Correlations of benthic invertebrate community metrics and co-located sediment samples at the TVA Kingston Ash Release Site in Tennessee

The failure of a dredge cell at the Tennessee Valley Authority (TVA) Kingston Fossil Plant in December 2008 discharged approximately 4.1 million cubic meters of coal fly ash into the adjacent aquatic and terrestrial systems.  Sediment toxicity tests conducted by TVA indicated toxicity to sensitive laboratory organisms when sediment concentrations had approximately 40% ash; consequently, TVA concluded that benthic invertebrates were at moderate risk in the Emory River, primarily due to arsenic concentrations in ash-contaminated sediment. While areas remain in the Emory River with ash percentages at or above the 40% range, previous benthic invertebrate community (BIC) results showed no differences associated with the ash release in the impacted Emory River locations compared to the reference locations.  These previous investigations evaluated BIC data and sediment data across a larger spatial scale, providing an “area-wide” interpretation of the relationships, rather than a one to one relationship of co-located samples.  This presentation addresses this knowledge gap and presents correlations between BIC metric results to co-located sediment chemistry and physical sediment properties.  This information is important for the informed monitoring, remediation, and damage assessment of the BIC at the Kingston Ash Release Site.