Loading...
HomeMy WebLinkAboutNC0004774_R. Hennet - Final Buck Expert Report_20160630Expert Report of Remy J.-C. Hennet Buck Steam Station Salisbury, North Carolina S.S. PAPADOPULOS & ASSOCIATES, INC. Environmental & Water -Resource Consultants June 30, 2016 7944 Wisconsin Avenue, Bethesda, Maryland 20814-3620 9 (301) 718-8900 Expert Report of Remy J.-C. Hennet Buck Steam Station Salisbury, North Carolina Prepared for: Duke Energy Carolinas, LLC Prepared by: Remy J.-C. Hennet, PhD S.S. PAPADOPULOS & ASSOCIATES, INC. Environmental & Water -Resource Consultants June 30, 2016 7944 Wisconsin Avenue, Bethesda, Maryland 20814-3620 9 (301) 718-8900 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' Table of Contents Page Listof Appendices.......................................................................................................................... ii Section1 Introduction................................................................................................................ 1 Section2 Background................................................................................................................ 2 Section 3 Geochemistry of the Ash Basins................................................................................ 4 Section 4 Natural Attenuation in Groundwater......................................................................... 7 Section 5 Cap -in -Place Remedy................................................................................................ 8 Section 6 Excavation and Removal........................................................................................... 9 Section7 Opinions................................................................................................................... 10 Opinion1.................................................................................................................. 10 Opinion2.................................................................................................................. 10 Opinion3.................................................................................................................. 10 Section 8 Bases for Opinions................................................................................................... 11 Opinion1.................................................................................................................. 11 Opinion2.................................................................................................................. 13 Opinion3.................................................................................................................. 16 Appendices I 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' 4M List of Appendices Appendix A Curriculum Vitae of Remy J.-C. Hennet Appendix B Documents Considered and/or Relied Upon Appendix C Background Concentration Ranges — USGS, Site Data, and Private Wells Appendix D Natural Attenuation — Ash Basins to Compliance Boundary ii REPORT 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' Section 1 Introduction This expert report was prepared by Remy J-C. Hennet. I am a Principal at S.S. Papadopulos & Associates (SSP&A). I hold a Ph.D. degree in geochemistry and a Master's degree in geology from Princeton University, and university degrees in hydrogeology and geology from the University of Neuchatel, Switzerland. My expertise includes the application of geochemistry, hydrogeology and geology to evaluate the origins, fate, and transport of chemicals in the environment and the remediation of environmental problems. I have more than 25 years of research and professional experience. My Curriculum Vitae and list of depositions and trial appearances are provided as Appendix A. The hourly rate charged by SSP&A for my services is $272. I was retained by Duke Energy Carolinas, LLC (Duke Energy) to evaluate the geochemical data that has been collected to characterize the nature and extent of any surface water and groundwater contamination from the operation of coal ash basins at the Buck Steam Station, near Salisbury, Rowan County, North Carolina (the Site), and to evaluate whether impacts have occurred to surface waters and private wells. I was also tasked to analyze and evaluate certain allegations made by Plaintiffs' experts Campbell and Spruill, and Parette with regards to the appropriateness of the remedy that is proposed for the Site, cap -in -place with monitored natural attenuation, and their contention that complete excavation of the ash is the only acceptable remedy. To conduct this evaluation and render my opinions, I relied on my education, research, and professional experience. I reviewed the Comprehensive Site Assessment Report, the Corrective Action Plan Part 1 and Part 2 reports for the Site. I also relied on the peer -reviewed literature and various professional reports cited herein that describe coal ash materials. I retrieved data from publically accessible internet sites (USEPA, USGS, and State web sites). The data, documents and information that I considered are of the type that can be reasonably relied upon to support my opinions. I visited the Site August 13, 2014 and September 22, 2015. The information that I considered for this report is listed as Appendix B. The opinions presented in this report were reached by applying accepted methodologies in the fields of geochemistry, hydrology, geology, and environmental remediation. The opinions expressed in the report are my own and are based on the data and facts available to me at the time of writing. Should additional relevant information become available, I reserve the right to supplement the discussion and findings presented in this report. 1 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Section 2 Background As required by the Coal Ash Management Act of 2014 (CAMA), Duke Energy conducted a series of investigations and studies to characterize the potential for environmental impact from operation of its ash basin system. Duke Energy submitted a Comprehensive Site Assessment Report and Corrective Action Plan Part 1 and Part 2 reports to North Carolina Department of Environment and Natural Resources (NCDENR). Operations at the Site started in 1926, and the last coal-fired unit ceased operation in 2013. The ash basin system consists of Cell 1, Cell 2, and Cell 3 as per the Site reports. The ash basin system is distributed between the three cells. The original ash basin system at the Site was constructed in 1957 and modified by raising the dam in 1977 in the Cell 2 and 3 area. Cell 1 was constructed in 1982. A pile of dewatered ash was constructed in the eastern portion of Cell 1 in 2009. The ash basin system is an integral part of the Site wastewater treatment system. The ash basin system received discharges from the ash removal system, coal pile runoff, landfill leachate, flue gas desulfurization wastewater, the station yard drain sump, and site storm water. Environmental impacts for groundwater when a party causes concentrations to exceed the North Carolina Groundwater Quality Standards, as specified in 15A NCAC 2L.0202 (2L Standards). Concentration exceedances to the Interim Maximum Allowable Concentration (IMAC) established by NCDENR pursuant to 15A NCAC 2L.0202(c) are also considered, even though these standards have not been finalized. Surface water impacts are defined by concentration exceedances to the North Carolina Surface Water Quality (2B) standards (2B Standards). The 2B Standards depend upon classification of a surface water body. For groundwater, the compounds of interest identified at the Site are: antimony, arsenic, barium, beryllium, boron, cadmium, total chromium, hexavalent chromium, cobalt, iron, manganese, nickel, selenium, sulfate, thallium, total dissolved solids (TDS), vanadium, and zinc. The compounds of interest were identified based on concentrations in groundwater that exceed the 2L Standards and IMAC. The available data for the Site includes results from chemical analysis of soil, sediment, rock, ash basin solids, ash basin pore water, groundwater, and surface water samples. Leaching data were collected for samples of ash materials from the basins. The data include information on mineralogical composition of geologic and ash materials, and general physical characteristics for these materials in place (i.e., grain size, porosity, permeability). Site background conditions were characterized through analysis of background soil, rock, and water samples. Additional data and information on coal ash chemistry are available from peer -reviewed literature and specialized professional reports. The extent of groundwater contamination is described in the Comprehensive Site Assessment Report and Corrective Action Plan reports for the Site. The Comprehensive Site Assessment Report concluded that there is no identified imminent hazard to human health or the environment as a result of groundwater migration from the ash basin or ash storage areas. 2 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' The Corrective Action Plan reports further evaluated the hydrology of the Site and the fate and transport of contaminants in the groundwater environment. The reports examined the need for remediation and the feasibility and adequacy of potential remedial measures for Site closure. Based on its evaluation of the available data and information, Duke Energy selected a Cap- in -place remedy for the ash basins, with additional source control measures being considered on an as needed basis. The remedy consists of an engineered cap system over the ash basins and the collection and treatment of storm water, runoff water, and seep water for permitted discharge. The additional source control measures could include hydraulic containment, drains, amendments, and other measures, as necessary to comply with future regulations and to address uncertainties and unforeseen conditions. For the restoration of groundwater, Duke Energy has proposed to rely on monitored natural attenuation. Monitoring after implementation of cap -in -place will provide the basis for assessing the need for additional source control measures for groundwater restoration. Plaintiffs' experts Campbell, Spruill, and Parette have submitted expert reports and opined that a cap -in -place remedy with monitored natural attenuation is inappropriate for the Site. These experts opined that excavation and removal of the ash basins should be the remedy for the Site. 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Section 3 Geochemistry of the Ash Basins Coal ash is a by-product from the combustion of coal. Under atmospheric conditions, some of the minerals in coal ash are metastable and undergo transformations that lead to the formation of secondary mineral phases that range from amorphous to crystalline (i.e., hydrous aluminosilicates, mullite, calcite, etc.). Over time, the rate of chemical leaching decreases and the formation of amorphous clays and other secondary minerals results in a decrease in coal ash permeability (Jones and Lewis, 1956; Warren and Dudas, 1988; Zevenberg et al., 1999a and 1999b; Bolanz et al., 2012; Fruchter, 1990; Ghuman et al., 1999; Mudd et al., 2004; EPRI, 2009). Depending on their properties, chemicals that are released or leached to pore water during mineral alteration can remain in the pore water and/or can be sequestered in the secondary mineral phases which are immobile. Sequestration in or immobilization onto the mineral phases can be through absorption, adsorption, ion exchange, and secondary mineral precipitation and co - precipitation. The organic carbon content of coal ash, typically measured at the low percent level by weight, provides a substrate for microbial activity. This activity depletes oxygen, making coal ash pore water generally reducing or anaerobic. As for pH conditions, fresh coal ash pore water at the Site is typically alkaline, whereas aged or weathered ash pore water tends to be neutral (reflecting the mineral alterations and prolonged contact with carbon dioxide from the atmosphere). Ash and coal materials that are exposed to atmospheric oxygen can become acidified as a side effect of the oxidation of their sulfidic mineral content. In the ash basins, the water (i.e., sluiced ash water, rain, storm water) that percolates through the ash to groundwater has a distinctive chemical fingerprint. The chemical fingerprint reflects the interaction between water and coal ash materials. Ash pore water is a sodium -calcium - sulfate aqueous solution, meaning that these compounds dominate the dissolved concentrations. Boron, chloride, strontium, magnesium, iron, manganese, and potassium are typically present at part per million level. Aluminum, barium, and arsenic are typically present at the low part per million or less level. Traces, at the part per billion level, are also typical for antimony, cobalt, vanadium and molybdenum. All of the constituents of interest occur in soils, rock, surface water, and groundwater under background conditions. The background range concentrations can be lower, similar, or higher than in the ash basins, depending on the compound considered. This is why it is necessary to account for the background range for evaluating the environmental impacts of the ash basins. For groundwater background concentrations, data is available from the United States Geological Survey, the State of North Carolina, and from the samples collected for Site characterization. The Site is located over metavolcanic rocks consisting of felsic metavolcanic, intermediate metavolcanic, and mafic metavolcanic (Goldsmith et al. 1988). Together, and in context, these data define the background range for the constituents of interest. Background data information for groundwater is illustrated in Appendix C. The water that percolates from coal ash basins into subsurface soil and rock materials is put in contact with different mineral phases that represent the geological materials onto which the E 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' �S coal ash lies. Water -mineral interactions in the geological materials and mixing with groundwater result in changes in chemical composition. Boron, because of its properties, remains in the water phase and tends to transport conservatively (little or no retardation) with groundwater. Other chemicals that include the constituents of interest such as iron, manganese, arsenic and other trace compounds in ash pore water are not conservative and partition between the mineral and aqueous (water) phases. Those reactive chemicals are attenuated in the subsurface environment by immobilization and sequestration through mineral precipitation or co -precipitation and by retardation through sorption and ion exchange processes. Iron is most important for natural attenuation in the subsurface environment as it is present at relatively high concentrations in ash and geological materials. Iron minerals, and mineral coatings are effective at attenuating (sequestering, immobilizing, and retarding) other chemicals