A batch of electrolysis cells was developed for tritium in water samples enrichment by at least a... more A batch of electrolysis cells was developed for tritium in water samples enrichment by at least a factor 10. The cell batch is controlled by a pre-programmable electronic system that interrupts the current through any cell when the planned electrolyte volume is attained. A starting and a final distillation of water samples are carried out before and after the electrolytic enrichment. Both distillations are made to dryness in order to avoid isotopic fractionation.
The paper describes a case of a natural emission of methane from soil in an urban development are... more The paper describes a case of a natural emission of methane from soil in an urban development area, generating a significant risk for the local population and buildings, due to gas explosiveness and asphyxiation potential. The site is located on the south-western margin of the East-European Platform in eastern Romania, in a hydrocarbon-prone area crossed by the Pericarpathian lineament and regional faults. Molecular composition of gas and stable isotopic analyses of methane (CH4>90%, δ13C1: −49.4‰, δD1: −173.4‰) indicate a dominant thermogenic origin, with significant amounts of C2-C5 alkanes (∼5%), likely migrating through faults from a deep reservoir. Possible candidates are the Saucesti and Secuieni gas fields, located in the same petroleum system. Two surface geochemical surveys, based on closed-chamber flux measurements, were performed to assess the degassing intensity and the extent of the affected area. Methane fluxes from soil reach orders of 104 mg m−2 day−1. Gas seepage mainly occurs in one zone 30 000 m2 wide, and it is likely controlled by channeling along a fault and gas accumulation in permeable sediments and shallow subsoil. The estimated total CH4 emission is about 40 t year−1 CH4, of which 8–9 t year−1 are naturally released from soil and 30–35 t year−1 are emitted from shallow boreholes. These wells have likely channeled the gas accumulated in shallow alluvial sediment but gas flux from soil is still high and mitigation measures are needed to reduce the risk for humans and buildings.
Methane (CH 4 ) flux to the atmosphere was measured from gas vents and, for the first time, from ... more Methane (CH 4 ) flux to the atmosphere was measured from gas vents and, for the first time, from soil microseepage at four quiescent mud volcanoes and one everlasting fire in eastern Azerbaijan. Mud volcanoes show different activity of venting craters, gryphons, and ...
Gas seepage from petroleum basins is the second largest natural source of methane to the atmosphe... more Gas seepage from petroleum basins is the second largest natural source of methane to the atmosphere, after wetlands. The uncertainty in global emission estimates should be reduced by extending the flux database which is fundamental for defining the emission factors and the actual area of seepage adopted for up-scaling. As a contribution to this goal, we report a new seepage data-set for the Transylvanian Basin, one of the largest natural gas producing regions of Europe, that is characterized by the widespread occurrence of natural leakages of gas at the surface, including at least 73 mud volcanoes and gas seeps. In this study, methane flux was measured using closed-chambers, from 12 seepage sites, in correspondence with focused gas vents (mud volcano craters, bubbling pools, and flammable gas leaks), in the soil surrounding the vents, and at 15 sites located far from macro-seep zones but close to gas fields. Fluxes from individual vents (macro-seeps) were found to reach orders of kg CH4 m−2 day−1 (up to 12 kg m−2 day−1) and diffuse fluxes from soils (miniseepage) were found to be up to a few g CH4 m−2 day−1. Far from seep zones, positive CH4 fluxes (microseepage) may occur locally, typically on the order of tens to hundreds of mg m−2 day−1. The values, as well as the occurrence of seepage even far from vent zones and in mud volcanoes that are apparently extinct, are coherent with results obtained in other countries. Gas fluxes from macro-seeps and soils may change seasonally, but the interannual variation of the average emission factor was found to be minimal. The total CH4 output for Transylvania macro-seeps is estimated conservatively to be around 680 t year−1; the total geo-CH4 seepage emission from the Transylvania petroleum system could be approximately 40 × 103 t year−1, and at least 100 × 103 t year−1 for all Romanian petroleum systems, that is roughly 10% of the total anthropogenic CH4 emission in the country.
Due to the occurrence of mud volcanoes and active seismic areas in close proximity in Romania, go... more Due to the occurrence of mud volcanoes and active seismic areas in close proximity in Romania, good conditions can be found for studying the relationship between the two phenomena. The most important earthquakes are generated within the Vrancea zone, related to a lithospheric fragment sunken into the astenosphere. Strong seismic shocks can be accompanied by an intensification of the mud volcanic activity, proving the sensitivity of the fluid reservoirs to strain variations in the shallow crust. Natural gas seeps and mud volcanoes are distributed over wide areas in Romania, and the monitoring of their activity in some selected points should give a better knowledge of the deformation field related to earthquakes. Mud volcano activity is strongly influenced by external factors, which alter the results of the measurements by introducing a high level of noise, which can be avoided by implementing a complex monitoring system.
