Selenium bioaccumulation in fish exposed to coal ash at the Tennessee Valley Authority Kingston spill site

Abstract

In December 2008, 4.1 million cubic meters of coal ash were released into the Emory and Clinch Rivers by the Tennessee Valley Authority Kingston Fossil Plant. Coal ash contains several contaminants, including the bioaccumulative metalloid selenium (Se). Because Se is predominantly accumulated in aquatic organisms through dietary rather than aqueous exposure, tissue-based toxicity thresholds for Se are currently being considered. The proposed threshold concentrations range between 4 μg/g and 9 μg/g Se (dry wt.) in whole body fish, with a proposed fillet threshold of 11.8 μg/g. In the present study, the authors examined the spatial and temporal trends in Se bioaccumulation and examined the relationship between the Se content in fillets and in whole bodies of fish collected around the Kingston spill site to determine whether Se bioaccumulation was a significant concern at the ash spill site. Whereas Se concentrations in fish (whole bodies and fillets) were elevated at sampling locations affected by the Kingston ash spill relative to reference locations, concentrations do not appear to be above risk thresholds and have not been increasing over the 5-yr period since the spill. These findings are not only relevant to guiding the human health and ecological risk assessments at the Kingston ash spill site, but because of current national discussions on appropriate guidelines for Se in fish as well for the disposal of coal combustion wastes, the results are also relevant to the general understanding of Se bioaccumulation in contaminated water bodies.

Influence of metal(loid) bioaccumulation and maternal transfer on embryo-larval development in fish exposed to a major coal ash spill

“…The concentrations of Se in the fish collected for this investigation were similar to concentrations previously reported for redear sunfish whole bodies and muscle tissue at these and other nearby coal ashexposed sites in related bio-assessment efforts associated with the Kingston ash spill (Adams et al, 2012a;Mathews et al, 2014). Both whole body and especially ovary concentrations of Se at these locations have remained below proposed freshwater ambient water quality chronic criteria for aquatic life of 15.2 mg/kg (d.w.) in fish ovary/eggs and 8.1 mg/kg for fish whole bodies (USEPA, 2014).…”

“…Redear sunfish were selected as the target species for this study for a variety of reasons, including: 1the relative abundance of this species of fish at each of the proposed study locations, as verified by preliminary sampling; (2) sufficient body and ovary sizes to provide tissues for metal analyses as well the number of eggs needed for crossing trials; (3) relatively high body burdens of Se at the coal-ash exposed study sites (Arcadis, 2012;Otter et al, 2012;Mathews et al, 2014); (4) a known sensitivity of this species to the adverse reproductive effects of Se exposure from coal ash settling basin discharges (Sorensen, 1988); and (5) a relatively compact home-range which contributes to a much greater sitefidelity than larger top-predators in the area such as largemouth bass. [Although the home-range of the redear sunfish is not well-documented, sunfish in general demonstrate a relatively high degree of siteaffinity (Etnier and Starnes, 1994), with the home range of the closely-related pumpkinseed (Lepomis gibbosus) being estimated to be only about 1 hectacre (Warren, 2009).…”

“…All quality assurance procedures (e.g., blanks, matrix spikes) were performed as specified in the respective analytical methods. Method detection limits and the use of standard reference materials were as described by Mathews et al (2014). Sample data were reported by the laboratory on a wet weight (w.w) basis and converted to dry weight (d.w.) values, where appropriate, using the moisture content reported for each sample.…”

Parental dietary seleno-L-methionine exposure and resultant offspring developmental toxicity

“…The discharge of Se-rich fly ash effluent into Martin Lake, TX was followed by liver and ovarian alterations with reduced reproductive success in adult redear sunfish ( Lepomis microlophus ) (Sorensen, 1988). Coal ash spills in Kingston, TN and more recently in the Dan River, NC released 4.1 million m 3 and 39,000 tons of Se-rich coal ash, respectively, threatening birds and fish in those ecosystems (Lemly, 2015; Mathews et al, 2014). …”

Spatial and temporal trends in contaminant concentrations in Hexagenia nymphs following a coal ash spill at the Tennessee Valley Authority's Kingston Fossil Plant

“…However, the concentrations of contaminants were not associated with any lethal or sublethal physiological effects [57,58]. Downstream of the ash spill redear sunfish (Lepomis microlophus), a species likely to have a diet predominantly of aquatic organisms, were found to have elevated levels of Se [59] and evidence of possible sublethal physiological changes [60]. In contrast to the aforementioned studies, Sousa et al [61] found no evidence of metal bioaccumulation or negative health effects in raccoons (Procyon lotor) from the spill site that could be attributed to the ash.…”