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- Karlsson, Lovisa, 1989-, et al.
(författare)
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Release of metals from unprocessed and processed black shale due to natural weathering
- 2013
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Ingår i: Reliable Mine Water Technology. Volume 1. - Colorado, USA : IMWA. - 9780615793856 ; , s. 391-397
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Konferensbidrag (refereegranskat)abstract
- Black shale was mined and processed for recovery of hydrocarbons in Kvarntorp, some 200 km SW of Stockholm, Sweden, during 1942–66. Remains from the mining period is a deposit with 40 Mm³ of crushed shale residues: Unprocessed 3ne-grained shale as well as processed shale. The deposit is still hot; oxidation of sulphides as well as burning of hydrocarbons are still in progress some 50 years a1er closure. Weathering of the shale leads to releases of metal-rich leachates which will increase with time. The release of metals from pristine shale as well as weathered shale (exposed to the atmosphere for 50 years) and two di2erent processed shale residues have been studied using water of di2erent pH as leaching solution, to simulate extreme pH-variations in environmental waters: 3.0 (determined by oxidation of iron sulphides), 5.5 (bu2ered by carbon dioxide), 8.5 (bu2ered by calcite) and 12.5 (bu2ered by calcium hydroxide). Extraction of cationic elements was substantial (several percent of the total content) for Ca and Mg, as well as Ni, Co and U at pH 3, and very high (up to 50–60 %) for anionic elements (V, Mo, As) at pH 12.5. Especially the high-temperature processed shale would be a potential source for As and Mo at high pH. The pH-dependence of the weathering processes should be considered when future remediation (or metal recovery) processes and strategies are designed.
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- Karlsson, Stefan, 1957-, et al.
(författare)
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Water quality in a black shale mining area : effects of pH and natural organic acids on weathering and subsequent metal releases
- 2014
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Ingår i: An Interdisciplinary Response to Mine Water Challenges. - : China University of Mining and Techno logy Press. - 9787564624378 ; , s. 136-136
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Konferensbidrag (refereegranskat)abstract
- Mining of black shale (alum shale) of Late Cambrium age for the extraction of alum started in the early 17th century in Sweden, and in the late 19th century there was an extensive use of shale, with its high content of organic carbon, as fuel in lime-burning processes. Full-scale recovery of hydrocarbons from shale took place in Kvarntorp during 1942-66, and recovery of uranium in Ranstad during 1965-76. Remains from the historic mining and processing of black shale are some 50 major deposits with processed and unprocessed shale residues, as well as water-filled pits, at the former mining sites. There are also large areas covered with crushed shale, e.g. as road filling material. Studies of the weathering of shale due to exposure to the atmosphere and water with pH within the natural range indicate a high leachability of cationic elements at low pH, as well as anionic elements at high pH. The presence of organic complexing acids of natural origin (microbial exudates and humic acids) may give an enhanced leaching, particularly at pH above 8, when hydroxy-groups would constitute active metal binding sites. Results from studies of weathering and leaching of processed and unprocessed black shale are presented, as well as the effects on the water quality observed at former mining sites and related environmental impact.
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- Rai, Neha, 1985-, et al.
(författare)
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Metal contaminated soil leachates from an art glass factory elicit stress response, alter fatty acid metabolism and reduce lifespan in Caenorhabditis elegans
- 2019
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 651, s. 2218-2227
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Tidskriftsartikel (refereegranskat)abstract
- The present study evaluated the toxicity of metal contamination in soils from an art glass factory in Smaland Sweden using a Caenorhabditis elegans nematode model. The aim of the study was to chemically analyze the soil samples and study the biological effects of water-soluble leachates on the nematodes using different physiological endpoints. The total metal content showed that As, Cd and Pb were at levels above the guideline values for soils in areas around the factory. Less than 10% of the total metal content in the soil was found in the water-soluble leachates, however, Al, As, Fe and Pb remained higher than the guideline values for safe drinking water. Exposure of C. elegans to the water-soluble leachates, at both post-hatching larvae stage (L1-young adult) for 48 h and at the young adult stage (L4) for 6 h, showed significant gene alteration. Although the nematodes did not exhibit acute lethality, lifespan was significantly reduced upon exposure. C. elegans also showed altered gene expression associated with stress response and fat metabolism, as well as enhanced accumulation of body fat. The study highlighted the significance of assessing environmental samples using a combination of gene expression analysis, fatty acid metabolism and lifespan for providing valuable insight into the negative impact of metals. The altered fat metabolism and reduced lifespan on exposure to soil leachates motivates further studies to explore the mechanism of the toxicity associated with the metals present in the environment.
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- Sjöberg, Viktor, et al.
(författare)
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Bioleaching of shale : impact of carbon source
- 2011
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Ingår i: The new uranium mining boom. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642221217 ; , s. 449-454
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Konferensbidrag (refereegranskat)abstract
- Bioleaching is often used for processing low-grade shale feedstock and the microbial community used for that purpose is supplied with nutrients such as sugar and/or Fe2+. In the present study, the leaching efficiency was tested when crushed weathered shale was mixed with aspen wood shavings and kept moist, at the mixtures field capacity. The purpose was to investigate whether a more complex carbon source and a lower content of water may be a feasible way of lowering the cost for bioleaching. After 56 days of incubation the amount of uranium mobilized from the shale reached some 1.7% with a minimum of effort and cost.
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- Allard, Bert, 1945-, et al.
(författare)
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Black shale : a biogeochemical archive
- 2014
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Ingår i: Sedimentary Pore Space Cementation: Role of Microbes. ; , s. 6-
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Konferensbidrag (refereegranskat)
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