids further resulted in mobilization of soluble contaminants to the aquatic phase and enrichment in 18 ACCEPTED MANUSCRIPT the pore water as compared to pore water extracted from a reference lake without a CCR impact. The association of CCR solids in lake sediments and pore water contamination demonstrated in this study implies that unmonitored spills may have occurred also in other lakes near CCR storage facilities, where pore water was previously shown to be elevated in CCRs associated T contaminants. The possible widespread transport of CCRs solids to the environment beyond IP storage facilities is of concern, and future studies should verify whether water resources US CR throughout the southeastern U.S and elsewhere are impacted by unmonitored coal ash spills. AN ACKNOWLEDGEMENTS The authors also gratefully acknowledge the support of the Nicholas School of the M Environment at Duke University. We thank and acknowledge Kemp Burdette from Cape Fear ED Riverkeeper for his assistance in the field, and Jon Karr for his assistance with laboratory work AC CE constructive review. PT and chemical analyses. We thank Jim Hower and two anonymous reviewers for their 19 PT ED M AN US CR IP T ACCEPTED MANUSCRIPT AC CE Figure 1: Map of coal ash ponds in southeastern U.S. and major hurricane tracks (> category 3) during the last two decades. Insert map shows the sampling sites locations in Sutton Lake collected in 2015 and 2018. The location of coal ash storage facilities in North Carolina is also included. Data on hurricane flow path were from the National Oceanic and Atmospheric Administration (2018). Stars on the map show locations where hydrographs were created for in figure 5. 20 ACCEPTED MANUSCRIPT s B am s s s s s AC CE PT ED M AN US CR IP T am Figure 2: Multiple lines of evidence for the occurrence of CCR solids in Sutton Lake sediments: A: Percent of identified fly ash versus measured magnetic susceptibility in sediments collected from different sources.; B: Light micrograph of Sutton 03 sample with examples of ash spheres (s) and amorphous opaque (am) nonspherical ash; C: Selenium versus arsenic concentrations in sediments from different sources; D: Antimony versus molybdenum concentrations in sediments from different sources. 21 CE PT ED M AN US CR IP T ACCEPTED MANUSCRIPT AC Figure 3: Distribution and enrichment of trace elements in sediments (A and B), pore water (C), and leachates (D) relative to the trace element concentrations of sediments, pore water, and leachates in the reference lake (Lake Waccamaw). A: Mean values of metals in Sutton lake sediments collected in 2018 and fly ash standard (NIST SRM 1633c, labeled “CCR”) compared to metals concentrations in Lake Waccamaw; B: Mean values of metals in Sutton lake sediments collected in 2015 and fly ash standard (NIST SRM 1633c, labeled “CCR”) compared to metals concentrations in Lake Waccamaw; C: Mean values of metals in pore water and Sutton lake sediments collected in 2015 compared to metals concentrations in Lake Waccamaw sediments and pore water (data from Brandt, 2018 ); and D: Mean values of metals in water leachates extracted from Sutton Lake sediments and 2018 Sutton Lake sediments compared to water leachates and bulk sediments from Lake Waccamaw. 22 AC CE PT ED M AN US CR IP T ACCEPTED MANUSCRIPT Figure 4: Box plot of Sr isotope variations of Sutton Lake sediments, water leachates extracted from Sutton Lake sediments, Sutton pore water collected in 2015, Waccamaw Lake sediments, and Waccamaw pore water collected in 2015. The Sr isotope data indicate that (1) sediments from Sutton Lake have a 87Sr/86Sr ratio that mimic the ratios reported for the Appalachian coals (Vengosh et al., 2013); and (2) that Sr isotope ratios in water leachates are identical to pore water in both the Sutton and Waccamaw lakes; and (3) selective mobilization of Sr to the water phase with a lower 87Sr/86Sr ratio relative to the 87Sr/86Sr in the bulk sediments. Sr isotope ratios in Sutton Lake and Lake Waccamaw pore waters from 2015 are from Brandt et al. (2018). 