Preliminary studies on the chemical, physical, and biological stability of Ba/RaSO4 precipitates

McCready, R. G. L.; Bland, C. J.; Gonzales, Denis

doi:10.1016/0304-386x(80)90032-8

Cited by 20 publications

(6 citation statements)

References 2 publications

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“…The possibility also exists that the concentrations of heterotrophic bacteria are underestimated because of the inability of some of the bacteria to grow on the rich nutrient agar medium or at the pH of this medium, which is higher than the pH of the tailings samples. Sulfate-reducing bacteria are found in the peat and earth layers beneath the tailings and may promote the instability of radium-bearing sulfate precipitates (22).…”

Section: Discussionmentioning

confidence: 99%

Distribution of Iron-Oxidizing Bacteria in the Nordic Uranium Tailings Deposit, Elliot Lake, Ontario, Canada

Silver

1987

Appl Environ Microbiol

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Iron-oxidizing bacteria are present within the top 2 m (but not always at the surface) and near the water table-capillary fringe of the vegetated Nordic uranium deposit, Elliot Lake, Ontario, Canada. They are distributed uniformly in the top 0.5 m of unvegetated tailings. The locations of these bacteria correlate with zones of pyrite oxidation as delineated in previous studies by the formation of soluble iron and sulfate. Heterotrophic bacteria are also present in the tailings, with greatest concentrations at the surface and near the water table-capillary fringe. Sulfate-reducing bacteria were detected in the soil and peat at the base of the tailings. The results of this study suggest that the establishment of vegetation directly upon the tailings surface does not arrest bacterial pyrite oxidation.

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Section: Discussionmentioning

confidence: 99%

Distribution of Iron-Oxidizing Bacteria in the Nordic Uranium Tailings Deposit, Elliot Lake, Ontario, Canada

Silver

1987

Appl Environ Microbiol

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“…In 1965 Römer and Schwartz (31) demonstrated that these bacteria grew with barium sulfate as the sole sulfur source and reprecipitated barium as witherite (BaCO 3 ) after 2 weeks of incubation. McCready et al (25), studying sulfur isotope fractionation by Desulfovibrio vulgaris with BaSO 4 as an electron acceptor, reported that the quantity of soluble barium measured (5.3 mg of Ba ⅐ liter Ϫ1 ) was much less than expected (188 mg ⅐ liter Ϫ1 ). The soluble barium concentration was 5.3 mg of Ba ⅐ liter Ϫ1 , whereas the amount of .…”

Section: Discussionmentioning

confidence: 95%

Dissolution of Barium from Barite in Sewage Sludges and Cultures of Desulfovibrio desulfuricans

Baldi¹,

Pepi²,

Burrini³

et al. 1996

Appl Environ Microbiol

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High concentrations of total barium, ranging from 0.42 to 1.58 mg ⅐ g ؊1 (dry weight) were found in sludges of two sewage treatment plants near Florence, Italy. Barium concentrations in the suspended matter decreased as redox potential values changed from negative to positive. An anoxic sewage sludge sample was aerated, and 30% of the total barium was removed in 24 h. To demonstrate that barium was solubilized from barite by sulfate-reducing bacteria, a strain of Desulfovibrio desulfuricans was used to study the solubilization of barium from barite under laboratory conditions. During cell growth with different concentrations of barite from 0.01 to 0.3 g ⅐ liter ؊1 (the latter is the MIC) as the only source of sulfates in the cultures, the D. desulfuricans strain accumulated barium up to 0.58 g ⅐ mg ؊1 (dry weight). Three times the quantity of barium was dissolved by bacteria than in the uninoculated medium (control). The unexpectedly low concentration of soluble barium (1.2 mg of Ba ⅐ liter ؊1) with respect to the quantity expected (109 mg of Ba ⅐ liter ؊1), calculated on the basis of the free H 2 S evolved from the dissimilatory reduction of sulfate from barite, was probably due to the formation of other barium compounds, such as witherite (BaCO 3) and the transient species barium sulfide (BaS). The D. desulfuricans strain, growing on barite, formed visible aggregates. Confocal microscopy analysis showed that aggregates consisted of bacteria and barite. After 3 days of incubation, several autofluorescent crystals surrounded by a dissolution halo were observed. The crystals were identified as BaS by comparison with the commercial compound.

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“…These assumptions may not be correct because a fraction of the radium may become readily available for migration and uptake into the food chain while allowing radon to be released into the atmosphere (Sill, 1994(Sill, ,1987. Studies of the solubility of Ba/RaSO 4 in uranium mill tailings were performed by Fedorak et al (1986), McCready et al (1980) that demonstrate that under certain, commonly-encountered environmental conditions, radium will be released in substantial amounts from the Ba/RaSO 4 matrix. For example, sulfatereducing bacteria have been shown to enhance microbial activities that result in the dissolution of 226 Ra .…”

Section: Figurementioning

confidence: 97%

Evaluation of residual soil contamination from commercial oil well drilling activities and its impact on the naturally occurring background radiation environment

Spitz

Lovins

Becker

1997

Journal of Soil Contamination

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Radiation exposure received by individuals living and working on a farmland contaminated with radium was evaluated by measuring the technologically enhanced radiation background using portable survey instruments and a highpressure ionization chamber. Analysis of selected organic compounds, metals, and radioactive material in samples of soil and water obtained from the farm demonstrate a potential risk to inhabitants that needs to be evaluated, especially for future generations living and working on this land who may not be aware of the potential hazard. The distribution of radium and several other hazardous waste materials was found to be significantly elevated in areas where sludge ponds and waste pits were formerly located. Transport of these contaminants in soil was detected by in situ measurement of radium, which may be a useful analog for determining the translocation of metals and other contaminants associated with oil well-drilling activities. Conventional risk assessment models, using default input parameters, assume that exposure to radium in the soil is via the food chain and radon, and that inhalation of resuspended particles is less important. These models also assume that the chemical and physical characteristics of the radium contamination remain constant in time. However, under certain environmental conditions, the radium compounds will become more soluble with time, increasing their significance as a source of radiation exposure, especially as the radium will persist in soil for many thousands of years. Assessment of present and future risk to populations living and working on these contaminated lands must account for the potential change in radium solubility with time and the increased risk from both inhalation and ingestion of radium.This research describes environmental conditions found at one former well site in the Martha oil field in eastern Kentucky and identifies several important concerns related to the current and future risk associated with use of land contaminated with naturally occurring radioactive material.

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Preliminary studies on the chemical, physical, and biological stability of Ba/RaSO4 precipitates

Cited by 20 publications

References 2 publications

Distribution of Iron-Oxidizing Bacteria in the Nordic Uranium Tailings Deposit, Elliot Lake, Ontario, Canada

Distribution of Iron-Oxidizing Bacteria in the Nordic Uranium Tailings Deposit, Elliot Lake, Ontario, Canada

Dissolution of Barium from Barite in Sewage Sludges and Cultures of Desulfovibrio desulfuricans

Evaluation of residual soil contamination from commercial oil well drilling activities and its impact on the naturally occurring background radiation environment

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