Clay mineralogy of sediments associated with a plume of creosote-contaminated ground water

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Authors:Bodine, Marc W., Jr.
Author Affiliations:Primary:
U. S. Geol. Surv., Denver, CO, United States
Volume Title:U.S. Geological Survey program on toxic waste-ground-water contamination; proceedings of the Second technical meeting, Cape Cod, Massachusetts, October 21-25, 1985
Volume Authors:Ragone, Stephen E., editor
Source:Open-File Report - U. S. Geological Survey, No.OF86-0481, p.A9-A15; U. S. Geological Survey program on toxic waste-ground-water contamination; second technical meeting, Cape Cod, MA, Oct. 21-25, 1985, edited by Stephen E. Ragone. Publisher: U. S. Geological Survey, Reston, VA, United States. ISSN: 0196-1497
Publication Date:1988
Note:In English. 5 refs.; illus. incl. 1 table, sect., sketch map
Summary:This study characterizes the clay minerals in sediments associated with a plume of creosote-contaminated groundwater. The plume of contaminated groundwater near Pensacola, FL, is in shallow, permeable, Miocene to Holocene quartz sand and flows southward toward Pensacola Bay. Clay-size fractions were separated from 41 cores, chiefly split-spoon samples at 13 drill sites. The most striking feature of the chemical analyses of the clay fractions from uncontaminated site 2 and contaminated sites 4,5,6, and 7 is the variability of iron oxide (species in some samples as Fe2O3); total iron oxide abundance is lowest (2.5%) in uncontaminated sample 2-40, but is > 4.5% (4.5 to 8.5%) in the remaining assemblages. One feature suggesting interaction between the indigenous clays and the waste plume is the presence of nontronite-rich smectite. Nontronite commonly has been identified as the product of hydrothermal alteration and deep-sea weathering of submarine basalts; it is not a common constituent of Cenozoic Gulf Coast sediments. At the Pensacola site, relatively abundant nontronitic smectite is confined to contaminated sands or associated muds; it is least abundant or absent in sands and muds peripheral to the waste plume. The geochemistry of the waste plume, its substantial dissolved, (chiefly ferrous iron), mildly acidic (pH 5-6), and low redox composition, provides an environment similar to that previously determined for the low-temperature synthesis of nontronite. Data from clay-size fractions confirm conclusions that neoformed pyrite in some grain coatings occurs in an assemblage with excess iron over that required in the pyrite. Continuing studies to evaluate these tentative conclusions include: (1) chemical analysis of clay fractions from remaining sites to further examine the apparent relation between iron content and abundance of nontronitic smectite; (2) clay separation and analysis, and pore fluid extraction (squeezing or ultracentrifugation) and analysis from a continuous core through the mud lens to determine pore fluid composition (presence or absence of waste fluid), and character of associated clay minerals; and (3) clay separation and analysis in both permeable sands and the intervening mud lens that are clearly outside the limits of the waste plume to further document the effects of the plume. (See also W90-00022) (Lantz-PTT)
Subjects:Clay mineralogy; Contaminant plumes; Creosote; Estuarine environment; Ground water; Hazardous waste; Organic compounds; Pollutants; Pollution; Sedimentary petrology; Sediments; Transport; USGS; Waste disposal; Water pollution; X-ray diffraction data; Escambia County Florida; Florida; Gulf Coastal Plain; Pensacola Florida; United States; Northwestern Florida; Organic materials
Coordinates:N302600 N302600 W0871200 W0871200
Record ID:1990063332
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from USGS product, Selected Water Resources Abstracts, Reston, VA, United States
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