23 PT ED M AN US CR IP T ACCEPTED MANUSCRIPT AC CE Figure 5: Hydrographs of mean monthly discharge rates (m3/s) of major river systems in North Carolina (see locations in Fig. 1). Data was generated from U.S. Geological Survey Current Water Data for North Carolina (2018). 24 PT ED M AN US CR IP T ACCEPTED MANUSCRIPT AC CE Figure 6: Box plots of selected metals with ecological impact measured in sediments collected from Sutton Lake in 2018 and 2015, Lake Waccamaw (reference lake), and in sediments impacted by the TVA Kingston (Tetra Tech Report, 2008) and Dan River (N.C. Water Quality Report, 2018) coal ash spills, compared to freshwater sediment screening benchmarks values for sediment toxicity used by U.S. EPA (MacDonald et al. 2000; MacDonald, 2003). Results from Sutton Lake sediments show high levels of metals comparable and in most cases higher than metals concentrations found in sediments impacted by the TVA Kingston and Dan River coal ash spills. The metals concentrations exceeded the acceptable screening thresholds for aquatic freshwater sediment toxicity used by U.S. EPA to define potential ecological impact (Long et al., 2000; 2006; MacDonald et al., 2000; MacDonald, 2003. 25 AN US CR IP T ACCEPTED MANUSCRIPT 176.8 170.5 172.0 174.1 173.4 Be mg/kg 16 14.8 14.7 14.6 14.4 14.6 91.4 B mg/kg 76.6 75.7 74.9 76.4 75.9 V mg/kg 286.2 236.4 229.4 229.5 228.3 230.9 80.7 Cr mg/kg 258 184.7 177.4 178.7 180.3 180.3 69.9 Mn mg/kg 240 222.1 216.7 211.4 216.3 216.6 90.3 CE Certified Value 1633c 1633c 1633c 1633c 1633c Mean Recovery % Li mg/kg AC Sample Name PT ED M Figure 7: Concentrations of arsenic and boron in pore water from lakes located near CCR storage sites (Sutton, Hyco, Mayo, High Rock, Wylie, and Mountain Island (Brandt, 2018; Ruhl et al., 2012) compared to reference lakes without potential impact from nearby CCR storage sites (Waccamaw and Jordan). The location of the lakes is shown in Figure 1. The enrichment of As and B in pore water from bottom sediments in lakes located nearby CCR storage sites is suggested to be derived from mobilization of As and B from CCR solids that were spilled and accumulated in the lakes, as evidenced from the Sutton Lake case. Co mg/kg 42.9 40.1 38.9 38.8 38.4 39.1 91.1 Ni mg/kg 132 138.7 129.0 124.2 124.0 129.0 97.7 Cu mg/kg 173.7 175.0 167.8 165.0 165.9 168.4 97.0 As mg/kg 186.2 186.2 181.0 182.8 182.0 183.0 98.3 Se mg/kg 13.9 19.3 18.8 16.7 15.7 17.6 126.9 Rb mg/kg 117.42 113.3 112.4 110.1 111.6 111.8 95.2 Sr mg/kg 901 906.9 894.0 879.4 875.3 888.9 98.7 Mo mg/kg Ag mg/kg 26.0 25.4 25.6 25.5 25.6 0.7 0.6 0.6 0.6 0.7 Cd mg/kg 0.758 0.7 0.6 0.6 0.7 0.7 88.6 Sb mg/kg 8.56 8.6 8.4 8.1 8.2 8.3 97.3 Ba mg/kg 1126 1098.3 1124.4 1069.3 1091.1 1095.8 97.3 Tl mg/kg 6.6 6.4 6.5 6.5 6.5 Table 1: Concentrations of trace elements measured in fly ash standards (NIST 1633c) as compared to certified values. The recovery of the extraction procedure is the ratio between measured (n=4) and certified values, expressed in percent. 26 Pb mg/kg 95.2 101.1 98.4 98.3 98.0 99.0 104.0 Th mg/kg 23 22.1 21.8 21.4 21.4 21.7 94.3 U mg/kg 9.25 9.0 8.9 8.9 8.7 8.9 95.8 Upstream Cape Fear -2 ΧLF (m /kg) Coal Ash % -5.85293E-09 0 Sutton Lake 2018 Sutton 1 1.38496E-07 Sutton 5 1.5704E-06 Sutton 7 1.30897E-06 Sutton 6 6.06219E-09 Sutton 3 6.21968E-06 Sutton 4 6.8189E-07 Cape Fear River - downstream Cape Fear -1 5.58152E-09 Cape Fear -3 -3.74826E-09 CR 0 0 US Sutton Lake 2015 Sutton 01 2015 Sutton 02 2015 Sutton 03 2015 Reference Lake (2015) Waccamaw 2 Waccamaw 3 5.0 38.7 27.7 0 89.0 21.0 IP 3 Sample T ACCEPTED MANUSCRIPT 28.6 58.6 16 M AN 1.03396E-06 4.49442E-06 3.28023E-07 0 0 ED 5.35389E-08 5.85811E-08 Sutton Lake 2018 Sutton 