In the present study, a simple procedure for the isolation by solid-phase extraction (SPE) and qu... more In the present study, a simple procedure for the isolation by solid-phase extraction (SPE) and quantification by UV-Vis spectrometry (400 nm) of the humic acids (HAs) in the natural waters was developed. Seven different sorbents: Porapak P (polystyrene-divinylbenzene copolymer), Florisil (chemical composition: 84.0% SiO2, 15.5% MgO and 0.5% Na2SO4), Silica gel C18 (octadecyl silane), Strata X (surface modified polystyrene-divinylbenzene), Strata NH2 (silica-based trifunctional amino ligand), Strata SAX (silica-based trifunctional quaternary amine) and Strata C18-E (silica-based trifunctional C18 with hydrophobic end-capping of silanols) were tested. The HAs, adsorbed on SPE cartridges, were eluted using: NaOH (0.1 M), sodium dodecyl sulphate (SDS) (20 g L−1), and a 1:1 v/v mixture of SDS (20 g L−1) and NaOH (0.1 M). The extraction efficiency was evaluated by comparing the HAs recovery levels. The repeatability of results was estimated by the relative standard deviation (RSD). The data confirmed that Porapak P, Silica gel C18, Florisil, Strata NH2 and Strata X could be good alternatives for the traditional isolation of the aquatic HAs with XAD resin. The proposed method was applied for the determination of HAs in some waters sampled from the Western Romanian Plain. The content of HAs was correlated with the arsenic concentration and total organic carbon (TOC) level.
The geochemistry of groundwaters from the Pannonian Basin (Hungary and Romania) were analysed to ... more The geochemistry of groundwaters from the Pannonian Basin (Hungary and Romania) were analysed to elucidate the general geochemistry and processes controlling elevated levels of arsenic. Using cluster analysis 4 main groups were identified. Group 4, influenced by geothermal and saline inputs (Na-HCO 3 to Na-Cl type, high Li, Si, NH 4 and B, low δ 7 Li values) with low As levels (mean 33.1 μg/L, range <0.5 to 240 μg/L). Group 3 waters, sampling only dug wells with geochemistry influenced by rain water and surface contamination (Ca-Mg-HCO 3 type, elevated K, NO 3 , S(tot) and Cl) and also with low As (mean 1 μg/L, range <0.5 to 2.1 μg/L).
... CRISTINA JIMENEZ 3, JASMIN MERTENS 4, CALIN BACIU 3, DAVID A. POLYA 1 AND JON R. LLOYD 1 1Sch... more ... CRISTINA JIMENEZ 3, JASMIN MERTENS 4, CALIN BACIU 3, DAVID A. POLYA 1 AND JON R. LLOYD 1 1School of Earth, Atmospheric and Environmental Sciences, The ... This is a contribution of AquaTRAIN (MRTN-CT-2006-035420) funded by the European Commission. ...
A batch of electrolysis cells was developed for tritium in water samples enrichment by at least a... more A batch of electrolysis cells was developed for tritium in water samples enrichment by at least a factor 10. The cell batch is controlled by a pre-programmable electronic system that interrupts the current through any cell when the planned electrolyte volume is attained. A starting and a final distillation of water samples are carried out before and after the electrolytic enrichment. Both distillations are made to dryness in order to avoid isotopic fractionation.
The paper describes a case of a natural emission of methane from soil in an urban development are... more The paper describes a case of a natural emission of methane from soil in an urban development area, generating a significant risk for the local population and buildings, due to gas explosiveness and asphyxiation potential. The site is located on the south-western margin of the East-European Platform in eastern Romania, in a hydrocarbon-prone area crossed by the Pericarpathian lineament and regional faults. Molecular composition of gas and stable isotopic analyses of methane (CH4>90%, δ13C1: −49.4‰, δD1: −173.4‰) indicate a dominant thermogenic origin, with significant amounts of C2-C5 alkanes (∼5%), likely migrating through faults from a deep reservoir. Possible candidates are the Saucesti and Secuieni gas fields, located in the same petroleum system. Two surface geochemical surveys, based on closed-chamber flux measurements, were performed to assess the degassing intensity and the extent of the affected area. Methane fluxes from soil reach orders of 104 mg m−2 day−1. Gas seepage mainly occurs in one zone 30 000 m2 wide, and it is likely controlled by channeling along a fault and gas accumulation in permeable sediments and shallow subsoil. The estimated total CH4 emission is about 40 t year−1 CH4, of which 8–9 t year−1 are naturally released from soil and 30–35 t year−1 are emitted from shallow boreholes. These wells have likely channeled the gas accumulated in shallow alluvial sediment but gas flux from soil is still high and mitigation measures are needed to reduce the risk for humans and buildings.
Methane (CH 4 ) flux to the atmosphere was measured from gas vents and, for the first time, from ... more Methane (CH 4 ) flux to the atmosphere was measured from gas vents and, for the first time, from soil microseepage at four quiescent mud volcanoes and one everlasting fire in eastern Azerbaijan. Mud volcanoes show different activity of venting craters, gryphons, and ...
