Geology topics

Shannon D. Williams

Publications and source records attributed to Shannon D. Williams.

8 recordsLinked to original sources

USGS2016

Stage-discharge relations and annual nitrogen and phosphorus load estimates for stream sites in the Elk River Basin, 2006–2008

The U.S. Geological Survey, in cooperation with the Tennessee Department of Environment and Conservation (TDEC), measured continuous discharge at 4 water-quality monitoring sites and developed stage-discharge ratings for 10 additional water-quality monitoring sites in the Elk River Basin during 2006 through 2008. The discharge data were collected to support stream load assessments by TDEC. Annual nitrogen and phosphorus loads were estimated for the four sites where continuous daily discharge records were collected. Reported loads for the period 2006 through 2008 are not representative of long-term mean annual conditions at the sites in this study, however, because of severe drought conditions in the Elk River Basin during this period.

Alabama, Tennessee↗

USGS2007

Soil gas screening for chlorinated solvents at three contaminated karst sites in Tennessee

Soil gas was sampled using active sampling techniques and passive collectors at three sites in Tennessee to evaluate the effectiveness of these techniques for locating chlorinated solvent sources and flowpaths in karst aquifers. Actively collected soil gas samples were analyzed in the field with a portable gas chromatograph, and the passive soil gas collectors were analyzed in the lab with gas chromatography/mass spectrometry. Results of the sampling indicate that the effectiveness of both techniques is highly dependent on the distribution of the contaminants in the subsurface, the geomorphic and hydrogeologic characteristics of the site, and, in one case, on seasonal conditions. Both active and passive techniques identified areas of elevated subsurface chlorinated solvent concentrations at a landfill site where contamination remains concentrated in the regolith. Neither technique detected chlorinated solvents known to be moving in the bedrock at a manufacturing site characterized by thick regolith and an absence of surficial karst features. Passive soil gas sampling had varied success detecting flowpaths for chloroform in the bedrock at a train derailment site characterized by shallow regolith and abundant surficial karst features. At the train derailment site, delineation of the contaminant flowpath through passive soil gas sampling was stronger and more detailed under Winter conditions than summer.

Tennessee↗

USGS2006

Fate and transport of petroleum hydrocarbons in soil and ground water at Big South Fork National River and Recreation Area, Tennessee and Kentucky, 2002-2003

In 2002 and 2003, the U.S. Geological Survey (USGS), by agreement with the National Park Service (NPS), investigated the effects of oil and gas production operations on ground-water quality at Big South Fork National River and Recreation Area (BISO) with particular emphasis on the fate and transport of petroleum hydrocarbons in soils and ground water. During a reconnaissance of ground-water-quality conditions, samples were collected from 24 different locations (17 springs, 5 water-supply wells, 1 small stream, and 1 spring-fed pond) in and near BISO. Benzene, toluene, ethylbenzene, and xylene (BTEX) compounds were not detected in any of the water samples, indicating that no widespread contamination of ground-water resources by dissolved petroleum hydrocarbons probably exists at BISO. Additional water-quality samples were collected from three springs and two wells for more detailed analyses to obtain additional information on ambient water-quality conditions at BISO. Soil gas, soil, water, and crude oil samples were collected at three study sites in or near BISO where crude oil had been spilled or released (before 1993). Diesel range organics (DRO) were detected in soil samples from all three of the sites at concentrations greater than 2,000 milligrams per kilogram. Low concentrations (less than 10 micrograms per kilogram) of BTEX compounds were detected in lab-analyzed soil samples from two of the sites. Hydrocarbon-degrading bacteria counts in soil samples from the most contaminated areas of the sites were not greater than counts for soil samples from uncontaminated (background) sites. The elevated DRO concentrations, the presence of BTEX compounds, and the low number of -hydrocarbon-degrading bacteria in contaminated soils indicate that biodegradation of petroleum hydrocarbons in soils at these sites is incomplete. Water samples collected from the three study sites were analyzed for BTEX and DRO. Ground-water samples were collected from three small springs at the two sites located on ridge tops. BTEX and DRO were not detected in any of the water samples, and petroleum hydrocarbons do not appear to have leached into ground water at these sites. Ground-water samples were collected from a small spring and from three auger holes at the third site, which is located in a stream valley. BTEX and DRO were not detected in these ground-water samples, and currently, petroleum hydrocarbons do not appear to be leaching into ground water at this site. Weathered crude oil, however, was detected at the water surface in one of the auger holes, indicating that soluble petroleum hydrocarbons may have leached into the ground water and may have migrated downgradient from the site in the past. The concentration of soluble petroleum hydrocarbons present in the ground water would depend on the concentration of the hydrocarbons in the crude oil at the site. A laboratory study was conducted to examine the dissolution of petroleum hydrocarbons from a fresh crude oil sample collected from one of the study sites. The effective solubility of benzene, toluene, ethylbenzene, and total xylenes for the crude oil sample was determined to be 1,900, 1,800, 220, and 580 micrograms per liter (?g/L), respectively. These results indicate that benzene and toluene could be present at concentrations greater than maximum contaminant levels (5 ?g/L for benzene and 1,000 ?g/L for toluene for drinking water) in ground water that comes into contact with fresh crude oil from the study area.