in groundwater (Dixit and Hering, 2003; Dzombak and Morel, 1990; Stumm and Morgan, 1996). Dissolved chemicals are present in groundwater as chemical species. The speciation of a chemical is primarily controlled by the redox and pH conditions in the subsurface and by interactions between chemicals in solution. The different chemical species of a given constituent have different properties. It is therefore important to consider chemical speciation in the evaluation of transport in the groundwater environment. For the compounds that are elevated in the ash pore water and the impacted groundwater beneath and downgradient of the ash basins, the chemical speciation can be derived from the Eh -pH diagrams (Atlas of Eh -pH Diagrams, 2005). Chemical speciation informs whether a chemical can be reduced or oxidized and if its aqueous solubility is controlled by mineral phases and/or other attenuating processes (e.g., sorption and ion exchange). As part of the Site assessment work and studies that were conducted with Site materials, solid -water partition coefficients (KD) were determined for 10 chemicals (arsenic, boron, cadmium, chromium, iron, manganese, molybdenum, selenium, thallium, and vanadium). The chemicals were dissolved in water and interacted with soil materials from the Site. The results were obtained under controlled laboratory conditions and are not directly applicable to the Site groundwater conditions; however, the results demonstrate that with the exception of boron, the chemicals that were tested interact with the Site soil materials. The results demonstrate that chemical attenuation is an active process at the Site for the tested compounds. Natural attenuation for boron is dominated by physical attenuation and takes place principally through the immobilization of the ash pore water and other physical processes that include dilution, diffusion, and dispersion. Groundwater samples from wells screened within the ash contained elevated concentrations of constituents of interest, confirming that attenuation is active with concentration diminishing in the soil and rock materials beneath and downgradient of the ash basins (Appendix D). These observations of concentrations attenuating away from the ash basins support Duke Energy's decision to propose using monitored natural attenuation for the restoration of groundwater as a supplement to the cap -in -place control measures. The limited chemical interaction between boron and soil materials explains why boron is a valid tracer for delineating the extent of the ash basin impacts; boron is typically present at low concentration in background groundwater (<50 ug/L range) and its presence at high concentration (-1000 ug/L range) in the ash pore water makes it a simple conservative tracer that can be used to delineate the extent of groundwater affected by the ash basins and evaluate the effectiveness of physical attenuation processes that would affect all mobile COI's equally. The results for the other chemicals tested for chemical interactions support the conclusion that natural attenuation, both 5 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' physically and chemically, is active under Site conditions and that natural attenuation can be considered as a restoration remedy for groundwater after the cap -in -place remedy has been implemented. G 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' Section 4 Natural Attenuation in Groundwater Natural attenuation results from physical, chemical, and biological processes that act alone or in combination to reduce or decrease the volume of impacted groundwater and compound mass, concentration, toxicity, and/or mobility in groundwater. The major processes that attenuate mass or concentrations in groundwater are dilution, dispersion, absorption, adsorption, ion exchange, precipitation, co -precipitation, complexation to organic substrate, and biomass accumulation. For conservative compounds such as boron in groundwater, dilution and dispersion dominate attenuation. For reactive compounds such as iron, manganese, or arsenic, adsorption, precipitation and co -precipitation processes also attenuate concentrations in addition to dilution and dispersion. USEPA provides guidance for the implementation of natural attenuation as a remedial measure for groundwater contamination by inorganic compounds (EPA, Directive 9283.1-36, August 2015; EPA 600-R-07-139; 2007a; EPA 600-R-07-140, 2007; EPA 600-R-10- 093, 2010; EPA, Directive 9200.4-17P, April 21, 1999). The USEPA guidance provides objectives for the performance of monitored natural attenuation: 1) Demonstrate that natural attenuation is occurring according to expectations; 2) Detect changes in environmental conditions (e.g., hydrogeologic, geochemical, microbiological, or other changes) that may reduce the efficacy of any of the natural attenuation processes; 3) Identify any potentially toxic and/or mobile transformation products; 4) Verify that the plume(s) is not expanding downgradient, laterally or vertically; 5) Verify no unacceptable impact to downgradient receptors; 6) Detect new releases of contaminants to the environment that could impact the effectiveness of the natural attenuation remedy; 7) Demonstrate the efficacy of institutional controls that were put in place to protect potential receptors; and 8) Verify attainment of remediation objectives. As discussed in Section 8 of this report, the Site data indicate that natural attenuation is occurring in the groundwater environment. The cap -in -place remedy will decrease the flux of constituents of concern to groundwater and result in a decrease of the extent of the groundwater impact. Monitored natural attenuation is therefore a valid remedial option for the restoration of groundwater for this Site. Progress toward the restoration of groundwater through natural attenuation will be monitored once the cap -in -place remedy and additional source control measures, if any are necessary, have been implemented. The monitoring data and information will be the basis for selection of the final groundwater remedy for the Site. 7 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' Section 5 Cap -in -Place Remedy The engineered cap -in -place remedy that Duke Energy plans to construct to cover the ash basins will have the effect of greatly reducing the infiltration of water and wastewater through the coal ash. The amount of ash pore water that will recharge to groundwater will be greatly diminished and the flux of chemicals entrained with infiltration water will also decrease. The ash materials have a high water retention capacity, meaning that absent recharge by infiltration water, as under a cap -in -place remedy, the ash pore water is mostly immobile, further decreasing the flux of constituents of interest from the ash materials to groundwater (Tiruta-Barna et al. 2006). Secondary mineral phases will continue to form in the coal ash and in the soil and rock materials beneath the coal ash basin. The permeability of coal ash materials under the cap is expected to continue to decrease over time because of accumulation of secondary minerals in the pore spaces. Groundwater -ash interactions will also decrease because of the lowering of the water table, exposing less of the ash materials to groundwater. If monitoring of the cap -in -place remedy indicates that restoration of groundwater is not taking place, additional source control measures (i.e., drains, pumping, slurry walls) could be implemented to intercept the impacted groundwater and/or to further depress the water table to further isolate the ash materials. The geochemical conditions in the capped coal ash will remain generally reducing and anaerobic from the continuous degradation of the organic substrate in the ash by micro-organisms, with a pH condition near neutral to alkaline, depending on the age and degree of weathering of the ash materials. Under an uncapped condition, atmospheric oxygen is introduced into the ash materials with infiltration water that contains dissolved oxygen. The atmospheric oxygen is consumed for the oxidation of the organic substrate that is present in the ash materials. Consumption of oxygen takes place primarily in the upper portion of the ash materials, as infiltration water progresses toward the water table, and the effect of atmospheric oxygen is typically limited to the shallow ash. Under a cap -in -place condition, the upper portion of the ash might possibly become more reducing. If there was a reduction in atmospheric oxygen because of capping, it would result in more reducing conditions in the pore water at depth in the ash materials. The geochemical result of more reducing conditions would be for some increased sulfide activity from the reduction of sulfate to sulfide. The presence of dissolved sulfide would result in the precipitation of sulfidic or pyritic minerals. Under such reducing conditions, iron, manganese, and other metals dissolved in the pore water would be precipitated or co -precipitated out of the pore water and become immobilized in the solid matrix within the coal ash and beneath. Mineral precipitation and co -precipitation would remove these constituents of interest from the aqueous phase, reduce their flux to groundwater, and contribute to the restoration of groundwater. 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Section 6 Excavation and Removal The excavation and removal of the ash in the ash basins and a portion of the soil materials beneath the basins was considered by Duke Energy, but determined not to be the preferred remedy for the Site based on environmental, engineering, social, and economic considerations. Excavation is typically conducted using specialized machinery to removed materials that are transported for disposal elsewhere. Excavation of the ash basins would expose subsurface soil and rock materials to geochemical conditions that are different from the conditions with the ash in place. A change in geochemical conditions would result in a rearrangement of the mineralogy in the aquifer, with dissolution and precipitation of secondary mineralogy affecting groundwater chemistry and redistributing the constituents of interest in the subsurface. The geochemical disturbance will induce transient changes in the chemistry of groundwater that would only gradually attenuate, long after the implementation of excavation. The presence of sulfidic minerals in the soil and rock materials beneath the ash basins would become oxidized by contact with infiltration water and atmospheric oxygen. Oxidation of sulfidic minerals (i.e., pyrite) generates acidity, dissolved sulfate, and dissolved metals and metalloids that are trace compounds of the minerals and are put into solution in the process. The acidity released to groundwater would dissolve additional metals and metalloids from the soil and aquifer matrices. The release of acidity to groundwater would decrease natural attenuation in the aquifer and increase the leaching of natural occurring constituents of interest from native materials. Excavation would not remove the impacted groundwater beneath and downgradient of the excavation. The impacted groundwater that is left behind would serve as a long term source that could sustain the groundwater impacts after excavation. Excavation of the large quantities of materials in the ash basins would take time to implement (i.e., years or decades). During that period of open excavation, precipitation, storm water, and runoff water would enter the excavation in great quantities and infiltrate to groundwater. This added infiltration would introduce additional contamination and force impacted groundwater farther into the aquifer system, therefore increasing the extent of the existing groundwater impacts. Geochemical processes that control aquifer restoration are typically slow and take time to effectively achieve restoration goals. This would be true under both the excavation and cap -in - place remedies. There are anticipated negative effects with regards to groundwater for the excavation and removal remedy advocated by Plaintiffs' experts. These effects have to be considered for a comparative evaluation of the cap -in -place and excavation options. L 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Section 7 Opinions Based on my education and experience, and a detailed review of the available data and information, I have reached the following opinions: Opinion 1. The constituents of interest at the Site are naturally occurring upgradient from the Site at concentrations that are within the background range. Certain constituents of interest are present under background conditions at concentrations that exceed the 2L Standards, IMAC, or 2B Standards. Opinion 2. The cap -in -place remedy will decrease the flux of constituents of interest from the ash basins to groundwater. Natural attenuation is and will continue to be active in the groundwater environment, resulting in a future decrease in the mass and concentration of the constituents of interest that are dissolved in groundwater. The cap -in -place remedy, supplemented by source control measures if necessary, and monitored natural attenuation are a reasonable and adequate remedy for the Site. Opinion 3. Excavation of the ash basins is not necessary for Site groundwater restoration.. Excavation alone cannot achieve the complete removal of the constituents of interest from the subsurface and provides no substantial benefit over a cap -in -place remedy to restore groundwater. I hold these opinions with a reasonable degree of scientific certainty. I reserve the right to modify and supplement these opinions should additional information become available. 