Thomas Barlow - Academia.edu (original) (raw)

Papers by Thomas Barlow

Research paper thumbnail of Determining constraints imposed by salt fabrics on the morphology of solution-mined energy storage cavities, through dissolution experiments using brine and seawater in halite

Quarterly Journal of Engineering Geology and Hydrogeology, 2018

Large-scale compressed air ene using solution-mined caverns in salt lithologies. For optimum gas ... more Large-scale compressed air ene using solution-mined caverns in salt lithologies. For optimum gas storage efficiency, cavern geometry should ideally be smooth: spherical to cylindrical with a circular cross-section. However, such caverns are often irregular with marked asymmetry or ellipticity, and whilst the reasons for non-circular crosssections developing during solution-mining in some caverns can be related to e.g. the presence of interbedded lithologies, in other instances they are not fully understood. Cavities from dissolution experiments using five main end-member salt facies fabrics from the Triassic Preesall and Northwich Halite formations have been assessed to determine factors affecting cavity geometry, formation and variability in dissolution behaviour. Identical sets of experiments were performed on each fabric type, using two solution concentration strengths: brine and synthetic seawater. Comparison of experimental results using a combination of analytical and imaging techniques show the extent to which the salt fabric and enhancement of features within the salt influences the resulting dissolution cavity. Observations show a visible increase in micropores within the adjacent halite matrix following dissolution. Smaller-scale features provide further insights into the dissolution processes, and salt fabric behaviour under different dissolution conditions.

Research paper thumbnail of Long-term CO2 injection and its impact on near-surface soil microbiology

FEMS microbiology ecology, Dec 8, 2016

Impacts of long-term CO2 exposure on environmental processes and microbial populations of near su... more Impacts of long-term CO2 exposure on environmental processes and microbial populations of near surface soils are poorly understood. This near-surface long-term CO2 injection study demonstrated that soil microbiology and geochemistry is influenced more by seasonal parameters than elevated CO2 Soil samples were taken during a three-year field experiment including sampling campaigns before, during and after 24 months of continuous CO2 injection. CO2 concentrations within CO2-injected plots increased up to 23% during the injection period. No CO2 impacts on geochemistry were detected over time. In addition, CO2-exposed samples did not show significant changes in microbial CO2 and CH4 turnover rates compared to reference samples. Likewise, no significant CO2-induced variations were detected for the abundance of Bacteria, Archaea (16S rDNA) and gene copy numbers of the mcrA gene, Crenarchaeota and amoA gene. The majority (75-95%) of the bacterial sequences were assigned into five phyla: Fi...

Research paper thumbnail of Investigations of alleged CO 2 leakage in Weyburn, Canada in the context of longer term surface gas monitoring

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of New and established techniques for surface gas monitoring at onshore CO2 storage sites

Energy Procedia, 2009

New methods for the monitoring of CO 2 near the ground surface at geological CO 2 storage sites h... more New methods for the monitoring of CO 2 near the ground surface at geological CO 2 storage sites have been tested over areas of natural CO 2 emission. Mobile open path laser measurements and ground-surface portable infrared measurements show great promise for rapid assessment of large areas. Such techniques would help to focus more detailed investigations needed to verify the extent and source of the gas being emitted. It is envisaged that they would be used in conjunction with established field and laboratory techniques and continuous monitoring methods as part of an overall monitoring strategy for a CO 2 storage site.

Research paper thumbnail of Optimisation of plutonium separations using TEVA cartridges and ICP-MS/MS analysis for applicability to large-scale studies in tropical soils

Analytical Methods

The optimisation of a TEVA column separation provides a simple, robust, and cost-effective method... more The optimisation of a TEVA column separation provides a simple, robust, and cost-effective method with low achievable detection limits, applicable to the detection of ultra-trace fallout Pu in African soils.

