224Ra,228Ra, and226Ra in Winyah Bay and Delaware Bay

Elsinger, Robert J.; Moore, Willard S.

doi:10.1016/0012-821x(83)90103-6

Cited by 65 publications

(22 citation statements)

References 12 publications

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“…Continued release of 228 Ra generated from 2 3 2 Th decay on sediments deposited in the estuary must cause a high flux of 2 2 8 Ra with little addition of 2 2 6 Ra. Similar mechanisms of 2 2 8 Ra enrichment in estuaries have been reported (Elsinger and Moore 1983;Elsinger and Moore 1984;Key et al 1985: Moore 1981Santschi et al 1979); but, in no other reported system is the effect as great as in the Orinoco. Increases of 2 2 4 Ra generally paralleled increases of 2 2 8 Ra through the estuary (Figure 1).…”

Section: Distribution Of Ra Isotopes During April a Estuary Samplessupporting

confidence: 81%

Radium Isotopes in the Orinoco Estuary and Eastern Caribbean Sea

Moore¹,

Todd²

1988

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Section: Distribution Of Ra Isotopes During April a Estuary Samplessupporting

confidence: 81%

Radium Isotopes in the Orinoco Estuary and Eastern Caribbean Sea

Moore¹,

Todd²

1988

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“…The four naturally occurring radium isotopes, which vary in half-life (3.7 days to 1600 years), are useful as tracers of SGD and have also been used to study groundwater input and mixing processes on a wide range of time scales (Elsinger and Moore, 1983;Moore, 1997;Yang et al, 2002;Charette et al, 2001;Krest and Harvey, 2003). The divalent cation radium isotopes are bound to soil particles and rocks in low ionic strength water.…”

Section: Article In Pressmentioning

confidence: 99%

“…The divalent cation radium isotopes are bound to soil particles and rocks in low ionic strength water. They readily desorb via ion exchange in the presence of solutions of high ionic strength (e.g., Elsinger and Moore, 1983;Webster et al, 1994;Yang et al, 2002). In coastal aquifers where seawater with high ionic strength mixes and interacts with freshwater and aquifer rocks, respectively, high radium waters can result.…”

Section: Article In Pressmentioning

confidence: 99%

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Boehm

Paytan

Shellenbarger³

et al. 2006

Continental Shelf Research

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The coastal, unconfined aquifer at Huntington Beach, California contains saline groundwater (33 psu) adjacent to the water line, and a brackish groundwater (BGW) mixing zone (3-9 psu) approximately 50 m from the water line. According to salinity and water isotope analyses, the BGW composition varies spatially in the alongshore direction. Measurements obtained from two BGW wells indicate this water is a mixture of seawater and a freshwater end member (likely infiltrated runoff); results from a third more southerly well suggest the BGW is composed of seawater, freshwater, and water from the confined Talbert Aquifer. Saline groundwater, on the other hand, shares similar salinity and water isotopic composition with seawater. The saline groundwater is enriched with short-and long-lived radium isotopes relative to the surf zone, which in turn is enriched relative to waters further offshore. We derive eddy diffusion coefficients for the nearshore using 223 Ra and 224 Ra, and in conjunction with 226 Ra activities, estimate a submarine groundwater discharge (SGD) rate between 4.2 and 8.9 L min À1 m À1 of shoreline, respectively. Using analytical models, we estimate that between 74 and 100% of this discharge represents seawater than has been forced by tides and waves through the beach aquifer. Under one set of model assumptions, results indicate that a portion (up to 56%) of seawater pumped into the beach aquifer by waves and tides is not discharged suggesting salt water intrusion may be occurring. Because saline groundwater is enriched with dissolved inorganic nitrogen and soluble reactive phosphate relative to the coastal ocean, our results suggest that tidally and wave-driven seawater circulated through the beach aquifer represents an important mechanism for nutrient input to the nearshore environment in dry weather. Estimates of nutrient flux to the coastal ocean via SGD along 16-17 km of shoreline are equivalent to nutrient fluxes from two salt water wetlands near the study site during the dry season. r

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“…This fact is attributed to the ion exchange with Ra for the available adsorption sites in the surface of the rock minerals of aquifers (Kraemer & Reid 1984, Lauria et al 2004. In surface, brackish or shallow groundwater the activity concentrations of 226 Ra are often lower than that of 228 Ra and the contents of both isotopes are usually very low, ranging from a hundredth to several milibekerels per liter (Elsinger & Moore 1983, Dickson 1985, Krest et al 1998). Vengosh and co-workers (2009) reported that in fossil groundwater from the Middle East the activity ratio ( 226 Ra/ 228 Ra) in the unconfined zone was lower than that in the confined one, and the radium activity ratio in the confined zone was equal to the adequate activity ratio ( 226 Ra/ 228 Ra) of the host rock aquifer.…”

Section: Introductionmentioning

confidence: 99%

Factors controlling 226Ra, 228Ra and their activity ratio in groundwater – an application in Polish Carpathian mineral waters

Nguyen

Kopeć

Nowak

2016

geol

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Abstract:The influences of aquifer formations and water chemical composition on the occurrence and activity ratio of radium isotopes in groundwater are discussed. Based on the model of desorption/adsorption processes of natural radionuclides in the rock-water system, the concentrations of radium isotopes and their activity ratio in groundwater are evaluated by the numerical Monte Carlo method (MC). In cases where the groundwater is of a similar age, limited flow (up to several meters/year), the physical conditions and the uranium and thorium activity ratios in host water formations are similar, the activity concentrations of radium isotopes ( 226 Ra, 228 Ra) and their activity ratio ( 226 Ra/ 228 Ra) are the highest in the water of high desorption coefficient for chloride sodium water (domination of Cl − , Na + ions), medium in water of moderate desorption (bicarbonate water -HCO 3 − , Ca 2+ ) and the lowest in waters with a low desorption coefficient (sulfate ions prevailing -SO 4 2− , Ca 2− ). The statements are well confirmed in the case of the natural mineral waters from the Polish Outer Carpathians. The total dissolved solids (TDS) of the Polish Carpathians waters varies from several hundred milligrams per liter to several tens of thousands milligrams per liter. The minimum, maximum and average concentrations of 226 Ra, 228 Ra and their activity ratio ( 226 Ra/ 228 Ra) are 82, 1340, 456 mBq/L, 19, 1240, 354 mBq/L and 0.89, 7.6 and 2.0 for chloride waters; 4, 140, 45.8 mBq/L, 12, 171, 62.7 mBq/L and 0.3, 1.7 and 0.70 for bicarbonate waters and 0.8, 9.3, 3.6 mBq/L, 5.3, 54, 20.1 mBq/L and 0.1, 1.0, 0.3 for sulfate ones, respectively. The desorption coefficients are the highest for the Cl-Na, moderate for the HCO 3 -Ca and the lowest for the SO 4 -Ca waters (in contrast to the adsorption properties of these waters).

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224Ra,228Ra, and226Ra in Winyah Bay and Delaware Bay

Cited by 65 publications

References 12 publications

Radium Isotopes in the Orinoco Estuary and Eastern Caribbean Sea

Radium Isotopes in the Orinoco Estuary and Eastern Caribbean Sea

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Factors controlling 226Ra, 228Ra and their activity ratio in groundwater – an application in Polish Carpathian mineral waters

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