10 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Section 8 Bases for Opinions Opinion 1. The constituents of interest at the Site are naturally occurring upgradient from the Site at concentrations that are within the background range. Certain constituents of interest are present under background conditions at concentrations that exceed the 2L Standards, IMAC, or 2B Standards. The compounds of interest identified in the Comprehensive Site Assessment Report for groundwater are: antimony, arsenic, barium, boron, total chromium, hexavalent chromium, cobalt, iron, manganese, pH, sulfate, total dissolved solids, thallium, and vanadium. These compounds and parameters are naturally occurring in natural soil and rock materials, surface water, and groundwater. I reviewed the publically accessible USGS data (http://nwis.waterdata.usgs.gov/nwis wdata) for the occurrence of constituents of interest in groundwater across North Carolina and compared that information with the data presented in the Comprehensive Site Assessment Report for the Site. Results are illustrated in Appendix C. The data sets compared include: • Site background wells; Private water wells in the vicinity of the Site; and • Site monitoring wells. I also evaluated natural attenuation in groundwater using the available Site data. Results are illustrated in Appendices D and E. From this evaluation of the available data I conclude that for the Site: • Boron is present at high concentration (— 1,000 ug/L) in the ash pore water and impacted groundwater and at low concentration in groundwater under background condition (i.e., not detected or < 50 ug/L). Under the redox and pH conditions encountered in the groundwater environment, boron is soluble in water and does not appreciably interact with the solid matrix. Boron therefore transports with groundwater with little or no retardation. Under Site conditions in the groundwater environment, boron can be considered a conservative tracer for environmental fate and transport at the Site. Boron is attenuated in groundwater primarily by dilution and dispersion (see Appendix D). • Sulfate is present over a wide range of concentrations in the ash pore water and groundwater beneath and downgradient of the ash basins. Sulfate concentration in background groundwater can vary greatly, but is typically lower than in the impacted groundwater. Sulfate is redox reactive and its concentration in groundwater can be controlled by several processes that include mineral precipitation (i.e., barite, pyrite). Sulfate is attenuated in groundwater primarily by dilution and dispersion. Additional attenuation is provided by processes that can include mineral precipitation (i.e., barite) and reduction of sulfate to sulfides under strongly reducing conditions. 11 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' �S • Iron, manganese, and arsenic are reactive in the groundwater environment and do not behave conservatively in groundwater, as boron does. Iron, manganese, and arsenic can occur within a wide range of concentrations in background groundwater (see Appendix Q. The compounds are present in background soil and rock materials. These compounds are sensitive to attenuation processes in the groundwater environment. Iron, manganese and arsenic attenuate in the groundwater environment (see Appendix D). This demonstrates that these compounds can occur naturally at concentrations that can exceed the standards and are attenuated at the Site. • Trivalent chromium and hexavalent chromium form a redox pair, and both chemical species are present in groundwater under background conditions. When not specified, chromium refers to the sum of all chromium species in a sample. Hexavalent chromium can form from trivalent chromium through oxidation under background conditions (Oze, 2007). The reducing conditions that prevail in the ash and impacted groundwater environments at the Site are not amenable to the formation of hexavalent chromium, and the amount of hexavalent chromium relative to trivalent chromium is small. Chromium and hexavalent chromium are present in background groundwater, soil, and rock materials. Chromium is also present in grout (Hewlett, 1988). There is no groundwater impact for chromium from the ash basins as the reported detections of chromium are within the background range. • Vanadium concentrations in soil and rock materials at the Site are naturally enriched reflecting the composition of the bedrock, decomposed bedrock, and soils (USGS, 2013b). Vanadium is a background condition at the Site. • Antimony, barium, and cobalt are present at trace levels that are typically within the groundwater background range. These compounds are present in soil and rock materials as well as in ash materials. There is no groundwater impact above the background range outside of the ash basins area for antimony, barium, and cobalt. Cobalt concentrations reported for wells GWA-9S and GWA-I IS are in the upper end of the background range. Boron is elevated at GWA-9S, but below the 2L Standard. The presence of boron indicates an impact from the ash basins at GWA-9S. The well is located downgradientfrom the ash basins. Boron is not detected in GWA- I I S, and this well is not impacted by the ash basins. • Thallium in groundwater samples is most often reported below detection) and only occasionally at concentrations that exceed the IMAC in groundwater samples from beneath the ash basins. Thallium is present at trace concentration in groundwater, soil and rock materials under background conditions and in ash materials and ash pore water. Thallium was not detected in groundwater samples taken outside of the ash basin area. The identified constituents of interest at the Site include pH and total dissolved solids. I reviewed the pH and total dissolved solids data in the context of the available chemical data and mineralogical information. I conclude that: ' The detection limit is 0.1 ug/l; less than 5% of analyzed samples for the Site and vicinity contained a detectable concentration. 12 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' �S • The elevated pH occurrences (i.e. pH > 8.5) in monitoring wells that do not have detectable boron concentrations is most likely a side effect of well construction. For the wells that show elevated pH values with no detectable boron, the leakage of grout into the wells' sand packs is the simplest and most likely explanation for the elevated pH values, since grout is strongly alkaline (Hewlett, 1988). For the monitoring wells that have detectable concentration of boron, the occurrence of elevated pH can be explained by either grout leakage and/or by the presence of coal ash leachate impacting groundwater3. Additional work by Duke Energy is on -going to address well construction issues at the Site. • There are a wells that report acidic pH values (i.e., pH< 5). Acidic pH is best explained by mineral reactions (i.e., sulfide oxidation) that takes place when materials that contain pyritic minerals are exposed to atmospheric oxygen and water. For the acidic wells4 that have no detectable boron (<50 ug/L) and low pH values within the background range (see Appendix D), the low values are most likely background related. The acidic wells that contain detectable boron are influenced by Site operations and the acidity in these wells could result from either the natural background or the ash materials. • Total dissolved solids represent the sum of all chemicals that are dissolved in a water sample. This parameter does not inform on chemical composition but can be used to appreciate the overall dissolved content in water samples. Total dissolved solids can vary over a large range in background groundwater. Total dissolved solids values are elevated in ash pore water and in the impacted groundwater beneath and downgradient of the ash basins. Concentrations in groundwater that exceed a criterion (2L Standard or IMAC) but that are within the background range are not indicative of a coal ash impact to groundwater. At the Site, a coal ash impact to groundwater is indicated by the presence of a geochemical fingerprint that includes boron, alone or together with other compounds of interest, at concentrations that are higher than the upper bound of the background range. Opinion 2. The cap -in -place remedy will decrease the flux of constituents of interest from the ash basins to groundwater. Natural attenuation is and will continue to be active in the groundwater environment, resulting in a future decrease in the mass and concentration of the constituents of interest that are dissolved in groundwater. The cap -in -place remedy, supplemented by source control measures if necessary, and monitored natural attenuation are a reasonable and adequate remedy for the Site. 2 For example, wells with elevated pH and no detectable boron: GWA-113, GWA-313RU, AB-313, GWA-713, AS-313, GWA-213R, BG-ID, GWA-13D, GWA-14D, GWA-19D, and BG-1BR. s For example, wells with elevated pH and detectable boron: AB-4SL, AB-8S, AB-7SL, GWA-413, AS-213, AS-113, AB-213R, AB-913, AB-7BRU, AB-413R, GWA-IOD, AB-913R, GWA-1813, and GWA-913R. 4 For example, wells with acidic pH values and no boron: BG 18, GWA-11 S, and MW-6S. 5 For example, wells with acidic pH values and detectable boron: AS- IS, and GWA-9S. 13 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' �S J The cap -in -place remedy proposed by Duke Energy and additional source control measures that will be implemented, if necessary, will decrease the flux of the constituents of interest from the ash basins to groundwater. This will be beneficial to Site remediation and groundwater restoration. The decrease in flux will be accompanied by a reduction of the extent of the groundwater plume and will allow natural attenuation to proceed at an accelerated rate toward restoration. The cap -in -place remedy will therefore represent a net improvement for groundwater quality beneath and downgradient of the ash basins. There is no human exposure to the impacted groundwater, and no imminent need for aggressive remediation beyond the actions that Duke Energy is planning for the Site. The addition of monitored natural attenuation to the source control measures will provide the means to follow the progress of groundwater restoration. The remediation planned by Duke Energy has flexibility built in to address unforeseen events or to implement additional remediation at the local scale, should such measures be necessary. For example, the interception of impacted groundwater (i.e., via pump and treat or some form of hydraulic controls) could be implemented in some portions of the ash basins, to complement the cap -in -place remedy if the restoration of groundwater does not occur as anticipated. Plaintiffs' expert Parette has opined that monitored natural attenuation is not an appropriate remedy for constituents of interest at the Site. Parette apparently based this on statements in the Comprehensive Site Assessment Report and Corrective Action Plan Part 1 and Part 2 reports that he took out of context. Duke Energy's proposed remedy for the Site is to implement a cap -in -place remedy supplemented by source control measures, if necessary, with monitored natural attenuation for groundwater restoration. The performance of the remedy will be evaluated through monitoring and a final groundwater remedy will be selected based on that information. Furthermore, as discussed in Sections 4 and 5 above, natural attenuation for the constituents of interest is active at the Site, and will remain active upon implementation of the cap -in -place remedy. Parette has opined that the utilization of monitored natural attenuation in combination with a cap -in -place remedy is problematic, as he believes conditions would be less favorable for natural attenuation following capping. First, less favorable conditions do not imply that natural attenuation is not taking place or cannot restore groundwater; and less favorable conditions do not negate the merits of natural attenuation. Second, one main reason given by Parette for this opinion is that capping of the ash basins would lead to more anoxic conditions in the Site groundwater. The coal ash pore water and the impacted groundwater are already depleted of dissolved oxygen (anaerobic). Water that contains atmospheric oxygen, and infiltrates into the ash, is readily depleted of its oxygen which is utilized to oxidize the organic content of the ash materials (the organic carbon content is reported to be at the percent level, providing an ample supply of organic substrate to sustain microbial activity in the ash materials). A cap would not change the situation, with the exception of a shallow zone of ash materials where oxygen from infiltration water is utilized to degrade the organic substrate in the ash in the absence of a cap. In the impacted groundwater environment, the conditions are typically reducing and anaerobic, and oxygen does not reach groundwater by infiltration through the ash. Third, some dissolved oxygen is present in the shallow groundwater upgradient from the ash basins; that condition will remain after capping. Furthermore, the available data demonstrate that natural attenuation is active at the Site (see 14 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Appendices D and E), and in the portion of the aquifer that has been impacted by the ash basins, the ratio of upgradient groundwater to the water that percolates through the ash will increase under the cap -in -place remedy. This will increase, not decrease the rate of natural attenuation. Parette opined that the partition coefficients (KD) obtained from the testing of Site materials in the laboratory are biased high because the synthetic groundwater used for the tests did not contain all the chemical species present in Site groundwater. Because of this, Parette appears to imply that because of this alleged bias, monitored natural attenuation is not appropriate for the restoration of groundwater. Even if all chemical species present in Site groundwater had been incorporated in the synthetic groundwater for testing, the main conclusion from the testing would remain valid. The main conclusion from the testing is that the constituents of interest in groundwater do interact with the solid matrix, demonstrating the occurrence of attenuation. Running the tests with all chemical species incorporated in the synthetic groundwater might have decreased somewhat the experimental KD values; however, this effect would not be a basis to negate the conclusion that the dissolved constituents of interest interact with the Site solid matrices that were tested. Boron is the exception, for which the testing showed that attenuation by interaction with the solid matrix does not contribute substantially to attenuation. Attenuation for boron is primary through dilution and dispersion, as discussed under Section 3 above. Parette opined that monitored natural attenuation should not be selected to remedy antimony, boron, chromium, hexavalent chromium, cobalt, and vanadium at the Site. Antimony, chromium, hexavalent chromium, cobalt and vanadium are within the groundwater background range and do not require active remediation at the Site. Parette's opinions on these constituents are therefore irrelevant. The exception is for cobalt in well GWA-9S. The well groundwater shows acidic condition with cobalt above the background range and IMAC. This well is located along the groundwater pathway from the ash basins to the river. The cap -in -place remedy and monitored natural attenuation are adequate for the restoration of groundwater in that area, as capping of the ash basins will reduced the available oxygen that contributes to acidity and pH can be expected to increase toward neutral as a result. At less acidic pH, cobalt will attenuate through sorption and mineral precipitation and co -precipitation.' As for boron in groundwater, the elevated concentrations will decrease under the planned source control measures because of a reduction in the flux of boron from the capped ash basins and through attenuation (primarily dilution and dispersion). There is no risk of exposure to unsafe level of boron at the Site and its vicinity now, or in the future. Plaintiffs' experts Spruill and Campbell jointly opined that background water quality data are insufficient for the Site, and that Duke Energy has not performed the evaluation required to establish any natural background concentration for any of the compounds of interest, at or near the Buck property. Spruill and Campbell ignore the data available from the United States Geological Survey and the State of North Carolina, and the fact that Duke Energy did consider that information. Combining that information with the Site characterization data allows for a reasonable evaluation of the background range for the Site (see Appendix C). 