+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Radium and radon radioisotopes in regional groundwater, intertidal groundwater, and seawater in the Adelaide Coastal Waters Study area Implications for the evaluation of submarine groundwater discharge

Radium and radon radioisotopes in regional groundwater, intertidal groundwater, and seawater in the Adelaide Coastal Waters Study area Implications for the evaluation of submarine groundwater discharge

Marine Chemistry 109(3-4): 318-336

The input of groundwater-bome nutrients to Adelaide's (South Australia) coastal zone is not well known but could contribute to the ongoing decline of seagrass in the area. As a component of the Adelaide Coastal Waters Study (ACWS), the potential for using the radium quartet (Ra-223, Ra-224, Ra-226 and Ra-228) and Rn-222 to evaluate submarine groundwater discharge (SGD) was evaluated. Potential isotopic signatures for SGD were assessed by sampling groundwater from three regional aquifers potentially contributing SGD to the ACWS area. In addition, intertidal groundwater was sampled at two sand beach sites. In general, the regional groundwaters were enriched in long-lived Ra isotopes (Ra-226 and Ra-228) and in Rn-222 relative to intertidal groundwater. Radium activity (but not Rn-222 activity) was positively correlated to salinity in groundwater from one of the regional aquifers and in intertidal groundwater. Radium isotope ratios (Ra-223/Ra-226, Ra-224/Ra-226 and Ra-224/Ra-226) were less variable than individual Ra isotope activities within potential SGD sources. Recirculated seawater (estimated from the intertidal groundwater samples with seawater-like salinities) also had distinctly higher Ra isotope ratios than the regional groundwaters. The activities for all radioisotopes were relatively low in seawater. The activity of the short-lived Ra-223 and Ra-224 were highest at the shoreline and declined exponentially with distance offshore. hi contrast, Ra-228 and Ra-226 activities had a weak linear declining trend with distance offshore. Rn-222 activity was at or near background in all seawater samples. The pattern of enrichment in short-lived Ra isotopes and the lack of Rn-222 in seawater suggest that seawater recirculation is the main contributor to SGD in the ACWS area. Preliminary modeling of the offshore flux of Ra-228 and Ra-226 suggest that the SGD flux to the ACWS area ranges between 0.2 and 3 center dot 10(-3) m(3) (m of shorefine)(-1) s(-1).

(PDF emailed within 0-6 h: $19.90)

Accession: 033078749

Download citation: RISBibTeXText

DOI: 10.1016/j.marchem.2007.08.010

Related references

Submarine Groundwater Discharge || Submarine Groundwater Discharge Estimates at a Florida Coastal Site Based on Continuous Radon Measurements. Biogeochemistry 66(1-2): 55-73, 2003

Geochemical and physical sources of radon variation in a subterranean estuary - Implications for groundwater radon activities in submarine groundwater discharge studies. Marine Chemistry 110(1-2): 120-127, 2008

Comprehensive evaluation of the groundwater-seawater interface and submarine groundwater discharge. IAHS-AISH Publication 312(Pages 86-92, 2007

-2. Evaluation of submarine groundwater discharge (SGD) based on the coastal topography and groundwater flow. Nippon Suisan Gakkaishi 82(5): 807-807, 2016

Submarine Groundwater Discharge || Sources and Fluxes of Submarine Groundwater Discharge Delineated by Radium Isotopes. Biogeochemistry 66(1-2): 75-93, 2003

Assessment of Submarine Groundwater Discharge (SGD) as a Source of Dissolved Radium and Nutrients to Moorea (French Polynesia) Coastal Waters. Estuaries and Coasts 39(6): 1651-1668, 2016

Seasonal changes in the groundwater-seawater interaction and its relation to submarine groundwater discharge, Ise Bay, Japan. IAHS-AISH Publication 312(Pages 68-74, 2007

Submarine groundwater discharge and seawater/ freshwater interface in the groundwater flow system. Technical Bulletin - Coordinating Committee for Coastal and Offshore Geoscience Programmes in East and Southeast Asia 28(Pages 21-35, 2000

An assessment of karstic submarine groundwater and associated nutrient discharge to a Mediterranean coastal area Balearic Islands, Spain using radium isotopes. Biogeochemistry (Dordrecht) 97.2-3, 2010

Estimations of groundwater discharge and changes in fresh-salt water interface by measurement s of submarine groundwater discharge in the coastal zone. Journal of Groundwater Hydrology 49(3): 191-204, 2007

Hydrologic forcing of submarine groundwater discharge: Insight from a seasonal study of radium isotopes in a groundwater-dominated salt marsh estuary. Limnology and Oceanography 52(1): 230-239, 2007

Development of a submarine radon monitor for investigations of groundwater discharge to the coastal zone and evaluation of potential earthquakes. Proceedings of, 1999

An evaluation of the efficacy of radium isotopes as tracers of submarine groundwater discharge to southern Rhode Islands coastal ponds. Marine Chemistry 130-131, 2012

Submarine groundwater discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawaii; Part 3, Spatial and temporal patterns in nearshore waters and coastal; groundwater plumes, December 2003-April 2006. Scientific Investigations Report: 76, 2010

Submarine Groundwater Discharge || Groundwater and Pore Water Inputs to the Coastal Zone. Biogeochemistry 66(1-2): 3-33, 2003