Research paper thumbnail of Arsenic speciation of sediments from the Thames estuary, London, UK

Research paper thumbnail of Comparison of the impacts of elevated CO2 soil gas concentrations on selected European terrestrial environments

International Journal of Greenhouse Gas Control, 2015

Selected European studies have illustrated the impacts of elevated CO 2 concentrations in shallow... more Selected European studies have illustrated the impacts of elevated CO 2 concentrations in shallow soils on pasture. For the first time, general unified conclusions can be made, providing CO 2 thresholds where effects on plants and soil microbiology are observed and making recommendations on how this information can be used when planning projects for CO 2 storage. The sites include those where CO 2 is being naturally released to the atmosphere from deep geological formations; and a non-adapted site, with no previous history of CO 2 seepage, where CO 2 has been injected into the unsaturated soil horizon. Whilst soil gas concentrations will be influenced by flux rates and other factors, the results suggest that a concentration of between 10-15% CO 2 soil gas at 20 cm depth, which is within the root zone, is an important threshold level for observing changes in plant coverage. Site-specific plant 'indicators' are also observed for CO 2 concentrations at ≥35%. Microbiological changes are seen where CO 2 soil gas concentrations are between 15-40%. As part of site characterisation, an evaluation of the risks of leakage and their potential environmental impacts should be undertaken.

Research paper thumbnail of Organic pollutants, heavy metals and toxicity in oil spill impacted salt marsh sediment cores, Staten Island, New York City, USA

Marine Pollution Bulletin, 2020

Research paper thumbnail of Soil type influences crop mineral composition in Malawi

Science of The Total Environment, 2015

Plant samples collected across Malawi and analysed for elemental composition. • Higher concentrat... more Plant samples collected across Malawi and analysed for elemental composition. • Higher concentrations of Ca, Se and Zn in cereal grains from calcareous soils. • Soil dust contributed 77% and 34% of Fe in leaf and grain samples, respectively. • Nationally, average dietary supplies of Ca, Se and Zn are inadequate; Cu, Fe, Mg adequate. • Estimated risks of Ca, Se and Zn deficiency lower in areas of calcareous soils.

Research paper thumbnail of Exposure of burrowing mammals to 222Rn

Science of The Total Environment, 2012

Estimates of absorbed dose rates to wildlife from exposure to natural background radionuclides ar... more Estimates of absorbed dose rates to wildlife from exposure to natural background radionuclides are required to put estimates of dose rates arising from regulated releases of radioactivity and proposed benchmarks into context. Recent review papers have estimated dose rates to wildlife from (40)K, and (238)U and (232)Th series radionuclides. However, only one study previous has considered the potential dose rates to burrowing animals from inhaled (222)Rn and its daughter products. In this paper we describe a study conducted at seven sites in northwest England. Passive track etch detectors were used to measure the (222)Rn concentrations in artificial burrows over a period of approximately one year. Results suggest that absorbed dose rates to burrowing mammals as a consequence of exposure to (222)Rn are likely to be at least an order of magnitude higher than those suggested in previous evaluations of natural background exposure rates which had omitted this radionuclide and exposure pathway. Dose rates in some areas of Great Britain will be considerably in excess of incremental no-effects benchmark dose rates suggested for use as screening levels. Such advised benchmark dose rates need to be better put into context with background dose rates, including exposure to (222)Rn, to ensure credibility; although the context will be determined by the purpose of the benchmark and the assessment level.

Research paper thumbnail of Testing surface gas monitoring methods at sites of natural and man-made CO2 seepage in Europe

Jones, David; Lister, Bob; Barkwith, Andrew; Barlow, Thomas; Shaw, Richard; Strutt, Michael; Lomb... more Jones, David; Lister, Bob; Barkwith, Andrew; Barlow, Thomas; Shaw, Richard; Strutt, Michael; Lombardi, S.; Beaubien, S.; Annunziatellis, A.; Graziani, S.. 2011 Testing surface gas monitoring methods at sites of natural and man-made CO2 seepage in Europe. In: ...

