Mercury contamination of the North Fork Holston River below Saltville, Virginia has nearly extirpated most mussel populations. Because natural recovery of these populations has not occurred, this research combined field and laboratory assessments to determine the extent of ecological impairment in the river. In situ 60-day Asian clam (Corbicula fluminea) growth studies in 2005 showed a positive correlation (p=0.03) between low clam growth and sediment mercury levels. Because of severe low flow conditions of the NFHR in late 2005 conductivity dissipation from a point source brine discharge downstream rarely reached background level (~345 µS/cm) and was observed as high as 690 µS/cm 640 m below the discharge site. In addition, conductivity doubled in the river section adjacent to the remediated Ponds 5 and 6 (rm 81.6 and 80.4). Such low flow conditions (mean flow < 50 ft3/sec) occur in the NFHR approximately every five years. This low flow situation also evidenced a thick white flocculent or floc observed to accumulate at the base of the two remediated ponds. Analysis of the flocculent determined it to be high in aluminum (1.9-38 mg/L) and iron (2.0-51.0 mg/L), well above US Environmental Protection Agency Water Quality Criteria limits (0.0087 and 1.0 mg/L, respectively); riverine sediments collected below the accumulated floc also had high levels of calcium (240,000-380,000 mg/kg) and mercury(0.62-1.7 mg/kg). Acute tests with juveniles of Villosa iris and <24-hr old Ceriodaphnia dubia were used to measure the toxicity of the brine discharge, which had a conductivity of ~ 14,000 µS/cm. Results of these tests indicated C. dubia to be more sensitive than V. iris; however, chronic toxicity test results were similar for V. iris and C. dubia. The Lowest Observed Adverse Effect Concentration (LOAEC) for mussel survivorship after 28 days was 10,000 µS/cm, while the LOAEC for growth was 5,000 µS/cm. LOAECs for the C. dubia 7-day chronic were 25 % (survivorship) and 12.5 % (reproduction), while mean conductivity at these two concentrations was 4,054 and 2,211 µS/cm, respectively. Toxicity tests conducted with Pond 6 dyke cut discharges resulted in similar lethal concentrations for C. dubia and V. iris. Forty-eight hour LC50s of these discharges ranged from 12.07-15.95 % for C. dubia, and 17.36-18.95 % for V. iris. Dyke cut discharges also exhibited exceedingly high alkaline pH (11.5-12.2), which caused 100 % mortality to C. dubia in 15 min. The Pond 5 and 6 dyke discharges are the likely source for the flocculent accumulation at the base of the two remediated pond areas. The combined effect of mercury, aluminum and iron, along with periodic fluxes of high conductivity and alkaline pH during low flow conditions may contribute to low mussel recruitment downstream of Saltville, VA. / Master of Science

The Clinch River (CR) and North Fork Holston River (NFHR) contain some of the most diverse freshwater mussel assemblages in the United States; however, both rivers are experiencing declines in mussel populations. The first component of this study used histological evaluations and water quality data to determine whether mussels were negatively impacted in the CR zone of decline (ZD) and to inform future management of freshwater mussels in the river. In the 91 kilometer (km) section from Carbo, Virginia (CRKM 431) downstream to Speers Ferry, Virginia (CRKM 340), referred to as the ZD, mussel density decreased >90% from 1979 to 2014 at key sites such as Semones Island (CRKM 378.3) and Pendleton Island (CRKM 364.2). Laboratory propagated mussels were placed in cages in the river for one year from June 2012 to May 2013 at four sites within the ZD and four sites in reaches where mussel populations remain stable or are increasing, a zone of stability (ZS). The survival, growth and histological results indicated that there are continuing impacts to mussels in the ZD. Research investigating impacts to the ZD and methods to improve water quality in this zone are needed. The laboratory component of this study examined sublethal effects of potassium (K⁺), chloride (Cl⁻), and un-ionized ammonia (NH₃-N) on mussel tissues at concentrations relevant to those found in the NFHR. Historical industrial activities at Saltville, Virginia, as well as continued pollution of the NFHR from chemical waste ponds at this location, are believed to be significant contributors to mussel declines. Contaminant seepages from the waste ponds that include Cl⁻, K⁺, and NH₃-N have been shown to be toxic to adult and juvenile mussels. A three-month laboratory study was conducted to assess impacts to organ tissues (gills, digestive glands, kidneys, and gonads) of adult Villosa iris exposed to environmentally relevant concentrations of K⁻ (4 and 8 mg/L), Cl⁻ (230 and 705 mg/L), and NH₃-N (0.014 and 0.15 mg/L) using histological evaluations. No detectable differences were observed among the histological endpoints from mussels held in treatments and control (p>0.05). The study design was modified and repeated using increased concentrations of K⁺ (8, 16, and 32 mg/L) and Cl⁻ (705, 1410, and 2820 mg/L) for a two-month exposure period. Due to issues with maintaining NH3-N in mussel holding chambers, the second study did not the second study did not include NH₃-N exposures. Control mussels in both studies had a higher abundance of lipofuscin in kidneys and degraded cytoplasm in the digestive gland diverticula compared to baseline mussels, indicating that captivity influenced mussel tissues. Future studies are needed to more thoroughly address these captivity effects. Both survival and histological data in the second test showed a significant negative effect of the increased concentrations of Cl⁻ and K⁻, which were representative of those found at some sites in the NFHR downstream of Saltville, Virginia. / Master of Science