6 The excavation remedy advocated by Plaintiffs' experts would not remove the impacted groundwater in that area. Excavation would promote the introduction of additional atmospheric oxygen into the subsurface, which can have the detrimental effect of further acidifying groundwater, resulting in increased metal concentrations in groundwater. 15 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' �S Spruill and Campbell jointly opined that four background wells? for the Site are not proven to be located hydraulically upgradient of the coal ash basins. Spruill and Campbell only considered the hydraulic uncertainty and failed to consider the available chemical data. There is no detectable boron reported in these four wells indicating that the wells have not been impacted by the ash basins. The chemical data indicate that the wells are upgradient from the ash basins. Spruill and Campbell jointly opined that hexavalent chromium in well BG-lBR is not representative of background. I concur. The available data for this well is not reliable and the reported hexavalent chromium concentration (78 ug/1) is anomalous and outside of the background range. Further measurements at that well, which is described as a dry well, is required to verify the anomalous hexavalent chromium reading. The evaluation of this well is on -going. Well BG-1BR is upgradient from the ash basins and the chemical fingerprint of the well water is not indicative of an ash basin impact. The well reported a high pH condition which is indicative of grout contamination during well construction. Data for well BG-lBR is not usable for background evaluation. Opinion 3. Excavation of the ash basins is not necessary for Site groundwater restoration. Excavation alone cannot achieve the complete removal of the constituents of interest from the subsurface and provides no substantial benefit over a cap -in -place remedy to restore groundwater. The excavation and removal of the ash in the ash basins and a portion of the soil materials beneath the basins was evaluated by Duke Energy and determined not to be the best remedy for the Site. Cap -in -place control measures with monitored natural attenuation combined with additional control measures, if necessary, was selected as a better remedy for the Site. The determination is based on a technical evaluation of the merits and limitations of these two options. Excavation and complete removal of ash and shallow soil materials from the ash basins is the remedy that Plaintiffs' experts advocate for the Site. I disagree with that conclusion for the following major reasons (see also Sections 5 and 6 above): • The engineered cap -in -place control measures that Duke Energy plans to construct to cover the ash basins will have the effect of greatly reducing the infiltration of water and wastewater through the coal ash. The amount of ash pore water that will recharge to groundwater will be greatly diminished and the flux of chemicals entrained with infiltration water will decrease. • Natural attenuation will provide for a gradual restoration of the impacted groundwater under either the cap -in -place and excavation scenarios. Geochemical processes that control aquifer restoration will be slow and gradual and will require a long period of time (i.e., years or decades) under both the excavation and cap -in -place remedies. • Excavation would not remove all the ash materials. It is simplistic to assume that excavation at the scale promoted by Plaintiffs' experts would be able to remove the totality 7 MW-6S; MW-6D; BG-3S; and BG-3D. 16 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' of the ash at the Site. Ash materials were placed on bare soils for several decades, and some ash most likely penetrated deeper in the subsurface than can be reached by the excavation promoted by Plaintiffs' experts. • Excavation would not remove the impacted groundwater beneath and downgradient of the excavation. The residual mass of ash materials and the impacted groundwater would serve as long term sources and sustain the groundwater impacts. Excavation will disturb large volumes of coal ash and exposed chemically reduced materials to atmospheric oxygen and water. A change in geochemical conditions would result in a rearrangement of the mineralogy of the aquifer, with dissolution and precipitation of secondary mineralogy affecting groundwater chemistry and redistributing the constituents of interest in the subsurface. The geochemical disturbance would induce transient changes in the chemistry of groundwater that would only gradually and slowly attenuate long after the implementation of excavation. Excavation of the large quantities of materials in the ash basins would take time to implement (i.e., years or decades). During that period of open excavation, precipitation, storm water, and runoff water would enter the excavation in great quantities and infiltrate to groundwater. This added infiltration would introduce additional contamination and force impacted groundwater farther into the aquifer system, thereby increasing the extent of the existing groundwater impacts. Plaintiffs' experts Spruill and Campbell jointly opined that the most protective remediation option for coal ash at the Buck property is complete excavation and transfer to an engineered, encapsulating, water -free, properly -maintained and monitored repository. Spruill and Campbell wrongly assume that the source of contamination could be entirely removed by the excavation remedy. The excavation would not remove the impacted groundwater. The excavation would not remove the mass of contaminants that is stored by sorption and mineral coatings in the soil, rock and aquifer materials that would not be excavated. The excavation would also not remove the naturally occurring compounds of concern that are components of the native soil and rock materials. Spruill and Campbell opined that coal ash -derived contamination impacting groundwater and surface water will require additional assessment after the coal ash is removed, and that the contamination will require remediation using methods protective of human health and the environment, in particular the potable groundwater resources used by many hundreds of people living near the Buck site. These additional measures and assessments will be implemented by Duke Energy under the planned cap -in -place, if necessary. The opinion of Spruill and Campbell that these measures will be required under the excavation remedy effectively negates most if not all of the alleged advantages of excavation. Plaintiffs' expert Parette advocates excavation and removal because he believes it would result in in a reduction of the clean-up time for groundwater by a factor 2.5 to 5 relative to the cap -in -place source control remedy. The uncertainty on estimating clean-up rates for groundwater is very large, and predictions based on such estimates are highly uncertain and unreliable. The time factor improvement claimed by Parette for clean-up under the excavation scenario fails to account for the time it would take to excavate the ash basins. It would take several years to excavate the ash basins, and accounting for this would delay the onset of the 17 2-2- bVbVDObnr02 9� V220CIV1E2' JWC' �S groundwater cleanup. The time factor improvement claimed by Parette for clean-up under the excavation scenario would provide little benefit since there is no imminent risk of exposure to unsafe contaminant levels at the Site. In addition, the flux of contaminants from the ash basins will decrease under the cap -in -place remedy (and the additional source control measures that will be implemented, if necessary), and the extent of contamination will be reduced. Natural attenuation will provide for gradual groundwater restoration, further reducing the need for aggressive excavation and removal of the ash basins. MV APPENDICES Appendix A Curriculum Vitae of Remy J.-C. Hennet 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist AREAS OF EXPERTISE ■ Geochemistry, Hydrogeology, Geology ■ Origin, Fate, and Transport of Chemicals in the Environment SUMMARY OF QUALIFICATIONS A geochemist with 25 years of research and professional experience, Dr. Hennet specializes in evaluating the origin, fate, and transport of organic and inorganic chemicals in the environment. Dr. Hennet is often retained as an expert witness for litigation in providing services to industry, law firms, and the U.S. Department of Justice. His areas of expertise include the analysis of geochemical fingerprints, the evaluation of the timing of chemical releases, allocation of responsibilities, geochemical modeling, and the evaluation and application of novel on -site technologies to solve environmental problems. He is a member of the American Academy of Forensic Sciences, the American Chemical Society, and the Association of Groundwater Scientists and Engineers. He was awarded the Woods Hole Oceanographic Institution's Postdoctoral Scholarship in 1987 and has numerous publications in the fields of inorganic and organic geochemistry. REPRESENTATIVE EXPERIENCE S.S. Papadopulos & Associates, Inc., Bethesda, Maryland ■ Environmental Forensics ■ Litigation Support U.S. Department of Justice — Served as an expert witness for several environmental litigation cases. Examples of this work include: the quantification of the history of benzene flux from the subsurface to ambient air following the release of military jet fuel; the evaluation of multi -source petroleum hydrocarbon releases and their individual extent; the evaluation of the impact of bleaching agent when released in a desert environment; the impact and duration of large herbicides, and other products); and the origin, fate, chlorinated solvents at several military bases. YEARS OF EXPERIENCE: 25+ EDUCATION PhD - Geochemistry, Princeton University, 1987 MA -Geology, Princeton University, 1983 Diplome - 3eme Cycle, Hydrogeologie, Universite de Neuchatel, 1981 Diplome - Geologie, Sciences Exactes, Universite de Neuchatel, 1980 REGISTRATIONS Certified Professional Geological Scientist: No. 10572, American Institute of Professional Geologists Licensed Professional Geoscientist: Texas No. 425 PROFESSIONAL HISTORY S.S. Papadopulos & Associates, Inc.: Principal, 1989 to present Woods Hole Oceanographic Institution: Postdoctoral Scholar, 1987-1989 Princeton University: Research Assistant, 1983-1987; Teaching Assistant, 1982-1985 Universite de Neuchatel: Research Assistant, 1980-1981 scale pesticide applications (fumigants, transport, and timing of the release of Atlantic Richfield Company, Montana —Provided technical support for natural resource damage litigation and testified as an expert witness. For the Anaconda tailings ponds site, collected data for a modeling simulation of the fate and transport of dissolved arsenic and cadmium in the alluvium beneath and down -gradient of the ponds. For the Butte mining district, evaluated the background condition for metals, arsenic, and sulfur chemical species. For the Montana Pole wood treatment site, evaluated the mobility of arsenic and pentachlorophenol (PCP) in the groundwater environment. For the Milltown Reservoir on the Clark Fork River; evaluated the background conditions and the mobility of metals and arsenic chemical species in sediments accumulated behind the reservoir. ■ Allocation of Responsibility and Costs (Confidential Clients), Nationwide — Reviewed and interpreted large volumes of information to support multi -party allocation models. 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 2 • Atlantic Richfield/BP, California, Nevada — Provided a detailed evaluation of the design and performance of abatement measures at closed sulfur and copper mines. Applied geochemical fingerprints and performed modeling to evaluate the origin fate and transport of contamination. ■ Rhone Poulenc Corporation, Pennsylvania, California, and New Jersey — Studied arsenic fixation in soil material by various physicochemical treatments as part of a collaborative effort with Pennsylvania State University, with a focus on understanding the processes that control the fixation of arsenic in soils. Advised on the interpretation of data to characterize the mobility of arsenic chemical species at the Bay Road Site in the San Francisco Bay area, and at the Factory Lane Site in New Jersey. ■ Panhandle Eastern Pipeline Company — Evaluated and characterized the fate, transport, and distribution of polychlorinated biphenyls (PCBs) in the subsurface at several sites along a major pipeline system. Pipeline liquid condensate was discharged to unlined pits located at pumping stations spread along the system. The condensate contained PCBs from the operational bleeding of oil from gas pressurization turbines. The disposal of condensate resulted in surface and subsurface contamination by PCBs and light hydrocarbon compounds. Provided guidance in site characterization, site remediation, and to the site closure process. • Envirosafe Services Landfill, Toledo, Ohio —Reviewed detailed organic, inorganic, and isotope data to evaluate the integrity of a large active landfill complex located in an area characterized by historical waste disposal activity. ■ Lone Pine Superfund Site, Freehold, New Jersey —Performed data collection and interpretation to predict chemical composition for the design of a treatment facility. ■ Heleva Superfund Site, Allentown, Pennsylvania —Conducted specialized sampling to assess trace amount of chlorinated hydrocarbons in acetone -rich groundwater. Acquired isotope and nutrient data to characterize subsurface conditions for natural attenuation and design of the treatment plant. • Love Canal, Niagara Falls, New York, and Stringfellow, Glen Avon, California, Superfund Sites — Performed detailed data interpretations to assess the validity of expert witness' testimonies related to the fate, behavior, and migration of toxic chemicals in the subsurface. ■ Tyson Superfund Site, Pennsylvania — Conducted a detailed technical investigation of the performance of a large vacuum -extraction system consisting of more than 250 individual extraction wells. The extraction of volatile organic compounds was impeded by subsurface heterogeneities and the presence of residual non -aqueous phase liquids in the subsurface. ■ Little Mississinewa River Superfund Site, Union City, Indiana, — Several miles of river sediments were contaminated with waste oil containing elevated PCBs, and PCTs, PAHs, and metals. The main sources of contamination consisted of two major industrial outflows that discharged to the river over a period of several decades. Using chromatograms and raw electronic instrument response data from the analysis of about 200 samples, characterized the chemical fingerprints of both sources and quantified relative contributions. ■ Coronet Company, Florida —Provided a detailed evaluation of the fate and transport of arsenic, boron, radium, polonium, and other chemicals in soil, ponds sediment, and groundwater at a former phosphate mining and fertilizer processing plant. Conducted geochemical modeling. • White Pine Sash Superfund Site, Missoula, Montana —The release of wood treatment product containing pentachlorophenol (PCP) in diesel resulted in contamination of the vadose zone above a major water supply aquifer. Chlorinated-dioxins/furans were also detected in soil samples. Concurrently with the PCP product release(s), diesel/fuel oil No 2 had been released from underground storage tanks in the area. Evaluated and delineated the extent of impact of the diesel/fuel oil No 2 release independently of the PCP -diesel release(s). 