Research paper thumbnail of Arsenic speciation in polychaetes (Annelida) and sediments from the intertidal mudflat of Sundarban mangrove wetland, India

Environmental Geochemistry and Health, 2012

This paper documents the concentration of total arsenic and individual arsenic species in four so... more This paper documents the concentration of total arsenic and individual arsenic species in four soft-bottom benthic polychaetes (Perenereis cultifera, Ganganereis sootai, Lumbrinereis notocirrata and Dendronereis arborifera) along with host sediments from Sundarban mangrove wetland, India. An additional six sites were considered exclusively for surface sediments for this purpose. Polychaetes were collected along with the host sediments and measured for their total arsenic using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Arsenic concentrations in polychaete body tissues varied greatly, suggesting speciesspecific characteristics and inherent peculiarities in arsenic metabolism. Arsenic was generally present in polychaetes as arsenate (As V ranges from 0.16-0.50 mg kg-1) or arsenite (As III ranges from 0.10-0.41 mg kg-1) (30 to 53% as inorganic As) and dimethylarsinic acid (DMA V ; <1 to 25%). Arsenobetaine (AB; <16%), and PO 4-arsenoriboside (8 to 48%) were also detected as minor constituents, whilst monomethylarsonic acid (MA V) was not detected in any of the polychaetes. The highest total As (14.7 mg kg-1 dry wt) was observed in the polychaete D. arborifera collected from the vicinity of a sewage outfall in which the majority of As was present as an uncharacterized compound (10.3 mg kg-1 dry wt) eluted prior to AB. Host sediments ranged from 2.5 to 10.4 mg kg-1 total As. This work supports the importance of speciation analysis of As, because of the ubiquitous occurrence of this metalloid in the environment, and its variable toxicity depending on chemical form. It is also the first work to report the composition of As species in polychaetes from the Indian Sundarban wetlands.

Research paper thumbnail of Erratum Geological controls on radon potential in Scotland

Scottish Journal of Geology, 2010

Research paper thumbnail of Bioaccessibility Performance Data for Fifty-Seven Elements in Guidance Material BGS 102

Microchemical Journal

BGS 102, a guidance material for bioaccessible arsenic (As) and lead (Pb), was produced during va... more BGS 102, a guidance material for bioaccessible arsenic (As) and lead (Pb), was produced during validation of the in vitro Unified Bioaccessibility Method (UBM). This paper reports a compilation of reproducible bioaccessible guidance values for fifty-five additional elements in BGS 102, providing guidance for analysts to broaden the scope of UBM analyses for a wider range of elements based on data collected over an average of 60 separate analytical batches per element. Data are presented in categories for both gastric (STOM) and gastrointestinal (STOM + INT) extraction phases, where reproducibility, measured as relative standard deviation (RSD) was; ≤ 10% RSD for 27 elements (Mg, Al, Si, P, Ca, Cr, Mn, Co, Ni, As, Rb, Sr, Y, Ba, La, Ce, Pr, Nd, Sm, Eu, Tb, Gd, Dy, Ho, Er, Tm, Yb); between 10-20% RSD for 10 elements (Li, K, V, Fe, Cu, Zn, Cd, Lu, Pb, U); and ≥ 20% RSD for 19 elements in the gastric phase (Be, B, S, Ti, Ga, Se, Zr, Nb, Mo, Ag, Sn, Sb, Cs, Hf, Ta, W, Tl, Bi, Th). Two el...

Research paper thumbnail of Using near-surface atmospheric measurements as a proxy for quantifying field-scale soil gas flux

We present a new method for deriving surface soil gas flux at the field scale, which is less fiel... more We present a new method for deriving surface soil gas flux at the field scale, which is less fieldwork intensive than traditional chamber techniques and less expensive than those derived from airborne or space surveys. The technique uses aspects of chamber and micrometeorological methods combined with a mobile platform and GPS to rapidly derive soil gas fluxes at the field-scale. There are several assumptions in using this method, which will be most accurate under stable atmospheric conditions with little horizontal wind flow. Results show that soil gas fluxes, when averaged across a field site, are highly comparable between the method presented and traditional chamber acquisition techniques. Atmospheric dilution is found to reduce the range of flux values under the open field-scale method, when compared to chamber derived results. Under ideal atmospheric conditions it may be possible to use the presented method to derive soil gas flux at an individual point, however this requires further investigation. The new method for deriving soil-atmosphere gas exchange at the field-scale could be useful for a number of applications including quantification of CCS leakage, diffuse degassing in volcanic and geothermal areas and greenhouse-gas emissions.