Scientific Investigations Report↗

USGS2003

Volatile organic compound data from three karst springs in middle Tennessee, February 2000 to May 2001

The U.S. Geological Survey (USGS), in cooperation with the Tennessee Department of Environment and Conservation, Division of Superfund, collected discharge, rainfall, continuous water-quality (temperature, dissolved oxygen, specific conductance, and pH), and volatile organic compound (VOC) data from three karst springs in Middle Tennessee from February 2000 to May 2001. Continuous monitoring data indicated that each spring responds differently to storms. Water quality and discharge at Wilson Spring, which is located in the Central Basin karst region of Tennessee, changed rapidly after rainfall. Water quality and discharge also varied at Cascade Spring; however, changes did not occur as frequently or as quickly as changes at Wilson Spring. Water quality and discharge at Big Spring at Rutledge Falls changed little in response to storms. Cascade Spring and Big Spring at Rutledge Falls are located in similar hydrogeologic settings on the escarpment of the Highland Rim. Nonisokinetic dip-sampling methods were used to collect VOC samples from the springs during base-flow conditions. During selected storms, automatic samplers were used to collect water samples at Cascade Spring and Wilson Spring. Water samples were collected as frequently as every 15 minutes at the beginning of a storm, and sampling intervals were gradually increased following a storm. VOC samples were analyzed using a portable gas chromatograph (GC). VOC samples were collected from Wilson, Cascade, and Big Springs during 600, 199, and 55 sampling times, respectively, from February 2000 to May 2001. Chloroform concentrations detected at Wilson Spring ranged from 0.073 to 34 mg/L (milligrams per liter). Chloroform concentrations changed during most storms; the greatest change detected was during the first storm in fall 2000, when chloroform concentrations increased from about 0.5 to about 34 mg/L. Concentrations of cis-1,2-dichloroethylene (cis-1,2-DCE) detected at Cascade Spring ranged from 0.30 to 1.8 ?g/L (micrograms per liter) and gradually decreased between November 2000 and May 2001. In addition to the gradual decrease in cis-1,2-DCE concentrations, some additional decreases were detected during storms. VOC samples collected at weekly intervals from Big Spring indicated a gradual decrease in trichloroethylene (TCE) concentrations from approximately 9 to 6 ?g/L between November 2000 and May 2001. Significant changes in TCE concentrations were not detected during individual storms at Big Spring. Quality-control samples included trip blanks, equipment blanks, replicates, and field-matrix spike samples. VOC concentrations measured using the portable GC were similar to concentrations in replicate samples analyzed by the USGS National Water Quality Laboratory (NWQL) with the exception of chloroform and TCE concentrations. Chloroform and TCE concentrations detected by the portable GC were consistently lower (median percent differences of ?19.2 and ?17.4, respectively) than NWQL results. High correlations, however, were observed between concentrations detected by the portable GC and concentrations detected by the NWQL (Pearson?s r > 0.96). VOC concentrations in automatically collected samples were similar to concentrations in replicates collected using dip-sampling methods. More than 80 percent of the VOC concentrations measured in automatically collected samples were within 12 percent of concentrations in dip samples.

