Geology topics

James Landmeyer

Publications and source records attributed to James Landmeyer.

At least 37 records · Page 2Linked to original sources

USGS2011

Assessment of Soil-Gas and Soil Contamination at the Former Military Police Range, Fort Gordon, Georgia, 2009-2010

Soil gas and soil were assessed for organic and inorganic contaminants at the former military police range at Fort Gordon, Georgia, from May to September 2010. The assessment evaluated organic contaminants in soil-gas samplers and inorganic contaminants in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers deployed and collected from May 20 to 24, 2010, identified masses above method detection level for total petroleum hydrocarbons, gasoline-related and diesel-related compounds, and chloroform. Most of these detections were in the southwestern quarter of the study area and adjacent to the road on the eastern boundary of the site. Nine of the 11 chloroform detections were in the southern half of the study area. One soil-gas sampler deployed adjacent to the road on the southern boundary of the site detected a mass of tetrachloroethene greater than, but close to, the method detection level of 0.02 microgram. For soil-gas samplers deployed and collected from September 15 to 22, 2010, none of the selected organic compounds classified as chemical agents and explosives were detected above method detection levels. Inorganic concentrations in the five soil samples collected at the site did not exceed the U.S. Environmental Protection Agency regional screening levels for industrial soil and were at or below background levels for similar rocks and strata in South Carolina.

Georgia↗

USGS2011

Assessment of soil-gas, soil, and water contamination at the former hospital landfill, Fort Gordon, Georgia, 2009-2010

Soil gas, soil, and water were assessed for organic and inorganic constituents at the former hospital landfill located in a 75-acre study area near the Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia, from April to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone of a creek adjacent to the landfill and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Results from the hyporheic-zone assessment in the unnamed tributary adjacent to the study area indicated that total petroleum hydrocarbons and octane were the most frequently detected organic compounds in groundwater beneath the creek bed. The highest concentrations for these compounds were detected in the upstream samplers of the hyporheic-zone study area. The effort to delineate landfill activity in the study area focused on the western 14 acres of the 75-acre study area where the hyporheic-zone study identified the highest concentrations of organic compounds. This also is the part of the study area where a debris field also was identified in the southern part of the 14 acres. The southern part of this 14-acre study area, including the debris field, is steeper and not as heavily wooded, compared to the central and northern parts. Fifty-two soil-gas samplers were used for the July 2010 soil-gas survey in the 14-acre study area and mostly detected total petroleum hydrocarbons, and gasoline and diesel compounds. The highest soil-gas masses for total petroleum hydrocarbons, diesel compounds, and the only valid detection of perchloroethene were in the southern part of the study area to the west of the debris field. However, all other detections of total petroleum hydrocarbons greater than 10 micrograms and diesel greater than 0.04 micrograms, and all detections of the combined mass of benzene, toluene, ethylbenzene, and xylene were found down slope from the debris field in the central and northern parts of the study area. Five soil-gas samplers were deployed and recovered from September 16 to 22, 2010, and were analyzed for organic compounds classified as chemical agents or explosives. Chloroacetophenones (a tear gas component) were the only compounds detected above a method detection level and were detected at the same location as the highest total petroleum hydrocarbons and diesel detections in the southern part of the 14-acre study area. Composite soil samples collected at five locations were analyzed for 35 inorganic constituents. None of the inorganic constituents exceeded the regional screening levels. One surface-water sample collected in the western end of the hyporheic-zone study area had a trichlorofluoromethane concentration above the laboratory reporting level and estimated concentrations of chloroform, fluoranthene, and isophorone below laboratory reporting levels.

Georgia↗

USGS2011

Assessment of soil-gas, soil, and water contamination at the former 19th Street landfill, Fort Gordon, Georgia, 2009-2010