Research paper thumbnail of Radon-222 dose rates to burrowing mammals

Research paper thumbnail of Baseline variability in onshore near surface gases and implications for monitoring at CO2 storage sites

Energy Procedia, 2014

The measurement of gas concentrations and fluxes in the soil and atmosphere is a powerful tool fo... more The measurement of gas concentrations and fluxes in the soil and atmosphere is a powerful tool for monitoring geological carbon capture and storage (CCS) sites because the analyses are made directly in the biosphere in which we live. These methods can be used to both find and accurately quantifying leaks, and are visible and tangible data for public and ecosystem safety. To be most reliable and accurate, however, the measurements must be interpreted in the context of natural variations in gas concentration and flux. Such baseline data vary both spatially and temporally due to natural processes, and a clear understanding of their values and distributions is critical for interpreting near-surface gas monitoring techniques. The best example is CO 2 itself, as the production of this gas via soil respiration can create a wide range of concentrations and fluxes that must be separated from, and not confused with, CO 2 that may leak towards the surface from a storage reservoir. The present article summarizes baseline studies performed by the authors at various sites having different climates and geological settings from both Europe and North America, with focus given to the range of values that can result from near surface processes and how different techniques or data processing approaches can be used to help distinguish a leakage signal from an anomalous, shallow biogenic signal.

Research paper thumbnail of Effects of elevated CO2 concentrations on the vegetation and microbial populations at a terrestrial CO2 vent at Laacher See, Germany

International Journal of Greenhouse Gas Control, 2011

CO 2 capture and geological storage offers an option for reducing man-made greenhouse gas emissio... more CO 2 capture and geological storage offers an option for reducing man-made greenhouse gas emissions. But one major concern related to geological CO 2 storage is the possibility of leakage from the reservoir and subsequent effects on the environment, which cannot completely be excluded. This study aims at investigating the environmental impact of CO 2 release from reservoirs into near surface terrestrial environments. To understand the effect of CO 2 leakage on such an ecosystem, detailed knowledge on the abundance and diversity of plants and microorganisms is essential. Therefore, an ecosystem study has been conducted within the Network of Excellence "CO 2 GeoNet" on a natural CO 2 vent at the Laacher See, Germany. Near surface CO 2 conditions and CO 2 fluxes of the venting area were described by means of conventional soil gas measurement equipment, and brought up the difference between the CO 2 anomalies and their surroundings. A comparison of the soil columns between control sites and the centre of the venting area showed a small but significant change in the soil pH below 10 cm. The botanical survey revealed some remarkable vegetation changes like the investigation of important soil microbial communities showed significant differences between the CO 2-rich sites (up to 90% and more of soil gas), medium CO 2 sites (~20%), and control locations with background CO 2 concentrations. The ecosystem appears to be adapted to the different conditions through species substitution or adaptation, showing a shift towards anaerobic and acidotolerant to acidophilic species under elevated CO 2 concentrations. At the end, this ongoing study should identify possible candidates in the botanical and microbial kingdoms, whose presence or absence provide easily detectable indicators for the leakage of CO 2 from deep reservoirs into near surface terrestrial ecosystems.

Research paper thumbnail of Geological controls on radon potential in Scotland

Scottish Journal of Geology, 2009

Rn, a natural radioactive gas produced by the radioactive decay of 238 U, accounts for about 50 %... more Rn, a natural radioactive gas produced by the radioactive decay of 238 U, accounts for about 50 % of the total radiation dose to the average person in the UK. Geology is the most important factor controlling the source and distribution of radon; which has been linked to an increased risk of lung cancer. In order to prevent the public receiving high exposures to radon, it is necessary to identify those areas most at risk. We present results of new mapping of radon potential for Scotland using a method that allows the spatial variation in radon potential to be delineated both within and between geological groupings. The main geological and geochemical associations with moderate to high radon potential areas are described. The highest radon potential values in Scotland are associated with U-rich, highly evolved Siluro-Devonian biotite granite intrusions, notably those clustered within a zone to the west of Aberdeen and at Helmsdale, in Caithness. U mineralisation plays a role in areas including the Helmsdale granite and the Middle Old Red Sandstone of the Orcadian Basin. Elevated radon potential is also associated with limestones-where fracture permeability is influential-and with Ordovician-Silurian greywackes. The radon potential of unconsolidated deposits, and how this affects the radon potential of the underlying bedrock, reflects both their permeabilities and their compositions.