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 3 • CSX Transportation, Florida — Evaluated the origin(s) fate and transport of arsenic in the environment. • Titan Tire Corporation, Iowa — Evaluated the origin of PCB contamination and conducted a detailed review of laboratory data packages. ■ Uranium Mine Tailings, New Mexico —Evaluated tailings piles (from the processing of uranium ore) for water balance, dewatering, contaminant flux to groundwater, the progress of groundwater plume development, and the effects of remedial measures. Recommended dose reconstruction in water wells. ■ Citizens about Rushton Rezoning, Inc., South Lyon, Michigan — Analyzed the potential environmental and hydrogeological impacts of water -treatment lagoons and infiltration spraying fields. Calculated the fate and transport of nitrogen and phosphorous in the soil and groundwater. [The lagoons and spraying fields were selected as a wastewater treatment for a large residential development. The spraying fields were located on sloped glacial till that has limited permeability and capacity. Regulated surface -water bodies were located adjacent to the spraying fields and lagoons.] Woods Hole Oceanographic Institution, Woods Hole, Massachusetts Studied the organic and inorganic chemistry of the Guaymas Basin hydrothermal system. Performed detailed trace analyses of metals and petroleum hydrocarbons. The research included the use of the research submarine Alvin for in -situ parameter measurements and sampling. Researched and studied the formation of natural petroleum and the effects of organic molecules degradation and migration on the formation of geopressured zones. Princeton University, Princeton, New Jersey As Research Assistant, studied metal -organic interaction in natural settings, and served as Senior Thesis Advisor for an experimental study of lead -organic complexing and for an experimental study of trichloroethane in groundwater. Served as Teaching Assistant in Historical Geology and Geomorphology. Universite de Neuchatel, Centre d'Hydrologie, Switzerland Studied tritium in groundwater and performed related laboratory work. Conducted geochemical fingerprinting in carbonate terrains as applied to the development of water resources. PROFESSIONAL SOCIETIES American Academy of Forensic Sciences American Chemical Society American Institute of Professional Geologists Geological Society of America National Ground Water Association — Association of Ground Water Scientists and Engineers HONORS & AWARDS Postdoctoral Scholar, Woods Hole Oceanographic Institution, 1987-1989 Princeton University Fellowship, 1982-1987 Swiss National Science Foundation Fellowship at Princeton University, 1981-1982 Mention Bien, Geologie, Universite de Neuchatel, 1980 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 4 APPOINTMENTS 2002-2005: Geological Sciences Advisory Board, University of Alabama. 1996-2001: Member of Governing Board, Association of Princeton Graduate Alumni. 2000: Convenor, THEIS 2000 Conference: Iron in Groundwater, National Ground Water Association. 1993-1999: Technical Advisory Board, Xetex Corporation. 1989-1992: Member of Steering Committee, Working Group 91, Scientific Commission for Oceanic Research. PUBLICATIONS Soderberg, K., D.P. McCarthy, and R. J.-C. Hennet, 2015. Volatilization of Polychlorinated Biphenyls: Implication for their Distribution, Forensics and Toxicity in Urban Environments. Presentation at the Geological Society of America Annual Meeting, November 1-4, 2015, Baltimore, MD. Soderberg, K. and R.J.-C. Hennet, 2014. Detection of Pharmaceuticals in the Environment: History of Use as a Forensic Tool. in Goldstein, W. ed. Pharmaceutical Accumulation the Environment: Prevention, Control, Health Effects and Economic Impact. CRC Press: Boca Raton, FL. 262 p. Hennet, R.J.-C, 2010. PCBs in the Interstate Natural Gas Transmission System — Status and Trends. White Paper prepared for the Interstate Natural Gas Association of America. Hennet, R.J.-C, 2010. Working with Lawyers: The Expert Witness Perspective. United States Attorneys' Bulletin, v. 58, no. 1, pp. 14-17. Soderberg, K., and R.J.-C. Hennet, 2007. Uncertainty and Trend Analysis -- Radium in Groundwater and Drinking Water. Ground Water Monitoring and Remediation, v. 27, no. 4, pp. 122-127. Soderberg, K., R. Hennet, and C. Muffels, 2005. Uncertainty and Trend Analysis for Radium in Groundwater and Drinking Water (abstract). Presentation at the 2005 National Ground Water Association Conference on Naturally Occurring Contaminants: Arsenic, Radium, Radon, and Uranium, February 24-25, 2005, Charleston, SC. in Abstract Book, pp. 30-44. Hennet, R.J.-C, 2002. The Application of Stable Isotope Ratios in Environmental Forensics. in American Academy of Forensic Sciences Proceedings, pp. 103-104. Hennet, R.J.-C, 2002. Life is Simply a Particular State of Organized Instability. in Fundamentals of Life, G. Palyi et al., eds. Paris, France: Elsevier, pp. 109-110. Hennet, R.J.-C., and L. Chapp, 2001. Using the Chemical Fingerprint of Pharmaceutical Compounds to Evaluate the Timing and Origin of Releases to the Environment. in Proceedings of the American Academy of Forensic Sciences, v.4, no. 1, p. 101. Vlassopoulos, D., C. Andrews, R. Hennet, and S. Macko, 1999. Natural Immobilization of Arsenic in the Shallow Groundwater of a Tidal Marsh, San Francisco Bay. Presentation at the American Geophysical Union Spring Meeting, Boston, MA, May 31-June 4, 1999. Hennet, R.J.-C, D. Carleton, S. Macko, and C. Andrews, 1997. Environmental Applications of Carbon, Nitrogen, and Sulfur Stable Isotope Data: Case Studies (abstract). Invited speaker at the Geological Society of America Annual Meeting, Salt Lake City, UT, November. Jiao, J., C. Zheng, and R. Hennet, 1997. Analysis of Under -pressured Reservoirs for Waste Disposal. Hydrogeology Journal, v.5, no. 3, pp. 19-31. 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 5 Jiao, J., C. Zheng, and R. Hennet, 1995. Study of the Feasibility of Liquid Waste Disposal in Underpressured Geological Formations. Proceedings of the American Geophysical Union Spring Meeting, Baltimore, MD, May 30—June 2, 1995. in Eos Supplement, v. 76, no. 17, S137. Vlassopoulos, D., P. Lichtner, W. Guo, and R. Hennet, 1995. Long -Term Controls on Attenuation of Mine -Waste Related Contamination in Alluvial Aquifers: The Role of Aluminosilicate Clay Minerals. Proceedings of the American Geophysical Union Spring Meeting, Baltimore, MD, May 30-June 2, 1995. in Eos Supplement, v. 76, no. 17, S150. Feenstra, S., and R. Hennet, 1993. Assessment of Performance Limitations on Soil Vapor Extraction (SVE) in Variable Soils. The Newsletter of the Association of Ground Water Scientists and Engineers, v. 9, no. 3, pp. 112-113. Hennet, R.J.-C., and S. Feenstra, 1993. Assessment of Performance Limitations on Soil Vapor Extraction (SVE) in Variable Soils (abstract). Presentation at the Symposium on Chlorinated Volatile Organic Compounds in Ground Water, National Ground Water Association 45th Annual Convention, Kansas City, MO, October 17-20, 1993. in Ground Water, v. 31, no. 5, pp. 828-829. Hennet, R.J.-C., and C. Andrews, 1993. PCB Congeners as Tracers for Colloid Transport in the Subsurface —A Conceptual Approach. in Manipulation of Groundwater Colloids for Environmental Restoration. Ann Arbor, MI: Lewis Publishers, pp. 241-246. Hennet, R.J.-C, 1992. Abiotic Synthesis of Amino Acid Under Hydrothermal Conditions and the Origin of Life: A Perpetual Phenomenon? Invited speaker at the Gordon Research Conference on Organic Geochemistry, New Hampshire. Hennet, R.J.-C, N. Holm, and M. Engel, 1992. Abiotic Synthesis of Amino Acid Under Hydrothermal Conditions and the Origin of Life: A Perpetual Phenomenon? Naturwissenschaften, v. 79, pp. 361-365. Hennet, R.J.-C, and N. Holm, 1992. Hydrothermal Systems: Their Varieties, Dynamics, and Suitability for Prebiotic Chemistry. in Origins of Life and Evolution of the Biosphere, Netherlands, v. 22, pp. 15-31. Holm, N., A. Cairns -Smith, R. Daniel, J. Ferris, R. Hennet, E. Shock, B. Simoneit, and H. Yanagawa, 1992. Future Research. in Origins of Life and Evolution of the Biosphere, v. 22, pp. 181-190. Hunt, J.M., and R. Hennet, 1992. Modeling Petroleum Generation in Sedimentary Basins. in Productivity, Accumulation, and Preservation of Organic Matter Recent and Ancient Sediments. J. Whelan and J. Farrington, eds. New York: Columbia University Press, pp. 20-52. Hunt, J.M., M. Lewan, and R. Hennet, 1991. Modeling Oil Generation with Time -Temperature Index Graphs Based on the Arrhenius Equation. AAPG Bulletin, v. 75, no. 4, pp. 795-807. Hennet, R.J.-C, D. Crerar, and J. Schwartz, 1988. The Effect of Carbon Dioxide Partial Pressure on Metal Transport in Low -Temperature Hydrothermal Systems. Chemical Geology, v. 69, pp. 321- 330. Hennet, R.J.-C, D. Crerar, and J. Schwartz, 1988. Organic Complexes in Hydrothermal Systems: Economic Geology, v. 83, pp. 742-767. Hennet, R.J.-C, and F. Sayles, 1988. Effect of Dissolved Organic Compounds on Trace Metal Mobility in Low -Temperature Hydrothermal Systems (abstract). Presentation at the Joint Oceanographic Assembly, Acapulco, Mexico, August 23-31, 1988. in Journal of Arboriculture, v. 14, Mexico 88, p. 43. 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 6 Hennet, R.J.-C, and J.K. Whelan, 1988. In -Situ Chemical Sensors for Detecting and Exploring Ocean Floor Hydrothermal Vents. Woods Hole Oceanographic Institution Technical Report WHOI-88-53, p. 69. Hennet, R.J.-C, 1987. The Effect of Organic Complexing and Carbon Dioxide Partial Pressure on Metal Transport in Low -Temperature Hydrothermal Systems. Unpublished PhD thesis, Department of Geochemistry, Princeton University. 308 p. Hennet, R.J.-C, D. Crerar, E. Brown, and J. Schwartz, 1986. Transport of Base Metals in Hydrothermal Brines by Organic and Possible Thiocarbonate Complexes: The Genesis of Stratiform Sediment -Hosted Lead and Zinc Deposits. Conference Proceedings. in Geological Science, Stanford University, v. 20, pp. 197-198. Hennet, R.J.-C, 1985. Partial Pressure of Carbon Dioxide and Base Metal Solubility: A Model for the Genesis of Hydrothermal Ore Deposits. Poster presentation at the Gordon Research Conference on Inorganic Geochemistry of Hydrothermal Deposits, New Hampshire. Hennet, R.J.-C, D. Crerar, and E. Brown, 1985. Base Metal Transport by Organic Complexing in Ore -Forming Brines (abstract). in Proceedings of the Second International Symposium on Hydrothermal Reactions. The Pennsylvania State University, p. 43. Hennet, R.J.-C, D. Crerar, and J. Schwartz, 1985. Metal -Organic Complexes in Ore -Forming Brines. Presentation at the1901h National Meeting of the American Chemical Society, Division of Environmental Chemistry, Chicago, IL, September 9, 1985. Hennet, R.J.-C, 1983. Formation Constants of Lead and Zinc Metal -Organic Complexes Using Polarography (ASV, DPP), Specific Ion Electrodes (ISE), and Nuclear Magnetic Resonance Spectroscopy (NMR). Unpublished MA thesis, Princeton University. Hennet, R.J.-C, D. Crerar, J. Schwartz, and T. Giordano, 1983. New Ligand-Bond Mechanisms for the Transport of Zinc in the Genesis of Mississippi Valley -Type Ore Deposits. Eos, v. 64, no. 45, p. 885. Flury, F.R., R. Hennet, and A. Matthys, 1981. Developpement des resources en eaux de la Ville de Delemont (Jura, Suisse). Unpublished Diplome d'Hydrogeologie. Centre d'Hydrogeologie. Universite de Neuchatel, Switzerland. Hennet, R.J.-C, 1980. Cartographie de la Region Neuchatel-Valangin: Etude de la Mineralogie par Diffraction-X, de la Stratigraphie et des Microfacies du Valanginien. Discussion de Stratotype de Valangin. Unpublished Diplome de Geologie. University de Neuchatel, Switzerland. DEPOSITION AND TESTIMONY EXPERIENCE DEPOSITIONS 2016 Tri-Realty Company v. Ursinus College. The United States District Court for the Eastern District of Pennsylvania. Civil Action No. 2:11-cv-05885-GP. April 20. 2015 Duke Energy Progress, Inc. v. N.0 Department of Environment Resources, et al. State of North Carolina, Wake County in the Office of Administrative Hearings. Case No. 15 HER 02581. July 9. 2014 United States of America v. Richard Middleton, Circle Environmental, Inc., BSJR, LLC, and WaterPollutionSolutions.com, Inc. The United States District Court for the Middle District of Georgia Albany Division. Case No. 1:11-cv-00127-WLS. November 3. 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 7 2014 Santa Fe Pacific Gold Corporation vs. United Nuclear Corporation vs. The Travelers Indemnity Company, et al, State of New Mexico, County of Cibola Eleventh Judicial District. No. CV-97-13911. February 6. 2013 State of New Mexico ex rel. vs. Kerr-McGee Corporation et al. State of New Mexico, County of Cibola Thirteenth Judicial District Court. No. CB-83-190-CV & CB-83-220-CV (Consolidated). April24-26. 2012 Grant Neibaur and Sons Farms, et al vs. The United States of America. U.S. District Court for the District of Idaho. No. CIV 4:11 -cv-001 59-BLW. September 19. 2012 State of New Mexico ex rel. vs. Kerr-McGee Corporation et al. State of New Mexico, County of Cibola Thirteenth Judicial District Court. No. CB-83-190-CV & CB-83-220-CV (Consolidated). September 11-14. 2012 Commissioner of the Department of Planning and Natural Resources, et al. vs Century Aluminum Company, et al. District Court of the Virgin Islands Division of St. Croix. Civil No. 2005-0062. June 26. 2012 Commissioner of the Department of Planning and Natural Resources, et al. vs Century Alumina Company, et al. District Court of the Virgin Islands Division of St. Croix. Civil No. 2005-0062. June 25. 2012 ExxonMobil Oil Corporation vs Nicoletti Oil, Inc., et al. U.S. District Court Eastern District of California. No. 1:09-cv-01498-A WI-DLB. June 14. 2012 United States of America vs Dico Inc. and Titan Corporation. U.S. District Court Southern District of Iowa. No. 4:10-cv-00503-RP-RAW. January 20. 