226Ra behavior in the Pee Dee River-Winyah Bay estuary

Elsinger, Robert J.; Moore, Willard S.

doi:10.1016/0012-821x(80)90187-9

Cited by 100 publications

(37 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…226 Ra displayed the opposite trend, with sediments from the bottom of PZ 11 desorbing 1 to 2.7 dpm/100g, with all other sediments desorbing 0.3 to 0.6 dpm/100g (Figure 3a-c). There are large ranges in the increase in desorption from salinity 5 to 25 (from 17 to 131%), but it is still apparent that increases in salinity result in increased radium desorption as has been previously observed (Elsinger and Moore, 1980;Webster et al, 1995). For an increase in salinity from 5 to 25, Ra desorption increased around 50%, a value that may be applicable for other settings with permeable siliceous sands.…”

Section: Ra Desorption and Salinity Of Groundwatersupporting

confidence: 54%

“…This fraction is the focus of this study, since under varying geochemical conditions, different fractions of this pool are available to exchange with adjacent pore waters. The surface bound 226 Ra is usually evaluated via the 222 Rn-emanation method (Elsinger and Moore, 1980;Corbett et al, 1998), while surface bound 224 Ra can be measured by coincidence counting of sediments (Sun and Torgersen, 1998). This study considers the various geochemical controls on Ra exchange between the surface bound Ra pool and groundwater dissolved Ra.…”

Section: Model Of Sediment Ra Partitioning: Caveats and Considerationsmentioning

confidence: 99%

“…Ra release in surface estuaries has been mainly attributed to desorption of Ra from suspended and bottom sediments as salinity increases (Li and Chan, 1979;Elsinger and Moore, 1980). However, radium behavior within the STE has additional complexity including varying fractions of exchangeable sediment Ra (Porcelli and Swarzenski, 2003); grain size and porosity of sediments (Webster et al, 1995, Hancock et al, 2006; changes in ionic strength (salinity) (Elsinger and Moore, 1980;Webster et al, 1995); temperature effects (Rama and Moore, 1996); pH (Sanchez and Rodriguez-Alvarez, 1999;Lauria et al, 2004); and barite solubility (Ba and Ra are chemical analogs) (Langmuir and Riese, 1985;Grundl and Cape, 2006). Other controls have been suggested but not thoroughly examined including the redox state of groundwater (including Eh and pH) (Puigdomènech and Bergström, 1995;Porcelli and Swarzenski, 2003) and the presence Fe and, in particular, Mn (hydr)oxides, since Ra has a very high affinity for Mn and Fe (Bollinger and Moore, 1993;Sun and Torgersen, 2001;Charette and Sholkovitz, 2006).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

New perspectives on radium behavior within a subterranean estuary

et al. 2008

View full text Add to dashboard Cite

Abstract:Over the past decade, radium isotopes have been frequently applied as tracers of submarine groundwater discharge (SGD). The unique radium signature of SGD is acquired within the subterranean estuary, a mixing zone between fresh groundwater and seawater in coastal aquifers, yet little is known about what controls Ra cycling in this system. The focus of this study was to examine controls on sediment and groundwater radium activities within permeable aquifer sands (Waquoit Bay, MA, USA) through a combination of field and laboratory studies. In the field, a series of sediment cores and corresponding groundwater profiles were collected for analysis of the four radium isotopes, as well as dissolved and sediment associated manganese, iron, and barium. We found that in addition to greater desorption at increasing salinity, radium was also closely tied to manganese and iron redox cycling within these sediments. A series of laboratory adsorption/desorption experiments helped elucidate the importance of 1) contact time between sediment and water, 2) salinity of water in contact with sediment, 3) redox conditions of water in contact with sediment, and 4) the chemical characteristics of sediment on radium adsorption/desorption. We found that these reactions are rapid (on the order of hours), desorption increases with increasing salinity and decreasing pH, and the presence of Fe and Mn (hydr)oxides on the sediment inhibit the release of radium.These sediments have a large capacity to sorb radium from fresh water. Combined with these experimental results, we present evidence from time series groundwater sampling 2 that within this subterranean estuary there are cyclic periods of Ra accumulation and release controlled by changing salinity and redox conditions.

show abstract

Section: Ra Desorption and Salinity Of Groundwatersupporting

confidence: 54%

Section: Model Of Sediment Ra Partitioning: Caveats and Considerationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

New perspectives on radium behavior within a subterranean estuary

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Radium is strongly adsorbed on riverine sediment and released to the dissolved state at increasing ionic strength at mid-salinities (Li et al, 1977;Elsinger and Moore, 1980;Moore, 1981;Key et al, 1985). The riverine contribution to 226 Ra in the surface ocean may be as high as 30% (Li et al, 1977).…”

Section: Introductionmentioning

confidence: 99%

228Ra and 226Ra in the Kara and Laptev seas

Loeff

Kühne

Wahsner

et al. 2003

Continental Shelf Research

View full text Add to dashboard Cite

The surface water in the Transpolar Drift in the Arctic Ocean has a strong signature of 228 Ra. In an earlier study of 228 Ra in the open Arctic we showed that the major 228 Ra source had to be in the Siberian shelf seas, but only a single shelf station was published so far. Here we investigate the sources of this signal on the Siberian shelves by measurements of 228 Ra and 226 Ra in surface waters of the Kara and Laptev Sea, including the Ob, Yenisey and Lena estuaries.In the Ob and Lena rivers we found an indication for a very strong and unexpected removal of both isotopes in the early stage of estuarine mixing, presumably related to flocculation of organic-rich material. Whereas 226 Ra behaves conservatively on the shelf, the distribution of 228 Ra is governed by large inputs on the shelves, although sources are highly variable. In the Kara Sea the maximum activity was found in the Baydaratskaya Bay, where tidal resonance and low freshwater supply favour 228 Ra accumulation. The Laptev Sea is a stronger source for 228 Ra than the Kara Sea. Since a large part of Kara Sea water flows through the Laptev Sea, the 228 Ra signal in the Transpolar Drift can be described as originating on the Laptev shelf.The combined freshwater inputs from the Eurasian shelves thus produce a common radium signature with a 228 Ra/ 226 Ra activity ratio of 4.0 at 20% river water. The radium signals of the individual Siberian rivers and shelves cannot be separated, but their signal is significantly different from the signal produced on the Canadian shelf (Smith et al., in press). In this respect, the radium tracers add to the information given by Barium. Moreover, with the 5.8 year half-life of 228 Ra, they have the potential to serve as a tracer for the age of a water mass since its contact with the shelves. r

show abstract

“…Ground-water inflow to the rivers and harbor is an apparent source of radium-226 (Miller and Sutcliffe, 1985). Background levels of radium-226 in the rivers and harbor reported by Stoker (1986) are an order of magnitude higher than those found in other parts of the United States (Elsinger and Moore, 1980). Runoff from pasture and cropland carries nutrients and, in some cases, pesticides to the river system.…”

Section: Sources Of Nutrient and Pollutant Loadsmentioning

confidence: 87%

Land use, water use, streamflow characteristics, and water-quality characteristics of the Charlotte Harbor inflow area, Florida

Hammett¹

1990

View full text Add to dashboard Cite

226Ra behavior in the Pee Dee River-Winyah Bay estuary

Cited by 100 publications

References 15 publications

New perspectives on radium behavior within a subterranean estuary

New perspectives on radium behavior within a subterranean estuary

228Ra and 226Ra in the Kara and Laptev seas

Land use, water use, streamflow characteristics, and water-quality characteristics of the Charlotte Harbor inflow area, Florida

Contact Info

Product

Resources

About