Research paper thumbnail of Soil type influences crop mineral composition in Malawi

Science of The Total Environment, 2015

Research paper thumbnail of Determining constraints imposed by salt fabrics on the morphology of solution-mined energy storage cavities, through dissolution experiments using brine and seawater in halite

Quarterly Journal of Engineering Geology and Hydrogeology, 2018

Large-scale compressed air ene using solution-mined caverns in salt lithologies. For optimum gas ... more Large-scale compressed air ene using solution-mined caverns in salt lithologies. For optimum gas storage efficiency, cavern geometry should ideally be smooth: spherical to cylindrical with a circular cross-section. However, such caverns are often irregular with marked asymmetry or ellipticity, and whilst the reasons for non-circular crosssections developing during solution-mining in some caverns can be related to e.g. the presence of interbedded lithologies, in other instances they are not fully understood. Cavities from dissolution experiments using five main end-member salt facies fabrics from the Triassic Preesall and Northwich Halite formations have been assessed to determine factors affecting cavity geometry, formation and variability in dissolution behaviour. Identical sets of experiments were performed on each fabric type, using two solution concentration strengths: brine and synthetic seawater. Comparison of experimental results using a combination of analytical and imaging techniques show the extent to which the salt fabric and enhancement of features within the salt influences the resulting dissolution cavity. Observations show a visible increase in micropores within the adjacent halite matrix following dissolution. Smaller-scale features provide further insights into the dissolution processes, and salt fabric behaviour under different dissolution conditions.

Research paper thumbnail of Long-term CO2 injection and its impact on near-surface soil microbiology

FEMS microbiology ecology, Dec 8, 2016

Impacts of long-term CO2 exposure on environmental processes and microbial populations of near su... more Impacts of long-term CO2 exposure on environmental processes and microbial populations of near surface soils are poorly understood. This near-surface long-term CO2 injection study demonstrated that soil microbiology and geochemistry is influenced more by seasonal parameters than elevated CO2 Soil samples were taken during a three-year field experiment including sampling campaigns before, during and after 24 months of continuous CO2 injection. CO2 concentrations within CO2-injected plots increased up to 23% during the injection period. No CO2 impacts on geochemistry were detected over time. In addition, CO2-exposed samples did not show significant changes in microbial CO2 and CH4 turnover rates compared to reference samples. Likewise, no significant CO2-induced variations were detected for the abundance of Bacteria, Archaea (16S rDNA) and gene copy numbers of the mcrA gene, Crenarchaeota and amoA gene. The majority (75-95%) of the bacterial sequences were assigned into five phyla: Fi...

Research paper thumbnail of Investigations of alleged CO 2 leakage in Weyburn, Canada in the context of longer term surface gas monitoring

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of New and established techniques for surface gas monitoring at onshore CO2 storage sites

Energy Procedia, 2009

New methods for the monitoring of CO 2 near the ground surface at geological CO 2 storage sites h... more New methods for the monitoring of CO 2 near the ground surface at geological CO 2 storage sites have been tested over areas of natural CO 2 emission. Mobile open path laser measurements and ground-surface portable infrared measurements show great promise for rapid assessment of large areas. Such techniques would help to focus more detailed investigations needed to verify the extent and source of the gas being emitted. It is envisaged that they would be used in conjunction with established field and laboratory techniques and continuous monitoring methods as part of an overall monitoring strategy for a CO 2 storage site.

Research paper thumbnail of Optimisation of plutonium separations using TEVA cartridges and ICP-MS/MS analysis for applicability to large-scale studies in tropical soils

Analytical Methods

The optimisation of a TEVA column separation provides a simple, robust, and cost-effective method... more The optimisation of a TEVA column separation provides a simple, robust, and cost-effective method with low achievable detection limits, applicable to the detection of ultra-trace fallout Pu in African soils.

