EVIDENCE FOR UNMONITORED COAL ASH SOLIDS SPILLS AND IMPACT ON THE ENVIRONMENT (Invited Presentation)

Coal combustion residuals (CCRs), in particular fly ash, contain high concentrations of toxic and carcinogenic elements that can pose ecological and human health risks upon their release to the environment. In the U.S., about half of the CCRs is stored in landfills and impoundments, and the lack of adequate regulations for safe disposal and storage of CCRs has been a major public debate. Major CCRs spills from storage sites into adjacent rivers, combined with evidence of leaking of CCR storage facilities and contamination of underlying groundwater and associated surface waters have demonstrated the environmental and human health risks associated with CCRs. New data collected from bottom sediments in Sutton Lake in eastern North Carolina indicate occurrence of CCRs solids at the bottom of the lake. Analyzing the magnetic susceptibility, microscopic screening, trace element composition, and strontium isotope ratios of bottom sediments collected in 2015 and in 2018 from Sutton Lake suggest multiple, apparently previously unmonitored, CCR spills into Sutton Lake from adjacent CCR storage sites. The enrichment of metals in Sutton Lake sediments, particularly those with known ecological impact such as As, Se, Cu, Sb, Ni, Cd, V, and Tl, was similar to or even higher than those in stream sediments impacted by the Tennessee Valley Authority (TVA) in Kingston, Tennessee and Dan River in North Carolina coal ash spills, and exceeded ecological screening standards for sediments. High levels of contaminants were also found in leachates extracted from Sutton Lake sediments and co-occurring pore water, reflecting their mobilization to the ambient environment. These findings highlight the risks of large-scale unmonitored spills of coal ash solids from storage facilities following major storm events and contamination of nearby water resources throughout the southeastern U.S. The association of CCR solids in lake sediments and pore water contamination demonstrated in this study implies that unmonitored spills may have occurred also in other lakes near CCR storage facilities, where pore water was previously shown to be elevated in CCRs associated contaminants. The possible widespread transport of CCRs solids to the environment beyond storage facilities is alarming and future studies should verify whether water resources throughout the southeastern U.S are impacted by unmonitored coal ash spills.