| 1. |
- Chi Fru, Ernest, et al.
(författare)
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Cu isotopes in marine black shales record the Great Oxidation Event
- 2016
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 113:18, s. 4941-4946
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Tidskriftsartikel (refereegranskat)abstract
- The oxygenation of the atmosphere similar to 2.45-2.32 billion years ago (Ga) is one of the most significant geological events to have affected Earth's redox history. Our understanding of the timing and processes surrounding this key transition is largely dependent on the development of redox-sensitive proxies, many of which remain unexplored. Here we report a shift from negative to positive copper isotopic compositions (delta Cu-65(ERM-AE633)) in organic carbon-rich shales spanning the period 2.66-2.08 Ga. We suggest that, before 2.3 Ga, a muted oxidative supply of weathering-derived copper enriched in Cu-65, along with the preferential removal of Cu-65 by iron oxides, left seawater and marine biomass depleted in Cu-65 but enriched in Cu-63. As banded iron formation deposition waned and continentally sourced Cu became more important, biomass sampled a dissolved Cu reservoir that was progressively less fractionated relative to the continental pool. This evolution toward heavy delta Cu-65 values coincides with a shift to negative sedimentary delta Fe-56 values and increased marine sulfate after the Great Oxidation Event (GOE), and is traceable through Phanerozoic shales to modern marine settings, where marine dissolved and sedimentary delta Cu-65 values are universally positive. Our finding of an important shift in sedimentary Cu isotope compositions across the GOE provides new insights into the Precambrian marine cycling of this critical micronutrient, and demonstrates the proxy potential for sedimentary Cu isotope compositions in the study of biogeochemical cycles and oceanic redox balance in the past.
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| 2. |
- Diaz Somoano, Mercedes, et al.
(författare)
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Stable Lead Isotope Compositions In Selected Coals From Around The World And Implications For Present Day Aerosol Source Tracing
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:4, s. 1078-1085
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Tidskriftsartikel (refereegranskat)abstract
- The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Here, we report lead concentration and isotopic composition for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 μg Pb g−1, with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The 206Pb/207Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that “old Pb pollution” from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the PbIC in coals is strongly influenced by the depositional coal forming environment.
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| 3. |
- Hansson, Sophia V., 1981-
(författare)
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Incorporation and preservation of geochemical fingerprints in peat archives
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present status of the environment, including environmental problems such as heavy metal accumulation in aquatic and terrestrial ecosystems, is in part the consequence of long-term changes. Cores from peatlands and other natural archives provide us with the potential to study aspects of the atmospheric cycling of elements, such as metal pollutants, on timescales much longer than the decade or two available to us with atmospheric deposition monitoring programs. The past decade especially has seen a rapid increase in interest in the biogeochemical record preserved in peat, particularly as it relates to environmental changes (e.g. climate and pollution). Importantly, recent studies have shown that carbon dynamics, i.e., organic matter decomposition, may influence the record of atmospherically derived elements such as halogens and mercury. Other studies have shown that under certain conditions some downward movement of atmospherically deposited elements may also occur, which adds complexity to establishing reliable chronologies as well as inherent problems of estimating accurate accumulation rates of peat and past metal deposition. Thus, we still lack a complete understanding of the basic biogeochemical processes and their effects on trace element distributions. While many studies have validated the general temporal patterns of peat records, there has been a limited critical examination of accumulation records in quantitative terms. To be certain that we extract not only a qualitative record from peat, it is important that we establish a quantitative link between the archive and the few to several decades of data that are available from contemporary monitoring and research. The main objective of this doctoral thesis was to focus on improving the link between the long-term paleorecord and the contemporary monitoring data available from biomonitoring and direct deposition observations. The main research questions have therefore been: Are peat archives an absolute or relative record? And how are geochemical signals, including dating, incorporated in the peat archive? What temporal resolution is realistic to interpret by using peat cores?
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| 4. |
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| 5. |
- Kylander, Malin E., et al.