1 Sutton 5 Sutton 7 Sutton 6 Sutton 2 Sutton 3 Sutton 4 Cape Fear River- downstream Cape Fear -1 Cape Fear -3 Sutton Lake 2015 Sutton 01 2015 Sutton 02 2015 Sutton 03 2015 Reference Lake (2015) Waccamaw 2 Waccamaw 3 0.9 16.7 12.2 7.3 BDL 17.6 27.5 22.5 133.2 369.1 121.7 3.4 278.5 205.5 242.0 31.1 93.7 38.7 2.7 73.9 105.4 89.6 895.3 821.7 157.8 35.6 739.5 863.6 801.6 21.3 46.1 17.1 0.1 33.0 37.1 35.1 79.8 130.6 52.8 BDL 116.9 92.0 104.4 420.3 648.0 228.6 0.5 475.3 284.3 379.8 82.5 185.8 65.1 15.2 154.7 111.4 133.1 33.7 46.8 11.4 BDL 34.8 16.8 25.8 23.2 42.7 7.7 BDL 19.0 13.2 16.1 26.0 62.2 32.8 4.1 55.2 106.1 80.7 189.7 228.0 94.3 20.1 127.1 438.9 283.0 12.3 23.6 8.4 BDL 25.1 3.4 14.3 0.1 0.5 0.2 0.0 0.3 0.4 0.4 1.0 2.3 0.3 BDL 0.9 0.7 0.8 6.8 14.4 3.3 BDL 9.6 6.4 8.0 526.0 675.2 250.4 70.0 482.1 1000.1 741.1 2.0 5.2 1.5 BDL 3.1 2.3 2.7 25.4 58.2 21.7 4.0 39.5 39.4 39.5 3.8 11.0 6.3 1.0 7.1 17.7 12.4 2.8 6.4 2.3 0.2 3.3 6.0 4.7 0.0 BDL 0.6 14.1 2.4 5.1 2.2 2.4 24.6 19.2 0.3 1.2 0.4 10.2 1.1 6.4 6.4 26.6 0.1 1.4 BDL BDL 7.7 10.8 17.5 25.9 BDL BDL BDL 0.1 BDL BDL BDL BDL 92.2 92.3 BDL 0.1 3.4 5.1 0.8 0.3 0.3 0.2 140.3 105.2 103.7 4.9 5.4 2.5 18.6 19.3 7.8 224.9 148.2 224.9 75.7 63.9 56.4 376.5 423.6 310.4 33.5 24.6 27.0 126.1 65.7 115.0 613.3 263.5 463.8 406.7 68.9 116.6 38.8 34.4 32.6 25.8 10.7 17.0 56.7 69.2 46.0 195.4 267.0 136.9 14.1 7.5 20.6 0.4 0.3 0.3 0.8 0.4 0.8 6.5 3.4 6.3 458.5 515.0 342.7 2.5 1.7 3.3 47.2 34.2 39.6 10.6 12.0 7.3 5.3 4.3 3.3 25.4 20.0 0.5 0.4 21.3 15.3 43.6 34.7 35.3 28.5 157.9 149.5 9.1 7.2 56.4 16.6 8.3 4.8 306.5 281.7 4.2 2.6 0.1 BDL 15.9 11.3 43.0 31.3 0.1 BDL 0.2 0.1 0.2 0.1 BDL BDL 160.7 110.8 0.2 0.2 34.3 28.5 7.3 5.8 2.0 1.4 Li Be B 2.2 0.2 0.6 36.3 125.4 58.1 2.8 126.1 148.6 137.3 2.6 6.5 2.4 0.5 2.8 9.7 6.3 2.4 3.1 V Cr Mn Co Ni Cu Zn As Se Rb Sr Mo Ag Cd Sb Ba Tl Pb Th U 1.9 1.6 28.5 0.9 0.8 19.5 0.1 BDL 19.2 31.1 0.0 0.0 0.0 BDL 191.6 0.1 7.3 1.2 0.3 AC Sample Upstream Cape Fear -2 CE PT Table 2: Frequency dependent mass-specific magnetic susceptibility and percent coal ash counting from physical observation in sediments from different sources investigated in this study. Table 3: Concentrations of trace elements in sediments from different sources investigated in this study. 27 ACCEPTED MANUSCRIPT Mean values Average Sutton 2018 Average Sutton 2015 Average Waccamow 2015 n 7 3 2 Li 90.7 116.4 22.7 Be 4.4 4.3 0.5 B 17.3 15.2 18.3 V 193.3 199.4 39.1 Cr 62.2 65.3 31.9 Mn 616.4 370.2 153.7 Co 27.1 28.4 8.1 Ni 96.1 102.3 36.5 Cu 348.1 446.9 6.6 Zn 106.8 197.4 294.1 As 28.2 35.3 3.4 Se 20.3 17.8 0.1 Rb 52.4 57.3 13.6 Sr 197.3 199.8 37.2 Mo 14.5 14.1 0.1 Ag 0.3 0.3 0.2 Cd 1.0 0.7 0.2 Sb 8.1 5.4 0.0 Ba 535.0 438.7 135.8 Tl 2.8 2.5 0.2 Pb 32.5 40.4 31.4 NIST 1633c (fly ash standard) 4 173.4 14.6 75.9 230.9 180.3 216.6 39.1 129.0 168.4 236.8 183.0 17.6 111.8 888.9 25.6 0.7 0.7 8.3 1095.8 6.5 99.0 0.78 3.99 5.12 1.02 9.42 9.20 1.14 0.95 0.83 0.97 4.94 5.09 0.95 1.95 2.05 1.67 4.01 2.41 0.96 3.33 3.48 0.94 2.63 2.80 0.78 53.05 68.10 0.54 0.36 0.67 0.80 8.27 10.34 1.14 265.23 232.65 0.91 3.85 4.21 0.99 5.30 5.37 1.03 109.96 106.58 0.84 1.78 2.12 1.51 5.57 3.69 1.50 363.82 242.85 1.22 3.94 3.23 1.14 12.43 10.94 0.81 1.03 1.28 Ratio Sutton Lake 2018/2015 Ratio Sutton Lake 2015/Lake Waccamaw Ratio Sutton Lake 2018/Lake Waccamaw US Value ED M AN Variable Lake Sutton Area Sediment Depth Sediment Depth Volume of Sediment Volume of Sediment Mean Solid Flow Rate Effluent Discharge Rate Effluent Discharge Rate Effluent Discharge Rate TSS of input water Percentage of Coal Ash In Sediment from App State or chemistry data CR IP T Table 4: Mean values of trace-element concentrations measured in sediments from Sutton Lake collected in 2018 and 2015, Waccamaw Lake, Cape Fear River (upstream and downstream from Sutton Lake), and fly ash standard (NIST 1633c). The lower panel shows the ratios of different