Matches in SemOpenAlex for { <https://semopenalex.org/work/W2012764047> ?p ?o ?g. }
Showing items 1 to 66 of
66
with 100 items per page.
- W2012764047 abstract "The purpose of this study is to understand the behaviour of the actinides in groundwater by combining data on the distribution of both longlived and short-lived nuclides of the U and Th decay series in an aquifer with a model for the nuclide transport along aquifer flow lines. The groundwater concentrations of the short-lived nuclides, such as 222Rn, 224Ra and 234Th, provide information only on local aquifer conditions, while the concentrations of the long-lived nuclides reflect geochemical processes along extended flow paths. In an important study, Krishnaswami et al. (1982) calculated sorption rate constants for many of the decay series nuclides in an aquifer using a batch model. However, no study yet has combined the data provided by both long and short-lived radionuclides to study the transport mechanisms along a flow line. Furthermore, although colloidal phases have been found to be important carriers of U and Th in numerous natural aqueous systems, very few investigations have been conducted on their importance in the transport of naturally-occurring actinides in groundwater. The aquifer investigated here is the sandy unconfined Upper Glacial Pleistocene aquifer situated in Long Island, NY. Extensive information regarding the geology and the hydrology of the aquifer is available and numerous high quality and well-documented wells are available for sample collection. This aquifer is underlain by a discontinuous layer of impermeable clay, below which is a sandy confined aquifer, the Magothy, where reducing conditions prevail. Radionuclide data from several wells in this aquifer have been reported by Copenhaver et al. (1993). Samples from the Upper Glacial aquifer have been taken along two flow lines at three different depths and filtered through 0.45 gm filter cartridges. In addition, cross-flow ultrafiltration has been used to separate colloids >10 kD from ultrafiltered water that represents the dissolved load. This technique, described in previous papers, has proven to be successful in studying the association of uranium and other elements with colloids (e.g. Porcelli et al., 1997). The concentrations of the long-lived radionuclides :3SU, 234U and 23eTh have been measured by thermal ionization mass spectrometry and the short-lived radiogenic daughters 222Rn, 226Ra, 228Ra, 224Ra, 234Th by counting methods. In addition, the water samples have been analysed for pH and conductivity in the field, and for concentrations of major cations, anions and trace elements. Water samples from the Upper Glacial aquifer have pH values of 5.4 to 6.5 and TDS (Total Dissolved Solid) of 20 to 100 mg/l. The high Mn concentration in a deep sample of the shallow aquifer likely indicates a difference in redox conditions. The Magothy aquifer has TDS o f 50 mg/1, comparable to that of the unconfined aquifer, but much higher Fe and Mn concentrations. The 222Rn activities generally full within a restricted range throughout the Upper Glacial aquifer of 65 to 170 dpm/kg, with two peak values of 3 36 and 522 dprn/kg. The amount of Rn in the water represents -4 % of the Rn produced in the rock by decay. Assuming that the aquifer rock consists of solid spherical grains with uniform distribution of Ra, this amount of Rn can only be supplied by grains of ~ 0.1 ~tm in size and therefore cannot be produced by the aquifer which average grain size is ~1 mm. This has been observed previously (e.g. Copenhaver et al., 1993). High Rn concentrations have been observed and lead to the requirement that Rn is circulating through nanopores or that the source of Rn is on the surface. We observe that the dissolved Rn concentration is generally greater where the dissolved 226Ra concentration is lower, suggesting that higher Rn concentrations in the water are due to increased amounts of 226Ra on aquifer surfaces due to deposition of dissolved 226Ra. Therefore we infer that Rn concentrations here are controlled by the distribution of Ra on surfaces rather than by enhanced release from" @default.
- W2012764047 created "2016-06-24" @default.
- W2012764047 creator A5076798992 @default.
- W2012764047 date "1998-01-01" @default.
- W2012764047 modified "2023-09-27" @default.
- W2012764047 title "Transport of U- and Th-Series Radionuclides in Groundwater" @default.
- W2012764047 doi "https://doi.org/10.1180/minmag.1998.62a.3.143" @default.
- W2012764047 hasPublicationYear "1998" @default.
- W2012764047 type Work @default.
- W2012764047 sameAs 2012764047 @default.
- W2012764047 citedByCount "0" @default.
- W2012764047 crossrefType "journal-article" @default.
- W2012764047 hasAuthorship W2012764047A5076798992 @default.
- W2012764047 hasConcept C121332964 @default.
- W2012764047 hasConcept C127313418 @default.
- W2012764047 hasConcept C131227075 @default.
- W2012764047 hasConcept C158973077 @default.
- W2012764047 hasConcept C159390177 @default.
- W2012764047 hasConcept C17409809 @default.
- W2012764047 hasConcept C177571023 @default.
- W2012764047 hasConcept C187320778 @default.
- W2012764047 hasConcept C33556824 @default.
- W2012764047 hasConcept C62520636 @default.
- W2012764047 hasConcept C75622301 @default.
- W2012764047 hasConcept C76177295 @default.
- W2012764047 hasConcept C76886044 @default.
- W2012764047 hasConceptScore W2012764047C121332964 @default.
- W2012764047 hasConceptScore W2012764047C127313418 @default.
- W2012764047 hasConceptScore W2012764047C131227075 @default.
- W2012764047 hasConceptScore W2012764047C158973077 @default.
- W2012764047 hasConceptScore W2012764047C159390177 @default.
- W2012764047 hasConceptScore W2012764047C17409809 @default.
- W2012764047 hasConceptScore W2012764047C177571023 @default.
- W2012764047 hasConceptScore W2012764047C187320778 @default.
- W2012764047 hasConceptScore W2012764047C33556824 @default.
- W2012764047 hasConceptScore W2012764047C62520636 @default.
- W2012764047 hasConceptScore W2012764047C75622301 @default.
- W2012764047 hasConceptScore W2012764047C76177295 @default.
- W2012764047 hasConceptScore W2012764047C76886044 @default.
- W2012764047 hasLocation W20127640471 @default.
- W2012764047 hasOpenAccess W2012764047 @default.
- W2012764047 hasPrimaryLocation W20127640471 @default.
- W2012764047 hasRelatedWork W1907008070 @default.
- W2012764047 hasRelatedWork W1964182679 @default.
- W2012764047 hasRelatedWork W1978613331 @default.
- W2012764047 hasRelatedWork W1999552930 @default.
- W2012764047 hasRelatedWork W2003587474 @default.
- W2012764047 hasRelatedWork W2028295675 @default.
- W2012764047 hasRelatedWork W2043515710 @default.
- W2012764047 hasRelatedWork W2117904581 @default.
- W2012764047 hasRelatedWork W2141148171 @default.
- W2012764047 hasRelatedWork W2141262970 @default.
- W2012764047 hasRelatedWork W2322792583 @default.
- W2012764047 hasRelatedWork W2621283915 @default.
- W2012764047 hasRelatedWork W2763762470 @default.
- W2012764047 hasRelatedWork W2805436197 @default.
- W2012764047 hasRelatedWork W2888797763 @default.
- W2012764047 hasRelatedWork W2894682497 @default.
- W2012764047 hasRelatedWork W2897722980 @default.
- W2012764047 hasRelatedWork W3004021384 @default.
- W2012764047 hasRelatedWork W3159784526 @default.
- W2012764047 hasRelatedWork W654952213 @default.
- W2012764047 isParatext "false" @default.
- W2012764047 isRetracted "false" @default.
- W2012764047 magId "2012764047" @default.
- W2012764047 workType "article" @default.