Soil gas, soil, and water were assessed for organic and inorganic constituents at the former 19th Street landfill at Fort Gordon, Georgia, from February to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone and flood plain of a creek and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. The passive soil-gas samplers deployed in the water-saturated hyporheic zone and flood plain of the creek adjacent to the former landfill indicated the presence of total petroleum hydrocarbon (TPH) and octane above method detection levels in groundwater beneath the creek bed and flood plain at all 12 soil-gas sampler locations. The TPH concentrations ranged from 51.4 to 81.4 micrograms per liter. Octane concentrations ranged from 1.78 to 2.63 micrograms per liter. These detections do not clearly identify specific source areas in the former landfill; moreover, detections of TPH and octane in a soil-gas sampler installed at a seep on the western bank of the creek indicated the potential for these constituents to be derived from source areas outside the estimated boundaries of the former landfill. A passive soil-gas sampler survey was conducted in the former landfill from June 30 to July 5, 2010, and involved 56 soil-gas samplers that were analyzed for petroleum and halogenated compounds not classified as chemical agents or explosives. The TPH soil-gas mass exceeded 2.0 micrograms in 21 samplers. Most noticeable are the two sites with TPH detections which are located in and near the hyporheic zone and are likely to affect the creek. However, most TPH detections were located in and immediately adjacent to a debris field located within the former landfill and in areas where debris was not visible, including the northwestern and southeastern parts of the study area. Two of the four soil-gas samplers installed within a former military training area adjacent to the landfill also had TPH detections above the method detection level. Benzene, toluene, ethylbenzene, and xylene (as combined BTEX mass) were detected at 0.02 microgram or greater in three soil-gas samplers installed at the northwestern boundary and in five samplers installed in the southeastern part of the study area. There was no BTEX mass detected above the method detection level in samplers installed in the debris field. Toluene was the most frequently detected BTEX compound. Compounds indicative of diesel-range organics were detected above 0.04 microgram in 12 soil-gas samplers and had a distribution similar to that of TPH, including being detected in the debris field. Undecane was the most frequently detected diesel compound. Chloroform and naphthalene were detected in eight and two soil-gas samplers, respectively. Five soil-gas samplers deployed during September 2010 were analyzed for organic compounds classified as chemical agents and explosives, but none exceeded the method detection levels. Five composite soil samples collected from within the estimated boundaries of the former landfill were analyzed for 35 inorganic constituents, but none of the constituents detected exceeded regional screening levels for industrial soils. The sample collected in the debris field exceeded background levels for aluminum, barium, calcium, chromium, lead, nickel, potassium, sodium, and zinc. Three surface-water samples were collected in September 2010 from a stormwater outfall culvert that drains to the creek and from the open channel of the creek at upstream and downstream locations relative to the outfall. Toluene was detected at 0.661 mi

Georgia↗

USGS2011

Assessment of groundwater, soil-gas, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2010

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the groundwater, soil gas, and soil for contaminants at the Vietnam Armor Training Facility (VATF) at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic compounds in the groundwater and soil gas, and inorganic compounds in the soil. In addition, organic contaminant assessment included organic compounds classified as explosives and chemical agents in selected areas. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Four passive samplers were deployed in groundwater wells at the VATF in Fort Gordon. Total petroleum hydrocarbons were detected above the method detection level at all four wells. The only other volatile organic compounds detected above their method detection level were undecane and pentadecane, which were detected in two of the four wells sampled. Soil-gas samplers were deployed at 72 locations in a grid pattern across the VATF. Total petroleum hydrocarbons were detected in 71 of the 72 samplers (one sampler was destroyed in the field and not analyzed) at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylene was detected above the detection level in 31 of the 71 samplers that were analyzed. Other volatile organic compounds detected above their respective method detection levels were naphthalene, 2-methyl-naphthalene, tridecane, 1,2,4-trimethylbenzene, and perchloroethene. Subsequent to the soil-gas survey, four areas determined to have elevated contaminant mass were selected and sampled for explosives and chemical agents. No detections of explosives or chemical agents above their respective method detection levels were found at any of the sampling locations. The same four locations that were sampled for explosives and chemical agents were selected for the collection of soil samples. A fifth location also was selected on the basis of the elevated contaminant mass of the soil-gas survey. No metals that exceeded the Regional Screening Levels for Industrial Soils as classified by the U.S. Environmental Protection Agency were detected at any of the five VATF locations. The soil samples also were compared to values from the ambient, uncontaminated (background) levels for soils in South Carolina, as classified by the South Carolina Department of Health and Environmental Control. Because South Carolina is adjacent to Georgia and the soils in the coastal plain are similar, these comparisons are valid. No similar values are available for Georgia to use for comparison purposes. The metals that were detected above the ambient background levels for South Carolina, as classified by the South Carolina Department of Health and Environmental Control, include aluminum, arsenic, barium, beryllium, calcium, chromium, copper, iron, lead, magnesium, manganese, nickel, potassium, sodium, and zinc.

