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PubMed2005

Genotoxic damage in mine workers exposed to diesel exhaust, and the effects of glutathione transferase genotypes.

This study was performed in an Estonian shale-oil mine with the purpose to develop and apply a number of biomarkers for occupational diesel-exhaust exposure monitoring. Increased breathing-zone exposures to exhaust from operators of diesel-powered trucks in the mine was confirmed in the environmental monitoring part of the study, showing a 7.5-fold higher exposure to particle-associated 1-nitropyrene (1-NP) in 50 underground workers compared with 42 surface workers [P.T.J. Scheepers, D. Coggon, L.E. Knudsen, R. Anzion, H. Autrup, S. Bogovski, R.P. Bos, D. Dahmann, P. Farmer, E.A. Martin, V. Micka, V. Muzyka, H.-G. Neumann, J. Poole, A. Schmidt-Ott, F. Seiler, J. Volf, I. Zwirner-Baier, Biomarkers for occupational diesel exhaust exposure monitoring (BIOMODEM)-a study in underground mining, Toxicol. Lett. 134 (2002) 305-317; P.T.J. Scheepers, V. Micka, V. Muzyka, R. Anzion, D. Dahmann, J. Poole, R.P. Bos, Exposure to dust and particle-associated 1-nitropyrene of drivers of diesel-powered equipment in underground mining, Ann. Occp. Hyg. 47 (2003) 379-388]. Analysis of DNA damage by the Comet assay on frozen blood samples was performed on the total study group and showed significantly higher levels (p=0.003) in underground workers (smokers) driving diesel-powered excavation machines (median 155 on a scale from 0 to 400, among 47 persons), compared with surface workers who smoked (median of 90, among 46 persons). The level of DNA damage in underground smokers was significantly higher (p=0.04) than in non-smokers. Samples from 2 of the 3 sampling weeks had significantly lower DNA damage compared with the third week, probably due to timely processing and freezing. These samples also showed significant differences (p<0.001) between underground workers (median 145, among 41 persons) and surface workers (median 60, among 30 persons). An HPLC method was developed for the analysis of (32)P-postlabelled 1-NP-DNA-adducts, and was applied to a sub-sample of 20 workers. No significant differences between surface and underground workers were found in this sub-sample with respect to the minor, unidentified adducts that had similar chromatographic properties to 1-NP adducts, and smoking did not have any effect on adduct levels. No significant effects of the genotypes of GSTM1, GSTP1 and GSTT1 on DNA-adducts and on DNA damage as measured by the Comet assay were found in the total study group. The study confirms an increased level of DNA damage in workers exposed to exhaust from truck-driving in the mine. However, the results of the environmental and biological monitoring of 1-NP did not correlate, suggesting that inhalation exposure to diesel exhaust is not reflected by an increase in 1-NP-DNA-adduct levels and/or that factors other than occupational exposure to diesel exhaust are primary determinants of these DNA-adduct levels.

Adult↗
PubMed2004

Influence of Typha latifolia and fertilization on metal mobility in two different Pb-Zn mine tailings types.

Storing metal-rich mine waste (tailings) under submerged and reduced conditions can prevent the release of metals to the water column, but introduction of wetland plants on these sediments may alter the reducing environment through root oxygen diffusion or organic matter accumulation. Fertilization of these wetlands can enhance plant growth, but also may either strengthen reducing conditions via microbial stimulation, or increase the redox potential (Eh) through increased root radial oxygen loss. This long-term study (2.25 years) investigated the porewater As, Fe, and Zn concentrations of waterlogged Pb-Zn tailings from two Irish mines, Silvermines and Tara mines, with addition of Typha latifolia, fertilizer, or both treatments combined. In both tailings types, the fertilized plants showed significantly increased total biomass production, but the plants grew greater biomass in Tara tailings relative to Silvermines tailings even without fertilization. In Tara mines tailings, the addition of plants increased Eh and mobilized Zn; the addition of fertilizer enhanced reducing conditions and increased porewater concentrations of As and soluble sulfides; and the combination of treatments on these tailings resulted in complex interactions. In Silvermines tailings, there were negligible effects of the treatments. For effective sequestration of metals in these tailings, Silvermines would require only water cover, but Tara mines tailings would require either both treatments or neither because each treatment individually would increase solubility of As or Zn. These results show also the necessity of evaluating treatment effects specific to individual tailings, that long-term studies (years) are crucial for tailings equilibration and valid experimental conclusions, and that passive accumulation of organic matter may take decades.

