Impact of coal properties on coal combustion by-product quality: examples from a Kentucky power plant

Hsu‐Kim

et al. 2014

Self Cite

In the U.S., coal fired power plants produce over 136 million tons of coal combustion residuals (CCRs) annually. CCRs are enriched in toxic elements, and their leachates can have significant impacts on water quality. Here we report the boron and strontium isotopic ratios of leaching experiments on CCRs from a variety of coal sources (Appalachian, Illinois, and Powder River Basins). CCR leachates had a mostly negative δ11B, ranging from −17.6 to +6.3‰, and 87Sr/86Sr ranging from 0.70975 to 0.71251. Additionally, we utilized these isotopic ratios for tracing CCR contaminants in different environments: (1) the 2008 Tennessee Valley Authority (TVA) coal ash spill affected waters; (2) CCR effluents from power plants in Tennessee and North Carolina; (3) lakes and rivers affected by CCR effluents in North Carolina; and (4) porewater extracted from sediments in lakes affected by CCRs. The boron isotopes measured in these environments had a distinctive negative δ11B signature relative to background waters. In contrast 87Sr/86Sr ratios in CCRs were not always exclusively different from background, limiting their use as a CCR tracer. This investigation demonstrates the validity of the combined geochemical and isotopic approach as a unique and practical identification method for delineating and evaluating the environmental impact of CCRs.

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Boron and Strontium Isotopic Characterization of Coal Combustion Residuals: Validation of New Environmental Tracers

Hsu‐Kim

et al. 2014

Self Cite

“…Leaching experiments were simulated reactions of the spilled TVA ash (Figure 1) with solutions exhibiting a wide range of acidity (pH of 0. [4][5][6][7][8][9][10][11][12] and ash/water ratios (1 × 10 -5 to 3.5 × 10 -3 ).…”

Section: Introductionmentioning

confidence: 99%

Environmental Impacts of the Coal Ash Spill in Kingston, Tennessee: An 18-Month Survey

Vengosh

et al. 2010

139

120

An 18 month investigation of the environmental impacts of the Tennessee Valley Authority (TVA) coal ash spill in Kingston, Tennessee combined with leaching experiments on the spilled TVA coal ash have revealed that leachable coal ash contaminants (LCACs), particularly arsenic, selenium, boron, strontium, and barium, have different effects on the quality of impacted environments. While LCACs levels in the downstream river water are relatively low and below the EPA drinking water and ecological thresholds, elevated levels were found in surface water with restricted water exchange and in pore water extracted from the river sediments downstream from the spill. The high concentration of arsenic (up to 2000 µg/L) is associated with some degree of anoxic conditions and predominance of the reduced arsenic species (arsenite) in the pore waters. Laboratory leaching simulations show that the pH and ash/water ratio control the LCACs' abundance and geochemical composition of the impacted water. These results have important implications for the prediction of the fate and migration of LCACs in the environment, particularly for the storage of coal combustion residues (CCRs) in holding ponds and landfills, and any potential CCRs effluents leakage into lakes, rivers, and other aquatic systems.

“…Some previous coal ash spills in the United States include the 2000 Martin County spill in Kentucky, which released over 1.1 million cubic meters of coal slurry into abandoned mines and nearby creeks (1), and the 1972 Buffalo Creek incident in West Virginia, which released almost a half million cubic meters of coal mining residue slurry into a nearby town (2). Numerous studies have shown that coal ash contains high levels of toxic metals that can harm the environment (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) and some of these elements are soluble in water and easily leached in aquatic systems (13)(14)(15)(16).…”

Section: Introductionmentioning

confidence: 99%

Survey of the Potential Environmental and Health Impacts in the Immediate Aftermath of the Coal Ash Spill in Kingston, Tennessee

Vengosh

et al. 2009

160

133

An investigation of the potential environmental and health impacts in the immediate aftermath of one of the largest coal ash spills in U.S. history at the Tennessee Valley Authority (TVA) Kingston coal-burning power plant has revealed three major findings. First, the surface release of coal ash with high levels of toxic elements (As = 75 mg/kg; Hg = 150 μg/kg) and radioactivity (226Ra + 228Ra = 8 pCi/g) to the environment has the potential to generate resuspended ambient fine particles (<10 μm) containing these toxics into the atmosphere that may pose a health risk to local communities. Second, leaching of contaminants from the coal ash caused contamination of surface waters in areas of restricted water exchange, but only trace levels were found in the downstream Emory and Clinch Rivers due to river dilution. Third, the accumulation of Hg- and As-rich coal ash in river sediments has the potential to have an impact on the ecological system in the downstream rivers by fish poisoning and methylmercury formation in anaerobic river sediments.