Georgia↗

USGS2011

Assessment of hyporheic zone, flood-plain, soil-gas, soil, and surface-water contamination at the Old Incinerator Area, Fort Gordon, Georgia, 2009-2010

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the hyporheic zone, flood plain, soil gas, soil, and surface-water for contaminants at the Old Incinerator Area at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic contaminants in the hyporheic zone, flood plain, soil gas, and surface water. In addition, the organic contaminant assessment included the analysis of explosives and chemical agents in selected areas. Inorganic contaminants were assessed in soil and surface-water samples. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Total petroleum hydrocarbons were detected above the method detection level in all 13 samplers deployed in the hyporheic zone and flood plain of an unnamed tributary to Spirit Creek. The combined concentrations of benzene, toluene, ethylbenzene, and total xylene were detected at 3 of the 13 samplers. Other organic compounds detected in one sampler included octane and trichloroethylene. In the passive soil-gas survey, 28 of the 60 samplers detected total petroleum hydrocarbons above the method detection level. Additionally, 11 of the 60 samplers detected the combined masses of benzene, toluene, ethylbenzene, and total xylene above the method detection level. Other compounds detected above the method detection level in the passive soil-gas survey included octane, trimethylbenzene, perchlorethylene, and chloroform. Subsequent to the passive soil-gas survey, six areas determined to have relatively high contaminant mass were selected, and soil-gas samplers were deployed, collected, and analyzed for explosives and chemical agents. No explosives or chemical agents were detected above their method detection levels, but those that were detected were above the nondetection level. The same six locations that were sampled for explosives and chemical agents were selected for the collection of soil samples. No metals that exceeded the Regional Screening Levels for Industrial Soils as classified by the U.S. Environmental Protection Agency were detected at any of the six Old Incinerator Area locations. The soil samples also were compared to values from the ambient, uncontaminated (background) levels for soils in South Carolina. Because South Carolina is adjacent to Georgia and the soils in the coastal plain are similar, these comparisons are valid. No similar values are available for Georgia to use for comparison purposes. The only metal detected above the ambient background levels for South Carolina was barium. A surface-water sample collected from a tributary west and north of the Old Incinerator Area was analyzed for volatile organic compounds, semivolatile organic compounds, and inorganic compounds (metals). The only volatile organic and (or) semivolatile organic compound that was detected above the laboratory reporting level was toluene. The compounds 4-isopropyl-1-methylbenzene and isophorone were detected above the nondetection level but below the laboratory reporting level and were estimated. These compounds were detected at levels below the maximum contaminant levels set by the U.S. Environmental Protection Agency National Primary Drinking Water Standard. Iron was the only inorganic compound detected in the surface-water sample that exceeded the maximum contaminant level set by the U.S. Environmental Protection Agency National Secondary Drinking Water Standard. No other inorganic compounds exceeded the maximum contaminant levels for the U.S. Environmental Protection Agency National Primary Drinking Water Standard, National Secondary Drinking Water Standard, or the Georgia In-Stream Water Quality Standard.

Georgia↗

USGS2011

Assessment of Hyporheic Zone, Flood-Plain, Soil-Gas, Soil, and Surface-Water Contamination at the McCoys Creek Chemical Training Area, Fort Gordon, Georgia, 2009-2010