elements in sediments from different sources. CE PT Mass input to lake Mass input to lake 4,597,952.0 25.0 0.3 1,149,488.0 1.15E+12 4.5 4.6 1.74E+07 6.36E+09 4.5 Units m^2 cm m m^3 cm^3 mg/L mgd L per day L per year mg/L 10% 2.86E+10 mg/yr 2.86E+07 g/yr 2650 2.65 1.6 2.93E+12 Time to fill 1.02E+05 years AC Density of Lake Sediment Density of Lake Sediment Density of coal ash Amount of sediment kg/m^3 g/cm^3 g/cm^3 g Table 5: Mass-balance calculations for possible discharge of CCRs from routine discharge of CCR effluents from the Sutton Lake outfall. The mass- calculations were based on the discharge rates reported from Sutton lake outfall multiple by the total solids in the effluents (TSS) for obtaining the annual mass of CCRs discharged from regulated outfall in 2010 to 2013. That annual mass flux was compared to the mass of the upper 30 cm of Sutton Lake bottom sediments. Given the known flux rate and the lake sediments volume (converted to mass) the time to fill the lake sediments with CCR was calculated. Data for effluents discharge and concentrations of total suspended solids (TSS) are from mean values calculated from NC DEQ reported data (2010-2013). 28 ACCEPTED MANUSCRIPT Be B V Cr Mn Co Ni Cu Zn As Se Rb Sr Mo Ag Cd Sb Ba Tl Pb Th U 0.1 175.8 29.3 35.3 235.1 31.0 115.2 9.6 420.4 3.6 2.5 7.5 58.0 1.9 BLD 0.1 0.7 70.8 0.1 21.3 0.0 0.7 BLD BLD 0.9 0.5 0.3 BLD BLD 1646.8 2975.8 842.7 514.9 1279.8 870.2 977.2 455.9 316.8 265.5 77.8 1947.6 173.3 553.3 43.9 39.6 32.5 70.1 28.6 75.2 24.3 14669.6 6678.9 2643.3 409.4 3834.2 2848.6 4758.8 130.5 30.0 26.9 15.9 32.3 32.1 30.7 344.7 224.5 168.6 314.8 245.1 405.6 185.2 156.9 237.1 156.8 56.9 196.5 368.6 178.9 549.0 440.6 444.7 1352.8 418.5 1461.7 402.2 317.6 157.1 77.4 21.2 240.2 38.9 253.6 76.9 129.9 49.7 0.0 131.0 56.9 131.0 121.2 159.2 112.3 6.0 124.8 128.9 134.6 4350.6 2563.0 1969.3 121.2 2458.0 1811.2 1787.1 342.9 697.8 1008.8 9.1 4619.5 158.3 2396.3 0.1 BLD BLD BLD BLD 0.1 0.0 1.9 2.6 1.7 0.0 6.1 0.5 3.5 126.2 86.3 86.5 1.4 408.8 72.9 133.4 1010.8 1171.5 692.6 62.1 868.8 612.2 889.5 32.6 46.8 26.8 0.8 26.2 19.0 39.8 34.6 10.9 9.6 10.0 7.0 11.4 3.6 0.0 0.0 0.2 0.3 0.0 0.2 0.0 0.8 1.1 1.2 1.3 1.0 0.5 0.4 BLD 0.3 645.1 527.1 60.1 12.3 114.3 67.6 397.4 131.9 38.0 15.9 383.5 317.1 32.6 12.4 1457.5 1402.6 12.8 1.6 2.1 0.0 7.3 7.6 188.6 49.0 7.8 0.0 0.1 BLD 0.0 0.0 2.6 0.6 104.5 35.3 0.1 0.2 33.2 4.6 1.4 0.0 1.0 0.4 3.3 0.0 11.0 1652.9 1856.0 1580.3 135.5 18.7 284.3 44.8 91.3 96.7 71055.2 95342.0 100334.5 546.9 399.4 3238.0 1253.8 1294.2 8618.5 1805.2 648.4 2208.1 1243.3 2050.3 8478.4 73.9 49.6 88.5 150.5 69.3 137.2 271.2 166.2 311.8 14269.1 11664.5 27409.9 32.5 11.7 71.4 BLD BLD BLD 27.9 19.7 97.0 38.6 17.4 68.5 1179.3 1172.1 1089.1 105.1 59.2 232.0 49.7 66.3 72.8 0.0 0.0 0.0 1.6 0.0 1.6 0.710009 0.710171 0.709932 BLD 1.3 430.8 938.4 15.4 122.6 23.5 120.5 7235.8 8887.0 15.9 29.4 128.2 441.9 12.4 63.8 538.0 1687.1 6.8 22.1 0.0 5.7 67.7 168.9 1940.8 2366.9 1.4 2.3 BLD 0.1 1.3 3.7 3.3 4.2 655.2 584.1 6.9 17.4 35.4 97.0 0.0 4.1 0.4 4.6 0.709563 0.709527 2.0 Acid Leaching 48.8 142.0 279.5 193.6 4773.2 412.4 360.3 103.7 3448.9 18.2 10.6 1407.2 2477.5 1547.7 12.9 1061.9 1441.5 3322.1 4436.6 1831.9 550.2 1480.7 2473.0 116927.9 331088.3 139422.8 483.5 194479.3 93395.0 6812.4 29928.1 14542.9 144.2 12392.6 6924.7 411625.7 352040.5 181449.8 4944.2 216724.1 331597.4 14235.4 27945.1 19065.0 100.7 14367.9 12194.4 56084.4 78901.8 50668.2 598.6 61485.4 29166.2 293384.2 495894.6 264335.0 1186.3 288295.9 159662.5 40687.9 98264.8 40663.2 2418.3 41669.5 38228.7 24992.8 34733.3 13977.3 165.3 20429.1 6600.3 4733.3 5125.7 1977.9 9.6 3024.0 1444.1 289.2 108.6 6.8 29.2 187.6 463.8 236.5 207.5 138.0 229.2 3970.0 4334.8 66.7 415.7 261.0 655.1 268.7 124.7 1468.2 4610.3 29674.0 29674.0 3312.7 1183.2 1183.2 494.5 3910.2 3910.2 1133.6 99691.2 99691.2 11272.5 7547.1 7547.1 6861.6 383623.7 383623.7 