Preparation of Mn-fiber standards for the efficiency calibration of the delayed coincidence counting system (RaDeCC)

Scholten, Jan; Pham, Mai Khanh; Blinova, Oxana; Charette, Matthew A.; Dulai, Henrietta; Eriksson, Mats

doi:10.1016/j.marchem.2010.04.009

Cited by 32 publications

(30 citation statements)

References 23 publications

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“…'SC' is the University of South Carolina, which served as a reference laboratory for the distribution of these IAEA fibers. The amount of tracer activity retained by each fiber is reported as the IAEA mean, however, these activities were shown by Scholten et al (2010) to have decreased by up to 30% before their distribution to participants, but were stable during the course of the intercomparison. It is, therefore, recommended that the IAEA values not be used for RaDeCC system calibration.…”

Section: Ra and 223mentioning

confidence: 99%

GEOTRACES radium isotopes interlaboratory comparison experiment

Charette

Dulai

Gonneea

et al. 2012

Limnology & Ocean Methods

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In anticipation of the international GEOTRACES program, which will study the global marine biogeochemistry of trace elements and isotopes, we conducted a multi-lab intercomparison for radium isotopes. The intercomparison was in two parts involving the distribution of: (1) Ra) well outside the 95% confidence interval. Many outliers were suspected to be a result of poorly calibrated detectors, though other method specific factors likely played a role (e.g., detector leakage, insufficient equilibration). Most methods for radium analysis in seawater involve a MnO 2 fiber column preconcentration step; as such, we evaluated the extraction efficiency of this procedure and found that it ranged from an average of 87% to 94% for the four stations. Hence, nonquantitative radium recovery from seawater samples may also have played a role in lab-to-lab variability.

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Section: Ra and 223mentioning

confidence: 99%

GEOTRACES radium isotopes interlaboratory comparison experiment

Charette

Dulai

Gonneea

et al. 2012

Limnology & Ocean Methods

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“…Two additional counting sessions were conducted after 3 wk to determine the 224 Ra supported by 228 Th, and again after 3 mo to determine the 223 Ra supported by 227 Ac. The RaDeCC system was calibrated with standards prepared in the same geometry as the Mn-fiber samples (37,38).…”

Section: Methodsmentioning

confidence: 99%

Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

Sanial

Buesseler

Charette

et al. 2017

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

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There are 440 operational nuclear reactors in the world, with approximately one-half situated along the coastline. This includes the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which experienced multiple reactor meltdowns in March 2011 followed by the release of radioactivity to the marine environment. While surface inputs to the ocean via atmospheric deposition and rivers are usually well monitored after a nuclear accident, no study has focused on subterranean pathways. During our study period, we found the highest cesium-137 (137Cs) levels (up to 23,000 Bq⋅m−3) outside of the FDNPP site not in the ocean, rivers, or potable groundwater, but in groundwater beneath sand beaches over tens of kilometers away from the FDNPP. Here, we present evidence of a previously unknown, ongoing source of Fukushima-derived 137Cs to the coastal ocean. We postulate that these beach sands were contaminated in 2011 through wave- and tide-driven exchange and sorption of highly radioactive Cs from seawater. Subsequent desorption of 137Cs and fluid exchange from the beach sands was quantified using naturally occurring radium isotopes. This estimated ocean 137Cs source (0.6 TBq⋅y−1) is of similar magnitude as the ongoing releases of 137Cs from the FDNPP site for 2013–2016, as well as the input of Fukushima-derived dissolved 137Cs via rivers. Although this ongoing source is not at present a public health issue for Japan, the release of Cs of this type and scale needs to be considered in nuclear power plant monitoring and scenarios involving future accidents.

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“…The water was pumped over MnO 2 -fibre cartridges with a pump rate of about 1 l/min in order to scavenge the radium quantitatively [8]. The short-lived 223 Ra and 224 Ra were measured using the RaDeCC delayed coincidence counting system [32] following the procedure described in Moore [8] and Scholten et al [33]. For the long-lived 226 Ra and 228 Ra measurements the MnO 2 -fibres were ashed and prepared for gamma spectrometry measurements [21].…”

Section: Methodsmentioning

confidence: 99%

Submarine Groundwater Discharge at a Single Spot Location: Evaluation of Different Detection Approaches

Schubert

Scholten²,

Schmidt

et al. 2014

Water

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Submarine groundwater discharge (SGD) into the ocean is of general interest because it acts as vehicle for the transport of dissolved contaminants and/or nutrients into the coastal sea and because it may be accompanied by the loss of significant volumes of freshwater. Due to the large-scale and long-term nature of the related hydrological processes, environmental tracers are required for SGD investigation. The water parameters of electrical conductivity and temperature, the naturally occurring radionuclides of radon and radium as well as the stable water isotopes 18 O and 2 H have proven in previous studies their general suitability for the detection and quantification of SGD. However, individual hydrogeological settings require a site-specific application of this "tool box". This study evaluates and compares the applicability of the abovementioned tracers for investigating SGD from a distinct submarine source in a karst environment at Cabbé, southern France. The specific advantages and disadvantages of each individual parameter under the given hydrogeological conditions are discussed. Radon appeared to be the most suitable environmental tracer in the site specific context. The water temperature was less reliable due to the little temperature difference between seawater and groundwater and since the diurnal variation of the air temperature masks potential SGD signals. Radium isotopes are less OPEN ACCESSWater 2014, 6 585 applicable in the studied region due to the lack of a well-developed subterranean estuary. The stable water isotopes showed results consistent with the salinity and radon data; however, the significantly higher effort required for stable isotope analyses is disadvantageous. A multi-temporal thermal remote sensing approach proved to be a powerful tool for initial SGD surveying.

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Preparation of Mn-fiber standards for the efficiency calibration of the delayed coincidence counting system (RaDeCC)

Cited by 32 publications

References 23 publications

GEOTRACES radium isotopes interlaboratory comparison experiment

GEOTRACES radium isotopes interlaboratory comparison experiment

Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

Submarine Groundwater Discharge at a Single Spot Location: Evaluation of Different Detection Approaches

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