Biodegradation, Environmental↗
PubMed2005

The contribution of science to risk-based decision-making: lessons from the development of full-scale treatment measures for acidic mine waters at Wheal Jane, UK.

The use of risk-based decision-making in environmental management is often assumed to rely primarily on the availability of robust scientific data and insights, while in practice socio-economic criteria are often of considerable importance. However, the relative contributions to decision-making made by scientific and socio-economic inputs are rarely assessed, and even less commonly reported. Such an assessment has been made for a major remediation project in southwest England, in which some 300 l/s of highly acidic, metalliferous mine waters are now being treated using oxidation and chemical neutralisation. In the process of reaching the decision to commission the treatment plant, a wide range of scientific studies were undertaken, including: biological impact assessments, hydrogeological investigations of the effect of pumping on the flooded mine system, and hydrological and geochemical characterisation, together with integrated catchment modelling, of pollutant sources and pathways. These investigations revealed that, despite the spectacular nature of the original mine water outburst in 1992, the ecology of the Fal estuary remains remarkably robust. No scientific evidence emerged of any grounds for concern over the estuarine ecology, even if mine water were left to flow untreated. However, a rare ecological resource known as "maerl" (a form of calcified seaweed) is harvested annually in the estuary, providing significant revenue to the local economy and underpinning the 'clean' image of local sea water. Social and environmental benefit surveys revealed strong public perceptions that any visible discoloration in the estuary must indicate a diminution in quality of the maerl, to the detriment of both the public image and economy of the area. This factor proved sufficient to justify the continued pump-and-treat operations at the mine site. Although the decisive factor in the end was socio-economic in nature, robust assessment of this factor could not have been made without robust scientific evidence. It is concluded that investment in investigating and contributing to the formation of public perceptions is just as important as investing in scientific investigations per se.

Decision Making↗
PubMed2006

Lead isotope ratio measurements by ICP-QMS to identify metal accumulation in vegetation specimens growing in mining environments.

The use of variations in stable Pb isotope ratios has become a well-established diagnostic technique for characterising sources of lead contamination. In this work, lead isotope ratios in mining wastes (lead content 320-130,000 mg kg-1) and vegetation specimens (lead concentration 7-650 mg kg-1) have been determined by inductively coupled plasma quadrupole-based mass spectrometry (ICP-QMS) in order to investigate lead bioaccumulation in Buddleia davidii growing on wastes from two abandoned Pb/Zn mining areas in Spain. The accuracy of the isotope ratio measurements was evaluated by analysing a certified isotopic standard NIST SRM 981. Good agreements were obtained between the lead isotope ratios measured and the certified values (deviations within 0.01-0.2%). The results indicate that the lead isotopic ratios in vegetation samples collected in the mining areas differed from those of a specimen from an uncontaminated site (control sample). However, close lead isotope ratio values were found between vegetation specimens and mining tailings. Therefore, the results suggest that lead in the collected vegetation specimens is most likely related to the influence of mining activities rather than to other sources like past leaded-petrol emissions.

Cluster Analysis↗
PubMed2004

Assessing the market opportunities of landfill mining.

Long-term estimates make clear that the amount of solid waste to be processed at landfills in the Netherlands will sharply decline in coming years. Major reasons can be found in the availability of improved technologies for waste recycling and government regulations aiming at waste reduction. Consequently, market size for companies operating landfills shrinks. Among the companies facing the problem is the Dutch company Essent. Given the expected market conditions, it looks for alternative business opportunities. Landfill mining, i.e., the recycling of existing landfills, is considered one of them. Proceeds of landfill mining are related to, for example, recycled materials available for re-use, regained land, and possibilities for a more efficient operation of a landfill. The market for landfill mining is of a considerable size--there are about 3800 landfills located in the Netherlands. Given market size the company faces the dilemma of how to explore this market, i.e., select the most profitable landfills in a fast and efficient way. No existing methods or tools could be found to do so. Therefore, to answer to the problem posed, we propose a step-wise research method for market exploration. The basic idea behind the method is to provide an adequate, cost-saving and timely answer by relying on a series of quick scans. Relevant aspects of a mining project concern the proceeds of regained land and recyclables, the costs of the mining operation and the associated business and environmental risks. The method has been tested for its practical use in a pilot study. The pilot study addressed 147 landfills located in the Dutch Province of Noord-Brabant. The study made clear how method application resulted in the selection of a limited number of high potential landfills in a few weeks, involving minimal research costs.