Open-File Report↗

USGS2003

Ground-Water Levels and Water-Quality Data for Wells in the Crumpton Creek Area near Arnold Air Force Base, Tennessee, November 2001 to January 2002

From November 2001 to January 2002, a study of the ground-water resources in the Crumpton Creek area of Middle Tennessee was conducted to determine whether volatile organic compounds (VOCs) from Arnold Air Force Base (AAFB) have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. VOC samples were collected from private wells that were not included in previous sampling efforts conducted in the Crumpton Creek area near AAFB. Ground-water-flow directions were investigated by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 68 private wells, 82 monitoring wells, and 1 cave during the period of study. Ground-water levels were determined for 42 of the private wells and for all 82 monitoring wells. Of the 82 monitoring wells, 81 withdraw water from the Manchester aquifer and 1 well withdraws water from the overlying shallow aquifer. The Manchester aquifer wells range in depth from 20 to 150 feet. Water-level altitudes for the Manchester aquifer ranged from 956 to 1,064 feet above the National Geodetic Vertical Datum of 1929. Water levels ranged from approximately 6 feet above land surface to 94 feet below land surface. Water-quality samples were collected from all 68 private wells, 8 of the monitoring wells, and the 1 cave. Of the 55 VOCs analyzed, 42 were not detected. Thirteen VOCs were detected; however, only tetrachloroethylene (PCE), methylene chloride, and toluene were detected at concentrations equal to or above reporting levels for the analytical method used. PCE was detected in water samples from 15 private wells and was the only VOC that exceeded drinking water maximum contaminant levels for public water systems. PCE concentrations in samples from five of the wells were below the reporting level and ranged from estimated concentrations of 0.46 to 0.80 microgram per liter (?g/L). Samples from 10 wells contained concentrations equal to or greater than the analytical reporting level of 1 ?g/L for PCE. Samples from one of these wells contained PCE concentrations (12 ?g/L and 11 ?g/L) exceeding the drinking water maximum contaminant level of 5 ?g/L for PCE. The spatial distribution of PCE detections and the relative concentrations of PCE and trichloroethylene suggest that the PCE detections are associated with a small and localized ground-water contamination plume unrelated to AAFB ground-water contamination.

Water-Resources Investigations Report↗

USGS2001

Ground-water levels and water-quality data for wells in the Spring Creek area near Arnold Air Force Base, Tennessee, April and May 2000

Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. Numerous site-specific ground-water contamination investigations have been conducted at designated solid waste management units (SWMU’s) at AAFB. Several synthetic volatile organic compounds (VOC’s), primarily chlorinated solvents, have been identified in groundwater samples collected from monitoring wells near SWMU 8 in the Spring Creek area. During April and May 2000, a study of the groundwater resources in the Spring Creek area was conducted to determine if VOC’s from AAFB have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. The study focused on sampling private wells located within the Spring Creek area that are used as a source of drinking water. Ground-water-flow directions were determined by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 35 private wells and 22 monitoring wells during the period of study. Depths to ground water were determined for 22 of the private wells and all 22 of the monitoring wells. The wells ranged in depth from 21 to 105 feet. Water-level altitudes ranged from 930 to 1,062 feet above sea level. Depths to water ranged from 8 to 83 feet below land surface. Water-quality samples were collected from 29 private wells which draw water from either gravel zones in the upper part of the Manchester aquifer, fractured bedrock in the lower part of the Manchester aquifer, or a combination of these two zones. Concentrations of 50 of the 55 VOC’s analyzed for were less than method detection limits. Chloroform, acetone, chloromethane, 2-butanone, and tetrachloroethylene were detected in concentrations exceeding the method detection limits. Only chloroform and acetone were detected in concentrations equal to or exceeding reporting limits. Chloroform was detected in a sample from one well at a concentration of 1.2 micrograms per liter (µg/L). Acetone was detected in a sample from another well at a concentration of 10 µg/L. Acetone also was detected in a duplicate sample from the same well at an estimated concentration of 7.2 µg/L, which is less than the reporting limit for acetone. The only contaminant of concern detected was tetrachloroethylene. Tetrachloroethylene was detected in only one sample, and this detection was at an estimated concentration below the reporting limit. None of the VOC concentrations exceeded drinking water maximum contaminant levels for public water systems.