Basin-wide visual estimation techniques developed in the Pacific Northwest for small streams were modified to survey about 180 river kilometers (rkm) of the North Fork Holston River and about 16 rkm of lower Little River (Clinch River tributary) in southwestern Virginia during the summer of 1992 and 1993, respectively. Presence-absence models were developed, using stepwise logistic regressions, from habitat characteristics measured on a scale ranging from large-scale (geographic location) to local-scale (habitat-unit characteristics) for blotchside logperch (<i>Percina burtoni</i>) and tangerine darter (<i>P. aurantiaca</i>) in the North Fork Holston River. Transferability of models, developed for both species in the North Fork Holston River, to Little River were tested by comparing the models' predictions with the data collected during the Little River survey. / Master of Science

The freshwater mussel fauna of the North Fork Holston River (NFHR) downstream of Saltville, VA declined from at least 24 species, as observed in 1918, to one species in 1974 due to mercury pollution. To determine the degree of recovery of mussels in the NFHR downstream of Saltville, and to provide recommendations for future mussel translocation sites, 19 sites were surveyed using a snorkeling catch-per-unit-effort (CPUE) method. At sites where investigator CPUE values (no./h) equaled or exceeded 5 mussels/h, a CPUE survey was conducted along transect lines. If investigator CPUE values equaled 10 mussels/h, a quadrat survey was conducted along the transects. Nine species of mussels were observed in the NFHR, and reproduction, as indicated by the presence of juveniles, was noted at 5 sites. Recovery of mussels was judged to be occurring downstream of NFHRM 56.4 based on species aggregations and recruitment. The number of mussels collected at sites, random CPUE (no./h), transect CPUE (no./h), and density (no./O.25m2) were generally inversely correlated to total Hg content, but not methyl mercury content, as measured in Corbicula fluminea from proximate sites. Random and transect CPUE (no./h) were found to be poor predictors of site densities (no./O.25m2) and popUlation estimates. Translocation recommendations for the NFHR downstream of Saltville, VA were made based on species aggregations, recruitment, and the distribution of total mercury. / Master of Science

Navigation Map of Cherokee Reservoir Holston River published in 1955 by the Tennessee Valley Authority, Maps and Surveys Branch. Sheet 1 of a series of 4 maps covering Cherokee Reservoir. This sheet covers mile 52.3 to mile 62.8. The Index to all 4 maps can be found on the lower right quadrant. The legend denotes several information items pertaining to lake levels, direction of flow, bridges, and other points of interest. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. Scale: 1" = .5 mile. Datum is mean sea level. / https://dc.etsu.edu/rare-maps/1027/thumbnail.jpg

Navigation Map of Cherokee Reservoir Holston River published in 1957 by the Tennessee Valley Authority, Maps and Surveys Branch. Sheet 4 of a series of 4 maps covering Cherokee Reservoir. This sheet covers mile 95.1 to mile 116.6. The inset located in the upper portion includes a detailed view of Miller Island and Honeycutt Creek. The legend denotes several information items pertaining to lake levels, direction of flow, bridges, and other points of interest. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. Scale: 1" = .5 mile. Datum is mean sea level. / https://dc.etsu.edu/rare-maps/1028/thumbnail.jpg

Navigation Map of Cherokee Reservoir Holston River published in 1956 by the Tennessee Valley Authority, Maps and Surveys Branch. Sheet 3 of a series of 4 maps covering Cherokee Reservoir. This sheet covers mile 79.3 to mile 95.1. The index to the entire 4 maps series can be found in the lower right quadrant. The legend denotes several information items pertaining to lake levels, direction of flow, bridges, and other points of interest. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. Scale: 1" = .5 mile. Datum is mean sea level. / https://dc.etsu.edu/rare-maps/1029/thumbnail.jpg