Commerce↗
PubMed1987

The pathogenicity of dust from a fluorite mine.

The pathogenicity of mixed dust from a fluorite mine was studied by animal experiments and in vitro tests. Animal experiments showed that calcium fluorite can induce only a foreign body reaction in the lungs; the fibrous nodular lesions induced by the fluorite mine dust are due mainly to its silica component. It was demonstrated that either silica or the mixed dust of a fluorite mine can stimulate pulmonary alveolar macrophages (PAMs) to release fibrogenetic factors in vitro, but calcium fluorite cannot. It was also demonstrated that having engulfed calcium fluorite, silica, or fluorite mine mixed dust, PAMs release an elastase-active substance. The authors suggest that the emphysematous lesion seen in autopsy material of pneumoconiosis of fluorite mine workers may be caused by calcium fluorite and silica.

Animals↗
PubMed2003

Ecological restoration of mine degraded soils, with emphasis on metal contaminated soils.

This paper reviews the ecological aspects of mined soil restoration, with special emphasis on maintaining a long-term sustainable vegetation on toxic metal mine sites. The metal mined soils are man-made habitats which are very unstable and will become sources of air and water pollution. Establishment of a vegetation cover is essential to stabilize the bare area and to minimize the pollution problem. In addition to remediate the adverse physical and chemical properties of the sites, the choice of appropriate vegetation will be important. Phytostabilization and phytoextraction are two common phytoremediation techniques in treating metal-contaminated soils, for stabilizing toxic mine spoils, and the removal of toxic metals from the spoils respectively. Soil amendments should be added to aid stabilizing mine spoils, and to enhance metal uptake accordingly.

Biodegradation, Environmental↗
PubMed2004

Plant community tolerant to trace elements growing on the degraded soils of São Domingos mine in the south east of Portugal: environmental implications.

The selection of trace element tolerant species is a key factor to the success of remediation of degraded mine soils. Mining activities generate a large amount of waste rocks and tailings, which get deposited at the surface. The degraded soils, the waste rocks and tailings are often very unstable and will become sources of pollution. The direct effects will be the loss of cultivated land, forest or grazing land, and the overall loss of production. The indirect effects will include air and water pollution and siltation of rivers. These will eventually lead to the loss of biodiversity, amenity and economic wealth. Restoration of a vegetation cover can fulfil the objectives of stabilization, pollution control, visual improvement and removal of threats to human beings. Thus, remediation of mine spoils/tailings and biogeochemical prospecting would rely on the appropriate selection of plant species. Plant community responds differently on their ability to uptake or exclude a variety of metals. In this work, plant species were sampled from all populations established in an abandoned copper mine of São Domingos, SE Portugal. Plants belonging to 24 species, 16 genera and 13 families were collected from the degraded copper mine of São Domingos. Plant samples were analysed for total Ag, As, Cu, Ni, Pb, and Zn. The highest concentrations of metals in soils dry matter were 11217.5 mg Pb kg(-1), 1829 mg Cu kg(-1), 1291 mg As kg(-1), 713.7 mg Zn kg(-1), 84.6 mg Cr kg(-1), 54.3 mg Co kg(-1), 52.9 mg Ni kg(-1) and 16.6 mg Ag kg(-1). With respect to plants, the higher concentrations of Pb and As were recorded in the semi-aquatic species Juncus conglomeratus with 84.8 and 23.5 mg kg(-1) dry weight (DW), Juncus efusus with 22.4 and 8.5 mg kg(-1) DW, and Scirpus holoschoenus with 51.7 and 8.0 mg kg(-1) DW, respectively. Thymus mastichina also showed high content of As in the aboveground parts, 13.6 mg kg(-1) DW. Overall, the results indicate accumulation of various metals by different plant species, with some of these metals being partitioned to the shoots. Environmental implications of these observations are discussed.

Copper↗
PubMed2002

Mobility of heavy metals associated with the natural weathering of coal mine spoils.

