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J. F. Robertson

Publications and source records attributed to J. F. Robertson.

18 recordsLinked to original sources
USGS2007

Temporal changes in VOC discharge to surface water from a fractured rock aquifer during well installation and operation, Greenville, South Carolina

Analysis of the vapor in passive vapor samplers retrieved from a streambed in fractured rock terrain implied that volatile organic carbon (VOC) discharge from ground water to surface water substantially increased following installation of a contaminant recovery well using air rotary drilling. The air rotary technique forced air into the aquifer near the stream. The injection produced an upward hydraulic gradient that appears to have transported water and contaminants from deeper parts of the aquifer through fractures into shallow parts of the aquifer. Once in the shallow flow regime, the contamination was transported to the stream, where it discharged during the next several weeks following well installation. After the recovery well was activated and began continuously pumping contaminated ground water to a treatment facility, the VOC concentrations in the stream bottom passive vapor samplers decreased to below detectable concentrations, suggesting that the withdrawal had captured the contaminated ground water that previously had discharged to the stream.

South Carolina↗
USGS2005

Locating VOC contamination in a fractured-rock aquifer at the ground-water/surface-water interface using passive vapor collectors

Chlorinated organic solvents introduced to unlined lagoons at an industrial waste-water treatment plant in the Inner Piedmont of South Carolina resulted in ground-water contamination of a fractured-rock aquifer. Part of the ground-water contamination discharges to Little Rocky Creek, downgradient from the waste-water treatment plant. Passive vapor collectors were buried in the bottom sediment of the creek to locate areas where ground water contaminated with volatile organic compounds was discharging to the creek. High concentrations of volatile organic compounds (VOCs) were found in passive vapor collectors in an area where VOCs were known to be discharging from ground water to surface water. This area was also a site where very low frequency electromagnetic anomalies (interpreted as fracture zones) intersected the creek or converged near the creek. The data show that passive vapor collectors in bottom sediment of Little Rocky Creek provided information on the location of fractures that were discharging contaminated ground water to surface water.

Groundwater↗
USGS1997

Water-quality, water-level, and lake-bottom-sediment data collected from the defense fuel supply point and adjacent properties, Hanahan, South Carolina, 1990-96

A 9-year scientific investigation to determine the potential for biore-mediation of ground-water contamination and to monitor the effectiveness of an engineered bioremediation system located at the Defense Fuel Supply Point and adjacent properties in Hanahan, S.C., has culminated in the collection of abundant water-quality and water-level data.This report presents the analytical results of the study that monitored the changes in surface- and ground-water quality and water-table elevations in the study area from December 1990 to January 1996. This report also presents analytical results of lake-bottom sediments collected in the study area.

South Carolina↗
USGS1997

Transport and transformations of chlorinated-solvent contamination in a saprolite and fractured rock aquifer near a former wastewater-treatment plant, Greenville, South Carolina

The transport and fate of chlorinated-ethene contamination was investigated in a fractured-rock aquifer downgradient from a wastewater-treatment plant at a gas-turbine manufacturing facility in Greenville, South Carolina. A vapor-diffusion-sampler technique, developed for this investigation, located fracture zones that discharged contaminated ground water to surface water. The distribution of chlorinated compounds and sulfate, comparison of borehole geophysical data, driller's logs, and the aquifer response to pumpage allowed subsurface contaminant-transport pathways to be delineated.The probable contaminant-transport pathway from the former aeration lagoon was southward. The probable pathway of contaminant transport from the former sludge lagoon was southward to and beneath Little Rocky Creek. South of the creek, the major pathway of contaminant transport appeared to be at a depth of approximately 80 to 107 feet below land surface. The contaminant-transport pathway from the former industrial lagoon was not readily discernible from existing data. A laboratory investigation, as well as examination of ground- water-chemistry data collected during this investigation and concentrations of chlorinated compounds collected during previous investigations,indicates that higher chlorinated compounds are being degraded to lower-chlorinated compounds in the contaminated aquifer. The approaches used in this investigation, as well as the findings, have potential application to other fractured-rock aquifers contaminated by chlorinated ethenes.

South Carolina↗
USGS1996

Assessment of petroleum-hydrocarbon contamination in the surficial sediments and ground water at three former underground storage tank locations, Fort Jackson, South Carolina, 1995