(författare)
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A rapid and reliable method for Pb isotopic analysis of peat and lichens by laser ablation-quadrupole-inductively coupled plasma-mass spectrometry for biomonitoring and sample screening
- 2007
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670. ; 582:1, s. 116-124
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- An analytical protocol for rapid and reliable laser ablation-quadrupole (LA-Q)- and multi-collector (MC-) inductively coupled plasma-mass spectrometry (ICP-MS) analysis of Pb isotope ratios (207Pb/206Pb and 208Pb/206Pb) in peats and lichens is developed. This technique is applicable to source tracing atmospheric Pb deposition in biomonitoring studies and sample screening. Reference materials and environmental samples were dry ashed and pressed into pellets for introduction by laser ablation. No binder was used to reduce contamination. LA-MC-ICP-MS internal and external precisions were <1.1% and <0.3%, respectively, on both 207Pb/206Pb and 208Pb/206Pb ratios. LA-Q-ICP-MS internal precisions on 207Pb/206Pb and 208Pb/206Pb ratios were lower with values for the different sample sets <14.3% while external precisions were <2.9%. The level of external precision acquired in this study is high enough to distinguish between most modern Pb sources. LA-MC-ICP-MS measurements differed from thermal ionisation mass spectrometry (TIMS) values by 1% or less while the accuracy obtained using LA-Q-ICP-MS compared to solution MC-ICP-MS was 3.1% or better using a run bracketing (RB) mass bias correction method. Sample heterogeneity and detector switching when measuring 208Pb by Q-ICP-MS are identified as sources of reduced analytical performance.
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| 6. |
- Kylander, Malin E., et al.
(författare)
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Lead Penetration and Leaching in a Complex Temperate Soil Profile
- 2008
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Ingår i: Environmental Science and Technology. ; 42, s. 3177-3184
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Tidskriftsartikel (refereegranskat)abstract
- The documented loss of anthropogenic Pb from soil organic horizons and its migration into the mineral soil below has raised several environmental concerns, especially over the leaching of Pb into groundwater aquifers and subsequently into other environmental compartments of the ecosystem. Here, a complex colluvial soil formed over the last 10,000 years in NW Spain is studied. The objective is to evaluate the behavior of Pb in soils, including its migration rates and the potential use of complex soils as archives of atmospheric Pb pollution. To this end, Pb concentrations and Pb isotope ratios for total soil, and for acid-extractable (0.5 M HNO3) and residual fractions were determined. We show that the acid-extractable fraction is more radiogenic than the residual one in most of the soil profile and that this relationship is reversed in the surface layers (<15 cm) where pollution is greatest. Radiogenic Pb seems to have been leached out during rock weathering and pedogenesis of the soil. Comparison with a nearby peat record of atmospheric Pb deposition over the last 8 kyears demonstrates that though signals from pollution are detected in the soil record, the soil itself does not provide an accurate reconstruction of Pb deposition. On the basis of the history of soil formation the most likely Pb migration rate is estimated at approximately 0.01 cm year−1. At this migration rate Pb would be retained in the soil column for ~20 kyear. In other words, there is no evidence for the relatively rapid movement of Pb into the soil.
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| 7. |
- Kylander, Malin E., et al.
(författare)
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Rare earth element and Pb isotope variations in a 52 kyr peat core from Lynch’s Crater (NE Queensland, Australia): Proxy development and application to paleoclimate in the Southern Hemisphere
- 2007
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Ingår i: Geochemica et Cosmochimica Acta. ; 71:4, s. 942-960
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Tidskriftsartikel (refereegranskat)abstract
- Accurate prediction of future climate scenarios is contingent on our understanding of past and present climate mechanisms. This is done in part through the reconstruction of historical climate changes using proxy records from terrestrial and marine archives. Terrestrial archives covering the Holocene and late Pleistocene are limited, most acutely in the Southern Hemisphere. Here, Rare earth elements (REE) and Pb isotopes are developed as inorganic geochemical proxies of mineral dust source changes and, by extension, climate change. Using a peat core from Lynch’s Crater in NE Queensland, Australia, we present the first long-term (c. 52 kyr) terrestrial record of atmospheric REE and Pb deposition (with the exception of four wet events which represent periods of erosion from the crater itself) in the Southern Hemisphere covering both glacial and interglacial times. Based on a combination of correlation analyses, Al and Ti normalised profiles and elemental patterns, we establish REE are immobile within the peat deposit and not subject to significant post depositional diagenetic changes (important particularly for Ce). This is vital as REE can be mobile under acid and organic rich conditions like those that can occur during the development of a peat deposit. The volcanic provinces of eastern Australia have characteristic Eu anomaly signatures, which allowed their use in a novel way to detect changes in dust source to Lynch’s Crater. Between 41,095 and 52,505 BP the deposit was under the influence of dust carried by long distance transport (>1500 km) from SE Australia. From 8525 to 40,815 BP regional sources (100–1500 km) dominated the deposited signals while between 1740 and 8390 BP the dust signal was controlled by local sources (<100 km). These findings were also confirmed by Pb isotope data. Changepoint modelling refined the timing of these changes in dust source, recognizing concurrent shifts in our tracing tools ((Eu/Eu*)PAAS and 206Pb/207Pb). These changepoints were then compared to other palaeoenvironmental records (pollen, lake levels and dune building) from eastern Australia and found to be similar. Our results demonstrate that REE and Pb isotopes are effective tools for tracing past changes in atmospheric dust sources and to the study of climate change using minerotrophic peat deposits.