Knowledge of chemical mobility of heavy metals is fundamental to understanding their toxicity, bioavailability, and geochemical behavior. In this paper, two different methods, i.e. mineralogical means and sequential extractions, were employed to analyze the total contents, existing states, and chemical forms of heavy metals in coal mine spoils. The results demonstrate that the mobility of heavy metals in coal mine spoils depends not only on their existing states and the stability of their host minerals but also on the properties of the coal mine spoils. In the process of coal mine spoils-water interaction, sulfides that contain heavy metals first break down and release metals, which are then adsorbed and complexed by the iron oxyhydroxide colloid resulting from pyrite oxidization and organic matter. During the natural weathering of coal mine spoils, only a small fraction of these metals are released to the environment, and most of them still remains in the residual material.

Biological Availability↗
PubMed2002

Mining in the Alligator Rivers Region, northern Australia: assessing potential and actual effects on ecosystem and human health.

This paper presents an overview of issues related to surface water contamination arising from uranium mining activities in the Alligator Rivers Region (ARR) of northern Australia, and a program of research and monitoring that must assess the potential and actual effects on ecosystem and human health. The program of assessing effects on aquatic ecosystems involves a four-tiered approach including the derivation of local water quality guideline trigger values, direct toxicity assessment of mine waters prior to their release, creekside or in situ monitoring for early warning of adverse effects during mine water release, and longer-term monitoring of macroinvertebrate and fish communities. Bioaccumulation in aquatic biota is also assessed, and is an issue of importance not only to ecosystem health, but also to the health of local Aboriginal people. The aquatic animals they consume represent potential sources of radiological dose, and as a result, a major component of the program to assess potential effects on human health is the prediction of doses to Aboriginal people living downstream of mining activities. Acknowledging the assumptions and uncertainties, the calculation of concentration factors for local aquatic (and other) food sources allows the prediction of potential radiological exposure to people following hypothetical mine water releases. The approaches described form the basis of best-practice protocols that are relevant at both regional and national levels.

Child↗
PubMed1999

Radon exhalation rate and uranium estimation in rock samples from Bihar uranium and copper mines using the SSNTD technique.

Widespread uranium mineralization is associated with copper, nickel and other sulphides in the Singhbhum shear zone developed at the northern margin of the Singhbhum craton in the state of Bihar of India. The south-eastern part of the shear zone between Surda-Mosabani-Badia is rich in copper mineralization while the central part between Jaduguda-Bhatin-Nimdih and Narwapahar-Garadih-Turamdih is enriched in uranium. In the present study, trace uranium concentration in geological samples from the Mosabani copper mine and the Narwapahar and Jaduguda uranium mine areas have been determined using fission track registration technique. For the measurement of the radon exhalation rate, the 'can technique' using alpha sensitive LR-115 type II plastic track detectors were used. Uranium concentrations were found to vary from 1.5 to 2097.9 ppm whereas the radon exhalation rate varied from 0.2 to 19.2 Bq m-2 h-1. The values of radon exhalation rate from crushed rock and soil samples are found to correspond with the measured values of uranium in the corresponding samples. A positive correlation has been found between radon exhalation rate and uranium concentration in the samples. The linear coefficients are found to be 0.40, 0.98 and 0.95 in the Mosabani, Narwapahar and Jaduguda mine areas respectively. High values of radon exhalation in subsurface mines like Jaduguda (depth approximately 800 m) and Mosabani (depth > 1000 m) seem to emphasize the need for adequate ventilation for the removal of radon and its progenies from the mines.

Copper↗
PubMed2002

Treatment of mine drainage using permeable reactive barrers: column experiments.

Permeable reactive barriers designed to enhance bacterial sulfate reduction and metal sulfide precipitation have the potential to prevent acid mine drainage and the associated release of dissolved metals. Two column experiments were conducted using simulated mine-drainage water to assess the performance of organic carbon-based reactive mixtures under controlled groundwater flow conditions. The simulated mine drainage is typical of mine-drainage waterthat has undergone acid neutralization within aquifers. This water is near neutral in pH and contains elevated concentrations of Fe(II) and SO4. Minimum rates of SO4 removal averaged between 500 and 800 mmol d(-1) m(-3) over a 14-month period. Iron concentrations decreased from between 300 and 1200 mg/L in the influent to between <0.01 and 220 mg/L in the columns. Concentrations of Zn decreased from 0.6-1.2 mg/L in the input to between 0.01 and 0.15 mg/L in the effluent, and Ni concentrations decreased from between 0.8 and 12.8 mg/L to <0.01 mg/L. The pH increased slightly from typical input values of 5.5-6.0 to effluent values of 6.5-7.0. Alkalinity, generally <50 mg/L (as CaCO3) in the influent, increased to between 300 and 1,300 mg/L (as CaCO3) in the effluent from the columns. As a result of decreased Fe(II) concentrations and increased alkalinity, the acid-generating potential of the simulated mine-drainage water was removed, and a net acid-consuming potential was observed in the effluent water.