100811.6 13680.7 13680.7 4416.6 30938.5 193075.5 39174.5 30938.5 193075.5 39174.5 5894.1 3666.6 36950.9 3686.5 3312.7 584.8 494.5 1164.8 1133.6 11085.4 11272.5 6586.3 6861.6 105005.7 100811.6 4832.2 4416.6 5549.7 5894.1 44.2 0.5 9.6 2.7 2185.8 4.9 431.9 26.2 24.0 103609.4 74491.4 45311.6 795.5 69854.3 83212.8 321.2 2552.8 8941.9 5407.0 43.9 7378.1 794.0 6.4 51.5 23.7 0.5 26.1 7.6 770.7 1641.9 686.1 2.7 644.9 384.8 585.8 1065.4 571.1 9.7 550.2 486.4 75727.9 67471.7 76665.9 1640.7 38386.7 124617.0 1711.1 4012.3 2076.0 10.6 2212.4 1073.6 19614.4 37029.8 22182.2 389.6 25227.6 16772.5 378.6 2286.3 1029.4 9.3 1452.2 669.3 2342.9 4079.6 2015.6 25.3 1949.2 1631.8 CR 59.1 9966.7 46990.2 31958.3 308.5 23308.5 27469.9 US 710.9 1894.3 1285.5 35.9 1823.4 1505.8 75.7 28.1 9.7 30.7 59.8 86.5 885.7 464.8 16.9 3.4 0.5 1.2 2.2 14.9 7.3 2.6 1561.3 2684.6 4.2 4.1 288.1 366.3 30.7 32.4 17.9 28.1 24087.1 24087.1 743.4 2314.7 2314.7 811.5 1211.2 1211.2 681.4 175682.9 175682.9 18597.1 2332.8 2332.8 65.1 3.3 3.3 4.4 384.4 384.4 418.4 475.5 475.5 25.4 119693.7 119693.7 49769.3 997.2 997.2 159.2 14267.0 14267.0 27729.3 553.7 553.7 337.5 1505.0 1505.0 827.9 AN Upstream Cape Fear -2 Sutton Lake 2018 Sutton 1 Sutton 5 Sutton 7 Sutton 6 Sutton 2 Sutton 3 Sutton 4 Cape Fear River downstream Cape Fear -1 Cape Fear -3 Sutton Lake 2015 Sutton 01 2015 Sutton 02 2015 Sutton 03 2015 Reference Lake Waccamaw 2 Waccamaw 3 T Li IP Sample Upstream water leaching Cape Fear -2 27.4 Sutton Lake 2018 Sutton 1 233.1 Sutton 5 104.7 Sutton 7 70.2 Sutton 6 61.5 Sutton 2 108.4 Sutton 3 94.6 Sutton 4 120.0 Cape Fear River downstream Cape Fear -1 74.6 Cape Fear -3 737.1 Sutton Lake 2015 Sutton 01 2015 1280.0 Sutton 02 2015 1205.7 Sutton 03 2015 3312.8 Reference Lake Waccamow 2 17.0 Waccamow 3 57.7 772.6 811.5 764.9 681.4 17425.0 18597.1 51.0 65.1 2.5 4.4 333.2 418.4 24.8 25.4 45677.6 49769.3 129.7 159.2 26490.9 27729.3 254.6 337.5 728.6 827.9 3272.5 3666.6 38368.3 36950.9 592.2 743.4 AC CE PT ED M Table 6: Concentrations of trace elements measured in water and acid (1N nitric acid) leachates extracted from sediments in Sutton Lake collected in 2018 and 2015, Waccamaw Lake, and Cape Fear River (upstream and downstream from Sutton Lake). 29 87Sr/86Sr ratio 0.709931 0.710375 0.710025 0.709997 ACCEPTED MANUSCRIPT References AC CE PT ED M AN US CR IP T Brandt, J.E. (2018) Coal combustion residuals in receiving lake ecosystems: Trophic transfer, toxicity, and tracers. PhD thesis, Duke University, Durham, NC. Brandt, J.E., Bernhardt, E.S., Dwyer, G.S. and Di Giulio, R.T. (2017) Selenium Ecotoxicology in Freshwater Lakes Receiving Coal Combustion Residual Effluents: A North Carolina Example. Env. Sci. Technol. 51, 9414-9414. Brandt, J.E., Lauer, N.E., Vengosh, A., Bernhardt, E.S. and Di Giulio, R.T. (2018) Strontium Isotope Ratios in Fish Otoliths as Biogenic Tracers of Coal Combustion Residual Inputs to Freshwater Ecosystems. Environ. Sci. Technol. Lett. 5, 5, 718–723. Cordoba, P., Ochoa-Gonzalez, R., Font, O., Izquierdo, M., Querol, X., Leiva, C., Lopez-Anton, M.A., Diaz-Somoano, M., Martinez-Tarazona, M.R., Fernandez, C. and Tomas, A. (2012) Partitioning of trace inorganic elements in a coal-fired power plant equipped with a wet Flue Gas Desulphurisation system. Fuel 92, 145-157. Cowan, E.A., Epperson, E.E., Seramur, K.C., Brachfeld, S.A. and Hageman, S.J. (2017) Magnetic susceptibility as a proxy for coal ash pollution within riverbed sediments in a watershed with complex geology (southeastern USA). Environmental Earth Sciences 76: 657. https://doi.org/10.1007/s12665-017-6996-8. Cowan, E.A., Gaspari, D.P., Brachfeld, S.A. and Seramur, K.C. (2015) Characterization of coal ash released in the TVA Kingston spill to facilitate detection of ash in river systems using magnetic methods. Fuel 159, 308-314. Cowan, E.A., Seramur, K.C. and Hageman, S.J. (2013) Magnetic susceptibility