Research paper thumbnail of Arsenic speciation of sediments from the Thames estuary, London, UK

Research paper thumbnail of Comparison of the impacts of elevated CO2 soil gas concentrations on selected European terrestrial environments

International Journal of Greenhouse Gas Control, 2015

Selected European studies have illustrated the impacts of elevated CO 2 concentrations in shallow... more Selected European studies have illustrated the impacts of elevated CO 2 concentrations in shallow soils on pasture. For the first time, general unified conclusions can be made, providing CO 2 thresholds where effects on plants and soil microbiology are observed and making recommendations on how this information can be used when planning projects for CO 2 storage. The sites include those where CO 2 is being naturally released to the atmosphere from deep geological formations; and a non-adapted site, with no previous history of CO 2 seepage, where CO 2 has been injected into the unsaturated soil horizon. Whilst soil gas concentrations will be influenced by flux rates and other factors, the results suggest that a concentration of between 10-15% CO 2 soil gas at 20 cm depth, which is within the root zone, is an important threshold level for observing changes in plant coverage. Site-specific plant 'indicators' are also observed for CO 2 concentrations at ≥35%. Microbiological changes are seen where CO 2 soil gas concentrations are between 15-40%. As part of site characterisation, an evaluation of the risks of leakage and their potential environmental impacts should be undertaken.

Research paper thumbnail of Organic pollutants, heavy metals and toxicity in oil spill impacted salt marsh sediment cores, Staten Island, New York City, USA

Marine Pollution Bulletin, 2020

Research paper thumbnail of Soil type influences crop mineral composition in Malawi

Science of The Total Environment, 2015

Plant samples collected across Malawi and analysed for elemental composition. • Higher concentrat... more Plant samples collected across Malawi and analysed for elemental composition. • Higher concentrations of Ca, Se and Zn in cereal grains from calcareous soils. • Soil dust contributed 77% and 34% of Fe in leaf and grain samples, respectively. • Nationally, average dietary supplies of Ca, Se and Zn are inadequate; Cu, Fe, Mg adequate. • Estimated risks of Ca, Se and Zn deficiency lower in areas of calcareous soils.

Research paper thumbnail of Exposure of burrowing mammals to 222Rn

Science of The Total Environment, 2012

Estimates of absorbed dose rates to wildlife from exposure to natural background radionuclides ar... more Estimates of absorbed dose rates to wildlife from exposure to natural background radionuclides are required to put estimates of dose rates arising from regulated releases of radioactivity and proposed benchmarks into context. Recent review papers have estimated dose rates to wildlife from (40)K, and (238)U and (232)Th series radionuclides. However, only one study previous has considered the potential dose rates to burrowing animals from inhaled (222)Rn and its daughter products. In this paper we describe a study conducted at seven sites in northwest England. Passive track etch detectors were used to measure the (222)Rn concentrations in artificial burrows over a period of approximately one year. Results suggest that absorbed dose rates to burrowing mammals as a consequence of exposure to (222)Rn are likely to be at least an order of magnitude higher than those suggested in previous evaluations of natural background exposure rates which had omitted this radionuclide and exposure pathway. Dose rates in some areas of Great Britain will be considerably in excess of incremental no-effects benchmark dose rates suggested for use as screening levels. Such advised benchmark dose rates need to be better put into context with background dose rates, including exposure to (222)Rn, to ensure credibility; although the context will be determined by the purpose of the benchmark and the assessment level.

Research paper thumbnail of Testing surface gas monitoring methods at sites of natural and man-made CO2 seepage in Europe

Jones, David; Lister, Bob; Barkwith, Andrew; Barlow, Thomas; Shaw, Richard; Strutt, Michael; Lomb... more Jones, David; Lister, Bob; Barkwith, Andrew; Barlow, Thomas; Shaw, Richard; Strutt, Michael; Lombardi, S.; Beaubien, S.; Annunziatellis, A.; Graziani, S.. 2011 Testing surface gas monitoring methods at sites of natural and man-made CO2 seepage in Europe. In: ...

Research paper thumbnail of Arsenic speciation in polychaetes (Annelida) and sediments from the intertidal mudflat of Sundarban mangrove wetland, India