Ground-water and sediment contamination by petroleum hydrocarbons resulting from leaks and overfills was detected during tank removal activities at three former underground storage tank locations at Fort Jackson, near Columbia, South Carolina. Investigations were initiated to assess the effect of contamination to the surficial aquifer at Sites 1062, 2438, and 2444. These investigations involved the installation of permanent monitoring wells and the collection and analysis of sediment and ground-water samples at the three sites. Water-level data were collected at all sites to determine hydraulic gradients and the direction of ground-water flow. In addition, aquifer tests were made at Site 1062 to determine the hydraulic conductivity of the surficial aquifer at that site. Sediment borings were made at the three sites to collect subsurface-sediment samples for lithologic description and laboratory analyses, and for the installation of ground-water monitoring wells. Laboratory analyses of sediment samples collected from boreholes at Site 1062 indicated elevated concentrations of petroleum hydrocarbons at three locations. Total Petroleum Hydrocarbons - Diesel Range Organics were detected at one borehole at a concentration of 388,000 micrograms per kilogram. Total benzene, toluene, ethylbenzene, and xylene concentrations in sediment from the site ranged from less than 350 to over 100,000 micrograms per kilogram. Total lead was detected at concentrations ranging from 2,900 to 5,900 micrograms per kilogram. Petroleum hydrocarbons were detected at Site 2438 in one borehole at a trace concentration of 112 micrograms per kilogram of para- and meta-xylenes. No concentrations exceeding the detection limits were reported for petroleum hydrocarbons in sediment samples collected from Site 2444; however, total lead was detected in sediment samples from two boreholes, each at concentrations of 600 micrograms per kilogram. Ground-water samples were collected from each site for laboratory analysis and field-property determinations. Petroleum hydrocarbons and lead were detected at concentrations exceeding regulatory limits for drinking water in ground water from Site 1062 only. Petroleum hydrocarbons were detected in ground water from three wells at Site 1062, with the highest concentrations occurring in the area of the former underground storage tanks. Benzene was detected at concentrations as much as 28 micrograms per liter; toluene as much as 558 micrograms per liter; para- and meta-xylenes as much as 993 micrograms per liter; and naphthalene as much as 236 micrograms per liter. Ethylbenzene and ortho-xylene were detected in one well at concentrations of 70 and 6 micrograms per liter, respectively. Dissolved lead was detected in ground water from four wells at concentrations from 5 to 152 micrograms per liter. Analysis of ground-water samples collected from Sites 2438 and 2444 showed little evidence of petroleum-hydrocarbon contamination. Petroleum hydrocarbons were not detected in any of the ground-water samples collected from Site 2438. With the exception of a low concentration of naphthalene (11 micrograms per liter) detected in ground water from one well, petroleum hydrocarbons and lead were not detected in ground water collected from Site 2444.

South Carolina↗
USGS1993

Distribution of volatile organic compounds in soil vapor in the vicinity of a defense fuel supply point, Hanahan, South Carolina

Two passive soil-vapor sampling techniques were used in the vicinity of a defense fuel supply point in Hanahan, South Carolina, to identify areas of potential contamination of the shallow water table aquifer by volatile organic compounds (VOC's). Both techniques involved the burial of samplers in the vadose zone and the saturated bottom sediments of nearby streams. One method, the empty-tube technique, allowed vapors to pass through a permeable membrane and accumulate inside an inverted empty test tube. A sample was extracted and analyzed on site by using a portable gas chromatograph. As a comparison to this method, an activated-carbon technique, also was used in certain areas. This method uses a vapor collector consisting of a test tube containing activated carbon as a sorbent for VOC's.

Water-Resources Investigations Report↗
USGS1985

Uranium mineralization in the Smith Lake district of the Grants uranium region, New Mexico.

The Mariano Lake and Ruby 1 uranium orebodies, which together comprise much of the uranium ore in the Smith Lake district of the Grants uranium region, New Mexico, occur in sandstones in the lower part of the Brushy Basin Member of the Upper Jurassic Morrison Formation. The orebodies, which are offset by faults of Laramide age, are enriched in an amorphous organic material that was introduced into the host sandstone after deposition. The enrichment by this organic material, in ore, is an important characteristic of the primary uranium deposits in the Grants uranium region. However, the close proximity of the chemically reduced ore zones to oxidized rock is suggestive that the deposits represent accumulations of uranium redistributed by reduction-oxidation processes from preexisting primary deposits.Within the ores, whole-rock abundances of organic carbon correlate positively with uranium contents. This correlation is consistent with petrologic evidence which indicates that uranium is everywhere intimately admixed with the amorphous organic material. Ore zones are also enriched in vanadium (as ore-stage vanadiferous chlorite) and sulfur (as ore-stage iron disulfide minerals with delta 34 S values ranging from -29 to -42ppm).Petrographic observations demonstrate that Smith Lake uranium mineralization occurred early (before major burial compaction) in the paragenetic sequence of host-rock diagenetic alterations but was preceded by precipitation of authigenic iron disulfides (delta 34 S values ranging from -11 to -38ppm), mixed-layered smectite-illite clays, and potassium feldspars.Additional preore alterations included dissolution of detrital sanidine and plagioclase and the leaching of iron from detrital iron-titanium oxide grains. Following mineralization, varying amounts of authigenic calcite and barite formed, both of which were partly replaced by kaolinitc. Oxidation of some previously formed iron disulfide minerals occurred late in the paragenetic sequence, as did localized precipitation of native selenium, pyrite, and very minor amounts of uranium minerals.The positive correlation between contents of uranium and organic carbon and the admixture of uranium with the amorphous organic material indicates that the Mariano Lake and Ruby 1 deposits are primary-type uranium orebodies. The offset of orebodies by Laramide faults and radiometric age determinations of the ores are also consistent with a primary origin for the deposits. Late Tertiary oxygenated ground waters locally modified original chemical and mineralogical characteristics of the ores in part by leaching some uranium. Secondary uranium minerals precipitated from the partly leached primary ores are sparse in the mine area; such recycled uranium appears to represent an insignificant proportion of the total uranium in the Smith Lake district.

Economic Geology↗