226Ra measurements through gamma spectrometric counting of radon progenies: How significant is the loss of radon?

Scholten, Jan; Osvath, I.; Pham, Mai Khanh

doi:10.1016/j.marchem.2013.03.001

Cited by 27 publications

(7 citation statements)

References 25 publications

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“…Numerous methods have been used to detect and quantify SGD (Burnett et al, 2006) including optical systems (Karpen et al, 2004); geochemical water column investigations of tracers like the natural radionuclides radium and radon (Burnett & Dulaiova, 2003; Moore, 1996; Moore et al, 2008; Scholten et al, 2013), dissolved silicon (Oehler et al, 2019), methane, and chloride (Dulaiova et al, 2010; Schlüter et al, 2004); remote sensing (Shaban et al, 2005; Tamborski et al, 2015; Wilson & Rocha, 2012); and direct investigations using cores and different types of seepage meters (Bugna et al, 1996; Burnett & Dulaiova, 2003; Cable et al, 1997; Sauter et al, 2001). Only a few geophysical methods, like geoelectric (Stieglitz, 2005; Viso et al, 2010), controlled source electromagnetic (Gustafson et al, 2019; Müller et al, 2011), or autonomous underwater vehicle investigations (Sauter et al, 2003) have been used to explore SGD.…”

Section: Introductionmentioning

confidence: 99%

Complex Eyed Pockmarks and Submarine Groundwater Discharge Revealed by Acoustic Data and Sediment Cores in Eckernförde Bay, SW Baltic Sea

Hoffmann

Deimling²,

Schröder³

et al. 2020

Geochem Geophys Geosyst

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Submarine groundwater discharge into coastal areas is a common global phenomenon and is rapidly gaining scientific interest due to its influence on marine ecology, the coastal sedimentary environment, and its potential as a future freshwater resource. We conducted an integrated study of hydroacoustic surveys combined with geochemical pore water and water column investigations at a well-known groundwater seep site in Eckernförde Bay (Germany). We aim to better constrain the effects of shallow gas and submarine groundwater discharge on high-frequency multibeam backscatter data and to present acoustic indications for submarine groundwater discharge. Our high-quality hydroacoustic data reveal hitherto unknown internal structures within the pockmarks in Eckernförde Bay. Using precisely positioned sediment core samples, our hydroacoustic-geochemical approach can differentiate intrapockmark regimes that were formerly assigned to pockmarks of a different nature. We demonstrate that high-frequency multibeam data, in particular the backscatter signals, can be used to detect shallow free gas in areas of enhanced groundwater advection in muddy sediments. Intriguingly, our data reveal relatively small (typically <15 m across) pockmarks within the much larger, previously mapped pockmarks. The small pockmarks, which we refer to as "intrapockmarks," have formed due to the localized ascent of gas and groundwater; they manifest themselves as a new type of "eyed" pockmarks, revealed by their acoustic backscatter pattern. Our data suggest that, in organic-rich muddy sediments, morphological lows combined with a strong multibeam backscatter signal can be indicative of free shallow gas and subsequent advective groundwater flow.Plain Language Summary Groundwater that seeps out of the ocean floor is a common global phenomenon. Marine ecosystems are highly dependent on nutrient supply from land, and recent studies have suggested that groundwater seeping out of the seafloor supplies even more nutrients to the world's oceans than rivers do. Also, nearshore freshwater springs have been used as a source of drinking water for decades and large offshore groundwater reserves in continental shelves can potentially prevent future freshwater shortages. We use echo sounding methods to search for indications for submarine groundwater. The methods enable us to carry out detailed investigations of intriguing seafloor depressions (i.e., "pockmarks"). Our accurate measurements give new insights into the morphology and characterization of the Eckernförde Bay pockmarks and reveal a new type of pockmark that is related to seeping groundwater. In the muddy sediment of Eckernförde Bay, methane gas forms in the sediments due to microbial decomposition of biomass. In areas of enhanced groundwater advection, this methane gas is brought closer to the seafloor, where pockmarks form and where we can detect the gas with our sonar system. Given the abundant global distribution of muddy gaseous sediments, our findings have important implications for the future detect...