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the hyporheic zone, flood plain, soil gas, soil, and surface water for contaminants at the McCoys Creek Chemical Training Area (MCTA) at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic contaminants in the hyporheic zone, flood plain, soil gas, and surface water. In addition, the organic contaminant assessment included the analysis of organic compounds classified as explosives and chemical agents in selected areas. Inorganic contaminants were assessed in soil and surface-water samples. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Ten passive samplers were deployed in the hyporheic zone and flood plain, and total petroleum hydrocarbons (TPH) and octane were detected above the method detection level in every sampler. Other organic compounds detected above the method detection level in the hyporheic zone and flood-plain samplers were trichloroethylene, and cis- and trans- 1, 2-dichloroethylene. One trip blank detected TPH below the method detection level but above the nondetection level. The concentrations of TPH in the samplers were many times greater than the concentrations detected in the blank; therefore, all other TPH concentrations detected are considered to represent environmental conditions. Seventy-one soil-gas samplers were deployed in a grid pattern across the MCTA. Three trip blanks and three method blanks were used and not deployed, and TPH was detected above the method detection level in two trip blanks and one method blank. Detection of TPH was observed at all 71 samplers, but because TPH was detected in the trip and method blanks, TPH was censored and, therefore, only 7 of the 71 samplers were reported as detecting TPH. In addition, benzene, toluene, ethylbenzene, and total xylene were detected above the method detection level in 22 samplers. Other compounds detected above the method detection level included naphthalene, octane, undecane, tridecane, 1,2,4-trimethylbenzene, trichloroethylene, perchloroethylene, chloroform, and 1,4-dichlorobenzene. Subsequent to the soil-gas survey, five locations with elevated contaminant mass were selected and a passive sampler was deployed at those locations to detect the presence of organic compounds classified as explosives or chemical agents. No explosives or chemical agents were detected above the method detection level, but some compounds were detected below the method detection level but above the nondetection level. Dimethyl disulfide, benzothiazole, chloroacetophenones, and para-chlorophenyl methyl sulfide were all detected below the method detection level but above the nondetection level. The compounds 2,4-dinitrotoluene, and para-chlorophenyl methyl sulfone were detected in samplers but also were detected in trip blanks and are not considered as present in the MCTA. The same five locations that were selected for sampling of explosives and chemical agents were selected for soil sampling. Metal concentrations in composite soil samples collected at five locations from land surface to a depth of 6 inches did not exceed the U.S. Environmental Protection Agency Regional Screening Levels for Industrial Soil. Concentrations in some compounds were higher than the South Carolina Department of Health and Environmental Control background levels for nearby South Carolina, including aluminum, arsenic, barium, beryllium, chromium, copper, iron, lead, manganese, nickel, and potassium. A surface-water sample was collected from McCoys Creek and analyzed for volatile organic compounds, semivolatile organic compounds, and inorganic compounds (metals). No volatile organic compounds and (or) semivolatile organic compounds were detected at levels above the maximum contaminant level of the U.S. Environmental Protection Agency (USEPA) National Primary Drinking Water Standard, and no inorganic compounds exceeded the maximum contaminant level of the USEPA National Primary Drinking Water Standard or the Georgia In-Stream Water-Quality Standard. Iron was the only inorganic compound detected in the surface-water sample (578 micrograms per liter) that exceeded the USEPA National Secondary Drinking Water Standard of 300 micrograms per liter.

Georgia↗

USGS2011

Investigation of the potential source area, contamination pathway, and probable release history of chlorinated-solvent-contaminated groundwater at the Capital City Plume Site, Montgomery, Alabama, 2008-2010

Detection of the organic solvent perchloroethylene (PCE) in a shallow public-supply well in 1991 and exposure of workers in 1993 to solvent vapors during excavation activities to depths near the water table provided evidence that the shallow aquifer beneath the capital city of Montgomery, Alabama, was contaminated. Investigations conducted from 1993 to 1999 by State and Federal agencies confirmed the detection of PCE in the shallow aquifer, as well as the detection of the organic solvent trichloroethylene (TCE) and various inorganic compounds, but the source of the groundwater contamination was not determined. In May 2000 the U.S. Environmental Protection Agency proposed that the site, called the Capital City Plume (CCP) Site, be a candidate for the National Priorities List. Between 2000 and 2007, numerous site-investigation activities also did not determine the source of the groundwater contamination. In 2008, additional assessments were conducted at the CCP Site to investigate the potential source area, contamination pathway, and the probable release history of the chlorinated-solvent-contaminated groundwater. The assessments included the collection of (1) pore water in 2008 from the hyporheic zone of a creek using passive-diffusion bag samplers; (2) tissue samples in 2008 and 2009 from trees growing in areas of downtown Montgomery characterized by groundwater contamination and from trees growing in riparian zones along the Alabama River and Cypress Creek; and (3) groundwater samples in 2009 and 2010. The data collected were used to investigate the potential source area of contaminants detected in groundwater, the pathway of groundwater contamination, and constraints on the probable contaminant-release history. The data collected between 2008 and 2010 indicate that the PCE and TCE contamination of the shallow aquifer beneath the CCP Site most likely resulted from the past use and disposal of industrial wastewater from printing operations containing chlorinated solvents into the sanitary sewer and (or) stormwater systems of Montgomery. Moreover, chlorinated-solvent use and disposal occurred at least between the 1940s and 1970s at several locations occupied by printing operations. The data also indicate that PCE and TCE contamination continues to occur in the shallow subsurface near potential release areas and that PCE and TCE have been transported to the intermediate part of the shallow aquifer.