measurements to detect coal fly ash from the Kingston Tennessee spill in Watts Bar Reservoir. Environ. Pollution 174, 179-188. Dai, S., Li, T., Seredin, V.V., Ward, C.R., Hower, J.C., Zhou, Y., Zhang, M., Song, X., Song, W. and Zhao, C. (2014) Origin of minerals and elements in the Late Permian coals, tonsteins, and host rocks of the Xinde Mine, Xuanwei, eastern Yunnan, China. Intern. J. of Coal Geol. 121, 53-78. Dai, S., Yan, X., Ward, C.R., Hower, J.C., Zhao, L., Wang, X., Zhao, L., Ren, D. and Finkelman, R.B. (2018) Valuable elements in Chinese coals: a review. Intern. Geol. Rev. 60, 590-620. Dearing, J.A. (1999) Environmental magnetic susceptibility, using the Bartington MS2 System. Bartington Instruments, Ltd, London, UK, p. 54. Dreesen, D.R., Gladney, E.S., Owens, J.W., Perkins, B.L., Wienke, C.L. and Wangen, L.E. (1977) Comparison of levels of trace-elements extracted from fly ash and levels found in effluent waters from a coal-fired power plant. Environ. Sci. & Technol. 11, 1017-1019. Fisher, G.L., Prentice, B.A., Silberman, D., Ondov, J.M., Biermann, A.H., Ragaini, R.C. and McFarland, A.R. (1978) Physical and morphological studies of size-classified coal fly-ash. Environ. Sci. & Technol. 12, 447-451. Flanders, P.J. (1999) Identifying fly ash at a distance from fossil fuel power stations. Environ. Sci. & Technol. 33, 528-532. Fletcher, D.E., Lindell, A.H., Stillings, G.K., Mills, G.L., Blas, S.A. and McArthur, J.V. (2014) Variation in Trace-Element Accumulation in Predatory Fishes from a Stream Contaminated by Coal Combustion Waste. Arch. Environ. Contam. Toxicol. 66, 341-360. 30 ACCEPTED MANUSCRIPT AC CE PT ED M AN US CR IP T Greeley, M.S., Jr., Adams, S.M., Elmore, L.R. and McCracken, M.K. (2016) Influence of metal(loid) bioaccumulation and maternal transfer on embryo-larval development in fish exposed to a major coal ash spill. Aquatic Toxicol. 173, 165-177. Grimley, D.A., Anders, A.M., Bettis, E.A., Bates, B.L., Wang, J.J., Butler, S.K. and Huot, S. (2017) Using magnetic fly ash to identify post-settlement alluvium and its record of atmospheric pollution, central USA. Anthropocene 17, 84-98. Gune, M., Harshavardhana, B.G., Balakrishna, K., Udayashankar, H.N., Shankar, R. and Manjunatha, B.R. (2016) Rock magnetic finger-printing of soil from a coal-fired thermal power plant. Environ. Monitor. and Assess. 188 , 272. doi: 10.1007/s10661-016-5279-2. Harkness, J.S., Sulkin, B. and Vengosh, A. (2016) Evidence for Coal Ash Ponds Leaking in the Southeastern United States. Environ. Sci. & Technol. 50, 6583-6592. Hower, J.C. (2012) Petrographic examination of coal-combustion fly ash. Internat. J Coal Geol. 92, 90-97. Ingersoll, C.G., MacDonald, D.D., Wang, N., Crane, J.L., Field, L.J., Haverland, P.S., Kemble, N.E., Lindskoog, R.A., Severn, C. and Smorong, D.E. (2001) Predictions of sediment toxicity using consensus-based freshwater sediment quality guidelines. Arch. Environ. Contam. Toxicol. 41, 8-21. Izquierdo, M. and Querol, X. (2012) Leaching behaviour of elements from coal combustion fly ash: An overview. Internat. J Coal Geol. 94, 54-66. Kharecha, P.A., Kutscher, C.F., Hansen, J.E. and Mazria, E. (2010) Options for Near-Term Phaseout of CO2 Emissions from Coal Use in the United States. Environ. Sci. Technol. 44, 4050-4062. Kosson, D.S., van der Sloot, H.A., Sanchez, F. and Garrabrants, A.C. (2002) An integrated framework for evaluating leaching in waste management and utilization of secondary materials. Environ. Engineer. Sci. 19, 159-204. Lauer, N.E., Hower, J.C., Hsu-Kim, H., Taggart, R.K. and Vengosh, A. (2015) Naturally Occurring Radioactive Materials in Coals and Coal Combustion Residuals in the United States. Environ. Sci Technol. 