| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | February 26, 2020 |
| Latest Amendment Date: | June 28, 2021 |
| Award Number: | 1932649 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Jonathan G Wynn
jwynn@nsf.gov (703)292-4725 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | March 1, 2020 |
| End Date: | February 28, 2023 (Estimated) |
| Total Intended Award Amount: | $227,296.00 |
| Total Awarded Amount to Date: | $298,953.00 |
| Funds Obligated to Date: |
FY 2021 = $71,657.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
2200 W MAIN ST DURHAM NC US 27705-4640 (919)684-3030 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
NC US 27705-4010 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Geobiology & Low-Temp Geochem |
| Primary Program Source: |
01002122DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Coal combustion residuals (known as coal ash) is the largest industrial solid waste generated in the U.S., with production rates of over 100 million tons per year. While some fraction of the generated coal ash is recycled, mostly for the cement industry, over half is stored in coal ash impoundments and landfills. Since coal ash contains high concentrations of heavy metals that are easily transported into water, the disposal of coal ash in leaky impoundments can damage the environment and water resources. Hurricane storms and large floods have been shown to cause spills of coal ash into Sutton Lake in eastern North Carolina and contamination of the lake ecological system. This NSF project seeks to detect coal ash contamination in sediments within different lakes throughout North Carolina and to evaluate the possible environmental impacts of coal ash in these lakes. The project will develop novel methods to detect coal ash in the environment. Understanding the potential occurrence of coal ash outside the major disposal sites and the ecological impact in the lakes is important for the communities living near coal ash ponds and the impacted lakes. The use of scientific methods to detect coal ash in the environment is important for an unbiased and scientific-base evaluation of the risks of coal ash to residents living in rural areas of North Carolina.
The proposed study aims to collect sediments and pore water samples from lakes near major coal ash disposal sites in North Carolina in order to detect the presence of coal ash and its impact on the ecosystem. The study is based on developing novel geochemical and physical methods for tracing coal ash and its contaminants in the environment through integration of independent proxies for the presence of coal ash in the bottom sediments including trace metals distribution, strontium isotope ratios (87Sr/86Sr), lead stable isotopes (206Pb/208Pb, 207Pb/206Pb), radionuclides (228Ra, 226Ra, 210Pb, 137Cs), magnetic susceptibility, and magnetic granulometry. This reconnaissance study will investigate the spatial and temporal distribution of coal ash and contaminants likely introduced during extreme hydrologic events into lakes near coal ash storage impoundments in North Carolina. The study will also evaluate the mobilization of contaminants from coal ash solids into the ecosystem through leaching experiments and measurement of pore water from the lake bottom sediments. The objectives of the study are (1) to develop methods for identification of coal ash in sediments and associated contaminants in pore water extracted from lake bottom sediments; (2) to evaluate the magnitude of unmonitored coal ash spills in the impacted lakes; (3) to determine the residence time of sediments in lakes impacted by coal ash spills; and (4) to evaluate the long-term ecological effects that could result from unmonitored coal ash spills into lakes in North Carolina. The environmental legacy of coal ash is one of the emerging topics in the southeastern U.S. Leaking of coal ash ponds and spills have shown to have environmental effects on the quality of groundwater and surface water near coal ash disposal sites. The expected decommissioning of the operating coal-fired power plants during the next decade requires permanent solutions for the large volumes of coal ash commonly stored in coal ash impoundments near lakes and streams. The evidence of a coal ash spills to Sutton Lake has further raised public concerns about the environmental and human health safety. This NSF project will establish scientific-based criteria for environmental risks assessment associated with coal ash storage and management. Graduate and undergraduate students from Duke University, and undergraduate students from Appalachian State and Montclair State University will take active roles in the project. The results of the project will be used to construct a module on coal ash pollution to ?Water on the Move?, a K-12 outreach program in the Department of Geological and Environmental Sciences at Appalachian State. In addition to publication in scientific journals and presentation in professional conferences, the results of this project will be disseminated to the general public and communities living near coal ash impoundments and impacted lakes through press releases following scientific publication, communications with environmental NGOs working with the local communities, townhall meetings with communities at larger risks with direct dialogue with residents, a designated website and social media, communication and presentation of the results in federal (U.S. EPA, Congress) and state (NC House of Representatives) agencies.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The adequate storage and management of coal combustion residuals (CCRs), or coal ash, is a major challenge for energy utilities in the U.S. Coal ash represents one of the largest industrial solid waste streams in the U.S., and typically contain high concentrations of toxic and carcinogenic elements that can easily leach out and contaminate water resources and the environment. Over 100 million tons of CCRs are generated annually in the US; about half is reused, mostly by the cement industry, while the other half is stored in open impoundments and landfills. Previous studies have shown that many of the coal ash storage facilities are leaking, causing surface water and groundwater contamination. Major spills of coal ash in Tennessee and North Carolina have raised the public awareness of the environment and human risks pose from coal ash storage. In addition to the potential of contamination of water resources, this collaborative NSF research project aims to evaluate the occurrence and distribution of coal ash solids in soils near coal plants and in bottom sediments from lakes located near coal ash ponds in North Carolina and determine the associated environmental risks.
