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Author (up) Pacheco, F.A.L.; Szocs, T.
Title “Dedolomitization reactions” driven by anthropogenic activity on loessy sediments, SW Hungary Type Journal Article
Year 2006 Publication Applied Geochemistry Abbreviated Journal
Volume 21 Issue 4 Pages 614-631
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Abstract In the Szigetvár area, SW Hungary, shallow groundwaters draining upper Pleistocene loess and Holocene sediments are considerably contaminated by domestic effluents and leachates of farmland fertilizers. The loess contains calcite and dolomite, but gypsum was not recognized in these sediments. The anthropogenic inputs contain significant amounts of Ca and SO4. The Ca from these anthropogenic inputs is promoting calcite growth, with concomitant consumption of carbonate alkalinity, undersaturation of the system with respect to dolomite, and dolomite dissolution; in brief, is driving “dedolomitization reactions”. Geochemical arguments supporting the occurrence of “dedolomitization reactions” in the area are provided by the results of mass balance and thermodynamic analyses. The mass balances predicted the weather sequence dolomite\textgreatercalcite\textgreaterplagioclase\textgreaterK-feldspar, at odds with widely accepted sequences of weatherability where calcite is the first mineral in the weathering sequence. The exchange between calcite and dolomite can be a side effect of “dedolomitization reactions” because they cause precipitation of calcite. The thermodynamic prerequisites for “dedolomitization reactions” are satisfied by most local groundwaters (70%) since they are supersaturated (or in equilibrium) with respect to calcite, undersaturated (or in equilibrium) with respect to dolomite, and undersaturated with respect to gypsum. The Ca vs. SO4 and Mg vs. SO4 trends are also compatible with homologous trends resulting from “dedolomitization reactions”.
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ISSN 0883-2927 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Pacheco2006 Serial 35
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Author (up) Panagopoulos, G.
Title Application of major and trace elements as well as boron isotopes for tracing hydrochemical processes: the case of Trifilia coastal karst aquifer, Greece Type Journal Article
Year 2009 Publication Environmental Geology Abbreviated Journal
Volume 58 Issue 5 Pages 1067-1082
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Language Summary Language Original Title
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ISSN 0943-0105 ISBN Medium
Area Greece Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Panagopoulos2009 Serial 36
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Author (up) Park, H.; Schlesinger, W.
Title Global biochemical cycle of boron Type Journal Article
Year 2002 Publication Global Biogeochemical Cycles Abbreviated Journal
Volume 16 Issue Pages 1072
Keywords
Abstract The global Boron (B) cycle is primarily driven by a large flux (1.44 Tg B/yr) through the atmosphere derived from seasalt aerosols. Other significant sources of atmospheric boron include emissions during the combustion of biomass (0.26-0.43 Tg B/yr) and coal, which adds 0.20 Tg B/yr as an anthropogenic contribution. These known inputs to the atmosphere cannot account for the boron removed from the atmosphere during rainfall (3.0 Tg B/yr) and estimated dry deposition (1.3-2.7 Tg B/yr). In addition to atmospheric deposition, rock weathering is a source of boron (0.19 Tg B/yr) for terrestrial ecosystems, and humans mine about 0.31 Tg B/yr from the Earth's crust. More than 4.8 Tg B/yr circulates in the biogeochemical cycle of land plants, and about 0.53-0.63 Tg B/yr is carried from land to sea by rivers. The biogeochemical cycle of boron in the sea includes 4.4 Tg B/yr circulating in the marine biosphere, and an annual loss of 0.47 Tg B/yr to the oceanic crust via a variety of sedimentary processes that collectively remove only a small fraction of the total annual inputs to the oceans. Thus with our current understanding of the global biogeochemistry of B, the atmospheric budget shows outputs > inputs, while the marine compartments show inputs > outputs. Despite these uncertainties, it is clear that the human perturbation of the global B cycle has more than doubled the mobilization of B from the crust and contributes significantly to the B transport in rivers.
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Call Number THL @ luqianxue.zhang @ article Serial 94
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Author (up) Pearce, C.R.; Parkinson, I.J.; Gaillardet, J.; Chetelat, B.; Burton, K.W.
Title Characterising the stable (δ88/86Sr) and radiogenic (87Sr/86Sr) isotopic composition of strontium in rainwater Type Journal Article
Year 2015 Publication Chemical Geology Abbreviated Journal
Volume 409 Issue Pages 54-60
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Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
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Notes Approved no
Call Number THL @ luqianxue.zhang @ pearce2015characterising Serial 96
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Author (up) Petelet-Giraud, E.; Négrel, P.; Aunay, B.; Ladouche, B.; Bailly-Comte, V.; Guerrot, C.; Flehoc, C.; Pezard, P.; Lofi, J.; Dörfliger, N.
Title Coastal groundwater salinization: Focus on the vertical variability in a multi-layered aquifer through a multi-isotope fingerprinting (Roussillon Basin, France) Type Journal Article
Year 2016 Publication Science of The Total Environment Abbreviated Journal
Volume 566-567 Issue Pages 398-415
Keywords Groundwater salinization, Coastal aquifer, Roussillon Basin, Isotopes, Westbay System, Barcarès and Canet sites
Abstract The Roussillon sedimentary Basin (South France) is a complex multi-layered aquifer, close to the Mediterranean Sea facing seasonally increases of water abstraction and salinization issues. We report geochemical and isotopic vertical variability in this aquifer using groundwater sampled with a Westbay System® at two coastal monitoring sites: Barcarès and Canet. The Westbay sampling allows pointing out and explaining the variation of water quality along vertical profiles, both in productive layers and in the less permeable ones where most of the chemical processes are susceptible to take place. The aquifer layers are not equally impacted by salinization, with electrical conductivity ranging from 460 to 43,000μS·cm−1. The δ2H–δ18O signatures show mixing between seawater and freshwater components with long water residence time as evidenced by the lack of contribution from modern water using 3H, 14C and CFCs/SF6. S(SO4) isotopes also evidence seawater contribution but some signatures can be related to oxidation of pyrite and/or organically bounded S. In the upper layers 87Sr/86Sr ratios are close to that of seawater and then increase with depth, reflecting water–rock interaction with argillaceous formations while punctual low values reflect interaction with carbonate. Boron isotopes highlight secondary processes such as adsorption/desorption onto clays in addition to mixings. At the Barcarès site (120m deep), the high salinity in some layers appear to be related neither to present day seawater intrusion, nor to Salses-Leucate lagoonwater intrusion. Groundwater chemical composition thus highlights binary mixing between fresh groundwater and inherited salty water together with cation exchange processes, water–rock interactions and, locally, sedimentary organic matter mineralisation probably enhanced by pyrite oxidation. Finally, combining the results of this study and those of Caballero and Ladouche (2015), we discuss the possible future evolution of this aquifer system under global change, as well as the potential management strategies needed to preserve quantitatively and qualitatively this water resource.
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ISSN 0048-9697 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Peteletgiraud2016398 Serial 181
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