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Section: Introductionmentioning

confidence: 99%

Complex Eyed Pockmarks and Submarine Groundwater Discharge Revealed by Acoustic Data and Sediment Cores in Eckernförde Bay, SW Baltic Sea

Hoffmann

Deimling²,

Schröder³

et al. 2020

Geochem Geophys Geosyst

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“…i) It calls for equilibrium between 226 Ra and its progeny, which normally requires a suitably long storage period (≥20 d ) (Scholten et al, 2013). ii) As a result of radon diffusion across the container holding the sample, 226 Ra activity may be underestimated by an unknown factor (Arafa, 2002;Zhang et al, 2009).…”

Section: Cam Filementioning

confidence: 99%

Use of Genie 2000 and Excel VBA to correct for γ-ray interference in the determination of NORM building material activity concentrations

Suárez-Navarro

Gascó

Alonso

et al. 2018

Applied Radiation and Isotopes

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The γ-radiation emitted by building materials is calculated from the activity indices for Th,Ra and K and expressed as the activity concentration index (ACI). Gamma spectroscopy is a non-destructive technique frequently used to simultaneously determine the indices for several radionuclides. Spectral interpretation poses a number of challenges, including identification of γ-lines subject to summing-in effects, interference from other γ-ray emitting radionuclides and the time required to reach secular equilibrium. These challenges are not fully addressed by Canberra Industries' Genie 2000, the software used by many laboratories to analyse samples. This article describes a Microsoft Excel workbook that exploits Genie 2000 flexibility to program applications with Visual Basic using Canberra's Nuclear Data Access Library and batch procedure tools. The workbook determinesK activity concentration after correcting for Ac interference andRa activity directly from the γ-peak at 186.5 keV. The method proposed was tested by participating in 13 national and international scale inter-comparison exercises. The results were statistically indistinguishable from the reference values at a coverage factor of k = 3 and no statistically significant differences were identified between the respective means by a Student's t pairwise comparison.

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“…Each standard sample is accurately sealed using vinyl tape and then left undisturbed for at least 4 weeks in order to establish radioactive equilibrium between 226 Ra and 222 Rn prior to be measured. In the case of materials characterized by high radon exhalation, the sealing is very important in order to reduce the 222 Rn loss [11,12]. The sealing effectiveness and consequently the 222 Rn growth within the container were successfully checked, as shown in Fig.…”

Section: Absolute Efficiency Determination and Uncertainty Analysismentioning

confidence: 99%

Calibration of HPGe detectors using certified reference materials of natural origin

Xhixha

Albéri

Baldoncini

et al. 2015

J Radioanal Nucl Chem

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The feasibility of using certified reference\ud materials for the full energy efficiency calibration of p-type\ud coaxial high-purity germanium detectors for the determination\ud of radioactivity in environmental samples is discussed.\ud The main sources of uncertainty are studied and the\ud contributions to the total uncertainty budget for the most\ud intense gamma lines are presented. The correction factors\ud due to self-absorption and true coincidence summing\ud effects are discussed in detail. The calibration procedure is\ud validated for natural and artificial radionuclide determination\ud in different matrices through an internal cross-validation\ud and through the participation in a world-wide open\ud proficiency test

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226Ra measurements through gamma spectrometric counting of radon progenies: How significant is the loss of radon?

Cited by 27 publications

References 25 publications

Complex Eyed Pockmarks and Submarine Groundwater Discharge Revealed by Acoustic Data and Sediment Cores in Eckernförde Bay, SW Baltic Sea

Complex Eyed Pockmarks and Submarine Groundwater Discharge Revealed by Acoustic Data and Sediment Cores in Eckernförde Bay, SW Baltic Sea

Use of Genie 2000 and Excel VBA to correct for γ-ray interference in the determination of NORM building material activity concentrations

Calibration of HPGe detectors using certified reference materials of natural origin

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