Environmental Geochemistry and Health, 2012

This paper documents the concentration of total arsenic and individual arsenic species in four so... more This paper documents the concentration of total arsenic and individual arsenic species in four soft-bottom benthic polychaetes (Perenereis cultifera, Ganganereis sootai, Lumbrinereis notocirrata and Dendronereis arborifera) along with host sediments from Sundarban mangrove wetland, India. An additional six sites were considered exclusively for surface sediments for this purpose. Polychaetes were collected along with the host sediments and measured for their total arsenic using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Arsenic concentrations in polychaete body tissues varied greatly, suggesting speciesspecific characteristics and inherent peculiarities in arsenic metabolism. Arsenic was generally present in polychaetes as arsenate (As V ranges from 0.16-0.50 mg kg-1) or arsenite (As III ranges from 0.10-0.41 mg kg-1) (30 to 53% as inorganic As) and dimethylarsinic acid (DMA V ; <1 to 25%). Arsenobetaine (AB; <16%), and PO 4-arsenoriboside (8 to 48%) were also detected as minor constituents, whilst monomethylarsonic acid (MA V) was not detected in any of the polychaetes. The highest total As (14.7 mg kg-1 dry wt) was observed in the polychaete D. arborifera collected from the vicinity of a sewage outfall in which the majority of As was present as an uncharacterized compound (10.3 mg kg-1 dry wt) eluted prior to AB. Host sediments ranged from 2.5 to 10.4 mg kg-1 total As. This work supports the importance of speciation analysis of As, because of the ubiquitous occurrence of this metalloid in the environment, and its variable toxicity depending on chemical form. It is also the first work to report the composition of As species in polychaetes from the Indian Sundarban wetlands.

Research paper thumbnail of Erratum Geological controls on radon potential in Scotland

Scottish Journal of Geology, 2010

Research paper thumbnail of Bioaccessibility Performance Data for Fifty-Seven Elements in Guidance Material BGS 102

Microchemical Journal

BGS 102, a guidance material for bioaccessible arsenic (As) and lead (Pb), was produced during va... more BGS 102, a guidance material for bioaccessible arsenic (As) and lead (Pb), was produced during validation of the in vitro Unified Bioaccessibility Method (UBM). This paper reports a compilation of reproducible bioaccessible guidance values for fifty-five additional elements in BGS 102, providing guidance for analysts to broaden the scope of UBM analyses for a wider range of elements based on data collected over an average of 60 separate analytical batches per element. Data are presented in categories for both gastric (STOM) and gastrointestinal (STOM + INT) extraction phases, where reproducibility, measured as relative standard deviation (RSD) was; ≤ 10% RSD for 27 elements (Mg, Al, Si, P, Ca, Cr, Mn, Co, Ni, As, Rb, Sr, Y, Ba, La, Ce, Pr, Nd, Sm, Eu, Tb, Gd, Dy, Ho, Er, Tm, Yb); between 10-20% RSD for 10 elements (Li, K, V, Fe, Cu, Zn, Cd, Lu, Pb, U); and ≥ 20% RSD for 19 elements in the gastric phase (Be, B, S, Ti, Ga, Se, Zr, Nb, Mo, Ag, Sn, Sb, Cs, Hf, Ta, W, Tl, Bi, Th). Two el...

Research paper thumbnail of Using near-surface atmospheric measurements as a proxy for quantifying field-scale soil gas flux

We present a new method for deriving surface soil gas flux at the field scale, which is less fiel... more We present a new method for deriving surface soil gas flux at the field scale, which is less fieldwork intensive than traditional chamber techniques and less expensive than those derived from airborne or space surveys. The technique uses aspects of chamber and micrometeorological methods combined with a mobile platform and GPS to rapidly derive soil gas fluxes at the field-scale. There are several assumptions in using this method, which will be most accurate under stable atmospheric conditions with little horizontal wind flow. Results show that soil gas fluxes, when averaged across a field site, are highly comparable between the method presented and traditional chamber acquisition techniques. Atmospheric dilution is found to reduce the range of flux values under the open field-scale method, when compared to chamber derived results. Under ideal atmospheric conditions it may be possible to use the presented method to derive soil gas flux at an individual point, however this requires further investigation. The new method for deriving soil-atmosphere gas exchange at the field-scale could be useful for a number of applications including quantification of CCS leakage, diffuse degassing in volcanic and geothermal areas and greenhouse-gas emissions.