Tennessee↗

USGS2000

Biodegradation of chlorinated ethenes at a karst site in middle Tennessee

This report presents results of field and laboratory investigations examining the biodegradation of chlorinated ethenes in a karst aquifer contaminated with trichloroethylene (TCE). The study site, located in Middle Tennessee, was selected because of the presence of TCE degradation byproducts in the karst aquifer and available site hydrologic and chlorinated-ethene information. Additional chemical, biological, and hydrologic data were gathered to evaluate whether the occurrence of TCE degradation byproducts in the karst aquifer was the result of biodegradation within the aquifer or simply transport into the aquifer. Geochemical analysis established that sulfate-reducing conditions, essential for reductive dechlorination of chlorinated solvents, existed in parts of the contaminated karst aquifer. Other areas of the aquifer fluctuated between anaerobic and aerobic conditions and contained compounds associated with cometabolism, such as ethane, methane, ammonia, and dissolved oxygen. A large, diverse bacteria population inhabits the contaminated aquifer. Bacteria known to biodegrade TCE and other chlorinated solvents, such as sulfate-reducers, methanotrophs, and ammonia-oxidizers, were identified from karst-aquifer water using the RNA-hybridization technique. Results from microcosms using raw karst-aquifer water found that aerobic cometabolism and anaerobic reductive-dechlorination degradation processes were possible when appropriate conditions were established in the microcosms. These chemical and biological results provide circumstantial evidence that several biodegradation processes are active in the aquifer. Additional site hydrologic information was developed to determine if appropriate conditions persist long enough in the karst aquifer for these biodegradation processes to be significant. Continuous monitoring devices placed in four wells during the spring of 1998 indicated that pH, specific conductance, dissolved oxygen, and oxidation-reduction potentials changed very little in areas isolated from active ground-water flow paths. These stable areas in the karst aquifer had geochemical conditions and bacteria conducive to reductive dechlorination of chlorinated ethenes. Other areas of the karst aquifer were associated with active ground-water flow paths and fluctuated between anaerobic and aerobic conditions in response to rain events. Associated with this dynamic environment were bacteria and geochemical conditions conducive to cometabolism. In summary, multiple lines of evidence developed from chemical, biological, and hydrologic data demonstrate that a variety of biodegradation processes are active in this karst aquifer.

Tennessee↗

USGS1996

Nutrient, sediment, and pesticide data collected at four small agricultural basins in the Beaver Creek watershed, West Tennessee, 1990-1995

In 1989, the U.S. Geological Survey began a cooperative study with the Tennessee Department of Agriculture to assess the impact of agricultural activities on water quality in the Beaver Creek watershed in West Tennessee. Quantification of the transport of nutrients, sediment, and pesticides from agricultural fields was one of the objectives of the study. This report presents nutrient, sediment, and pesticide data collected during selected storm events from 1990 through 1995 at four relatively small, agricultural basins (28 to 422 acres) in the Beaver Creek watershed. Approximately 3,000 water samples (500 to 1,000 at each site) were analyzed for nitrogen and phosphorus species. Total nitrogen (N) concentrations ranged from 0.2 to 41.2 milligrams per liter (mg/L). Median concentrations for samples from each site ranged from 2.0 to 2.7 mg/L for total nitrogen, 1.2 to 1.9 mg/L for organic nitrogen, 0.05 to 0.14 mg/L for ammonia (measured as N), and 0.2 to 0.8 mg/L for nitrate plus nitrite (measured as N). Total phosphorus (P) concentrations ranged from 0.03 to 16.0 mg/L. Median concentrations for samples from each site ranged from 0.80 to 1.2 mg/L for total phosphorus and 0.15 to 0.72 for orthophosphate (measured as P). Approximately 6,000 water samples (1,300 to 1,800 at each site) were analyzed for suspended sediment. Suspended-sediment concentrations ranged from 8.0 to 98,353 mg/L. Concentrations exceeded 1,000 mg/L in 33 percent of the samples collected and exceeded 10,000 mg/L in 6 percent of the samples. Median concentrations ranged from 347 to 713 mg/L at the four sites. Several herbicides and insecticides were detected in water samples. Maximum concentrations detected were 37 micrograms per liter for metolachlor, 3.2 for trifluralin, 150 for fluometuron, and 430 for aldicarb. Aldicarb metabolites were also detected in several samples. The maximum aldicarb sulfoxide and aldicarb sulfone concentrations detected were 68.4 and 14.3 micrograms per liter, respectively.

Tennessee↗