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| 8. |
- Kylander, malin, et al.
(författare)
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Lead Penetration and Leaching in a Complex Temperate Soil Profile
- 2008
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Ingår i: Environmental Science & Technology. ; 42:9, s. 3177-3184
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Tidskriftsartikel (refereegranskat)abstract
- The documented loss of anthropogenic Pb from soil organic horizons and its migration into the mineral soil below has raised several environmental concerns, especially over the leaching of Pb into groundwater aquifers and subsequently into other environmental compartments of the ecosystem. Here, a complex colluvial soil formed over the last 10,000 years in NW Spain is studied. The objective is to evaluate the behavior of Pb in soils, including its migration rates and the potential use of complex soils as archives of atmospheric Pb pollution. To this end, Pb concentrations and Pb isotope ratios for total soil, and for acid-extractable (0.5 M HNO3) and residual fractions were determined. We show that the acid-extractable fraction is more radiogenic than the residual one in most of the soil profile and that this relationship is reversed in the surface layers (
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| 9. |
- Kylander, Malin, 1977-, et al.
(författare)
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Natural lead isotope variations in the atmosphere
- 2010
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Ingår i: Earth and Planetary Science Letters. - : Elsevier BV. - 0012-821X .- 1385-013X. ; 290:1-2, s. 44-53
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Tidskriftsartikel (refereegranskat)abstract
- Stable lead (Pb) isotope data from pre-contamination peat sections has the potential to contribute to our understanding of earth system processes (e.g., atmospheric circulation, erosion, volcanic activity) in the past. Key questions arise however. Can the Pb isotopes archived in peat records be used for assessing aerosol dynamics on a hemispheric scale or do they mainly reflect inputs from local soils? What natural Pb sources are important and do contributions vary over time? In order to answer these questions we have synthesized all available Pb isotope data from pre-contamination peat sections in Europe, Australia, North America and South America. We specifically examine the spatial and temporal variability of the Pb isotope records and identify regionally important trends and Pb sources. A pooling of all available pre-contamination peat data generated an average natural 206Pb/207Pb background ratio of 1.21±0.05 (2σ, n=300)(206Pb/204Pb= 18.90±0.86, 207Pb/204Pb= 15.66±0.10 and 208Pb/204Pb= 38.74±0.57, n=207). The majority of the records showed limited temporal and compositional agreement, suggesting that the peat record receives mainly inputs from local (<10 km) and/or regional (10-500 km) sources. Three-isotope plots also support local and regional control and evidence a wide natural spread at some sites, particularly those located in radiogenic geological settings. A temporally synchronous isotope excursion to values between 1.16-1.18 at sites across Europe ca 4000-3000 B.C. was detected, however. While usually associated with anthropogenic sources, there are indeed natural aerosols having 206Pb/207Pb signatures as low as 1.16 as evidenced in several peat and ice core records globally. Three-isotope plots suggest that this unlikely to be a signal of mineral dust contributions, which tend to have 206Pb/207Pb ratios ≥1.19, but rather sourced to volcanic emissions. These results stress caution when using estimates of the upper continental crust to constrain natural Pb sources in, e.g., mixing equations. Considering the strong influence from local and regional sources on Pb-containing aerosols in the peat record, the assessment of aerosol dynamics at lower latitudes is likely best achieved using a compliment of archives rather than just polar ice cores, for example.