Chemical Precipitation↗
PubMed1998

An integrated algal sulphate reducing high rate ponding process for the treatment of acid mine drainage wastewaters.

Acid mine drainage pollution may be associated with large water volume flows and exceptionally long periods of time over which the drainage may require treatment. While the use and role of sulphate reducing bacteria has been demonstrated in active treatment systems for acid mine drainage remediation, reactor size requirement and the cost and availability of the carbon and electron donor source are factors which constrain process development. Little attention has focussed on the use of waste stabilisation ponding processes for acid mine drainage treatment. Wastewater ponding is a mature technology for the treatment of large water volumes and its use as a basis for appropriate reactor design for acid mine drainage treatment is described including high rates of sulphate reduction and the precipitation of metal sulphides. Together with the co-disposal of organic wastes, algal biomass is generated as an independent carbon source for SRB production. Treatment of tannery effluent in a custom-designed high rate algal ponding process, and its use as a carbon source in the generation and precipitation of metal sulphides, has been demonstrated through piloting to the implementation of a full-scale process. The treatment of both mine drainage and zinc refinery wastewaters are reported. A complementary role for microalgal production in the generation of alkalinity and bioadsorptive removal of metals has been utilised and an Integrated 'Algal Sulphate Reducing Ponding Process for the Treatment of Acidic and Metal Wastewaters' (ASPAM) has been described.

Acids↗
PubMed2002

Environmental impact assessment of the mining and concentration activities in the Kola Peninsula, Russia by multidate remote sensing.

On the Kola Peninsula, the mining and concentration industry exerts anthropogenic impact on the environment. Tailing dumps cause airborne pollution through dusting, and waterborne pollution due to direct dumping and accidental releases. The objectives were: (1) to analyse multidate satellite images for 1964-1996 to assess the environmental pollution from the mining and concentration activity in the Kola in temporal perspective; (2) to evaluate remote sensing methods for integrated environmental impact assessment. The area of mining and industrial sites steadily expands and amounted to 94 km2 in 1996. The polluted water surface amounted to at least 150 km2 through dumping in 1978 and to 106 km2 in 1986 due to dusting. Thus, the impact from the mining and concentration activity should be reconsidered as more significant than it was officially anticipated. In the past the main mechanism of pollution was direct dumping into the lakes. Currently and in future, airborne pollution after dusting storms will dominate. The effective recultivation of the tailing dumps will be a long-term process. For effective assessment of impacts from the mining and concentration industry, remote sensing methods should be complemented by in-situ measurements, fieldwork, and mathematical modelling.

Air Pollutants↗
PubMed1980

Stomach cancer mortality in Worksop and other Nottinghamshire mining towns.

Mortality from stomach cancer was examined over the period 1958-75 on Workshop and 5 other nearby mining towns, and in 4 non-mining towns in Nottinghamshire. For each town, expected numbers of deaths at national rates were adjusted to allow for local/national differences in social-class distribution and number of miners, since mortality is known to be high nationally among miners and miners' wives, and to vary markedly with social class. After adjustment, the stomach-cancer Standardized Mortality Ratios (SMRs) for the aggregate of mining towns were 92 for men and 104 for women. For the non-mining towns equivalent SMRs were 91 and 86, and mortality was markedly low at ages under 65 for both sexes. Mortality in Workshop was not significantly raised, and appeared similar to that elsewhere in the mining towns. This result does not support the earlier finding by others that stomach-cancer mortality in the town was significantly raised, nor the accompanying suggestion of an association with the high nitrate content of the local drinking water via the action of nitrosamines.

Adolescent↗
PubMed2004

The impact of a disused mine on uranium transport in the River Fal, South West England.