Alabama↗

USGS2010

Field note--Successful establishment of a phytoremediation system at a petroleum-hydrocarbon contaminated shallow aquifer--Trends, trials, and tribulations

We report the establishment of a mixed hybrid poplar ( Populus spp .) and willow ( Salix spp .) phytoremediation system at a fuel-contaminated site. Several approaches were used to balance competing goals of cost-effectiveness yet successful tree establishment without artificial irrigation or trenching. Bare root and unrooted cuttings were installed using either: (1) 1.2 m deep holes excavated with an 8 cm diameter auger using a direct-push rig and backfilled with the excavated, in situ soil; (2) 1.2 m deep holes created with a 23 cm diameter auger attached to a Bobcat rig and backfilled with clean topsoil from offsite; and (3) shallow holes between 15–30 cm deep that were created with a 1.3 cm diameter rod and no backfill. Tree mortality from initial plantings indicated contaminated zones not quantified in prior site investigations and remedial actions. Aquifer heterogeneity, underground utilities, and prior remediation infrastructure hampered the ability of the site to support a traditional experimental design. Total stem length and mortality were measured for all planted trees and were incorporated into a geographic information system. Planting early in the growing season, augering a larger diameter hole, and backfilling with clean, uncontaminated topsoil was cost effective and allowed for greater tree cutting growth and survival.

International Journal of Phytoremediation↗

USGS2010

Assessment of soil-gas, surface-water, and soil contamination at the Installation Railhead, Fort Gordon, Georgia, 2008-2009

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, assessed soil gas, surface water, and soil for contaminants at the Installation Railhead (IR) at Fort Gordon, Georgia, from October 2008 to September 2009. The assessment included delineation of organic contaminants present in soil-gas samples beneath the IR, and in a surface-water sample collected from an unnamed tributary to Marcum Branch in the western part of the IR. Inorganic contaminants were determined in a surface-water sample and in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samples collected within a localized area on the western part of the IR contained total petroleum hydrocarbons; benzene, toluene, ethylbenzene, and total xylenes (referred to as BTEX); and naphthalene above the method detection level. These soil-gas samples were collected where buildings had previously stood. Soil-gas samples collected within a localized area contained perchloroethylene (PCE). These samples were collected where buildings 2410 and 2405 had been. Chloroform and toluene were detected in a surface-water sample collected from an unnamed tributary to Marcum Branch but at concentrations below the National Primary Drinking Water Standard maximum contaminant level (MCL) for each compound. Iron was detected in the surface-water sample at 686 micrograms per liter (ug/L) and exceeded the National Secondary Drinking Water Standard MCL for iron. Metal concentrations in composite soil samples collected at three locations from land surface to a depth of 6 inches did not exceed the U.S. Environmental Protection Agency Regional Screening Levels for industrial soil.

Georgia↗

USGS2010

Applying GORE-TEX technology for rapid contaminant assessments at Fort Gordon, Georgia

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army at Fort Gordon, Georgia, deployed GORE1 adsorbent samplers along creeks and floodplains to rapidly assess potential contamination at abandoned facilities and in adjacent surface water. The samplers provide screening-level data to determine the presence or absence of volatile organic compounds, semi-volatile organic compounds, and polycyclic aromatic hydrocarbons and were deployed in saturated creek and floodplain sediments adjacent to four abandoned waste-disposal/warfare-training sites. Fuelrelated compounds, not solvents, are the most prevalent organic compounds detected along segments of McCoys Creek adjacent to the 19th Street landfill; South Prong Creek adjacent to the South Prong Creek waste-disposal area; an unnamed tributary to Butler Creek adjacent to the old hospital landfill; and the Brier Creek floodplain adjacent to the Patterson anti-tank range. All 37 samplers deployed in these assessments had detections of total petroleum hydrocarbons ranging from just above 3 (laboratory method detection level) to 344 micrograms per liter. Detections of octane that ranged from 1 to 7.6 micrograms per liter were common in all assessments, except for South Prong Creek. Calculated concentrations of benzene are at or just above the National Primary Drinking Water Standard maximum contaminant level for all samplers deployed in the floodplain at the Patterson anti-tank range. The highest calculated concentration of a specific fuel-related compound was for toluene collected at one sampling site on McCoys Creek adjacent to the 19th Street landfill, but the concentration was below the National Primary Drinking Water Standard. These results are being used by Fort Gordon environmental compliance personnel to decide if further assessments are needed at these abandoned waste-disposal/warfare-training sites

Georgia↗

USGS2010

Contamination of groundwater by the fumigants ethylene dibromide (EDB) and dibromochloropropane (DBCP) near McBee, South Carolina