2011 Joseph A. Pookatas, Donald L.Michel and the Confederated Tribes of the Colville Reservation and the State of Washington (Plaintiff Intervenor) vs Teck Cominco Metals, LTD. U.S. District Court Eastern District of Washington at Yakima. CB-04-0256-LRS. June 10. 2010 United States Virgin Islands Department of Planning and Natural Resources vs. St. Croix Renaissance Group, L.L.L.P., et al. District Court of the Virgin Islands Division of St. Croix. Civil No. 2007/114. October 20. 2010 In the Matter of the Application for Water Rights of Leadville Water, JV., in Park County, Colorado. District Court, Water Division No. 1, State of Colorado. 07CW251. September 22-23. 2009 Timm Adams et al. vs. United States of America et al. U.S. District Court, District of Idaho. 03-0049-E-BLW. January 15. 2008 Pennsauken Solid Waste Management Authority vs. Devoe et al. New Jersey Superior Court, Camden County, Law Division. No. L-13345-91. October 15. 2007 Arbitration in the Issue of PCB Contamination in the Little Mississinewa River, Union City, Indiana. Pittsburgh, Pennsylvania. August 22. 2007 San Diego Unified Port District vs. TDY Industries, Inc.; Ryan Aeronautical Company; Teledyne Ryan Company; Teledyne Ryan Aeronautical Company; Teledyne Industries, Inc; Allegheny Teledyne, Inc.; Allegheny Technologies, Inc. United States District Court, Southern District of California. Case Number 03 CV 1146-B (POR). January 5. 2006 Sierra Club, Natural Resources Defense Council, and Natural Parks Conservation Association vs. Robert B. Flowers, Chief of Engineers, United States Army Corps of 2.2- bV6VD06rlr'02 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 8 Engineers et al. U.S. District Court, Southern District of Florida. Case No. 03-23427-CIV- Hoeveler. October 31 and November 17. 2003 Linda Akee et al. vs. The Dow Chemical Company et al., Dole Food Company, Inc., Third - Party Plaintiffs vs. The United States of America, Third -Party Defendant. U.S. District Court for the District of Hawaii. Civil Action No. CV00-00382 BMK. August 25. 2000 Chevy Chase Bank, FSB, Plaintiff/Counter-Defendant vs. Shell Oil Company and Motiva Enterprises, LLC, Defendants/Counter-Plaintiffs. U.S. District Court for the District of Maryland, Southern Division. December 14. 1999 Textron vs. Ashland, Inc. et al. Superior Court of New Jersey. 1999 McMahon vs. The United States of America. U.S. District Court, Southern District of Texas, Laredo Division. Case No. L-99-009. December 1. 1998 Kay Bettis et al. vs. Ruetgers-Nease Corp. et al. U.S. District Court for the Northern District of Ohio Eastern Division. Case No. 4:90 CV 0502. 1996 State of Montana vs. Atlantic Richfield Company. U.S. District Court, District of Montana, Helena Division. Case No. CV-83-317-HLN-PGH. 1996 Kenneth Bowers vs. The United States and Tenco Services, Inc. U.S. District Court for the District of South Carolina. Case No. 2:95-5568. 1995 Reichhold Chemicals, Inc. vs. Textron Inc. et al. U.S. District Court, Northern District of Florida. Case No. 92-30393RV. TESTIMONY 2015 United Nuclear Corporation vs. London Insurance Companies. Eleventh Judicial District Court. County of McKinley, State of New Mexico. No. D-1 1 13-CV-9700139. January 21 and 22. 2013 United States of America vs Dico Inc. and Titan Corporation. U.S. District Court Southern District of Iowa. No. 4:10-cv-00503-RP-RAW. December 4. 2009 Timm Adams et al. vs. United States of America and E.I. DuPont de Nemours and Company, a Delaware corporation. U.S. District Court, District of Idaho. Case No. CIV-03- 0049-E-BLW. August 4, 5, 6. 2008 Attorney General of the State of Oklahoma and Oklahoma Secretary of the Environment vs. Tyson Foods, Inc., et al. U.S. District Court for the Northern District of Oklahoma. 4:05-CV- 00329-TCK-SAJ. March 7. 2006 Sierra Club, Natural Resources Defense Council, and Natural Parks Conservation Association vs. Robert B. Flowers, Chief of Engineers, United States Army Corps of Engineers et al. U.S. District Court, Southern District of Florida. Case No. 03-23427-CIV- Hoeveler. November 28 and 29. 2004-2005 Universal Waste, Inc. and Clearview Acres, Ltd. Regarding Delisting Petition for Site Number 0633009. Adjudicatory Hearing by New York Department of Environmental Conservation, Office of Hearings and Mediation. Site Number 0633009. October 27 and February 3. 2004 Part 31, City of South Lyon and the Citizens About Rushton Rezoning, Inc., Permit No.: M 00994; and Permit No: GW186300602. State of Michigan, Department of Environmental Quality, Office of Administrative Hearings, Lansing, MI. May 20, 21, and 27. 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' REMY J.-C. RENNET Geochemist Page 9 2003 Robert McMahon vs. The United States of America. U.S. District Court, Southern District of Texas. Case No. L-99-009. February. 2001 Bolinder et al. vs. United States. U.S. District Court, District of Utah. Case No. 2:97CV0912. May. 1998 State of Montana vs. Atlantic Richfield Company. U.S. District Court, District of Montana, Helena Division. Case No. CV-83-317-HLN-PGH, Natural Resource Damage Claim. January. 1997 In the matter of the claim of Missoula White Pine Sash Company, Missoula, Montana. Administrative hearing before the Petroleum Tank Release Compensation Board vs. Department of Environmental Quality, State of Montana. Claim No. 97-960307-P-00037. October. 1996 Doria Tartsah Goombi et al. vs. U.S. Department of the Interior. U.S. Department of Interior, Office of Hearings and Appeals, Hearings Division, Oklahoma City, Oklahoma. Case No. D95-179 (1-41). August. Appendix B Documents Considered and/or Relied Upon 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' MSU Documents Considered and/or Relied Upon 2016. Duke AB Groundwater Data from MANAGES June 22, 2016 Request - All Wells. June 23. 2016. Duke NPDES DMR Data from MANAGES June 22, 2016 Request. June 22. 2016. Duke Seep-AOW Data from MANAGES June 22, 2016 Request. June 23. Abernethy, R.F., M.J. Peterson, and F.H. Gibson. 1969. Spectrochemical Analyses of Coal Ash for Trace Elements. Report of Investigations 7281. United States Department of the Interior. Akinyemi, S.A., A. Akinlua, W.M. Gitari, N. Khuse, P. Eze, R.O. Akinyeye, and L.F. Petrik. 2012. Natural Weathering in Dry Disposed Ash Dump: Insight from Chemical, Mineralogical and Geochemical Analysis of Fresh and Unsaturated Drilled Cores: Journal of Environmental Management 102: 96-107. Amstaetter, K., T. Borch, P. Larese-Casanova, and A. Kappler. 2010. Redox Transformation of Arsenic by Fe(II)-Activated Goethite (a-FeOOH): Environmental Science and Technology 44: 102-108. Bolanz, R.M., J. Majzlan, L. Jurkovic, and J. G6ttlicher. 2012. Mineralogy, Geochemistry, and Arsenic Speciation in Coal Combustion Waste from Novaky, Slovakia: Fuel 94: 125-136. Butler, J.R. 1953. The Geochemistry and Mineralogy of Rock Weathering (1) The Lizard Area, Cornwall: Geochimica et Cosmochimica Acta 4: 157-178. Butler, J.R., and D.T. Secor. 1991. Chapter 4 - The Central Piedmont. In The Geology of the Carolinas: CGS 50th Anniversary Volume. (1st ed.): University of Tennessee Press. Campbell, S.K., and R.K. Spruill. 2016. Expert Report Addendum #1 Buck Steam Station. May 12. Campbell, S.K., and R.K. Spruill. 2016. Expert Report Addendum #1 Buck Steam Station (State). May 12. Campbell, S.K., and R.K. Spruill. 2016. Expert Report Buck Steam Station. February 29. Campbell, S.K., and R.K. Spruill. 2016. Expert Report. Buck Steam Station (Federal). May 12. Campbell, S.K., and R.K. Spruill. 2016. Expert Report. Buck Steam Station (State). February 29. Catalano, J.G., B.L. Huhmann, Y. Luo, E.H. Mitnick, A. Slavney, and D.E. Giammar. 2012. Metal Release and Speciation Changes during Wet Aging of Coal Fly Ashes: Environmental Science and Technology 46: 11804-11812. Choi, S., P.A. O'Day, and J.G. Hering. 2009. Natural Attenuation of Arsenic by Sediment Sorption and Oxidation: Environmental Science and Technology 43: 4253-4259. Daniels, J.L., and G.P. Das. 2014. Practical Leachability and Sorption Considerations for Ash Management: Geo-Congress 2014 Technical Papers: Geo-Characterizationand Modeling for Sustainability: 15. 1 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Delany, J.M., and S.R. Lundeen. 1990. The LLNL Thermochemical Database -- Revised Data and File Format for the EQ316 Package. Lawrence Livermore National Laboratory. UCID- 21658. March. Deutsch, W.J. 1997. Chapter 3 - Water/Rock Interactions. In Groundwater Geochemistry - Fundamentals and Applications to Contamination: Lewis Publishers. 31. Dicken, C.L., S.W. Nicholson, J.D. Horton, M.P. Foose, and J.A.L. Mueller. 2007. Preliminary Integrated Geologic Map Databases for the United States - Alabama, Florida, Georgia, Mississippi, North Carolina, and South Carolina, Version L I. Open -File Report 2005- 1323. U.S. Geological Survey. Available at: http://pubs.usgs.gov/of/2005/1323/. Dixit, S., and J.G. Hering. 2003. Comparison of Arsenic(V) and Arsenic(III) Sorption onto Iron Oxide Minerals: Implications for Arsenic Mobility: Environmental Science and Technology 37: 4182-4189. Duke Energy. Guiding Principles for Ash Basin Closure. Duke Energy. 2016. Duke Energy Coal Plants and Ash Management. https://www.duke- energy.com/pdfs/duke-energy-ash-metrics.pdf. June 2. Duke Energy. 2016. Emergency Action Plan (EAP), Duke Energy Buck Station Ash Basin Dam. DUK-EAP-00-0001, Rev. 003. May 16. Duke Energy, M.A. Abney, J.J. Hall, and J.R. Quinn. 2011. Assessment of Balanced and Indigenous Populations in the Yadkin River and High Rock Lake Near Buck Steam Station. NC0004774. March. Duke Energy Corporation. 2011. Duke Energy Carolinas LLC - NPDES Permit Application Buck Steam Station - #NC0004774. February 28. Dzombak, D.A., and F.M.M. Morel. 1990. Surface Complexation Modeling: Hydrous Ferric Oxide. New York: John Wiley & Sons. Electric Power Research Institute (EPRI). 2005. Chemical Constituents in Coal Combustion Product Leachate: Boron. Technical Report. 1005258. March. Electric Power Research Institute (EPRI). 2006. Groundwater Remediation of Inorganic Constituents at Coal Combustion Product Management Sites. Overview of Technologies, Focusing on Permeable Reactive Barriers. Technical Report. 1012584. October. Electric Power Research Institute (EPRI). 2009. Coal Ash: Characteristics, Management and Environmental Issues. Technical Update - Coal Combustion Products - Environmental Issues. 1019022. September. Electric Power Research Institute (EPRI). 2010. Comparison of Coal Combustion Products to Other Common Materials. Chemical Characteristics. 1020556. September. Fetter, C.W. 1999. Contaminant Hydrogeology (2nd ed.): Prentice Hall, Inc. Freeze, R.A., and J.A. Cherry. 1979. Groundwater. Englewood Cliffs, NJ: Prentice -Hall, Inc. 2 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Fruchter, J.S., D. Ral, and J.M. Zachara. 1990. Identification of Solubility -Controlling Solid Phases in a Large Fly Ash Field Lysimeter: Environmental Science and Technology 24: 1173-1179. Ghuman, G.S., K.S. Sajwan, and M.E. Denham. 1999. Impact of Coal Pile Leachate and Fly Ash on Soil and Groundwater. In Biogeochemistry of Trace Elements in Coal and Coal Combustion Byproducts. Sajwan, K.S., Alva, A.K., and Keefer, R.F. eds. New York: Kluwer Academic/Plenum Publishers. 235-246. Haley & Aldrich. 2016. Report on Evaluation of Water Supply Wells in the Vicinity of Duke Energy Coal Ash Basins in North Carolina. April. Hall, G.E.M., J.E. Vaive, R. Beer, and M. Hoashi. 1996. Selective Leaches Revisited, with Emphasis on the Amorphous Fe Oxyhydroxide Phase Extraction: Journal of Geochemical Exploration 56: 59-78. Harte, P.T., J.D. Ayotte, A. Hoffman, K.M. Revesz, M. Belaval, S. Lamb, and J.K. Bohlke. 2012. Heterogeneous Redox Conditions, Arsenic Mobility, and Groundwater Flow in a Fractured -Rock Aquifer near a Waste Repository Site in New Hampshire, USA: Hydrogeology Journal 20: 1189-1201. Hasany, S.M., and M.A. Qureshi. 1981. Adsorption Studies of Cobalt(II) on Manganese Dioxide from Aqueous Solutions: International Journal of Applied Radiation and Isotopes 32: 747- 52. HDR Engineering Inc of the Carolinas. 2015. Comprehensive Site Assessment Report. Buck Steam Station Ash Basin. August 23. HDR Engineering Inc of the Carolinas. 2015. Corrective Action Plan Part 1. Buck Steam Station Ash Basin. November 20. HDR Engineering Inc of the Carolinas. 2016. Corrective Action Plan Part 2. Buck Steam Station Ash Basin. February 19. He, Y.T., A.G. Fitzmaurice, A. Bilgin, S. Choi, P.A. O'Day, J. Horst, J. Harrington, H.J. Reisinger, D.R. Burris, and J.G. Hering. 2010. Geochemical Processes Controlling Arsenic Mobility in Groundwater: A Case Study of Arsenic Mobilization and Natural Attenuation: Applied Geochemistry 25: 69-80. Hewlett, P.C. 1988. Lea's Chemistry of Cement and Concrete (4th ed.): Elsevier Butterworth - Heinemann. Holm, T.R. 2002. Effects of C032-/bicarbonate, Si, and P043- on Arsenic Sorption to HFO: American Water Works Association 94, no. 4: 174-181. Horton, J.W., and V.A. Zullo. 1991. The Geology of the Carolinas: CGS 50th Anniversary Volume (1st ed.): University of Tennessee Press. Interstate Technology Regulatory Council (ITRC). 2010. Technical/Regulatory Guidance: A Decision Framework for Applying Monitored Natural Attenuation Processes to Metals and Radionuclides in Groundwater. December. 3 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Jones, G.W., and T. Pichler. 2007. Relationship between Pyrite Stability and Arsenic Mobility during Aquifer Storage and Recovery in Southwest Central Florida: Environmental Science and Technology 41: 723-730. Jones, L.H., and A.V. Lewis. 1956. Weathering of Fly Ash: Nature 185, no. 4710: 404-405. Karamalidis, A.K., and D.A. Dzombak. 2010. Surface Complexation Modeling: Gibbsite: John Wiley & Sons, Inc. Keon, N.E., C.H. Swartz, D.J. Brabander, C. Harvey, and H.F. Hemond. 2001. Validation of an Arsenic Sequential Extraction Method for Evaluating Mobility in Sediments: Environmental Science and Technology 35: 2778-2784. Kim, K., S.-H. Kim, S.-M. Park, J. Kim, and M. Choi. 2010. Processes Controlling the Variations of pH, Alkalinity, and CO2 Partial Pressure in the Porewater of Coal Ash Disposal Site: Journal of Hazardous Materials 181: 74-81. L.Tiruta-Barna, Z. Rakotoarisoa, and J. M6hu. 2006. Assessment of the Multi -Scale Leaching Behaviour of Compacted Coal Fly Ash: Journal of Hazardous Materials B 137: 1466-1478. Lee, S.-Z., H.E. Allen, C.P. Huang, D.L. Sparks, P.F. Sanders, and W.J.G.M. Peijnenburg. 1996. Predicting Soil - Water Partition Coefficients for Cadmium: Environmental Science and Technology 30: 3418-3424. LeGrand, H.E. 1988. Region 21, Piedmont and Blue Ridge. In The Geology of North America. Black, W.B., Rosenshein, J.S., and Seaber, P.R. eds. Vol. 0-2: Geological Society of America. 201-207. Lengke, M.F., C. Sanpawanitchakit, and R.N. Tempel. 2009. The Oxidation and Dissolution of Arsenic -Bearing Sulfides: The Canadian Mineralogist 47: 593-613. Lengke, M.F., and R.N. Tempel. 