Environmental Impacts of the Tennessee Valley Authority Kingston Coal Ash Spill. 1. Source Apportionment Using Mercury Stable Isotopes

Abstract

Mercury stable isotope abundances were used to trace transport of Hg-impacted river sediment near a coal ash spill at Harriman, Tennessee, USA. δ(202)Hg values for Kingston coal ash released into the Emory River in 2008 are significantly negative (-1.78 ± 0.35‰), whereas sediments of the Clinch River, into which the Emory River flows, are contaminated by an additional Hg source (potentially from the Y-12 complex near Oak Ridge, Tennessee) with near-zero values (-0.23 ± 0.16‰). Nominally uncontaminated Emory River sediments (12 miles upstream from the Emory-Clinch confluence) have intermediate values (-1.17 ± 0.13‰) and contain lower Hg concentrations. Emory River mile 10 sediments, possibly impacted by an old paper mill has δ(202)Hg values of -0.47 ± 0.04‰. A mixing model, using δ(202)Hg values and Hg concentrations, yielded estimates of the relative contributions of coal ash, Clinch River, and Emory River sediments for a suite of 71 sediment samples taken over a 30 month time period from 13 locations. Emory River samples, with two exceptions, are unaffected by Clinch River sediment, despite occasional upstream flow from the Clinch River. As expected, Clinch River sediment below its confluence with the Emory River are affected by Kingston coal ash; however, the relative contribution of the coal ash varies among sampling sites.

Sedimentary records of mercury stable isotopes in Lake Michigan

“…(Figure 3), which is consistent with the photo-reduction of Hg(II) reported by Bergquist and Blum (2007). Evidences for stability of Hg isotope ratios in sediments over time have been document by Bartov et al (2013). Loss of Hg during microbial Hg reduction may cause changes in Hg isotopic compositions over time (Kritee et al, 2013).…”

“…High organic matter content has been shown to inhibit Hg(II) reduction to Hg(0) (Mauclair et al, 2008;Gu et al, 2011). The variation of Hg isotopes in sediments then, is largely the result of varied Hg sources both spatially (Foucher and Hintelmann, 2009;Feng et al, 2010;Liu et al, 2011;Bartov et al, 2013;Donovan et al, 2013;Ma et al, 2013;Yin et al, 2013a;Lepak et al, 2016).…”

“…202 Hg and D 199 Hg values have been reported in environmentally relevant matrices such as rocks (Smith et al, 2008), mineral deposits (Hintelmann and Lu, 2003;Smith et al, 2005Smith et al, , 2008Stetson et al, 2009;Sonke et al, 2010), coals (Biswas et al, 2008;Lefticariu et al, 2011;Sun et al, 2014;Yin et al, 2014b), soils (Biswas et al, 2008;Zhang et al, 2013;Feng et al, 2013), sediments (Gehrke et al, 2011;Foucher and Hintelmann, 2009;Feng et al, 2010;Liu et al, 2011;Bartov et al, 2013;Donovan et al, 2013;Ma et al, 2013;Yin et al, 2013aYin et al, , 2015, water (Štrok et al, 2014), air (Demers et al, 2013;Rolison et al, 2013), precipitation (Gratz et al, 2010;Chen et al, 2012;Demers et al, 2013;Sherman et al, 2011Sherman et al, , 2015 and biological samples Blum et al, 2013;Demers et al, 2013;Yin et al, 2013b). With well-defined source signatures, researchers may estimate the relative contribution of sources of Hg through the utilization of binary and/or triple mixing models (Foucher and Hintelmann, 2009;Feng et al, 2010;Liu et al, 2011;Bartov et al, 2013;Donovan et al, 2013;Ma et al, 2013;…”

“…With well-defined source signatures, researchers may estimate the relative contribution of sources of Hg through the utilization of binary and/or triple mixing models (Foucher and Hintelmann, 2009;Feng et al, 2010;Liu et al, 2011;Bartov et al, 2013;Donovan et al, 2013;Ma et al, 2013;Yin et al, 2013a;Lepak et al, 2016).…”

Bioaccumulation of metals in three freshwater mussel species exposed in situ during and after dredging at a coal ash spill site (Tennessee Valley Authority Kingston Fossil Plant)

“…As unfortunate as the spill was, it provided an opportunity to directly study the impact of coal fly ash in a large lotic system where the amount of downstream transport of ash was also being investigated and monitored (TVA 2010b). Previous research on the Kingston spill has provided insight on the contaminants of concern from multiple perspectives including sediment biogeochemistry, metal speciation, and metal bioaccumulation across multiple organisms (Ruhl et al 2010;Bednar et al 2010;Ruhl et al 2009;Otter et al 2013;Deonarine et al 2013;Bartov et al 2012;Liu et al 2013;Beck et al 2013;Souza et al 2013). Otter et al (2012) showed elevated concentrations of arsenic and selenium in various tissues of multiple fish species at ash-associated sites compared to reference sites.…”