Research paper thumbnail of Radon-222 dose rates to burrowing mammals

Research paper thumbnail of Baseline variability in onshore near surface gases and implications for monitoring at CO2 storage sites

Energy Procedia, 2014

The measurement of gas concentrations and fluxes in the soil and atmosphere is a powerful tool fo... more The measurement of gas concentrations and fluxes in the soil and atmosphere is a powerful tool for monitoring geological carbon capture and storage (CCS) sites because the analyses are made directly in the biosphere in which we live. These methods can be used to both find and accurately quantifying leaks, and are visible and tangible data for public and ecosystem safety. To be most reliable and accurate, however, the measurements must be interpreted in the context of natural variations in gas concentration and flux. Such baseline data vary both spatially and temporally due to natural processes, and a clear understanding of their values and distributions is critical for interpreting near-surface gas monitoring techniques. The best example is CO 2 itself, as the production of this gas via soil respiration can create a wide range of concentrations and fluxes that must be separated from, and not confused with, CO 2 that may leak towards the surface from a storage reservoir. The present article summarizes baseline studies performed by the authors at various sites having different climates and geological settings from both Europe and North America, with focus given to the range of values that can result from near surface processes and how different techniques or data processing approaches can be used to help distinguish a leakage signal from an anomalous, shallow biogenic signal.

Research paper thumbnail of Effects of elevated CO2 concentrations on the vegetation and microbial populations at a terrestrial CO2 vent at Laacher See, Germany

International Journal of Greenhouse Gas Control, 2011

CO 2 capture and geological storage offers an option for reducing man-made greenhouse gas emissio... more CO 2 capture and geological storage offers an option for reducing man-made greenhouse gas emissions. But one major concern related to geological CO 2 storage is the possibility of leakage from the reservoir and subsequent effects on the environment, which cannot completely be excluded. This study aims at investigating the environmental impact of CO 2 release from reservoirs into near surface terrestrial environments. To understand the effect of CO 2 leakage on such an ecosystem, detailed knowledge on the abundance and diversity of plants and microorganisms is essential. Therefore, an ecosystem study has been conducted within the Network of Excellence "CO 2 GeoNet" on a natural CO 2 vent at the Laacher See, Germany. Near surface CO 2 conditions and CO 2 fluxes of the venting area were described by means of conventional soil gas measurement equipment, and brought up the difference between the CO 2 anomalies and their surroundings. A comparison of the soil columns between control sites and the centre of the venting area showed a small but significant change in the soil pH below 10 cm. The botanical survey revealed some remarkable vegetation changes like the investigation of important soil microbial communities showed significant differences between the CO 2-rich sites (up to 90% and more of soil gas), medium CO 2 sites (~20%), and control locations with background CO 2 concentrations. The ecosystem appears to be adapted to the different conditions through species substitution or adaptation, showing a shift towards anaerobic and acidotolerant to acidophilic species under elevated CO 2 concentrations. At the end, this ongoing study should identify possible candidates in the botanical and microbial kingdoms, whose presence or absence provide easily detectable indicators for the leakage of CO 2 from deep reservoirs into near surface terrestrial ecosystems.

Research paper thumbnail of Geological controls on radon potential in Scotland

Scottish Journal of Geology, 2009

Rn, a natural radioactive gas produced by the radioactive decay of 238 U, accounts for about 50 %... more Rn, a natural radioactive gas produced by the radioactive decay of 238 U, accounts for about 50 % of the total radiation dose to the average person in the UK. Geology is the most important factor controlling the source and distribution of radon; which has been linked to an increased risk of lung cancer. In order to prevent the public receiving high exposures to radon, it is necessary to identify those areas most at risk. We present results of new mapping of radon potential for Scotland using a method that allows the spatial variation in radon potential to be delineated both within and between geological groupings. The main geological and geochemical associations with moderate to high radon potential areas are described. The highest radon potential values in Scotland are associated with U-rich, highly evolved Siluro-Devonian biotite granite intrusions, notably those clustered within a zone to the west of Aberdeen and at Helmsdale, in Caithness. U mineralisation plays a role in areas including the Helmsdale granite and the Middle Old Red Sandstone of the Orcadian Basin. Elevated radon potential is also associated with limestones-where fracture permeability is influential-and with Ordovician-Silurian greywackes. The radon potential of unconsolidated deposits, and how this affects the radon potential of the underlying bedrock, reflects both their permeabilities and their compositions.

Research paper thumbnail of Soil type influences crop mineral composition in Malawi

Science of The Total Environment, 2015