Journal ArticleDOI
Measurement of 223Ra and 224Ra in coastal waters using a delayed coincidence counter
Willard S. Moore,Ralph Arnold +1 more
TLDR
In this article, a nuclear detector system for measuring low activities of 223Ra and 224Ra in natural waters based on the original design of Giffin et al. is described. But the system is calibrated using 232Th and 227Ac standards with daughters in equilibrium adsorbed on Mn fiber.Abstract:
We describe a nuclear detector system for measuring low activities of 223Ra and 224Ra in natural waters based on an original design of Giffin et al. (1963). Samples are obtained by adsorbing 223Ra and 224Ra onto a column of MnO2 coated fiber (Mn fiber). The short-lived Rn daughters of 223Ra and 224Ra which recoil from the Mn fiber are swept into a scintillation detector where alpha decays of Rn and Po occur. Signals from the detector are sent to a delayed coincidence circuit, which discriminates decays of the 224Ra daughters, 220Rn and 216Po, from decays of the 223Ra daughters, 219Rn and 215Po. The system is calibrated using 232Th and 227Ac standards with daughters in equilibrium adsorbed on Mn fiber. Results of samples from Tampa Bay, Florida, and the Atchafalaya and Mississippi Rivers mixing zones are reported. The method is extendible to measurements of 227Ac, 231Pa, 228Th, and 228Ra.read more
Citations
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Journal ArticleDOI
Quantifying Submarine Groundwater Discharge in the Coastal Zone via Multiple Methods
William C. Burnett,Pradeep K. Aggarwal,Alice Aureli,Henry Bokuniewicz,Jaye E. Cable,Matthew A. Charette,Evgeny A. Kontar,Steve L. Krupa,Kshitij M. Kulkarni,A. Loveless,Willard S. Moore,June A. Oberdorfer,Joselene de Oliveira,N. Nur Ozyurt,Pavel P. Povinec,A.M.G. Privitera,Rudi Rajar,Roshan T Ramessur,Jan Scholten,Thomas Stieglitz,Makoto Taniguchi,Jeffrey V. Turner +21 more
TL;DR: While the process is essentially ubiquitous in coastal areas, the assessment of its magnitude at any one location is subject to enough variability that measurements should be made by a variety of techniques and over large enough spatial and temporal scales to capture the majority of these changing conditions.
Journal ArticleDOI
Estimating the dynamics of groundwater input into the coastal zone via continuous radon-222 measurements.
TL;DR: This work explored the use of a continuous radon monitor to measure radon concentrations in coastal zone waters over time periods from hours to days and showed that the mixing loss derived from the 223Ra gradient agreed very favorably to the estimated range based on the calculated radon fluxes.
Journal ArticleDOI
Utility of radium isotopes for evaluating the input and transport of groundwater-derived nitrogen to a Cape Cod estuary
TL;DR: In this article, a mass-balance approach for radium and dissolved inorganic nitrogen (DIN) was used to calculate a submarine groundwater flux of ~37,000 m3 d−1, which compared well with aquifer recharge rates calculated from rainfall.
Journal ArticleDOI
Determining coastal mixing rates using radium isotopes
TL;DR: In this article, the authors used observations that were made during vertically stratified conditions in the South Atlantic Bight to assess the factors that control the export of radium isotopes.
Journal ArticleDOI
Tidal pumping drives nutrient and dissolved organic matter dynamics in a Gulf of Mexico subterranean estuary
Isaac R. Santos,William C. Burnett,Thorsten Dittmar,I. G. N. A. Suryaputra,Jeffrey P. Chanton +4 more
TL;DR: In this article, the authors estimate nutrient production rates using the standard estuarine model and a non-steady-state box model, separate nutrient fluxes associated with fresh and saline submarine groundwater discharge (SGD), and estimate offshore fluxes from radium isotope distributions.
References
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Journal ArticleDOI
Sampling 228Ra in the deep ocean
TL;DR: A sampler using manganese impregnated acrylic fibers inside a 30-1.5 liter Niskin bottle is used to concentrate radium isotopes from 500 to 1500 1.
Journal ArticleDOI
231Pa/230Th ratios in sediments as a proxy for past changes in Southern Ocean productivity
TL;DR: In this paper, the authors exploit established relationships between 231Pa/230Th ratios and particle flux to infer, from the analysis of dated sediment cores, variability through time of fluxes of particulate biogenic material exported from surface waters.
Journal ArticleDOI
The flux of 226Ra from estuarine and continental shelf sediments
TL;DR: In this article, a pronounced desorption phenomenon of 226 Ra from sediment was observed in the Hudson River estuary, which is an important source of 226Ra to the oceans.
Journal ArticleDOI
Delayed coincidence counter for the assay of actinon and thoron
TL;DR: In this paper, a highly sensitive system for the detection of small quantities of Rn219 (T1/2 = 3.92 sec) and Rn220 (T 1 /2 = 54.5 sec) has been developed.
Journal ArticleDOI
Radium, thorium, and actinium extraction from seawater using an improved manganese-oxide-coated fiber
TL;DR: In this paper, improved manganese-oxide-coated acrylic fibers were used to extract radium, thorium, and actinium from seawater, and experiments were made using surface seawater spiked with227Ac,227Th, and223Ra.
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Quantifying Submarine Groundwater Discharge in the Coastal Zone via Multiple Methods
William C. Burnett,Pradeep K. Aggarwal,Alice Aureli,Henry Bokuniewicz,Jaye E. Cable,Matthew A. Charette,Evgeny A. Kontar,Steve L. Krupa,Kshitij M. Kulkarni,A. Loveless,Willard S. Moore,June A. Oberdorfer,Joselene de Oliveira,N. Nur Ozyurt,Pavel P. Povinec,A.M.G. Privitera,Rudi Rajar,Roshan T Ramessur,Jan Scholten,Thomas Stieglitz,Makoto Taniguchi,Jeffrey V. Turner +21 more