This project included extensive fieldwork and sampling of surface soils near coal plants in North Carolina and Tennessee, as well as sediments and cores collected from several lakes located near coal ash storage facilities across North Carolina. Soil and lake sediments, as well as lake water and water extracted from the lake sediments samples were measured for major and trace elements, isotopic composition of strontium and lead isotopes, and radionuclides (radium, lead-210, cesium-137) variations, combined with microscopy counting, magnetic susceptibility, and magnetic granulometry.
The results of the project show two major outcomes. First, the study demonstrates the utility of using an integration of geochemical and physical tools to detect trace levels of coal fly ash in surface soils collected from both recreational and residential areas near coal-fired power plants. The data show evidence for the occurrence of fly ash particles on the surface soils, likely derived from fugitive emission from nearby coal power plants and deposition on the surrounding soils. Although only only low levels of heavy metals were detected in the impacted soils, these soils could further become house dust, and therefore, a source of human exposure to heavy metals in house dust.
The second outcome of this NSF project is the revelation that large quantities of coal ash have contaminated freshwater lakes over the past 100 years since the beginning of coal combustion in North Carolina. The data show clear physical and chemical evidence for accumulation of coal ash in the lake sediments from five freshwater lakes adjacent to coal-fired power plants across North Carolina. The results indicated significant sediment contamination and potential chronic ecological risks posed by the occurrence of hundreds of thousands of tons of coal ash solids mainly resulting from large stormwater runoff/flooding and direct effluent discharge from the nearby coal ash disposal sites. This is the first study to show evidence of large volumes of coal ash that were transported into the open environment of open lakes from the designated storage facilities. While previous research has shown contamination derived from the discharge of coal ash effluents and leaking of coal ash ponds, this study shows that coal ash solids have been continuously released into nearby lakes that are used for recreational activities and even as a drinking water source. North Carolina has 14 coal-fired power plants (both active and retired) and over 30 coal ash impoundments, which means that the presence of coal ash solids in lake sediments is likely ubiquitous across the state. Furthermore, there are hundreds of coal ash ponds across the U.S., and many of them are located near natural waterways. Given that these coal ash disposal units are known to constantly discharge coal ash effluents into adjacent public waterways and are vulnerable to high stream flow and/or flooding, the unmonitored historic releases of coal ash shown in this study are likely to occur nationwide. The study also showed that some of the toxic coal ash contaminants are chemically mobile and were leached out to the ambient environment, casing contamination of the water within the lake sediments and thus bioaccumulation in the ecosystem.
Overall, the findings of this study highlight the legacy of inadequate coal ash storage, its vulnerability to extreme weather conditions, and its chronic risks to aquatic ecosystems. The study found that coal ash contamination of the lakes from the nearby coal ash impoundments is still happening today, even near retired coal plants or thermoelectric plants that were switched to natural gas. While this study was focused on North Carolina, we assert that the magnitude of sediment contamination by coal ash and its consequential ecological risks are much more prevalent than previously realized, suggesting a problem of a national scale.
Last Modified: 04/02/2023
Modified by: Avner Vengosh
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