2003. Natural Realgar and Amorphous AsS Oxidation Kinetics: Geochimica et Cosmochimica Acta 67, no. 5: 859-871. Liu, G., H. Zhang, L. Gao, L. Zheng, and Z. Peng. 2004. Petrological and Mineralogical Characterizations and Chemical Composition of Coal Ashes from Power Plants in Yanzhou Mining District, China: Fuel Processing Technology 85: 1635-1646. Masscheleyn, P.H., R.D. Delaune, and W.H. Patrick. 1991. Heavy Metals in the Environment. Arsenic and Selenium Chemistry as Affected by Sediments Redox Potential and pH: Journal of Environmental Quality 20: 522-527. Meng, X., S. Bang, and G.P. Korfiatis. 2000. Effects of Silicate, Sulfate, and Carbonate on Arsenic Removal by Ferric Chloride: Water Resources 34, no. 4: 1255-1261. Meng, X., G.P. Korfiatis, S. Bang, and K.W. Bang. 2002. Combined Effects of Anions on Arsenic Removal by Iron Hydroxides: Toxicology Letters 133: 103-111. Miller, G.P. 2011. Monitored Natural Attenuation: A Remediation Strategy for Groundwater Impacted by Coal Combustion Product Leachate. World of Coal Ash (WOCA) Conference, Denver, CO, May 9-12. 14. Mineralogical Society of America. 1983. Carbonates: Mineralogy and Chemistry. Reviews in Mineralogy. Vol. 11. E 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Mineralogical Society of America. 1990. Mineral -Water Interface Geochemistry. Reviews in Mineralogy. Vol. 23. Mudd, G.M., T.R. Weaver, and J. Kodikara. 2004. Environmental Geochemistry of Leachate from Leached Brown Coal Ash: Journal of Environmental Engineering 130, no. 12: 1514-1526. Mudd, G.M., T.R. Weaver, J. Kodikara, and T. McKinley. 1998. Groundwater Chemistry of the Latrobe Valley Influences by Coal Ash Disposal - 1: Dissimilatory Sulphate Reduction and Acid Buffering. International Association of Hydrogeologists Conference: Groundwater - Sustainable Solutions, Melbourne, VIC, February. 12. National Institute of Advanced Industrial Science and Technology. 2005. Atlas of Eh pH Diagrams. Intercomparison of Thermodynamic Databases. Open File Report No. 419. Geological Survey of Japan. May. North Carolina Department of Environment and Natural Resources. 2008. Permit NC0004774 - Permit for Duke Power Company to Discharge Wastewater Under the National Pollutant Discharge Elimination System. Buck Steam Station. June 24. North Carolina Department of Environment and Natural Resources. 2011. Permit NC0004774 - Permit for Duke Energy to Discharge Wastewater Under the National Pollutant Discharge Elimination System. Buck Steam Station. December 2. North Carolina Department of Environment and Natural Resources. 2013. North Carolina Administrative Code. Title 15A. Subchapter 2L Section .0100, .0200, .0300. Classifications and Water Quality Standards Applicable to the Groundwaters of North Carolina. April 1. North Carolina Department of Environmental Quality. 2016. Well Test Information for Residents near Duke Energy Coal Ash Impoundments. Summary and Table. https:Hdeq.nc.gov/about/divisions/water-resources/water-resources-hot-topics/dwr-coal- ash-regulation/well-test-information-for-residents-near-duke-energy-coal-ash- impoundments. North Carolina Department of the Environmental and Natural Resources. 2013. 15A NCAC 02L .0202 Groundwater Rules. Groundwater Standards Table. April 1. North Carolina Department of the Environmental and Natural Resources. 2013. 15A NCAC 02L .0202 Groundwater Rules. Interim Maximum Allowable Concentrations (IMACs) Table. April 1. North Carolina Department of the Environmental and Natural Resources. 2016. 15A NCAC 02B Surface Water Standards and Protective Values & EPA Nationally Recommended Water Quality Criteria. March. North Carolina Department of the Environmental and Natural Resources. 2016. Coal Combustion Residual Impoundment Risk Classifications. January. North Carolina Department of the Environmental and Natural Resources. 2016. Environmental Review Commission. Report on the Status of Assessment, Corrective Action, Prioritization, and Closure for Each Coal Combustion Residuals Surface Impoundment as Required by the Coal Ash Management Act. January 13. 5 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' North Carolina Department of the Environmental and Natural Resources. 2016. Proposed Classification Chart. May 18. North Carolina Department of the Environmental and Natural Resources. 2016. Proposed Classifications. May 18. Oze, C., D.K. Bird, and S. Fendorf. 2007. Genesis of Hexavalent Chromium from Natural Sources in Soil and Groundwater: PNAS 104, no. 16: 6544-6549. Parette, R. 2016. Opinions on the Appropriateness of Monitored Natural Attenuation in Conjunction with Cap -in -Place at the Buck Steam Station (Federal). May 13. Parette, R., and Matson & Associates. 2016. Opinions on the Appropriateness of Monitored Natural Attenuation in Conjunction with Cap -in -Place at the Buck Steam Station. May 13. Poulton, S.W., and D.E. Canfield. 2005. Development of a Sequential Extraction Procedure for Iron: Implications for Iron Partitioning in Continentally Derived Particulates: Chemical Geology 214: 209-221. Reisinger, H.J., D.R. Burris, and J.G. Hering. 2005. Remediating Subsurface Arsenic Contamination with Monitored Natural Attenuation: Environmental Science and Technology 39: 458A-464A. Rightnour, T.A., and K.L. Hoover. 1998. The Springdale Project: Applying Constructed Wetland Treatment to Coal Combustion By -Product Leachate. Electric Power Research Institute (EPRI). TR-111473. November. Schwartz, G.E., N. Rivera, S.-W. Lee, J.M. Harrington, J.C. Hower, K.E. Levine, A. Vengosh, and H. Hsu -Kim. 2016. Leaching Potential and Redox Transformations of Arsenic and Selenium in Sediment Microcosms with Fly Ash: Applied Geochemistry 67: 177-185. Schwarzenbach, R.P., P.M. Gschwent, and D.M. Imboden. 1993. Environmental Organic Chemistry: John Wiley & Sons, Inc. Smedley, P.L., and D.G. Kinniburgh. 2002. A Review of the Source, Behaviour and Distribution of Arsenic in Natural Waters: Applied Geochemistry 17: 517-568. Stefaniak, S., E. Miszczak, J. Szczepanska-Plewa, and I. Twardowska. 2015. Effect of Weathering Transformations of Coal Combustion Residuals on Trace Element Mobility in View of the Environmental Safety and Sustainability of their Disposal and Use. I. Hydrogeochemical Processes Controlling pH and Phase Stability: Journal of Environmental Management 156: 128-142. Stumm, W. 1992. Chemistry of the Solid -Water Interface. Processes at the Mineral -Water and Particle -Water Interface in Natural Systems. New York: John Wiley & Sons. Stumm, W., and J.J. Morgan. 1996. Aquatic Chemistry, Chemical Equilibria and Rates in Natural Waters (3rd ed.): John Wiley & Sons, Inc. Swedlund, P.J., and J.G. Webster. 1999. Adsorption and Polymerisation of Silicic Acid on Ferrihydrite, and its Effect on Arsenic Adsorption: Water Resources 33, no. 16: 3413-3422. Taylor, H.F.W. 1997. Cement Chemistry (2nd ed.): Thomas Telford. 2 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' Tessier, A., P.G.C. Campbell, and M. Bisson. 1979. Sequential Extraction Procedure for the Speciation of Particulate Trace Metals: Analytical Chemistry 51, no. 7: 844-851. Thomas, M. 2007. Optimization the Use of Fly Ash in Concrete: 24. U.S. Environmental Protection Agency (USEPA). 1989. Sampling Frequency for Ground -Water Quality Monitoring. EPA 600-S4-89-032. September. U.S. Environmental Protection Agency (USEPA). 1992. Technical Resource Document. Batch - Type Procedures for Estimating Soil Adsorption of Chemicals. EPA 530-SW-87-006-F. April. U.S. Environmental Protection Agency (USEPA). 1994. Method 1312. Synthetic Precipitation Leaching Procedure. EPA SW-846 (Ch. 6). U.S. Environmental Protection Agency (USEPA). 1999a. Understanding Variation in Partition Coefficient, Ka, Values. Volume I: The Kd Model, Methods of Measurement, and Application of Chemical Reaction Codes. EPA 402-R-99-004A. August. U.S. Environmental Protection Agency (USEPA). 1999b. Understanding Variation in Partition Coefficient, Kd, Values. Volume II: Review of Geochemistry and Available Kd Values for Cadmium, Cesium, Chromium, Lead, Plutonium, Radon, Strontium, Thorium, Tritium (H), and Uranium. E 402-R-99-004B. August. U.S. Environmental Protection Agency (USEPA). 2006. Design Manual Removal of Arsenic from Drinking Water Supplies by Iron Removal Process. EPA 600-R-06-030. April. U.S. Environmental Protection Agency (USEPA). 2007a. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water. Volume I - Technical Basis for Assessment. EPA 600-R-07-139. Washington, D.C. October. U.S. Environmental Protection Agency (USEPA). 2007b. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water. Volume II - Assessment for Non -Radionuclides Including Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Nitrate, Perchlorate, and Selenium. EPA 600-R-07-140. Washington, D.C. October. U.S. Environmental Protection Agency (USEPA). 2009. Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities Unified Guidance. EPA 530-R-09-007. March. U.S. Environmental Protection Agency (USEPA). 2010. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water. Volume III - Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium -Americium. EPA 600-R-10-093. Washington, D.C. September. U.S. Environmental Protection Agency (USEPA). 2012. A Citizen's Guide to Monitored Natural Attenuation. EPA 542-F-12-014. Washington, D.C. September. U.S. Environmental Protection Agency (USEPA). 2015. Hazardous and Solid Waste Management Systems: Disposal of Coal Combustion Residuals from Electric Utilities. Federal Register. Vol. 80 No. 74. April 17. 7 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' U.S. Environmental Protection Agency (USEPA). 2015. Use of Monitored Natural Attenuation for Inorganic Contaminants in Groundwater at Superfund Sites. Directive 9283.1-36. August. U.S. Environmental Protection Agency (USEPA). 2016. Coal Ash Basics. https://www.epa.gov/coalash/coal-ash-basics. U.S. Geological Survey (USGS). 1963. Data of Geochemistry, Sixth Edition. Chapter F. Chemical Composition of Subsurface Waters. Geological Survey Professional Paper 440-F. U.S. Geological Survey (USGS). 1973. United States Mineral Resources. Geological Survey Professional Paper 820. U.S. Geological Survey (USGS). 1976. Numerical Simulation Analysis of the Interaction of Lakes and Ground Water. Professional Paper 1001. U.S. Geological Survey (USGS). 1980. Basic Elements of Ground -Water Hydrology With Reference to Conditions in North Carolina. Water -Resources Investigations Open -File Report. 80-44. U.S. Geological Survey (USGS). 1988. Geologic Map of the Charlotte I degree x 2 degrees Quadrangle, North Carolina and South Carolina. Miscellaneous Investigations Series. MAP I-1251-E. U.S. Geological Survey (USES). 1992. Trace Elements and Radon in Groundwater Across the United States, 1992-2003. Scientific Investigations Report 2011-5059. U.S. Geological Survey (USGS). 1997. Ground Water Atlas of the United States, Segment 11 -- Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, West Virginia. Hydrologic Investigations Atlas 730-L. U.S. Geological Survey (USGS). 1997. Water Quality in the Appalachian Valley and Ridge, The Blue Ridge, and the Piedmont Physiographic Provinces, Eastern United States. 1422-D. U.S. Geological Survey (USGS). 2001. Geochemical Landscapes of the Conterminous United States -- New Map Presentations for 22 Elements. Professional Paper. 1648. U.S. Geological Survey (USGS). 2002. Preliminary Hydrogeologic Assessment and Study Plan for a Regional Ground -Water Resource Investigation of the Blue Ridge and Piedmont Provinces of North Carolina. Water -Resources Investigations Report 02-4105. U.S. Geological Survey (USGS). 2009. Characterization of Groundwater Quality Based on Regional Geologic Setting in the Piedmont and Blue Ridge Physiographic Provinces, North Carolina. Scientific Investigations Report. 2009-5149. U.S. Geological Survey (USGS). 2013a. Description of Input and Examples for PHREEQC Version 3 - A Computer Program for Speciation, Batch -Reaction, One -Dimensional Transport, and Inverse Geochemical Calculations. Techniques and Methods. 6-A43. U.S. Geological Survey (USGS). 2013b. Naturally Occurring Contaminants in the Piedmont and Blue Ridge Crystalline -Rock Aquifers and Piedmont Early Mesozoic Basin Siliciclastic- Rock Aquifers, Eastern United States, 1994-2008. Scientific Investigations Report 2013- 5072. 2-2- bVbVDObnr02 9� V220CIV1E2' IMC' U.S. Geological Survey (USGS). 2014. Geochemical and Mineralogical Maps for Soils of the Conterminous United States. Open -File Report 2014-1082. VanDerHoek, E.E., and R.N.J. Comans. 1996. Modeling Arsenic and Selenium Leaching from Acidic Fly Ash by Sorption on Iron (Hydr) oxide in the Fly Ash Matrix: Environmental Science and Technology 30: 517-523. Wallis, I., H. Prommer, T. Pichler, V. Post, S.B. Norton, M.D. Annable, and C.T. Simmons. 2011. Process -Based Reactive Transport Model to Quantify Arsenic Mobility during Aquifer Storage and Recovery of Potable Water: Environmental Science and Technology 45: 6924- 6931. Wang, S., and C.N. Mulligan. 2006. Review: Natural Attenuation Processes for Remediation of Arsenic Contaminated Soils and Groundwater: Journal of Hazardous Materials B138: 459-470. Warren, C.J., and M.J. Dudas. 1988. Leaching Behaviour of Selected Trace Elements in Chemically Weathered Alkaline Fly Ash: The Science of the Total Environment 76: 229- 246. Wenzel, W.W., N. Kirchbaumer, T. Prohaska, G. Stingeder, E. Lombi, and D.C. Adriano. 2001. Arsenic Fractionation in Soils Using an Improved Sequential Extraction Procedure: Analytica Chimica Acta 436: 309-323. Williamson, M.A., and J.D. Rimstidt. 1994. The Kinetics and Electrochemical Rate -Determining Step of Aqueous Pyrite Oxidation: Geochimica et Cosmochimica Acta 58, no. 24: 5443- 5454. Wright, M.T., and K. Belitz. 2010. Factors Controlling the Regional Distribution of Vanadium in Groundwater: Ground Water 47, no. 4: 515-525. Zevenbergen, C., J.P. Bradley, L.P. VanReeuwijk, and A.K. Shyam. 1999a. Clay Formation During Weathering of Alkaline Coal Fly Ash: International Ash Utilization Symposium, Center for Applied Energy Research, University of Kentucky Paper #14: 8. Zevenbergen, C., J.P. Bradley, L.P. VanReeuwijk, A.K. Shyam, O. Hjelmar, and R.N.J. Comans. 1999b. Clay Formation and Metal Fixation during Weathering of Coal Fly Ash: Environmental Science and Technology 33: 3405-3409. Zevenbergen, C., L.P. VanReeuwijk, J.P. Bradley, P. Bloemen, and R.N.J. Comans. 1996. Mechanism and Conditions of Clay Formation During Natural Weathering of MSWI Bottom Ash: Clays and Clay Minerals 44, no. 4: 546-552. 