49, 11227-11233. Lemly, A.D. (2018) Selenium poisoning of fish by coal ash wastewater in Herrington Lake, Kentucky. Ecotoxicol. Environ. Safety 150, 49-53. Lemly, A.D. and Skorupa, J.P. (2012) Wildlife and the Coal Waste Policy Debate: Proposed Rules for Coal Waste Disposal Ignore Lessons from 45 Years of Wildlife Poisoning. Environ. Sci. Technol. 46, 8595-8600. Liu, Y.-T., Chen, T.-Y., Mackebee, W.G., Ruhl, L., Vengosh, A. and Hsu-kim, H. (2013) Selenium Speciation in Coal Ash Spilled at the Tennessee Valley Authority Kingston Site. Environ. Sci Technol. 47, 14001-14009. Long, E.R., Ingersoll, C.G. and Macdonald, D.D. (2006) Calculation and uses of mean sediment quality guideline quotients: A critical review. Environ. Sci Technol. 40, 1726-1736. Long, E.R., MacDonald, D.D., Severn, C.G. and Hong, C.B. (2000) Classifying probabilities of acute toxicity in marine sediments with empirically derived sediment quality guidelines. Environ. Toxicol. . Chem. 19, 2598-2601. MacDonald, D.D., Ingersoll, C.G. and Berger, T.A. (2000) Development and Evaluation of Consensus-Based Sediment Quality Guidelines for Freshwater Ecosystems. Arch. Environ. Contam. Toxicol. 39, 20-31. MacDonald, D.D.I., C.G., Smorong, D.E., Lindskoog, R.A., Sloane, G., Biernacki, T. (2003) Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for 31 ACCEPTED MANUSCRIPT AC CE PT ED M AN US CR IP T Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL, Tallahassee, FL. Magiera, T., Jabłońska, M., Strzyszcz, Z. and Rachwal, M. (2011) Morphological and mineralogical forms of technogenic magnetic particles in industrial dusts. Atmos. Enviro. 45, 4281-4290. Meij, R. and Winkel, B.H.t. (2009) Trace elements in world steam coal and their behaviour in Dutch coal-fired power stations: A review. Internat. J Coal Geol. 77, 289-293. Meij, R. and Winkel, H.t. (2007) The emissions of heavy metals and persistent organic pollutants from modern coal-fired power stations. Atmos. Environ. 41, 9262-9272. National Oceanic and Atmospheric Administration, N.H.C. (2018) NHC GIS Archive - Tropical Cyclone Best Track. National Oceanic and Atmospheric Administration. Nelson, P.F., Shah, P., Strezov, V., Halliburton, B. and Carras, J.N. (2010) Environmental impacts of coal combustion: A risk approach to assessment of emissions. Fuel 89, 810816. North Carolina Department of Environment and Natural Resources, D.o.W.Q. (2018) NPDES permits and effluent data (https://deq.nc.gov/about/divisions/water-resources/waterresources-permits/wastewater-branch/npdes-wastewater-permits; access 3/19/2019). Punshon, T.S., Sajwan, K. S. (2003) The production and use of coal combustion products, in: Sajwan, K.S.A., Keefer, R. F. (ed.), Chemistry of Trace Elements in Fly Ash. Springer, pp. 1-11. RJ Lee Group (2010) Standard Operating Procedure for Determination of Fly Ash in Bulk Samples by Polarized Light Microscopy, OPT 023, 9 pp. Rowe, C.L., Hopkins, W.A. and Congdon, J.D. (2002) Ecotoxicological implications of aquatic disposal of coal combustion residues in the United States: A review. Environ. Monit. Assess. 80, 207-276. Ruhl, L., Vengosh, A., Dwyer, G.S., Hsu-Kim, H. and Deonarine, A. (2010) Environmental Impacts of the Coal Ash Spill in Kingston, Tennessee: An 18-Month Survey. Environ. Sci Technol. 44, 9272-9278. Ruhl, L., Vengosh, A., Dwyer, G.S., Hsu-Kim, H., Deonarine, A., Bergin, M. and Kravchenko, J. (2009) Survey of the Potential Environmental and Health Impacts in the Immediate Aftermath of the Coal Ash Spill in Kingston, Tennessee. Environ. Sci Technol.43, 63266333. Ruhl, L., Vengosh, A., Dwyer, G.S., Hsu-Kim, H., Schwartz, G., Romanski, A. and Smith, S.D. (2012) The Impact of Coal Combustion Residue Effluent on Water Resources: A North Carolina Example. Environ. Sci Technol.46, 12226-12233. Ruhl, L.S., Dwyer, G.S., Hsu-Kim, H., Hower, J.C. and Vengosh, A. (2014) Boron and Strontium Isotopic Characterization of Coal Combustion Residuals: Validation of New Environmental Tracers. Environ. Sci Technol. 