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| 10. |
- Kylander, Malin, et al.
(författare)
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Two high resolution terrestrial records of atmospheric Pb deposition from New Brunswick, Canada, and Loch Laxford, Scotland
- 2009
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 407:5, s. 1644-1657
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Tidskriftsartikel (refereegranskat)abstract
- Environmental archives like peat deposits allow for the reconstruction of both naturally and anthropogenically forced changes in the biogeochemical cycle of Pb and the quantification of past and present atmospheric Pb pollution. Records of atmospheric Pb deposition from pre-industrial times however, are lacking. In a publication by Weiss et al. (2002) Pb isotope data measured by Q-ICP-MS and TIMS, concentration and enrichment data was presented for sites in eastern Canada (PeW1) and northwestern Scotland (LL7c), dating to 1586 A.D and 715 A.D., respectively. Here we re-analyse these same cores for Pb isotopes by MC-ICP-MS thereby acquiring 204Pb data and improving on the original data in terms of resolution and temporal coverage. Significant differences were found between the Q-ICP-MS/TIMS and MC-ICP-MS measurements, particularly at PeW1. These discrepancies are attributed to the problematic presence of organic matter during sample preparation and analysis compounded by the heterogeneity of the organic compounds that survived sample preparation steps. The precision and accuracy of Pb isotopes in complex matrices like peat is not always well estimated by industrial standards like NIST-SRM 981 Pb. Lead pollution histories at each site were constructed using the MC-ICP-MS data. The entire LL7c record is likely subject to some amount of anthropogenic pollution. Contributions from local mining were detected in Medieval times. Later, coal use and mining in Scotland, Wales and England became important. After industrialization (ca. 1885 A.D.) contributions from Broken Hill type ores and hence, leaded petrol, dominate atmospheric Pb signatures right up to modern times. At PeW1 anthropogenic impacts are first distinguishable in the late 17th century with the mining and use of local coal. After industrialization (ca. 1810 A.D.), coal and petrol are the main Pb sources. A comprehensive estimate of the natural atmospheric background 206Pb/207Pb signature in eastern Canadian aerosols is made with a value of ~1.19.
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| 11. |
- Menkveld, Albert J., et al.
(författare)
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Nonstandard Errors
- 2024
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Ingår i: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Tidskriftsartikel (refereegranskat)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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| 12. |
- Muller, Joanne, et al.
(författare)
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Possible evidence for wet Heinrich phases in tropical NE Australia: The Lynch's Crater deposit
- 2008
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Ingår i: Quaternary Science Reviews. ; 27, s. 468-475
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Tidskriftsartikel (refereegranskat)abstract
- Unarguably, one of the most significant paleoclimatological discoveries of the last two decades has been that of abrupt climate events (Dansgaard-Oeschger cycles and Heinrich events). Most evidence for these events has originated from the high-latitude Northern Hemisphere, with few records documenting the response of the low latitude Southern Hemisphere. Here we present new data from Lynch's Crater, a unique terrestrial record from NE-Australia that may show evidence for southward propagations of the Intertropical Convergence Zone (ITCZ) during abrupt climate perturbations as a result of alteration of the low latitude air masses. Proxies for precipitation/wetness indicate enhanced rainfall in the region during Heinrich events (H events 1-3) and the 8.2 ka Northern Hemisphere cold event. A fully coupled atmosphere/ocean climate model simulating a 1 Sv freshwater influx to the North Atlantic Ocean produces a scenario which agrees with the climate changes shown by the Lynch's Crater record. The model shows precipitation anomalies that include a southward migration of the ITCZ and a zonal shift in mid-latitude storm tracks over the Southern Hemisphere equatorial region. These data indicate large-scale shifts of the austral summer ITCZ position that is known to control monsoonal precipitation in NE Australia. This terrestrial record from Australia may demonstrate the involvement of the tropical western Pacific Ocean in ITCZ migrations during abrupt climate events of the last glacial period. Defining such past migrations offers insight into the importance and role of the equatorial region in global climate dynamics.