0 Appendix C Background Concentration Ranges - USGS, Site Data, and Private Wells 2.2- bV6VD06nr oe 8F b220CIVIE2' INC' Appendix C Explanation Sheet Background concentration cumulative distribution plots were created for the following analytes: • Boron • Chromium • Sulfate • Antimony • Arsenic • Vanadium • Iron • Cobalt • Manganese • pH • Barium • Total Dissolved Solids The cumulative distribution plots illustrate the differences in the range of concentrations sampled from different locations. Locations (site background wells, private wells, and USGS wells) can be compared by the relationships between their sample concentrations at different percentiles. Data Sources The site background data was obtained from the from the Duke Energy MANAGES environmental database, queried on 6/23/2016 by Tim Hunsucker. USGS well dataset was obtained from the USGS National Water Information System' (NWIS). The NWIS was queried on 6/10/2016 for all groundwater data from North Carolina wells for the analytes listed above. The NWIS query results did not contain data for total boron or total vanadium. The private well data was obtained from the NC DEQ websitez from the document "Full Well Water Testing Results For Posting 8.2031,. Estimated values (J qualifier) were omitted from the analysis for the private well data. Data Handling The following site wells were considered background wells for the calculations: • BG-1BR • BG-3BRU • BG-1D • BG-3D • BG-1S • BG-3S • BG-2D • MW-6D • BG-2S • MW-6S All non -detects samples in the site background and private wells datasets were set to one half their detection limit. The USGS dataset sample values were averaged by well after setting values to one half their detection limit, in an effort to try to avoid unnecessary spatial bias in sites sampled more frequently. Sites where ' http://nwis.waterdata.usgs.gov/nwis/qwdata z https://deg.nc.gov 3 https://ncdenr.s3.amazonaws.com/s3fs-public/document- Iibra ry/Full%20WeII%20Water%20Testing%20Results%20For%2OPosting%208.20.pdf 2.2- bV6VD06nr'o2 8F b220CIVIE2' INC' all the values in the average calculation were non -detects were 1AIMM.Mred non -detects for plotting purposes. For percentile calculations and plotting, all non -detect values for a given analyte were set to the lowest non -detect value in that dataset. This ensured non -detect samples would be the top (highest) ranks for the percentile calculation. This was necessary because they cannot be assumed to be greater than any detected value. 100% 90% 80% 70% 60% c 50% L 40% 30% 20% 10% 0% Site Background Wells/Private Wells for Buck - Boron (Unfiltered) Site Background Wells Boron pg/L n = 79 Private Wells Boron pg/L n = 79 Site Background Wells Non -detect Private Wells Non -detect NC 2L Standard, 700 fag/L 10 Concentration pg/L 100 1000 Site Background Wells/USGS Wells/Private Wells for Buck - Sulfate (Unfiltered) • Site Background Wells Sulfate mg/L n = 79 • USGS Wells Sulfate, Averaged by Location mg/L n =60 Private Wells Sulfate mg/L n = 80 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect 100% 90 % 80 % 70 % 60% a� 40% 30 20% f� 10% 0% 0.01 0.10 NG 2L Standard, 25U 1.00 10.00 Concentration mg/L • 100.00 1000.00 100% 90% 80% 70% 60% c 50% L 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Arsenic (Unfiltered) Site Background Wells Arsenic pg/L n = 79 USGS Wells Arsenic, Averaged by Location pg/L n =122 Private Wells Arsenic fag/L n = 78 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect 0.01 0.10 1.00 10.00 Concentration pg/L 100.00 1000.00 100% 90% 80% 70% 60% c 50% L 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Iron (Unfiltered) Site Background Wells Iron pg/L n = 79 USGS Wells Iron, Averaged by Location pg/L n =2221 Private Wells Iron fag/L n = 83 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect INU zL z:)tanaara, ,5uu 4p 0.1 1.0 10.0 100.0 1000.0 10000.0 Concentration pg/L • *0 100000.0 1000000.0 100% 90% 80% 70% 60% a� 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Manganese (Unfiltered) • Site Background Wells Manganese fag/L n = 79 • USGS Wells Manganese, Averaged by Location pg/L n =813 Private Wells Manganese pg/L n = 72 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect INU ZL bianaara, aU Pgiu 0.01 0.10 1.00 10.00 100.00 Concentration pg/L 1000.00 10000.00 100000.00 100% 90 % 80 % 70 % 60% a� 40% 30 20% 10% 0%-4 1 Site Background Wells/USGS Wells/Private Wells for Buck - Barium (Unfiltered) • Site Background Wells Barium fag/L n = 79 • USGS Wells Barium, Averaged by Location pg/L n =77 Private Wells Barium pg/L n = 80 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect 10 NU 2L Standard, NU 100 Concentration pg/L 1000 10000 100% 90% 80% 70% 60% a� 50% a 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Chromium (Unfiltered) • Site Background Wells Chromium pg/L n = 79 • USGS Wells Chromium, Averaged by Location pg/L n =124 Private Wells Chromium pg/L n = 83 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect NU 1L Standard, 10 0.01 0.10 1.00 10.00 Concentration pg/L 100.00 1000.00 100% 90% 80% 70 % 60% a� 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Antimony (Unfiltered) • Site Background Wells Antimony pg/L n = 63 • USGS Wells Antimony, Averaged by Location pg/L n =61 Private Wells Antimony pg/L n = 78 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect NC IMAC Standard, 1 /L •i • _ • i • 0 • 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.01 0.10 1.00 10.00 Concentration pg/L 100.00 1000.00 Site Background Wells/Private Wells for Buck - Vanadium (Unfiltered) 100% 90 % 80 % 70 % 60% a� 40% • 30 20% 10% 0% 0.1 • Site Background Wells Vanadium pg/L n = 37 Private Wells Vanadium pg/L n = 74 Site Background Wells Non -detect Private Wells Non -detect NC IMAC Standard, 0.3 pg/L 1.0 Concentration pg/L 10.0 100.0 100% 90% 80% 70% 60% a� 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Cobalt (Unfiltered) • Site Background Wells Cobalt pg/L n = 37 • USGS Wells Cobalt, Averaged by Location pg/L n =2 Private Wells Cobalt pg/L n = 77 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect NC IMAC Standard, 1 /L • • • • • • • • • • • • • • • • • • 0.01 0.10 1.00 Concentration pg/L 10.00 100.00 100% 90% 80% 70% 60% a� 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - pH • Site Background Wells pH n = 80 • USGS Wells pH, Averaged by Location n =875 Private Wells pH n = 83 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect N[; 91 Stgndgrd R 5 - R 5 2 4 6 8 10 12 14 16 18 20 pH 100% 90% 80% 70% 60% c 50% L 40% 30% 20% 10% 0% Site Background Wells/USGS Wells/Private Wells for Buck - Total Dissolved Solids (Filtered) Site Background Wells Total Dissolved Solids mg/L n = 79 USGS Wells Dissolved solids, Averaged by Location mg/L n =2014 Private Wells Total Dissolved Solids mg/L n = 83 Site Background Wells Non -detect USGS Wells Non -detect Private Wells Non -detect NC 2L Standard, 500 m /L y • c, 00=+000� •� • ••w 1 10 100 1000 Concentration mg/L 10000 100000 Appendix D Natural Attenuation — Ash Basins to Compliance Boundary 2.2- bV6VD06nr oe 8F b22OCIVIE2' INC' Appendix D Explanation Sheet Box plots were created for boron, sulfate, arsenic, iron, manganese, vanadium, barium, chromium, antimony, cobalt, pH, and total dissolved solids (TDS) to illustrate concentration changes that occur from the ash basins to the compliance boundary. Box plots were created for ash pore -water data, wells within the waste boundary, and wells outside the waste boundary but within the compliance boundary. Any sample event in which boron was not detected (>50 ug/L) was excluded from the analysis since it would not be indicative of groundwater impacted by the ash basins. For comparison purposes box plots of the Site background data, private drinking water supply well (<0.5 mile radius from site), and USGS data are included, even if boron was not detected during the sampling event. The Site background and USGS data are included in the illustration for comparison and are referenced in Appendix C. Ash porewater, inside waste boundary, and outside waste boundary groups only included concentrations if boron was detected (>50 ug/L) at that well for the sample date. Estimated values (J qualifier) were omitted from the analysis for the private well data. Groups in which samples have been screened for boron detects are colored differently from groups which use all sample results regardless if boron was detected. The box plots were constructed to show the median with the upper and lower "hinges" corresponding to the first and third quartiles (25th and 75th percentiles). Values for non -detects are set at half of the detection limit. All data analyzed for unfiltered samples to allow for comparison to the 2L standards and IMAC. The exception is for TDS which requires filtration. The box plots contain two categories of six groups, and are defined as follows: Wells with boron detected > 50 ug/L in sample Ash Porewater — Wells screened within the ash Inside Waste Boundary— Wells screened below the ash, within the waste boundary Outside Waste Boundary — Wells screened outside the waste boundary, downgradient from ash All wells, regardless if boron was detected in sample Site Background — Wells screened outside compliance boundary, up -gradient of ash basin Private Water Supply — All private drinking wells samples within 0.5-mile radius of the Site' USGS Groundwater— North Carolina USGS well data' The following table is a list of all Site wells used for the box plot analysis and which group they were sorted in. No wells were excluded from the private water supply data or USGS groundwater. ' https://ncdenr.s3.amazonaws.com/s3fs-public/document- libra ry/Full%20WeII%20Water%20Testing%20Res ults%20For%20Posting%208.20.pdf Z http://nwis.waterdata.usgs.gov/nwis/qwdata queried downloaded on 6/10/2016 and included all data from North Carolina for the analytes listed above 2.2- bV6VD06nr oe 8F b22OCIb.LE2' INC' Buck Box Plot Well Group List All Wells Wells with Boron > 50 ug/L Background Porewater Inside Waste Outside Waste BG-1BR AB-2S AB-10D GWA-10D MW-1D BG-1D AB-2SL AB-10S GWA-10S MW-1S BG-1S AB-3S AB-11D GWA-11D MW-3D BG-2D AB-4S AB-2BR GWA-11S MW-3S BG-2S AB-4SL AB-21D GWA-12BRU MW-4D BG-3BRU AB-5S AB-31D GWA-12D MW-4S BG-3D AB-5SL AB-4BR GWA-12S MW-5D BG-3S AB-7S AB-4BRU GWA-11D MW-5S MW-61D AB-7SL AB-5BRU GWA-1S MW-71D MW-6S AB-8S AB-6BRU GWA-22D MW-7S AB-7BRU AB-BBRU AB-81D AB-9BR AB-9BRU AB-91D AB-9S AS-11D AS-1S AS-21D AS-31D AS-3S BC-18 GWA-2BR MW-8D GWA-213RU MW-8S GWA-3BR MW-9D GWA-3BRU MW-9S GWA-3S GWA-13D GWA-41D GWA-13SR GWA-4S GWA-14D GWA-513RU GWA-14S GWA-5S GWA-15D GWA-6BR GWA-15S GWA-6BRU GWA-17S GWA-6S GWA-18D GWA-71D GWA-18S GWA-7S GWA-19D GWA-81D GWA-19S GWA-9BR GWA-20D GWA-91D GWA-20S GWA-9S GWA-2S MW-10D MW-6BR MW-11D MW-21D MW-11S MW-2S MW-12D MW-13D MW-12S Antimony (Unfiltered) - Buck 150 - J 1 0 100 - .6 50 - • 0- Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=78 Groundwater n=31 n=71 n=63 n=61 Sample Location Type. Red Line: NC IMAC Standard (1 ug/L) m M 10.0 O J M i • • • • Milo b Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=78 n=31 n=71 n=63 Sample Location Type. Red Line: NC IMAC Standard (1 ug/L) USGS Groundwater n=61 Arsenic (Unfiltered) - Buck r�1zni C CD U O 500 - U • • , 0- Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=78 Groundwater n=31 n=139 n=79 n=122 100 = C _ U - Cn - 0) - O J - c 1= a> _ U - C - O - Sample Location Type. Red Line: NC 2L Standard (10 ug/L) 0 • • • ' • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=78 Groundwater n=31 n=139 n=79 n=122 Sample Location Type. Red Line: NC 2L Standard (10 ug/L) Barium (Unfiltered) - Buck illifilz J 1 C • O O C 0 U C (j 500 - • 0- Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=80 Groundwater n=31 n=139 n=79 n=77 Sample Location Type. Red Line: NC 2L Standard (700 ug/L) IIIH 10- Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=80 Groundwater n=31 n=139 n=79 n=77 Sample Location Type. Red Line: NC 2L Standard (700 ug/L) Boron (Unfiltered) - Buck 7500 - J 0) 1 5000 - MO 2500 - 0- 1 M I• Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=79 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (700 ug/L) 10000 — 100 — Ash Porewater Inside Waste Outside Waste Site Groundwater n=30 Boundary Boundary Background n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (700 ug/L) • Private Wells n=79 Chromium (Unfiltered) - Buck 250 - 200 - J 0 150- • C O c 1100 - 0 U .MN • i • 0- • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=83 Groundwater n=31 n=139 n=79 n=124 Sample Location Type. Red Line: NC 2L Standard (10 ug/L) 100 — N - U 0) O J J 1 C O A Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=83 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (10 ug/L) • USGS Groundwater n=124 Cobalt (Unfiltered) - Buck 911I1M J 200 O U 100 - • a 0 Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=77 Groundwater n=31 n=45 n=37 n=2 Sample Location Type. Red Line: NC IMAC Standard (1 ug/L) 100 — • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=77 n=31 n=45 n=37 Sample Location Type. Red Line: NC IMAC Standard (1 ug/L) USGS Groundwater n=2 Iron (Unfiltered) - Buck 3e+05 - 2e+05 - C O U C U 1 e+05 - Oe+00 1e+05 N U O J ' 1 e+03 - J 1 C O U C _ O U 1e+01 — • s A H Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=83 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (300 ug/L) • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=83 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (300 ug/L) i USGS Groundwater n=2221 i • USGS Groundwater n=2221 Manganese (Unfiltered) - Buck 0111101M 20000 - J 1 C O a) U U) 0) O J 0 10000 — 100- C a> U C O _ U 1— Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=72 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (50 ug/L) Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=72 n=31 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (50 ug/L) i uSGS Groundwater n=813 uSGS Groundwater n=813 pH (Unfiltered) - Buck 12- O 9 c N U C O i [01 In am A Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=19 Boundary Boundary Background n=83 Groundwater n=20 n=191 n=80 n=875 Sample Location Type. Red Line: NC 2L Standard (6.5 - 8.5) • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=19 Boundary Boundary Background n=83 Groundwater n=20 n=191 n=80 n=875 Sample Location Type. Red Line: NC 2L Standard (6.5 - 8.5) Sulfate (Unfiltered) - Buck C N U C O U 200 - m 100 — a> - M _ U _ U) 0) O J J E C O M L C v 1— O Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=80 Groundwater n=30 n=139 n=79 n=60 Sample Location Type. Red Line: NC 2L Standard (250 mg/L) i . Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS n=30 Boundary Boundary Background n=80 Groundwater n=30 n=139 n=79 n=60 Sample Location Type. Red Line: NC 2L Standard (250 mg/L) Total Dissolved Solids (Filtered) - Buck 25000 - 20000 - J 15000 - 0 chi 10000 - c O U 5000 - Ole 10000 a> M U U) 0) O J E _ C 23O L 100 = am - U - C - O — U = Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=83 n=30 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (500 mg/L) • • • • • Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=83 n=30 n=139 n=79 Sample Location Type. Red Line: NC 2L Standard (500 mg/L) USGS Groundwater n=2014 I • • USGS Groundwater n=2014 Vanadium (Unfiltered) - Buck 300 - J o)200 - C O M U 100 - 0 i[eIl" Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=74 n=31 n=45 n=37 Sample Location Type. Red Line: NC IMAC Standard (0.3 ug/L) Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells n=30 Boundary Boundary Background n=74 n=31 n=45 n=37 Sample Location Type. Red Line: NC IMAC Standard (0.3 ug/L)