McBee is a small town of about 700 people located in Chesterfield County, South Carolina, in the Sandhills region of the upper Coastal Plain. The halogenated organic compounds ethylene dibromide (EDB) and dibromochloropropane (DBCP) have been detected in several public and domestic supply and irrigation wells since 2002 at concentrations above their U.S. Environmental Protection Agency Maximum Contaminant Limits of 0.05 and 0.2 microgram per liter (µg/L), respectively. The source(s) and release histories of EDB and DBCP to local groundwater are unknown, but believed to be related to their historical use between the 1940s and their ban in the late 1970s as fumigants to control nematode damage in peach orchards. However, gasoline and jet-fuel supplies also contained EDB and are an alternative source of contamination to groundwater. The detection of EDB and DBCP in water wells has raised health concerns because groundwater is the sole source of water supply in the McBee area. In April 2010, forensic, geochemical-based investigation was initiated by the U.S. Geological Survey in cooperation with the Alligator Rural Water & Sewer Company to provide additional data regarding EDB and DBCP in local groundwater. The investigation includes an assessment of the use, release, and disposal history of EDB and DBCP in the area, the distribution of EDB and DBCP concentrations in the unsaturated zone, and transport and fate in groundwater.

South Carolina↗

USGS2010

Development of a conceptual model of groundwater flow, Chesterfield County, South Carolina

Chesterfield County is located in the north central part of South Carolina (SC) and is adjacent to the North Carolina border. The County lies along the Fall Line, the geologic boundary between the Atlantic Coastal Plain (ACP) and Piedmont physiographic provinces. Between 2000 and 2007, the population increased from 42,768 to 43,191 people (U.S. Census Bureau, 2007). Associated with this population growth is an increased demand for domestic, public, industrial, and agricultural water supplies. The ACP sediments underlying Chesterfield County contain abundant supplies of highquality groundwater (Newcome, 2004). The U.S. Geological Survey, in cooperation with the South Carolina Department of Natural Resources is investigating the ACP groundwater resources of Chesterfield County. The initial task of the study is to establish a hydrologic data-collection network for the ACP part of the County. A groundwater-flow model and derived water budgets for the ACP aquifer that underlies most of the County will be constructed and calibrated later in the study. Both anthropogenic and natural groundwater contaminants that have been identified in the study area will be quantified and described as part of a companion study.

South Carolina↗

USGS2009

MTBE, TBA, and TAME attenuation in diverse hyporheic zones

Groundwater contamination by fuel-related compounds such as the fuel oxygenates methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA), and tert-amyl methyl ether (TAME) presents a significant issue to managers and consumers of groundwater and surface water that receives groundwater discharge. Four sites were investigated on Long Island, New York, characterized by groundwater contaminated with gasoline and fuel oxygenates that ultimately discharge to fresh, brackish, or saline surface water. For each site, contaminated groundwater discharge zones were delineated using pore water geochemistry data from 15 feet (4.5 m) beneath the bottom of the surface water body in the hyporheic zone and seepage-meter tests were conducted to measure discharge rates. These data when combined indicate that MTBE, TBA, and TAME concentrations in groundwater discharge in a 5-foot (1.5-m) thick section of the hyporheic zone were attenuated between 34% and 95%, in contrast to immeasurable attenuation in the shallow aquifer during contaminant transport between 0.1 and 1.5 miles (0.1 to 2.4 km). The attenuation observed in the hyporheic zone occurred primarily by physical processes such as mixing of groundwater and surface water. Biodegradation also occurred as confirmed in laboratory microcosms by the mineralization of U- 14 C-MTBE and U- 14 C-TBA to 14 CO 2 and the novel biodegradation of U- 14 C-TAME to 14 CO 2 under oxic and anoxic conditions. The implication of fuel oxygenate attenuation observed in diverse hyporheic zones suggests an assessment of the hyporheic zone attenuation potential (HZAP) merits inclusion as part of site assessment strategies associated with monitored or engineered attenuation.

Ground Water↗

USGS2009

Source, Transport, and Fate of Groundwater Contamination at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina

Groundwater contamination by tetrachloroethene and its dechlorination products is present in two partially intermingled plumes in the surficial aquifer near a former dry-cleaning facility at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina. The northern plume originates from the vicinity of former above-ground storage tanks. Free-phase tetrachloroethene from activities in this area entered the groundwater and the storm sewer. The southern plume originates at a nearby new dry-cleaning facility, but probably was the result of contamination released to the aquifer from a leaking sanitary sewer line from the former dry-cleaning facility. Discharge of dissolved groundwater contamination is primarily to leaking storm sewers below the water table. Extensive biodegradation of the contamination takes place in the surficial aquifer; however, the biodegradation is insufficient to reduce trichloroethene to less than milligram-per-liter concentrations prior to discharging into the storm sewers. The groundwater volatile organic compounds entering the storm sewers are substantially diluted by tidal flushing upon entry and are subject to volatilization as they are transported through the storm sewer to a discharge point in a tributary to Ballast Creek. TCE concentrations of about 2-6 micrograms per liter were present in storm-sewer water near the discharge point (sampled at manhole STS26). On three out of four sampling events at manhole STS14, the storm-sewer water contained no vinyl chloride. During a time of relatively high groundwater levels, however, 20 micrograms per liter of vinyl chloride was present in STS14 storm-sewer water. Because groundwater leaks into that storm sewer and because the storm sewer upgradient from manhole STS14 is adjacent to part of the aquifer where 2,290 micrograms per liter of vinyl chloride have been detected, there is a potential for substantially increased concentrations of vinyl chloride to discharge at the storm-sewer outfall under conditions of high groundwater levels and low tidal flushing. In addition, the observation that free-phase tetrachloroethene may have entered the storm-sewer system during the 1994 discharge means that dense nonaqueous phase liquid tetrachloroethene could have leaked from various parts of the storm sewer or discharged to surface water at the storm-sewer outfall.

South Carolina↗

USGS2009

Tritium concentrations in environmental samples and transpiration rates from the vicinity of Mary's Branch Creek and background areas, Barnwell, South Carolina, 2007-2009

Tritium in groundwater from a low-level radioactive waste disposal facility near Barnwell, South Carolina, is discharging to Mary's Branch Creek. The U.S. Geological Survey conducted an investigation from 2007 to 2009 to examine the tritium concentration in trees and air samples near the creek and in background areas, in groundwater near the creek, and in surface water from the creek. Tritium was found in trees near the creek, but not in trees from background areas or from sites unlikely to be in direct root contact with tritium-contaminated groundwater. Tritium was found in groundwater near the creek and in the surface water of the creek. Analysis of tree material has the potential to be a useful tool in locating shallow tritium-contaminated groundwater. A tritium concentration of 1.4 million picocuries per liter was measured in shallow groundwater collected near a tulip poplar located in an area of tritium-contaminated groundwater discharge. Evapotranspiration rates from the tree and tritium concentrations in water extracted from tree cores indicate that during the summer, this tulip poplar may remove more than 17.1 million picocuries of tritium per day from the groundwater that otherwise would discharge to Mary's Branch Creek. Analysis of air samples near the tree showed no evidence that the transpirative release of tritium to the air created a vapor hazard in the forest.

South Carolina↗

USGS2007

Fate of MTBE relative to benzene in a gasoline-contaminated aquifer (1993-98):

Methyl tert -butyl ether (MTBE) and benzene have been measured since 1993 in a shallow, sandy aquifer contaminated by a mid-1980s release of gasoline containing fuel oxygenates. In wells downgradient of the release area, MTBK was detected before benzene, reflecting a chromatographic-like separation of these compounds in the direction of ground water flow. Higher concentrations of MTBE and benzene were measured in the deeper sampling ports of multilevel sampling wells located near the release area, and also up to 10 feet (3 m) below the water table surface in nested wells located farther from the release area. This distribution of higher concentrations at depth is caused by recharge events that deflect originally horizontal ground water flowlines. In the laboratory, microcosms containing aquifer material incubated with uniformly labeled 14 C-MTBE under aerobic and anaerobic. Fe(III)-reducing conditions indicated a low but measurable biodegradation potential (<3% 14 C-MTBW as 14 CO 2 ) after a seven-month incubation period, Tert -butyl alcohol (TBA), a proposed microbial-MTBE transformation intermediate, was detected in MTBE-contaminated wells, but TBA was also measured in unsaturated release area sediments. This suggests that TBA may have been present in the original fuel spilled and does not necessarily reflect microbial degradation of MTBE. Combined, these data suggest that milligram per liter to microgram per liter decreases in MTBE concentrations relative to benzene are caused by the natural attenuation processes of dilution and dispersion with less-contaminated ground water in the direction of flow rather than biodegradation at this point source gasoline release site.