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| 13. |
- Muller, Joanne, et al.
(författare)
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The use of principle component analyses in characterising trace and major elemental distribution in a 55 kyr peat deposit in tropical Australia: Implications to paleoclimate
- 2008
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Ingår i: Geochimicia et Cosmochimica Acta. ; 72, s. 449-463
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Tidskriftsartikel (refereegranskat)abstract
- The Lynch's Crater peat deposit in NE-Australia is a sensitive environmental archive located in the tropical Southern Hemisphere. This unique deposit illustrates that local and regional changes had a profound effect on the local Australian ecosystem over the past 55 kyr. To obtain a proxy of past climate changes, trace and major element geochemistry analyses were applied to a 13 m peat core from the crater. Principle component analysis (PCA) was used to identify the main factors that control elemental distribution in the peat and to add interpretative strength to the geochemical behavior of selected major and trace elements. For example, Sc, Al, Cu, and Pb were found to be related to increased erosion of the basin soils, and from this, several periods of significant flux from atmospheric input and/or terrigenous run-off were identified. Geochemically mobile elements during rock weathering and pedogenesis, such as Mg, Ca, and Sr helped to identify the peat ombrotrophic-minerotrophic boundary at ~1.5 m depth and offered important information about fluxes of these nutrients to the mire and their dynamics within the deposit. Arsenic and V comparisons between the peat record (high concentrations in some peat sections) and in local basin rocks (very low concentrations), suggested the presence of a long range, atmospheric dust source early in the formation of the mire. The Lynch's Crater peat record presents a continuous record of environmental change in tropical Australia and contributes new understanding to geochemical processes in peatlands.
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| 14. |
- Rauch, Sebastien, 1971, et al.
(författare)
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Anthropogenic Forcings on the Surficial Osmium Cycle
- 2010
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 44:3, s. 881-887
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Tidskriftsartikel (refereegranskat)abstract
- Osmium is among the least abundant elements in the Earth's continental crust. Recent anthropogenic Os contamination of the environment from mining and smelting activities, automotive catalytic converter use, and hospital discharges has been documented. Here we present evidence for anthropogenic overprinting of the natural Os cycle using a ca. 7000-year record of atmospheric Os deposition and isotopic composition from an ombrotrophic peat bog in NW Spain. Preanthropogenic Os accumulation in this area is 0.10 +/- 0.04 ng m(-2) y(-1). The oldest strata showing human influence correspond to early metal mining and processing on the Iberian Peninsula (ca. 4700-2500 cal. BP). Elevated Os accumulation rates are found thereafter with a local maximum of 1.1 ng m(-2) y(-1) during the Roman occupation of the Iberian Peninsula (ca. 1930 cal. BP)and a further increase starting in 1750 AD with Os accumulation reaching 30 ng m(-2) y(-1) in the most recent samples. Osmium isotopic composition (Os-187/Os-188) indicates that recent elevated Os accumulation results from increased input of unradiogenic Os from industrial and automotive sources as well as from enhanced deposition of radiogenic Os through increased fossil fuel combustion and soil erosion. We posit that the rapid increase in catalyst-equipped vehicles, increased fossil fuel combustion, and changes in land-use make the changes observed in NW Spain globally relevant.