Gas seepage from petroleum basins is the second largest natural source of methane to the atmosphe... more Gas seepage from petroleum basins is the second largest natural source of methane to the atmosphere, after wetlands. The uncertainty in global emission estimates should be reduced by extending the flux database which is fundamental for defining the emission factors and the actual area of seepage adopted for up-scaling. As a contribution to this goal, we report a new seepage data-set for the Transylvanian Basin, one of the largest natural gas producing regions of Europe, that is characterized by the widespread occurrence of natural leakages of gas at the surface, including at least 73 mud volcanoes and gas seeps. In this study, methane flux was measured using closed-chambers, from 12 seepage sites, in correspondence with focused gas vents (mud volcano craters, bubbling pools, and flammable gas leaks), in the soil surrounding the vents, and at 15 sites located far from macro-seep zones but close to gas fields. Fluxes from individual vents (macro-seeps) were found to reach orders of kg CH4 m−2 day−1 (up to 12 kg m−2 day−1) and diffuse fluxes from soils (miniseepage) were found to be up to a few g CH4 m−2 day−1. Far from seep zones, positive CH4 fluxes (microseepage) may occur locally, typically on the order of tens to hundreds of mg m−2 day−1. The values, as well as the occurrence of seepage even far from vent zones and in mud volcanoes that are apparently extinct, are coherent with results obtained in other countries. Gas fluxes from macro-seeps and soils may change seasonally, but the interannual variation of the average emission factor was found to be minimal. The total CH4 output for Transylvania macro-seeps is estimated conservatively to be around 680 t year−1; the total geo-CH4 seepage emission from the Transylvania petroleum system could be approximately 40 × 103 t year−1, and at least 100 × 103 t year−1 for all Romanian petroleum systems, that is roughly 10% of the total anthropogenic CH4 emission in the country.
Due to the occurrence of mud volcanoes and active seismic areas in close proximity in Romania, go... more Due to the occurrence of mud volcanoes and active seismic areas in close proximity in Romania, good conditions can be found for studying the relationship between the two phenomena. The most important earthquakes are generated within the Vrancea zone, related to a lithospheric fragment sunken into the astenosphere. Strong seismic shocks can be accompanied by an intensification of the mud volcanic activity, proving the sensitivity of the fluid reservoirs to strain variations in the shallow crust. Natural gas seeps and mud volcanoes are distributed over wide areas in Romania, and the monitoring of their activity in some selected points should give a better knowledge of the deformation field related to earthquakes. Mud volcano activity is strongly influenced by external factors, which alter the results of the measurements by introducing a high level of noise, which can be avoided by implementing a complex monitoring system.
In the present study, a simple procedure for the isolation by solid-phase extraction (SPE) and qu... more In the present study, a simple procedure for the isolation by solid-phase extraction (SPE) and quantification by UV-Vis spectrometry (400 nm) of the humic acids (HAs) in the natural waters was developed. Seven different sorbents: Porapak P (polystyrene-divinylbenzene copolymer), Florisil (chemical composition: 84.0% SiO2, 15.5% MgO and 0.5% Na2SO4), Silica gel C18 (octadecyl silane), Strata X (surface modified polystyrene-divinylbenzene), Strata NH2 (silica-based trifunctional amino ligand), Strata SAX (silica-based trifunctional quaternary amine) and Strata C18-E (silica-based trifunctional C18 with hydrophobic end-capping of silanols) were tested. The HAs, adsorbed on SPE cartridges, were eluted using: NaOH (0.1 M), sodium dodecyl sulphate (SDS) (20 g L−1), and a 1:1 v/v mixture of SDS (20 g L−1) and NaOH (0.1 M). The extraction efficiency was evaluated by comparing the HAs recovery levels. The repeatability of results was estimated by the relative standard deviation (RSD). The data confirmed that Porapak P, Silica gel C18, Florisil, Strata NH2 and Strata X could be good alternatives for the traditional isolation of the aquatic HAs with XAD resin. The proposed method was applied for the determination of HAs in some waters sampled from the Western Romanian Plain. The content of HAs was correlated with the arsenic concentration and total organic carbon (TOC) level.
The geochemistry of groundwaters from the Pannonian Basin (Hungary and Romania) were analysed to ... more The geochemistry of groundwaters from the Pannonian Basin (Hungary and Romania) were analysed to elucidate the general geochemistry and processes controlling elevated levels of arsenic. Using cluster analysis 4 main groups were identified. Group 4, influenced by geothermal and saline inputs (Na-HCO 3 to Na-Cl type, high Li, Si, NH 4 and B, low δ 7 Li values) with low As levels (mean 33.1 μg/L, range <0.5 to 240 μg/L). Group 3 waters, sampling only dug wells with geochemistry influenced by rain water and surface contamination (Ca-Mg-HCO 3 type, elevated K, NO 3 , S(tot) and Cl) and also with low As (mean 1 μg/L, range <0.5 to 2.1 μg/L).
... CRISTINA JIMENEZ 3, JASMIN MERTENS 4, CALIN BACIU 3, DAVID A. POLYA 1 AND JON R. LLOYD 1 1Sch... more ... CRISTINA JIMENEZ 3, JASMIN MERTENS 4, CALIN BACIU 3, DAVID A. POLYA 1 AND JON R. LLOYD 1 1School of Earth, Atmospheric and Environmental Sciences, The ... This is a contribution of AquaTRAIN (MRTN-CT-2006-035420) funded by the European Commission. ...
Uploads
Papers by calin baciu