A recent survey of the amount of coal ash generation in the USA revealed that 500 power plants nationwide generate approximately 130 million tons of coal ash each year, 43% of which is recycled into other materials. The remaining 70 million tons is stored in 194 landfills and 161 ponds in 47 states. On December 22, 2008, the retaining wall broke on a waste retention pond at the Kingston Tennessee Valley Authority (TVA) fossil plant in Tennessee, and an estimated 4.1 million m3 of coal ash slurry was spilled onto the land surface and into the adjacent Emory and Clinch Rivers. A week after the spill EOS graduate student Laura Ruhl and Avner Vengosh began studying the impact of the coal ash spill on the environment and possible health impact upon re-suspension of the fine particles of the coal ash in the atmosphere (Publication 1). Based on these results, we were awarded a NSF grant for a project that expended the monitoring of the impact of the ash spill on the environment.
The TVA ash spill has demonstrated that storage and management of coal ash poses a serious threat to the aquatic system due to the high level of trace metals in the coal ash and their high mobilization into the aquatic system. These metals have distinguished isotopic compositions that could be used to detect their contribution to the environment. We have established systematic isotopic (for boron and strontium) fingerprints for the major coal ash produced in the USA (reference). This database can be used as a fundamental monitoring tool for delineation of the origin of metals in aquatic systems. Results from the TVA spill have revealed that boron is highly mobilized from coal ash and also has a distinguished isotopic signature relative to natural boron. We have began collecting a large set of coal ash samples from different plants in the USA and we hope to measure their boron and strontium isotopes for building the “tool box” for identification of contaminants derived from even small contribution of leaching of coal ash.
The next phase of this research is monitoring the water quality be implementation of the geochemical and isotopic tools for water resources associated with major coal ash storage in North Carolina.
Overall, this research would provide the necessary analytical tools for exploring the fate and transport of contaminants in surface and groundwater environments downstream of a coal-ash storage site.