Unfiltered and filtered (0.45 and 0.2 microm) water samples and sediment samples (sieved to <180 microm and 180-1000 microm) were collected along an approximately 15 km transect of the River Fal, Cornwall, UK, to examine the impact of the disused South Terras uranium mine on the uranium concentrations of the river water and underlying sediments. The uranium concentration of the water samples fluctuated along the river, with the 0.45 microm filtered water showing the largest, seven-fold, difference between minimum (0.19 microg L(-1)) and maximum (1.34 microg L(-1)) concentrations. The historical uranium mine and spoil heaps were not a significant source of uranium to the river water, as water concentrations were low next to the site, but a highly elevated uranium concentration (1000 mg kg(-1)) was found in sediment below an outflow pipe from this mine. Operationally defined "colloidal" (0.2-0.45 microm) and "dissolved" (<0.2 microm) uranium were the predominant forms of the element in the river water (35 and 45% respectively). The uranium concentration in the dissolved phase showed a correlation coefficient of 0.83 (n= 9) with the total cation concentration, suggesting that the uranium concentration in this fraction is directly linked to weathering of rocks and minerals. The observation that weathering is the dominant mechanism delivering uranium to the river water explains the low uranium concentrations in the river water close to South Terras mine, despite the proximity of the spoil heaps, and the maximum uranium concentrations close to a china clay mining area.

England↗
PubMed2003

Mediation of arsenic oxidation by Thiomonas sp. in acid-mine drainage (Carnoulès, France).

AIMS: To isolate, identify, and characterize heterotrophic bacteria in acid-mine drainage that mediate oxidation of As(III). METHODS AND RESULTS: Samples of acid-mine drainage were collected over a period of 14 months. Heterotrophic and non-obligatory acidophilic bacteria in the samples were cultured on a solid medium (pH 7.0-7.2), and three strains were isolated. The three different strains belong to the genus Thiomonas, and have more than 99% homology with the group Ynys1. Culturing in mineral media demonstrated that the isolated strains used thiosulphate as an energy source, and oxidized iron in the presence of thiosulphate. However, none of the strains were able to oxidize arsenic in the presence of thiosulphate, nor could they use iron or arsenic alone as an energy source. In vitro experiments demonstrated that two of the Thiomonas strains were able to oxidize more than 90% of the As(III) present in the acid-mine drainage, whereas no abiotic oxidation of arsenic occurred. CONCLUSIONS: Two strains of newly identified Thiomonas sp. found in acid-mine drainage are capable of oxidizing arsenic. SIGNIFICANCE AND IMPACT OF STUDY: These results represent the first reported oxidation of arsenic by Thiomonas sp. Biologically mediated oxidation and subsequent immobilization of arsenic is of great interest for the remediation of contaminated mine sites.

Arsenic↗
PubMed2003

Indigenous and contaminant microbes in ultradeep mines.

Rock, air and service water samples were collected for microbial analyses from 3.2 kilometres depth in a working Au mine in the Witwatersrand basin, South Africa. The approximately metre-wide mined zone was comprised of a carbonaceous, quartz, sulphide, uraninite and Au bearing layer, called the Carbon Leader, sandwiched by quartzite and conglomerate. The microbial community in the service water was dominated by mesophilic aerobic and anaerobic, alpha-, beta- and gamma-Proteobacteria with a total biomass concentration approximately 10(4) cells ml(-1), whereas, that of the mine air was dominated by members of the Chlorobi and Bacteroidetes groups and a fungal component. The microorganisms in the Carbon Leader were predominantly mesophilic, aerobic heterotrophic, nitrate reducing and methylotrophic, beta- and gamma-Proteobacteria that were more closely related to service water microorganisms than to air microbes. Rhodamine WT dye and fluorescent microspheres employed as contaminant tracers, however, indicated that service water contamination of most of the rock samples was < 0.01% during acquisition. The microbial contaminants most likely originated from the service water, infiltrated the low permeability rock through and accumulated within mining-induced fractures where they survived for several days before being mined. Combined PLFA and terminal restriction fragment length profile (T-RFLP) analyses suggest that the maximum concentration of indigenous microorganisms in the Carbon Leader was < 10(2) cells g(-1). PLFA, 35S autoradiography and enrichments suggest that the adjacent quartzite was less contaminated and contained approximately 10(3) cells gram(-1) of thermophilic, sulphate reducing bacteria, SRB, some of which are delta-Proteobacteria. Pore water and rock geochemical analyses suggest that these SRB's may have been sustained by sulphate diffusing from the adjacent U-rich, Carbon Leader where it was formed by radiolysis of sulphide.

Air Microbiology↗