Groundwater Monitoring & Remediation↗

USGS2005

Hydrogeology, water quality, and saltwater intrusion in the Upper Floridan Aquifer in the offshore area near Hilton Head Island, South Carolina, and Tybee Island, Georgia, 1999-2002

To assess the hydrogeology, water quality, and the potential for saltwater intrusion in the offshore Upper Floridan aquifer, a scientific investigation was conducted near Tybee Island, Georgia, and Hilton Head Island, South Carolina. Four temporary wells were drilled at 7, 8, 10, and 15 miles to the northeast of Tybee Island, and one temporary well was drilled in Calibogue Sound west of Hilton Head Island. The Upper Floridan aquifer at the offshore and Calibogue sites includes the unconsolidated calcareous quartz sand, calcareous quartz sandstone, and sandy limestone of the Oligocene Lazaretto Creek and Tiger Leap Formations, and the limestone of the late Eocene Ocala Limestone and middle Avon Park Formation. At the 7-, 10-, and 15-mile sites, the upper confining unit between the Upper Floridan and surficial aquifers correlates to the Miocene Marks Head Formation. Paleochannel incisions have completely removed the upper confining unit at the Calibogue site and all but a 0.8-foot-thick interval of the confining unit at the 8-mile site, raising concern about the potential for saltwater intrusion through the paleochannel-fill sediments at these two sites. The paleochannel incisions at the Calibogue and 8-mile sites are filled with fine- and coarse-grained sediments, respectively. The hydrogeologic setting and the vertical hydraulic gradients at the 7- and 10-mile sites favored the absence of saltwater intrusion during predevelopment. After decades of onshore water use in Georgia and South Carolina, the 0-foot contour in the regional cone of depression of the Upper Floridan aquifer is estimated to have been at the general location of the 7- and 10-mile sites by the mid-1950s and at or past the 15-mile site by the 1980s. The upward vertical hydraulic gradient reversed, but the presence of more than 17 feet of upper confining unit impeded the downward movement of saltwater from the surficial aquifer to the Upper Floridan aquifer at the 7- and 10-mile sites. At the 10-mile site, the chloride concentration in the Upper Floridan borehole-water sample and the pore-water samples from the Oligocene and Eocene strata support the conclusion of no noticeable modern saltwater intrusion in the Upper Floridan aquifer. The chloride concentration of 370 milligrams per liter in the borehole-water sample at the 7-mile site from the Upper Floridan aquifer at 78 to 135 feet below North American Vertical Datum of 1988 is considerably higher than the chloride concentration of 25 milligrams per liter measured at the 10-mile site. The higher concentration probably is the result of downward leakage of saltwater through the confining unit at the 7-mile site or could reflect downward leakage of saltwater through an even thinner layer of the upper confining unit beneath the paleochannel to the northeast and lateral movement (encroachment) from the paleochannel to the 7-mile site. Carbon-14 concentrations at both sites, however, are low and indicate that most of the water is relict fresh ground water. The hydrogeology at the 15-mile site includes 17 feet of the upper confining unit. The chloride concentration in the Upper Floridan aquifer is 6,800 milligrams per liter. The setting for the Upper Floridan aquifer beneath the 15-mile site is interpreted as a transitional mixing zone between relict freshwater and relict saltwater. At the Calibogue site, 35 feet of fine-grained paleochannel-fill sediments overlies the Oligocene strata of the Upper Floridan aquifer. The vertical hydraulic conductivity of the paleochannel fill at this site is similar to the upper confining unit and effectively replaces the missing upper confining unit. Chloride concentrations and low carbon-14 and tritium concentrations in borehole water from the Upper Floridan aquifer, and low chloride concentrations in pore water from the upper confining unit indicate relict freshwater confined in the Upper Floridan aquifer at the Calibogue site. The coarse-grained paleochannel-f

Georgia, South Carolina↗

USGS2001

Monitoring the effect of poplar trees on petroleum-hydrocarbon and chlorinated-solvent contaminated ground water

At contaminated groundwater sites, poplar trees can be used to affect ground-water levels, flow directions, and ultimately total groundwater and contaminant flux to areas downgradient of the trees. The magnitude of the hydrologic changes can be monitored using fundamental concepts of groundwater hydrology, in addition to plant physiology-based approaches, and can be viewed as being almost independent of the contaminant released. The affect of poplar trees on the fate of groundwater contaminants, however, is contaminant dependent. Some petroleum hydrocarbons or chlorinated solvents may be mineralized or transformed to innocuous compounds by rhizospheric bacteria associated with the tree roots, mineralized or transformed by plant tissues in the transpiration stream or leaves after uptake, or passively volatilized and rapidly dispersed or oxidized in the atmosphere. These processes also can be monitored using a combination of physiological- or geochemical-based field or laboratory approaches. When combined, such hydrologic and contaminant monitoring approaches can result in a more accurate assessment of the use of poplar trees to meet regulatory goals at contaminated groundwater sites, verify that these goals continue to be met in the future, and ultimately lead to a consensus on how the performance of plant-based remedial strategies (phytoremediation) is to be assessed.

International Journal of Phytoremediation↗