Geology topics

Research about Escambia County, Florida

Source-linked reports with geographic coverage including Escambia County, Florida.

3 recordsLinked to original sources

USGS2007

Chloroethene dechlorination in acidic groundwater: Implications for combining fenton's treatment with natural attenuation

A sulfuric acid leak in 1988 at a chloroethene-contaminated groundwater site at the Naval Air Station Pensacola has resulted in a long-term record of the behavior of chloroethene contaminants at low pH and a unique opportunity to assess the potential impact of source area treatment technologies, which involve acidification of the groundwater environment (e.g., Fenton's-based in situ chemical oxidation), on downgradient natural attenuation processes. The greater than 75 percent decrease in trichloroethene (TCE) concentrations and the shift in contaminant composition toward predominantly reduced daughter products (dichloroethene [DCE] and vinyl chloride [VC]) that were observed along a 30-m groundwater flow path characterized by highly acidic conditions (pH = 3.5 ± 0.4) demonstrated that chloroethene reductive dechlorination can continue to be efficient under persistent acidic conditions. The detection of Dehalococcoides -type bacteria within the sulfuric acid/chloroethene co-contaminant plume was consistent with biotic chloroethene reductive dechlorination. Microcosm studies conducted with 14 C-TCE and 14 C-VC confirmed biotic reductive dechlorination in sediment collected from within the sulfuric acid/chloroethene co-contaminant plume. Microcosms prepared with sediment from two other locations within the acid plume, however, demonstrated only a limited mineralization to 14 CO 2 and 14 CO, which was attributed to abiotic degradation because no significant differences were observed between experimental and autoclaved control treatments. These results indicated that biotic and abiotic mechanisms contributed to chloroethene attenuation in the acid plume at NAS Pensacola and that remediation techniques involving acidification of the groundwater environment (e.g., Fenton's-based source area treatment) do not necessarily preclude efficient chloroethene degradation.

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USGS1975

Hydrology of sand-and-gravel aquifer in central and southern Escambia County, Florida

The sand-and-gravel aquifer is the only fresh-water aquifer in the Pensacola area. Problems related to development of the aquifer include maximum safe yield, local contamination, local salt-water intrusion, corrosiveness of the water, areas of high iron concentration, and increasing nitrate concentration. The city of Pensacola is seeking hydrologic information, including water-quality data, to plan for future expansion of the water-supply system. This report summarizes the third year's findings of a 6-year study of the sand-and-gravel aquifer. Although the thickness of the aquifer locally exceeds 1,000 feet (300 metres) most of the clean sand layers are no more than 450 feet (140 metres) below land surface. The highest head is at the north edge of the area; the head is drawn down below sea level in areas of heavy pumping. Ground water moves southward from the northern half of the county to be intercepted near Cantonment. Virtually all ground water discharged south of Cantonment derives from local precipitation. The report contains maps showing concentrations of carbon dioxide, nitrate, and iron in water from the aquifer, potentiometric maps, geohydrologic sections, and lithologic and radioactive logs of test holes.

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USGS1971

Availability of ground water for public-water supply in the Pensacola area, Florida: interim report, June 1971

Statement of the problem Earlier hydrologic studies show that ample quantities of soft water of low dissolved solids content are obtainable from the sand-and-gravel aquifer in the Pensacola area. Some wells drilled for the city of Pensacola have yielded water with unacceptably high amounts of iron and carbon dioxide, and wells have had disappointingly low yields. The city, therefore, is seeking hydrologic information, including water-quality data, in an effort to avoid the high cost of well abandonment and to plan for future expansion of the water-supply system. Objectives and approach This study is intended to provide information on the quality and quantity of water available from the sand-and-gravel aquifer, the only fresh-water aquifer in the Pensacola area, and to delineate those areas favorable for public-supply well sites. The project area is southern Escambia County, from Pensacola to S.R. (State Road) 196 north of Quintette (fig. 1). During the first year, effort was concentrated in the southern half of the area, generally south of 30°30', which approximately coincides with Interstate Highway 10 in southeastern Escambia County. The investigation included the collection of well data, chemical analyses of water samples, test drilling, radioactivity logging of test holes and other wells, and water-level measurements.

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