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| 15. |
- Rodríguez, Nathalie Pérez
(författare)
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Biotic and abiotic isotope fractionation of copper and iron : From the lab to the field scale
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The distribution of the stable isotopes of Cu and Fe in nature is susceptible to isotope fractionation processes during the biogeochemical cycle. Since Cu and Fe are redox sensitive metals, differences in their oxidation states can lead to variations in the stable isotope composition of the aquatic species or compounds that they form. Stable isotopes of Cu and Fe have recently been used to trace metal redox cycles, nutrient pathways, metal contaminant sources and to develop isotopic biosignatures. The objective of this project was to study the geochemical processes governing the isotopic fractionation of Cu and Fe in mine impacted sites, including processes related to mineral processing. One of the key questions was to explain the role of bacteria in the variations of the isotopic composition of Cu and Fe. First, bioleaching and electroleaching of a chalcopyrite concentrate were performed. During the chalcopyrite leaching in both experiments the first release of Cu to the leachate is enriched in the heavier Cu isotope as a product of oxidative dissolution. At the later stages of leaching, the δ65Cu values for the leachate are similar to the initial material, confirming an equilibrium fractionation in a closed system. In the case of Fe isotope fractionation the dissolution of pyrite at redox potentials higher than 600mV leads to an enrichment of the heavier Fe isotope in the leachate in the bioleaching experiment, mainly regulated by the formation of secondary minerals such as jarosite. Soil bacteria were studied in three different experimental scales using pot, lysimeters and field experiments, amended with autochthonous plant growth promoting bacteria. Roots and plants from pots showed no variation in their Fe and Cu isotope composition compared to non-amended samples. However, plants growing in the amended substrates regardless of their experimental scale, showed variations in the Fe and Cu isotope composition of their roots with an increase in the heavier Cu isotope. Siderophores released either by bacteria or the plant can complexate available Cu and Fe in the soil, causing a change in the isotope fractionation of those metals. The second question is related to the biogeochemical cycle of Cu and Fe. In mine tailings the sulphide oxidation resulted in an enrichment of the lighter Cu isotope in secondary phases in the oxidized zone of the tailings compared to the original isotope composition in the unoxidised mineral. Precipitation of covellite at the oxidation front of the tailings profile resulted in a significant enrichment of the lighter Cu isotope in the bulk soil with a δ65Cu value as low as -4.35 ±0.02 ‰. Fe isotope fractionation in the Kristineberg test cell varied due to processes such as Fe(II)-Fe(III) equilibrium and precipitation of Fe-(oxy)hydroxides at the oxidation front, where δ56Fe values were higher than in the initial material. As a way to link the obtained results from this thesis, a self-restored mine site was studied. A variation towards higher δ65Cu values was seen from rocks, to water and biofilms. Cu absorption mainly by extrapolymeric substances and secondary mineral precipitation regulates the isotopic composition of the biofilm. Oxidative weathering of sulphide minerals and further precipitation of Fe-(oxy)hydroxides are considered to be the main causes for Fe isotope fractionation in this area. Summing up, this thesis provides several field studies to corroborate the data observed in the lab regarding processes that are important for the biogeochemical cycling of metals and could be further applied to the extraction of metals or for remediation purposes.
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| 16. |
- Weiss, Dominik J., et al.
(författare)
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The environmental geochemistry of lead
- 2007
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Ingår i: Advances in Earth Science. - : Imperial College Press. - 9781860947612 ; , s. 344-
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Bokkapitel (refereegranskat)abstract
- The global biogeochemical cycles of several trace metals are presently dominated by human activities, a result of the nature and magnitude of historical resource consumption. Lead has been mined since ancient times, often as a by-product of silver extraction, and has one of the longest associations with man of all heavy metals [Nriagu, 1983]. As of 1983, human activities accounted for an estimated 97% of the global mass balance of lead [Nriagu and Pacyna, 1988]. At that time as well as today, most of the lead was derived from leaded gasoline [Nriagu, 1990], where it was used as an anti-knock agent.New estimates of anthropogenic sources of lead suggest that the overall burden of anthropogenic lead emissions has decreased but new pollution sources (e.g., China, Mexico) have become important [Pacyna and Pacyna, 2001; Pacyna et al., 1995] leaving anthropogenic Pb emission to remain a global problem and leaded gasoline as the main source. In addition, as metals are not biodegradable, the Pb in the environment has accumulated over the decades and its fate and pathways within the ecosystem need to be investigated.In a manner similar to chlorofluorocarbons and radionuclides derived from atomic testing, the release of lead into the environment represents an inadvertent geochemical tracer experiment, providing new insights into its fate and transport within marine and terrestrial systems. There have been several review papers and books discussing lead, its historical place in society and its impact on human and environmental health [Boutron, 1995; Needleman, 1997; Nriagu, 1983; Nriagu, 1989b; Nriagu, 1990; Reuer and Weiss, 2002; Shotyk and Le Roux, 2005; Weiss et al., 1999] and the reader is encouraged to refer to these works as well.
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