Uncertainties associated with 223Ra and 224Ra measurements in water via a Delayed Coincidence Counter (RaDeCC)

García-Solsona, Ester; García-Orellana, Jordi; Masqué, Pere; Dulai, Henrietta

doi:10.1016/j.marchem.2007.11.006

Cited by 164 publications

(95 citation statements)

References 32 publications

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“…Lake water, active layer water, and river water samples were collected in August 2011 and July 2012 following standard procedures for 224 Ra activities (35,36), 222 Rn activities (37)(38)(39), and CH 4 concentration (40,41). Surface lake water samples were collected from both the interior and perimeter areas of the lake.…”

Section: Methodsmentioning

confidence: 99%

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Methane transport from the active layer to lakes in the Arctic using Toolik Lake, Alaska, as a case study

Paytan

Lecher

Dimova

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Methane emissions in the Arctic are important, and may be contributing to global warming. While methane emission rates from Arctic lakes are well documented, methods are needed to quantify the relative contribution of active layer groundwater to the overall lake methane budget. Here we report measurements of natural tracers of soil/groundwater, radon, and radium, along with methane concentration in Toolik Lake, Alaska, to evaluate the role active layer water plays as an exogenous source for lake methane. Average concentrations of methane, radium, and radon were all elevated in the active layer compared with lake water (1.6 × 104 nM, 61.6 dpm⋅m−3, and 4.5 × 105 dpm⋅m−3 compared with 1.3 × 102 nM, 5.7 dpm⋅m−3, and 4.4 × 103 dpm⋅m−3, respectively). Methane transport from the active layer to Toolik Lake based on the geochemical tracer radon (up to 2.9 g⋅m−2⋅y−1) can account for a large fraction of methane emissions from this lake. Strong but spatially and temporally variable correlations between radon activity and methane concentrations (r2 > 0.69) in lake water suggest that the parameters that control methane discharge from the active layer also vary. Warming in the Arctic may expand the active layer and increase the discharge, thereby increasing the methane flux to lakes and from lakes to the atmosphere, exacerbating global warming. More work is needed to quantify and elucidate the processes that control methane fluxes from the active layer to predict how this flux might change in the future and to evaluate the regional and global contribution of active layer water associated methane inputs.

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Section: Methodsmentioning

confidence: 99%

“…Standards were run on a monthly basis as part of the quality control for maintenance of the instrument. Analytical error was calculated using established procedures (36) and was typically <10%.…”

Section: Methodsmentioning

confidence: 99%

Methane transport from the active layer to lakes in the Arctic using Toolik Lake, Alaska, as a case study

Paytan

Lecher

Dimova

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…Standard aliquots of known activities analyzed under conditions identical to those of the water samples were used as reference material. 223 Ra and 224 Ra measurements Radium was extracted usually from 40 to 90 L of sample water in each case, these volumes having been shown to be in the optimum range for minimising counting errors (Garcia-Solsona et al 2008). Occasionally, lower volumes were processed because of high particle loads or limited availability (fresh groundwater).…”

Section: Weser Estuarymentioning

confidence: 99%

“…Analyses of the Bremerhaven (2002) estuarine samples were performed in air as carrier gas. The decay of these samples was monitored by repeated (every 2-3 days) measurements over 2 weeks to verify the concentrations of individual radionuclides via their half-life, and to exclude artefacts of counts from the 224 Ra-decay chain that may occur in the 219 Rn channel (Garcia-Solsona et al 2008). All other samples were analyzed in He as carrier gas.…”

Section: Weser Estuarymentioning

confidence: 99%

228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

et al. 2011

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“…For fibers with less than 20 total alpha counts per minute at time of analysis, 224 Ra was quantified using the 220 Rn channel, corrected for chance coincidence events. For fibers with greater than 20 counts per minute, 224 Ra was quantified by total counts, corrected for activity attributable to 223 Ra (Garcia-Solsona et al, 2008) and for 224 Ra-220 Rn disequilibrium during short run times. 224 Ra was calibrated by an old, equilibrated 232 Th solution that was transferred onto Mn oxide fibers.…”

Section: Radium Isotope Analysismentioning

confidence: 99%

Relationships between radium and radon occurrence and hydrochemistry in fresh groundwater from fractured crystalline rocks, North Carolina (USA)

et al. 2009

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a b s t r a c t a r t i c l e i n f oNaturally-occurring radionuclides (uranium, radium, and radon), major dissolved constituents, and trace elements were investigated in fresh groundwater in 117 wells in fractured crystalline rocks from the Piedmont region (North Carolina, USA). Chemical variations show a general transition between two water types: (1) slightly acidic (pH 5.0-6.0), oxic, low-total dissolved solids (TDS) waters, and (2) near neutral, oxic to anoxic, higher-TDS waters. The uranium, radium, and radon levels in groundwater associated with granite (Rolesville Granite) are systematically higher than other rock types (gneiss, metasedimentary, and metavolcanic rocks). Water chemistry plays a secondary role on radium and radon distributions as the 222 Rn/ 226 Ra activity ratio is correlated with redox-sensitive solutes such as dissolved oxygen and Mn concentrations, as well as overall dissolved solids content including major divalent cations and Ba. Since 224 Ra/ 228 Ra activity ratios in groundwater are close to 1, we suggest that mobilization of Ra and Rn is controlled by alpha recoil processes from parent nuclides on fracture surfaces, ruling out Ra sources from mineral dissolution or significant long-distance Ra transport. Alpha recoil is balanced by Ra adsorption that is influenced by redox conditions and/or ion concentrations, resulting in an approximately one order of magnitude decrease (~20,000 to~2000) in the apparent Ra distribution coefficient between oxygensaturated and anoxic conditions and also across the range of dissolved ion concentrations (up to~7 mM). Thus, the U and Th content of rocks is the primary control on observed Ra and Rn activities in groundwater in fractured crystalline rocks, and in addition, linked dissolved solids concentrations and redox conditions impart a secondary control.

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Uncertainties associated with 223Ra and 224Ra measurements in water via a Delayed Coincidence Counter (RaDeCC)

Cited by 164 publications

References 32 publications

Methane transport from the active layer to lakes in the Arctic using Toolik Lake, Alaska, as a case study

Methane transport from the active layer to lakes in the Arctic using Toolik Lake, Alaska, as a case study

228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

Relationships between radium and radon occurrence and hydrochemistry in fresh groundwater from fractured crystalline rocks, North Carolina (USA)

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