Sediment Toxicity Testing at Smokey Mountain Smelter Superfund Site

Smokey Mountain Smelter - Knoxville, TN

Sediment Toxicity Testing at Smokey Mountain Smelter Superfund Site

Smokey Mountain Smelter - Knoxville, TN

Smokey Mountain Smelter Superfund Site

Overview:

  • Sediment toxicity testing
  • Habitat quality evaluations and taxonomic metrics

Description:

On 1 January 2019, Bluestone purchased Avatar Environmental, LLC. Avatar (now part of Bluestone) led the HHRA and ERA for the Smokey Mountain Smelter (SMS) RI/FS in Knoxville, Tennessee. This biological sampling effort was conducted as part of a large human health and ecological risk assessment, completed under the framework of a RI/FS. The RI/FS was a collaborative effort between EPA and the Tennessee Department of Environmental Conservation (TDEC). The SMS RI/FS evaluated the extent of contamination and potential impacts on the 27-acre site, the Flenniken Branch Watershed that receives runoff and discharge from the site and the Knob Creek Embayment portion of the Tennessee River. Primary contaminants of concern at this site include aluminum, arsenic, chromium, copper, lead and zinc that were discharged during smelting activities and continue to be released from on-site landfills, settling ponds, and groundwater.

The HHRA was conducted in order to characterize the potential exposure and risks associated with soil, groundwater, fish tissue, and soil gas at the SMS Site. The evaluation of the SMS Site was unique due to the presence of a clay cap of the onsite aluminum dross and salt cake landfill.

The ERA focused on impacts to the benthic community in Flenniken Branch and the fish and benthic communities in the Knob Creek Embayment. Benthic community and habitat assessments followed TDEC macroinvertebrate survey procedures (modified Rapid Bioassessment Protocols) including habitat quality evaluations and taxonomic metrics comparisons. Sediment toxicity testing (28-day Hyalella azteca) was conducted to complete a sediment triad evaluation. Bottom feeder and upper trophic level fish species were collected from the Knob Creek Embayment and health condition indices were collected prior to submission for chemical analysis. Food chain models for both avian and mammalian receptors were evaluated.

In addition, the Team negotiated state agency support in the collection and enumeration of benthic community samples and the collection of fish samples, thereby saving the project over $37K and worked with the sediment toxicity contract laboratory in the development of a serial dilution study that simplified the estimation of clean-up levels and saved the project the expense of collecting additional sediment samples, estimated saving approximately $21K.