48, 14790-14798. Schwartz, G.E., Hower, J.C., Phillips, A.L., Rivera, N., Vengosh, A. and Hsu-Kim, H. (2018) Ranking Coal Ash Materials for Their Potential to Leach Arsenic and Selenium: Relative Importance of Ash Chemistry and Site Biogeochemistry. Environ. Engineer. Sci. 35, 728738. Schwartz, G.E., Rivera, N., Lee, S.W., Harrington, J.M., Hower, J.C., Levine, K.E., Vengosh, A. and Hsu-Kim, H. (2016) Leaching potential and redox transformations of arsenic and selenium in sediment microcosms with fly ash. Appl. Geochem. 67, 177-185. 32 ACCEPTED MANUSCRIPT AC CE PT ED M AN US CR IP T Shin, J., Natanson, A., Khun, J., Odorizzi, N., DeCreny-Jackson, J., Fowowe, H., Jackson, C., Springthorpe, S., Rhodes, T., Lutz, H., Askey, J., Aleman, L., Ciccolella, A., Wesley, B., Lewis, K., Kuppinger, D. and DeFord-Watts, L. (2017) Assessing the impact of coal ash exposure on soil microbes in the Dan River. Bios 88, 72-85. Silva, L.F.O., DaBoit, K., Sampaio, C.H., Jasper, A., Andrade, M.L., Kostova, I.J., Waanders, F.B., Henke, K.R. and Hower, J.C. (2012) The occurrence of hazardous volatile elements and nanoparticles in Bulgarian coal fly ashes and the effect on human health exposure. Sci. Total Environ. 416, 513-526. Swaine, D.J. (1992) Environmental aspects of trace-elements in coal. Environ. Geochem. Health 14, 2-2. Swaine, D.J. (1994) Trace-elements in coal and their dispersal during combustion. Fuel Process. Technol. 39, 121-137. Swanson, S.M., Engle, M.A., Ruppert, L.F., Affolter, R.H. and Jones, K.B. (2013) Partitioning of selected trace elements in coal combustion products from two coal-burning power plants in the United States. Internat. J. Coal Geol. 113, 116-126. Tetra Tech Inc (2008) Soil and ash sampling results, Kingston Fossil fly ash response, Harriman, Roane County, Tennessee. Tetra Tech Inc., Duluth, GA, p. 9. (https://archive.epa.gov/pesticides/region4/kingston/web/pdf/10644912.pdf, accsess 3/19/2019). Thorneloe, S.A., Kosson, D.S., Sanchez, F., Garrabrants, A.C. and Helms, G. (2010) Evaluating the Fate of Metals in Air Pollution Control Residues from Coal-Fired Power Plants. Environ. Sci Technol. 44, 7351-7356. Tian, Q.Z., Guo, B.L., Nakama, S. and Sasaki, K. (2018) Distributions and Leaching Behaviors of Toxic Elements in Fly Ash. Acs Omega 3, 13055-13064. Twardowska, I.S., J.; Stefaniak, S. (2003) Occurrence and Mobilization Potential of Trace Elements from Disposed Coal Combustion Fly Ash, in: Sajwan, K.S.A., Keefer, R. F. (eds.), Chemistry of Trace Elements in Fly Ash. Springer. U.S. Environmental Protection Agency (2015) Hazardous and Solid Waste Management System; Disposal of Coal Combustion Residuals From Electric Utilities: Final Rule. United States Environmental Protection Agency, Washington DC, pp. 21301-21501. U.S. Environmental Protection Agency (2018) Sampling Results for Duke Energy Coal Ash Spill in Eden, NC, Duke Energy Coal Ash Spill in Eden, NC. (https://www.epa.gov/dukeenergy-coalash/sampling-results-duke-energy-coal-ash-spilleden-nc; access 3/19/2019). U.S. Geological Survey Current Water Data for North Carolina (2018). United States Geological Survey (https://waterdata.usgs.gov/nc/nwis/rt; access 3/19/2019). Vengosh, A., Lindberg, T.T., Merola, B.R., Ruhl, L., Warner, N.R., White, A., Dwyer, G.S. and Di Giulio, R.T. (2013) Isotopic Imprints of Mountaintop Mining Contaminants. Environ. Sci Technol. 47, 10041-10048. Yang, Y., Colman, B.P., Bernhardt, E.S. and Hochella, M.F. (2015) Importance of a Nanoscience Approach in the Understanding of Major Aqueous Contamination Scenarios: Case Study from a Recent Coal Ash Spill. Environ. Sci Technol. 49, 3375-3382. Zhao, S.L., Duan, Y.F., Lu, J.C., Gupta, R., Pudasainee, D., Liu, S., Liu, M. and Lu, J.H. (2018) Thermal stability, chemical speciation and leaching characteristics of hazardous trace elements in FGD gypsum from coal-fired power plants. Fuel 231, 94-100. 33 17E 1313.11qu [133qung